Which Are the Principal Established or Potential Risks for Donors Undergoing Cytapheresis Procedures and How Can They Be Prevented

I International Forum

Vox Sang. 39: 169-179 (1980)

Which Are the Principal Established or Potential Risks for Donors Undergoing Cytapheresis Procedures and How Can They Be Prevented?'

H. Borberg. Side effects occurring during the utilization of blood cell separators may be related to the equipment or to simultaneously applied sup- porting agents.

So far, there has been no reason to discuss whether any of the disposables in current use may lead to reactions like temporary decrease of leucocytes or complement activation described for other extracorporeal systems [1,2]. It may thus be assumed that side effects occurring during the application of blood cell separators are rather due to the technique of cytapheresis than to the equipment itself. This does not imply that undesirable reactions may not occur due to an inaccurate usage of the equipment. Intermittent flow centrifugation, for instance, applying disposable bowls, filled with cells rather than whole blood at the end of each cycle, may lead to a volume challenge, if the size of an appropriate bowl has not correctly been chosen. Also, by way of precaution, the operator may wish to control the donor's blood pressure routinely at the end of each cycle, to maintain a proper control of the circulation, especially in labile donors.

Platelet collection is generally performed using 2-3% citrate in a ratio of 1:8-1:12 for anticoagulation. An even lower concentration of about 1.5% may in rare instances lead to platelet aggregation, whereas hypocalcaemia occurs if a high citrate concentration, which does not meet the require- ments of the donor, is used. Since we cannot pro-

1 Berne, June 1980.

vide a specific monitoring of calcium and/or citrate levels in the donor during plateletpheresis, we start with a standard 1 : l O relation of citrate versus whole blood, which is subsequently decreased if visible platelet aggregation occurs. We usually observe the disappearance of aggregates, but rarely do platelet aggregation and hypocalcaemia occur together. This refers to the use of continuous flow blood cell separators. If intermittent flow blood cell separators are used, the concentration of the citrate may be increased; if aggregates are observed or the rate of retransfusion may be slowed down if hypocalcaemia occurs. Hypocalcaemia, initially presenting as paraesthesia, can also be controlled by providing calcium. We estimate that the frequency of minor hypocalcaemia is in the range of 5-10% if 2% citrate is used.

The collection of leucocytes using blood cell separators and citrate for anticoagulation implies the occurrence of the same problems as mentioned previously. If heparin is used for anticoagulation, sensitization may rarely occur, also bleeding is possible, even after the donation has terminated. Neither one has been observed in a serious degree at our institution during 10 years of experience with blood cell separators and filtration leucapheresis, though it is still considered a potential risk. Thus, comprehensive information about the possible risks during and after heparinization is given to the donor, not only prior to the donation along with his written consent, but also after the procedure has been terminated. Also, we tend to diminish the theoretical risk by monitoring the plasma partial thromboplastin time of the donor

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prior to, during and 1 h before the end of the donation: this ensures a donor-specific use of heparin. Heparin is still necessary for our procedure, due to the combination of continuous flow centrifugation with reversible leucocyte adhesion.

When discussing potential risks of leucocyte preparation it is necessary to mention three more problems of rather theoretical importance: the use of steroids for donor conditioning, the application of sedimenting agents, and the removal of memory cells along with granulocytes.

From the clinical point of view one single injection of prednisone or related substances into a healthy donor cannot be considered to be harm- ful. It is much more a psychological and an ethical problem if one questions whether donor conditioning with steroids can be routinely performed. From our point of view, family members of a patient, who are, in general, considerably motivated to donate, can always be exposed to conditioning procedures with steroids, whereas unrelated donors should usually not be pretreated. So far we have not seen any side effects attributable to the prior application of methylprednisolone, which we are using exclusively.

Sedimenting agents may cause more concern, as they are known to induce immediate hypersensi- tivity reactions on rare occasions [5] . Frequent ap- plications may also lead to a retention of high molecular weight material or decrease the clearing capacity of the reticulo-endothelial system. We try to minimize these problems by restricting the total volume of sedimenting agents used during each run and by assuring a minimal interval of 2 days between subsequent donations from the same donor. Granulocyte collection using blood cell separators without sedimenting agents is in- efficient. The introduction of sedimenting agents with a somewhat lower molecular weight may decrease the problem. The potential risk of sensitization against dextran, gelatine and hydroxyethyl starch cannot generally be eliminated; however, a test injection of small amounts prior to each application is easily performed and can be used to recognize hypersensitivities prior to the occurrence of serious reactions.

As the percentage of mononuclear cells removed during each run is rather low, it appears unlikely that the immunological memory of donors may be influenced if granulocytes are collected.

This problem may be worth further elucidation at a later date.

Alternatively, reversible leucocyte adhesion (filtration leucapheresis) does not need sedimenting agents, and the amount of mononuclear cells removed is negligible. Though of proven clinical value, the frequency of side reactions in the reci- pients appears to limit the application. A rather small number of undesirable reactions such as chills, shaking, respiratory distress, abdominal pain and - in very rare instances - priapism in donors was the reason for restricting the spread of this technology; in addition, controversy arose about the functional quality of the cells procured. We found that undue bleeding could be eliminated by lowering the heparin dosage and adding small amounts of citrate without a decrease of the over- all granulocyte yield. The use of citrate may be helpful to depress side reactions, though it will not block the alternate pathway of complement activation.

The origin of these side reactions is largely unknown, and one may wish to limit the use of filtration leucapheresis for routine purpose - with reasonable exceptions. Alternatively, the development and investigation of this most promising technology should be supported strongly to eliminate side effects and to further improve the quality of the preparation.

References

Craddock, P.R.; Fehr, J.; Dalmasso, A. P.; Brigham, K. L., and Jakob, H. S.: Hemodialysis leucopenia. J. clin. Invest. 59: 879 (1977). Craddock, P. R.; Fehr, J.; Brigham, K. L.; Dro- nenber, R. S., and Jakob, H. S.: Complement and leucocyte medicated pulmonary dysfunction in hemodialysis. New Engl. J. Med. 296: 769 (1977). Freireich, E. J.; Hesters, J. P., and McCredie, K.B.: Prevention of side effects with the continuous flow blood cell separator; in Rainer, Borberg, Mishler and Schafer, Cell separation and cryobiology, p. 311 (Schattauer, Stuttgart 1978). Djerassi, I.; Kim, J. S., and Ohamissian, H.: Prevention of side effects from collection and transfusion of granulocytes by filtration leuka-


pheresis; in Rainer, Borberg, Mishler and Schli- fer, Cell separation and cryobiology, p. 168 (Schattauer, Stuttgart 1978).

5 Ring, J.; Seifert, J.; Messmer, K., and Brendel, W.: Anaphylactic reactions due to hydroxyethyl starch infusions. Eur. surg. Res. 8: 389 (1976).

Dr. H. Borberg, Medizinische Universitatsklinik, Joseph-Stelzmann-Strasse 9, D-5000 Koln-Lindenthal (FRG)

Miriam B . Dahlke. There are both established and potential risks for the donor during cytapheresis procedures. A specific risk is usually the result of an alteration or a change in the blood of the donor as the result of some aspect of the procedure. In most instances the cause, the alteration in the blood and the effect or the risk to the donor are obvious. For example, citrate causes hypocalcemia, and the risk to the donor is tetany. All donors are at risk, but this disorder is readily preventable. Where the tripartite association is established and understood, the disorder may be prevented by preselection of donors based upon medical criteria or by attention to technique. Where the side-effects are not understood or the effects of an observed alteration in the blood are not known, the risk is not preventable. Some risks are speculative, and data to confirm or refute them are not yet available.

The donor is at risk both as a result of what is removed and as a result of what is returned. The potential risks of withdrawal and retention include hypovolemia, thrombocytopenia, loss of reticulocytes and loss of lymphocytes. Signs and symptoms of hypovolemia may be avoided by determining the extracorporeal volume required by the procedure and assuring that this volume does not exceed 15% of the donor’s blood volume. Sig- nificant lowering of the donor’s platelet count might occur as the result of the removal of platelets in a donor with an initial low count. It is known that the mean post-pheresis platelet count is 30% less than the count prior to a plateletpheresis procedure. The restriction of procedures wherein platelets are removed to donors whose platelet counts are 150,000/mma or greater elimi- nates the remote possibility of an induced, sig-

nificant thrombocytopenia and hemorrhage in the donor. Since the red cells removed with the buffy coat are largely reticulocytes and may measure 50 ml, one might speculate regarding the effect on the donor of the daily removal of the red cells newly released from the marrow as might occur if an HLA-matched family member were cyto- pheresed on consecutive days. The risk to such a donor presuming a normally functioning bone marrow and a normal red cell survival time probably is no greater than the degree of hematopoietic suppression associated with a viral infection.

The risks, if any, to the donor of the removal of lymphocytes are speculative at present. Up to 1 x 1010 lymphocytes may be removed during a centrifugation procedure. Up to 1 x loo lymphocytes are removed at the time of a whole blood donation. 40 years of whole blood donations by millions of people have not been associated with observed adverse effects upon the immune re- sponse of whole blood donors. However, it is possible following a plateletpheresis procedure to separate the lymphocytes and red cells from the platelet-rich plasma by a light centrifugation, and the red cell, lymphocyte by-product may be returned to the donor. Separation of the lymphocytes from the granulocytes in a leukapheresis product is not possible without significant loss of granulocytes. In contrast, the leukocyte concentrates obtained by filtration leukapheresis contained fewer lymphocytes and these were the adherent cells, the B cells.

The potential risks to the donor as a result of the return of blood which has been exposed to foreign surfaces, to mechanical and centrifugal forces and admixed with medications and solutions are greater and some are more difficult to define than those associated with withdrawal and retention. Included are events in which all donors are at risk and events in which the rare donor is a t risk. When the incidence of an event is very low, cognizance of the potential for the event may occur only after many procedures.

An example of an alteration in the blood with the potential of risk, described 3 years after fil. tration leukapheresis had been introduced and was gaining wide acceptance, was the activation of complement following the exposure of heparinized blood to nylon fibers. Margination of granulocytes and pulmonary capillary obstruction by aggregates

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of granulocytes following the infusion of activated complement was documented in the rabbit [l]. The risk to the human of the return of activated complement components was speculative. It is likely the side-effects commonly and transiently observed in the donor shortly after the return of blood newly exposed to the filters, namely conjunctival infection, edema of the nasal mucosa, erythema of the face and neck and the neutropenia were mediated by complement. It is possible that priapism, uncommon in that only 2 cases have been reported during filtration leukapheresis, may also be casually related to the return of activated complement [2]. These common side-effects are not observed during centrifugation procedures nor has priapism been described.

All additives necessary to accomplish the procedure have the potential of risk. Hydroxyethyl starch or another red cell sedimenting agent is required to harvest granulocytes by all current centrifugation techniques. These sedimenting agents also ex- pand the blood volume. The donor who receives 30g of hydroxyethyl starch has an expansion of the blood volume by approximately 12%, and the effect of the daily administration of this agent is cumulative. Precautions include the exclusion of those donors with an underlying disorder which might not preclude whole blood donations but which might be adversely affected by an expansion of the blood volume. Examples are migraine, hy- pertension and diabetes controlled by diet because of the commonly associated vascular disease in the latter two diseases. Other precautions include the judicious use of crystalloid solutions when hydroxyethyl starch is administered. Excess administration of saline may occur inadvertently in donors when difficulty is encountered maintaining the outflow of blood. A donor should not receive hydroxyethyl starch on successive days because of its cumulative effect on the blood volume.

Another potential risk is the inadvertent administration of hydroxyethyl starch and other solutions contaminated with either bacteria or fungi which have gained entrance through hair-line cracks in the glass bottle. A recent report describes such a case, and the authors by survey learned of other instances in the United States [3]. Precautions include the meticulous examination of glass con- tainers for hair-line cracks and the contents for clarity.

Hydroxyethyl starch, although poorly antigenic. has been reported to be associated with anaphylaxis in Europe [4]. The incidence of a severe reaction to hydroxyethyl starch was reported as 6 in 100,OOO hospitalized patients compared to 3 in 100,000 to plasma derivatives. This complication has not been reported in the United States where the only ap- proved use of hydroxyethyl starch is in leukapheresis. This risk is not preventable and, therefore, the ideal technique for the harvest of granulocytes would be a method not requiring a red cell sedimenting agent.

The inherent risks of the anticoagulants are bleeding when heparin is used and signs and symptoms of hypocalcemia following citrate infusion. A careful bleeding history will identify those donors who should not be given heparin. Of 2,358 donors who received heparin prior to a filtration procedure during a 4-year period at the Penn-Jersey Regional Red Cross Blood Service, not one episode of bleeding was observed other than hematoma formation. The incidence of hematomas usually in the return arm was greater than is now observed during centrifugation procedures wherein blood is returned by gravity. The higher incidence of hematomas during filtration leukapheresis was, probably in part, due to the heparin and in part due to the fact that blood was returned by the action of a roller pump. Symptoms of hypocalcemia are readily controlled by careful attention to the rate of re- infusion of citrated blood to the small donor.

Mechanical trauma to normal red cells and subsequent hemolysis may occur if blood is pumped through twisted tubing or improperly adjusted roller pumps. The effect of the mechanical trauma of even properly adjusted roller pumps and the force of centrifugation on the red cells of a donor with undetected sickle cell trait, thalassemia minor, or congenital elliptocytosis is unknown. Hemolysis might be observed during the procedure of the survival time of the reinfused red cells might be shortened.

In summary, the risks associated with cytapheresis procedures employing centrifugation are largely preventable by donor selection and attention to technique. A centrifugation technique not requiring the use of a red cell sedimenting agent would eliminate all potential risk. The risks associated with filtration leukapheresis, presumably due to the activation of complement, are not pre-

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ventable and because all donors are thus at risk, the future of this procedure is in question.

References

1 Fehr, J.; Craddock, P.R., and Jacob, H. S.: Complement (Cl) mediated granulocyte (PMN) and pulmonary dysfunction during nylon fiber leukapheresis. Blood 46: 1054 (1975).

2 Dahlke, M. B.; Shah, S. L.; Sherwood, W. C.; Shafer, A. W., and Brownstein, P. K.: Priapism during filtration leukapheresis. Transfusion, Phil- ad. 19: 482 (1979).

3 Daisy, J. A.; Abrutyn, E. A., and MacGregor, R. R.: Inadvertent administration of intravenous fluids contaminated with fungus. Ann. intern. Med. 91: 563 (1979).

4 Ring, J. and Messmer, K.: Incidence and se- verity of anaphylactoid reactions to colloid volume substitutes. Lancet i: 466 (1977).

Miriam B. Dahlke, MD, Medical Director, American Red Cross Blood Services, 23rd & Chestnut Streets, Philadelphia, PA 19103 (USA)

I. D. Fraser. Blood cell separators are now widely used in Transfusion Centres and Clinical Hae- matology departments for the collection of platelets and leucocytes, from normal donors, that are used for the supportive care of patients suffering from a wide variety of both malignant and non- malignant haematological disorders. Cell separators are also used therapeutically to remove large numbers of leucocytes and stem cells in certain types of leukaemia. They are also used extensively in the procedure of plasma exchange.

There are at present two major types of cell separator, one operates on a continuous flow and the other on an intermittent flow procedure.

Many thousands of the population who are in normal health and between the ages of 18 and 65 years donate 1 unit of blood two or three times a year. As long as the screening haemoglobin and

the blood pressure are within the normal range, 4401111 of blood can be safely removed. Donors undergoing cytopheresis procedures will experience a completely different type of blood donation which may last up to 2 h or more. During the procedure they receive anticoagulants, either acid citrate dextrose or heparin, to maintain blood flow. When they are donating their leucocytes they have to be ‘stimulated’ by taking oral corticosteroids 1 2 h before and they also receive one of the following red cell sedimenting agents, hydroxyethyl starch, high molecular weight dextran or modified fluid gelatin, during the procedure. The rather limited type of medical examination required for ordinary blood donation has therefore to be far more thorough when cell separator techniques are going to be used. Apart from a general physical examination it is necessary to ensure that the potential donor’s blood count and coagulation screening tests are normal and that the syphilis and HBsAg tests are negative before the procedure is started. For donors over the age of 40 years it is advisable to take an electrocardiogram. I t is also advisable to take a chest X-ray if the donor is to be given steroids. It is preferable to limit the age of voluntary donors for this type of procedure to between 18 and 45 years.

The medical and nursing staff looking after the donor on the cell separator must be fully con- versant with the machine and the problems that can arise from such a procedure. The cell separator must be close to a cardiac arrest team in case the donor collapses during donation.

Before a donor actually donates on the cell separator the procedure should be fully explained and a consent form signed.

It is important for the donor to be comfortable during donation. A comfortable reclining couch with the facility to rapidly elevate the end should be provided.

The common initial donor reactions to the procedure are a feeling of anxiety, chilliness and nausea. These usually take place during the first run and the symptoms can be kept to a minimum by ensuring the donor has the confidence of the nurse and doctor, and keeping the donor warm. Vasovagal reactions may also occur during the first run, and these can easily be controlled by elevating the donor’s feet and temporarily increasing the saline flow. When acid citrate dextrose is used it


is very common for the donor, when the blood is being re-infused, to complain of a headache and paraesthesiae of the mouth, hands and feet. This symptom can be alleviated by slowing down the re-infusion rate and also by giving the donor a drink of milk at the beginning of the procedure. Occasionally, if symptoms persist it is necessary to give 10 ml of 10% calcium gluconate intravenously. Hypovolaemic shock may occur with the intermittent flow cell separator, if the re-infusion of blood falls behind the rate of withdrawal. Tachycardia may occur if the rate of donation is too fast. Ana- phylactic reactions to replacement fluid may occur but this is rare in cytopheresis procedures, it is more common in plasma exchange when plasma is re-infused. I t is important, therefore, to take a careful drug or allergy history prior to donation. The most dangerous consequence of cytopheresis is cardiac insufficiency. It is imperative that donors over the age of 40 years are carefully monitored. The procedure must take place close to re- suscitation facilities.

Pyrexia is an occasional complication of cytopheresis, particularly if the donation rate is fast. It is advisable to make sure that any excess anticoagulant given to the donor is neutralised at the end of the procedure to ensure there are no haemor- rhagic complications. The development of thrombocytopenia is a possible complication of the donor who undergoes frequent plateletpheresis. Cyto- pheresis donors should be limited to twelve donations per annum. Venous thrombosis or haemato- mata may occur as a consequence of poor vene- puncture technique.

The operators must ensure that there are no kinks in the tubing and that the pumps are working satisfactorily. It is possible for the donor blood to undergo mechanical trauma and haemolysis, if it is forced through kinked tubing. If the pumps are faulty the anticoagulant may not flow properly and the blood may clot. Air embolism is a possible complication at the re-infusion site, particularly with the intermittent flow separators, however, the fitting of bubble sensors can exclude this complication. The operators must also look for leaks in the harness and junctions during cell separation as this is a source of possible infection to the donor. The machines must be serviced properly and reg- ularly, with particular emphasis to the electrical components.

Cell separators are also used therapeutically to remove circulating cells in patients with leukaemia. The same criteria apply to these patients as for normal donors except that there is no definite upper age limit. Patients over the age of 45 years should be carefully monitored during the procedure.

References

1 Goldman, J.M. and Lowenthal, R.M.: Leuco- cytes: separation, collection and transfusion (Academic Press, London 1975).

2 Leucapheresis and plasmapheresis. Expl Hemat. 5: suppl. 1 (1977).

Dr. I. D. Fraser, Regional Transfusion Centre, Bristol (England)

I . C. Fratantoni and J . E. French. We will re- strict comments to cytapheresis performed by centrifugation and will not address the problems associated with filtration leukapheresis. The latter is being used with decreasing frequency in the USA, which is consistent with the widely held view that granulocytes derived from filtration procedures are functionally inferior to those obtained by centrifugal separation.

The risks of centrifugal cytapheresis, potential and actual, derive from the following: (1) mechanical problems including cell damage; (2) in- appropriate anticoagulant (citrateheparin) dosage; (3) red cell loss; (4) recurrent administration of corticosteroids; (5 ) retention of hydroxyethyl starch (I-IES); (6) depletion of the lymphocyte pool.

(1,2) Mechanical and Anticoagulant Problems. These will be discussed briefly and together since we regard them as a group of technical problems, rather well understood, and amenable to solution or control by appropriate design, engineering and training of users. Machine malfunction per se, bubbles and vein collapse fit into this category. Episodes of hemolysis are more troublesome and occasionally are reported by cytapheresis centers. These are usually corrected by procedural adjust- ments.

A more serious problem may arise if platelets are activated by the mechanical shear forces encountered. Although the platelet product from cen-


trifugal pheresis has been found satisfactory 111, changes in the platelet function of the donor have been only partially investigated [2]. Specifically, changes leading to bleeding complications have been sought, and not found, while potentially thrombogenic changes have not been sought with appropriate methodology. Such experiments are feasible with available techniques.

(3) Red Cell Loss. The amount of red cell removal in any procedure will be a function of the instrumentation employed, operator technique and sedimenting agent. This risk can be controlled by careful accounting of the donor's estimated red cell loss at each donation. Such data should be a factor in deciding upon the frequency of donation.

(4) Complications of Adrenocorticosteroids. Pre- treatment of the donor with adrenocorticosteroids results in increased relative and absolute yields of granulocytes. The possible complications are of two general types: those caused by long-term use of large doses, and those resulting from pituitary- adrenal suppression and subsequent withdrawal. It is unlikely that the former would be encountered by apheresis donors. Pituitary-adrenal suppression occurs under varied circumstances, depending upon the individual, the dosage, the frequency and duration of administration. The intermittent, non-daily schedule of pheresis usually employed mitigates against such a problem, and actual cases have not been documented. However, it is a potential problem and is a valid reason for limiting apheresis donation frequency and duration. The minimal effective dose for this use is still to be determined.

(5) Accumulation of Hydroxyethyl Starch (HES). The increase in the use of HES and the reports of adverse reactions [3] require additional investigation on its safety and efficacy. Questions of antigenicity and biological retention, degrada- tion and excretion of different components of this heterogeneous substance still exist. Strauss et al. have recently reexamined intravascular persistence of HES and found that it is of a much greater duration than predicted by earlier studies 131. This is especially true in subjects exposed t o multiple apheresis procedures, Conclusions regarding the clinical implications for the donor could not be drawn from these studies. HES has been a very important adjunct in improving neutrophil yields to expected effective therapeutic levels. However, its safety and efficacy still require additional in-

vestigation to establish safe levels for administration in leukapheresis procedures.

(6) Lymphocyte Depletion. Will normal, hema- topoietically active donors undergoing intense leukapheresis (twice or more per week for extended periods) be depleted of any population or sub- population of lymphocytes to the extent that immune function is compromised? Of particular importance seems to be T-lymphocyte memory cells, which can indirectly be inferred to live and cir- culate for a lifetime. It has been demonstrated that exogenously administered hydrocortisone, and presumably other corticosteroids as well, induce a transient lymphopenia, with a return to normal lymphocyte levels within 24 h [4]. This transient lymphopenia is not due to lympholysis and is char- acterized by migration of both T and B cells from the peripheral circulation to lymphoid tissue. How- ever, reduction of the T-cell population is greater than reduction of the B-cell population.

Initially, leukapheresis procedures by automated cell separators were performed without pretreatment of the donor or addition of additives to the extracorporeal circuit, except for anticoagulants. With the recognition that certain macromolecular compounds, such as the dextrans, modified fluid gelatins, and hydroxyethyl starch were RBC rou- leaux-forming agents, those compounds have been used advantageously to dramatically increase the yield of granulocytes. With a combination of do- nor corticosteroid pretreatment to raise the peripheral granulocyte counts and sedimenting agents to improve cell separation in the bowl, even greater yields were obtained. This evolution of leukapheresis technology along with machine improvement now allows collection of granulocyte numbers that approach expected therapeutically effective dos- ages (1-2 x 1010 neutrophils per unit). However, the number of lymphocytes removed is fairly constant and in most published studies is r\, 6 x 100 lympho- cytedunit. The amount of lymphocytes removed along with granulocytes is dependent upon total volume of blood processed as well as whether corticosteroids and/or sedimenting agents are used.

Experimental treatment of rheumatoid arthritis by lymphapheresis indicates that temporary clinical improvement can be achieved after 5-6 weeks with three lymphaphereses procedures per week [51. A total of approximately 1 x l W i lymphocytes were removed. Limited in vitro studies on peripherally

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circulating lymphocytes from these patients demonstrated decreased mitogenic responsiveness. After the course of the treatment, a profound lymphopenia and T-cell reduction may last for at least 1 year. The intensity of leukapheresis of normal donors might approach this level of lymphocyte removal. It is, of course, not known if normal immune competent individuals would be compromised by such treatment. Neither is it known what pre-donation test, if any, would indicate borderline immune competent donors.

Development of an animal model of the leukapheresis donor would permit studies of immune function which would test the whole organism (e.g., graft rejection) and not be limited to isolated blood cells. Studies directed toward this end are in prog- ress in our laboratories.

Until safe limits can be based on reliable data, conservative, and perhaps arbitrary, restrictions of the frequency and total number of donations must be seriously considered. At the present time we be- live that donations should not exceed one per week with a maximum of eight donations per year. WBC counts and differentials should be performed prior to each donation and the lymphocyte count monitored carefully. At this time, the Bureau of Biologics is collecting data by questionnaire and soliciting opinions in order to make regulatory decisions.

References

Slichter, S. J.: Efficacy of platelet collected by semi-continuous flow centrifugation (Haemo- netics Model 30). Br. J. Haemat. 38: 131-140 (1978). Maguire, L. C.; Strauss, R. G.; Henriksen, R. A., and Koepke, J. A.: Effects of intermittent-flow centrifugation plateletpheresis or leukapheresis on donor platelet functions. Abstr. 32nd Meet. Am. Ass. Blood Banks, 1979, p.35. Leukapheresis and Donor Safety Workshop, Bethesda, Md., June 4, 1979. Fauci, A. S.; Dale, D. C., and Balow, J. E.: Glucocorticosteroid therapy: mechanisms of action and clinical considerations. Ann. intern. Med. 84: 304 (1976). Karsh, J.; Wright, D. S.; Klippel, J. A.; Decker, J. L.; Deisseroth, A,, and Flye, M. W.: Lym- phocyte depletion by continuous flow cell cen-

trifugation in rheumatoid arthritis. Arthritis Rheum. 22: 1055 (1979) and personal commun.

Joseph C. Fratantoni, MD John E.French, PhD Division of Blood and Blood Products, Bureau of Biologics, Food and Drug Administration, Bethesda, MD 20205 (USA)

P . V . Holland and H . G . Klein. We have performed both single and serial pheresis procedures on normal blood donors and recorded immediate and delayed effects. In the process, we have become aware of several donor risks and have utilized means to minimize them.

Removal of 1 liter of platelet-rich plasma each day for 5 days can result in a significant depletion of platelets and serum proteins [l]. Recovery of the platelet count has been prompt (usually within 3 days) and neither thrombocytosis nor thrombocytopenia was noted during a 3-month period of follow-up; we have had no reports of bleeding in these donors. Return of total protein levels required 2-4 weeks, but y-globulin levels remained depressed as long as 12 weeks. With plateletpheresis alone, far less plasma is usually removed than the 1.5 liter per week which blood donors can generally tolerate [l]. Several of our donors have given 4 units of platelet concentrates at weekly intervals for more than 1 year (one man has given 202 times) without adverse effect on platelet count, hemoglobin concentration, white blood cell count, or serum protein levels; these donors remain in good health without apparent long-term effect.

Leukapheresis can be employed to obtain granulocytes for transfusion to leukopenic, septic patients. A fall in the leukocyte count might be expected with leukapheresis, and may occur early in the procedure, but a rebound leukocytosis generally results [2]. While some risks of leukapheresis are attributed to the agents used to raise the white blood cell count before the procedure, others are unique to the type of leukapheresis performed. Nylon fiber filtration leukapheresis (FL) has been associated with occasional bleeding problems, and 1% of women may experience perineal pain of unknown etiology [3]; to minimize the risk of the former, protamine sulfate to neutralize heparin may be given and donors with menses or a history


of a peptic ulcer should not be used. Continuous flow leukapheresis (CF) may cause shivering in donors and, rarely, hypotension; the former is ob- viated by keeping the donor warm and the latter by carefully monitoring the volume of blood out of the donor at any one time. Both CF and FL may result in consistent falls in hemoglobin concentration (0.6-0.9 g/dl) and platelet counts (- 18 to -30%) with each pheresis procedure [2]; the first may be more apparent than real due to volume expansion, especially when sedimenting agents are used, but the second is due to the acute removal of platelets which is routinely accomplished during leukapheresis, either by the filter or through the use of the centrifuge. Leukapheresis donors may thus have to wait between procedures until their hemoglobin level and platelet count return to the normal range. Long-term effects of leukapheresis have not been noted [3], but we have no protocol designed to detect donor reactions in a prospective fashion. Elimination of sedimenting agents and stimulants to elevate the white count in leukapheresis donors would minimize the risks of this procedure: unfortunately, such measures also limit the yields in the granulocyte concentrates.

Neocytapheresis is an experimental procedure which uses a continuous flow cell separator to obtain young red cells for chronically transfused patients with congenital anemias [4]. This procedure requires that the donor spend up to 4 h on continuous flow instruments to obtain whole units of neocytes for transfusion. We have performed more than 300 such procedures. While the hemoglobin loss is the same as that with regular blood donation, additional risks, and potential risks, have become apparent.

When ACD-A is used as the sole anticoagulant, approximately 20% of donors will have some evidence of citrate toxicity. Paresthesias are by far the most common manifestations; but we have also encountered donors who become nauseated, experience abdominal cramping, flatulence and vomiting. One donor developed transient muscle spasms in both feet. Flow rates for this procedure ranged from 50 to 60 ml/min. A similar frequency of citrate toxicity is seen when CPD is used as the anticoagulant; one donor reported the onset of hoarseness during the procedure, as well as a ‘delayed’ reaction consisting of fatigue, facial edema and pruritus beginning 2 h after the proce-

dure and lasting approximately 12 h. For these procedures we have selected larger donors (over 65 kg) and have decreased the donor flow rate when evidence of citrate toxicity appeared. The majority of our donors are pheresed every 8 weeks and have been followed for up to 2years.

When the anticoagulant is modified such that 1,OOO units of heparin are instilled into both the draw and return lines at the onset of the procedure and ACD-B is used as the anticoagulant, less than 10% of donors have experienced any dis- comfort related to the citrate. We have had no instances of hemorrhage using any of these reg- imens, including systemic heparinization.

Because we are collecting the young red cells just below the buffy coat, we remove substantial numbers of leukocytes and platelets. Platelet counts fall approximately by 25% but return to normal within 24 h. Each bag of neocytes contains approximately 3 x 10’0 leukocytes, 70% of which are lymphocytes. This is substantially fewer lymphocytes of all subtypes than are removed by standard lymphocyte depletion procedures. Therefore, we d o not expect that such procedures, even if they are carried out every 8weeks for years, should compromise cellular immunity; but we have no long-term data to confirm this feeling.

References

1 Kliman, A.; Carbone, P. P.; Gaydos, L. A., and Freireich, E. J.: Effects of intensive plasmapheresis on normal blood donors. Blood 23:

2 Russel, J. A. and Powles, R.: White cell therapy. Clinics Haem. 5: 81-93 (1976).

3 Djerassi, I. and Kim, J. A.: Problems and solutions with filtration leukapheresis. Prog. clin. biol. Res. 13: 305-313 (1976).

4 Corash, L.; Klein, H.; Deisseroth, A., and Nien- huis, A.: Collection and survival of young erythrocytes for transfusion support of thalassemia major. Abstract. Blood 54: suppl. 1, p. 121a (1979).

Paul V. Holland, MD, Harvey G. Klein, MD, Clinical Center Blood Bank, NIH, Bethesda, MD 20205 (USA)

647-656 (1964).


H. F. Polesky. The experience at the Minnea- polis War Memorial Blood Bank with cytapheresis donors suggests that this procedure is quite safe. In 1979 we did 450 phereses using the Haemonetics Model 30. The majority of procedures (70%) were to obtain granulocytes. The donors, who are usually friends or relatives of the patients, must meet the criteria of the American Association of Blood Banks Standards for Blood Banks and Transfusion Services. Our standard protocol (leukapheresis) uses 30ml of 46.7% trisodium citrate, 250ml of normal saline, and 500 ml of 6% hydroxyethyl starch. No additional medications are used to enhance yields. Routinely, we use the 225-m1 bowl and do six to eight passes.

Review of the records of all leukapheresis donors during the past year showed that a ‘reaction’ was observed in 24% of donors. 50% of these ‘reactions’ were reports by the donor of chilling. In 40 donors mild reactions including weakness, pallor, tingling, faintness, etc. were observed. In these donors the symptoms were usually during the first pass, and slowing the draw rate ameliorated the problems. The procedure had been discon- tinued only 10 times, in 2 of these cases we had equipment failures and in 8 more severe symptoms were observed. In each case these were transient. In one donor (2 procedures) severe leg cramps occurred. This appeared to be secondary to hyper- ventilation. One donor developed hives, and one donor’s cells appeared to hemolyze during the fourth pass. No donors have reported any delayed symptoms or problems following a pheresis procedure.

It is my impression that the number of donor problems has been minimized by the use of dilute citrate (1.8%), careful attention to the flow rates and volumes withdrawn and the psychological support provided by the skilled nurses doing the procedures.

H. F. Polesky, MD, Director, The Minneapolis War Memorial Blood Bank, 2304 Park Avenue, Minneapolis, MN 55404 (USA)

S. G. Sandler. As the final contributor to this Forum, I would like to take the opportunity to address one of several ethical issues pertinent to

cytapheresis [l, 21. Specifically, I would like to address the issue that risks to cytapheresis donors - whatever they might be - may be underestimated in bedside decisions whose goals are providing maximal benefits for critically, and often ter- minally, ill patients.

Traditionally, the physician’s responsibility has been to provide patients with the highest quality of available medical care. When promising new treatments such as cytapheresis blood products are developed, the physician’s role is to select those that offer reasonable chances for benefit with minimal risks to the patients. In this context, cytapheresis for single donor platelet and granulocyte concentrates has grown rapidly as an integral service for hematology and oncology programs. Ini- tially, family members and other relatives were recruited for cytapheresis to assist in providing intensive, and often lifesaving, support. As experience with cytapheresis products has accumulated and the clinical indications have become more se- lective, the percentage of successful therapeutic results has increased [3,4] and the search for volunteer donors has broadened [5].

Escalating demands for cytapheresis blood products have resulted in a proliferation of cytapheresis programs, many of them distant from the purview of the primary physician. In 1975, 25 American Red Cross Blood Services Centers performed a total of 4,245 plateletphereses and 836 leukaphereses. In 1979, 42 Red Cross pheresis programs performed a total of 22,945 plateletphereses and 9,848 leukaphereses [6]. Under these circumstances the bedside physician finds it increas- ingly difficult to participate actively in recruiting and caring for cytapheresis donors. Of necessity, he is removed from day-to-day encounters with the ‘principal established and potential risks for donors undergoing cytapheresis’. From the bedside viewpoint, cytapheresis blood products con- stitute essential therapies that the physician must provide to fulfill his role as patient-advocate. It is only natural that in bedside decisions his focus is on potential lifesaving benefits to his patient. Consequently, he may not always take fully into account the risks being assumed by an anonymous volunteer cytapheresis donor.

Accordingly, the physician in the cytapheresis unit, whether in a hospital blood bank or regional blood center, must fulfill the role of donor-advo-


cate. It is his responsibility to be aware of the advantages and disadvantages of various cytapheresis technologies and, in particular, in the ‘principal established or potential risks for donors undergoing cytapheresis’. Along with the bedside physician, the pheresis unit physician shares the responsibility for determining whether the anti- cipated benefits for the patient justify the potential risks for the donor. The physician in the pheresis unit as donor-advocate should participate in transfusion-related decisions with physicians requesting cytapheresis products.

In summary, a potential risk for cytapheresis donors is underrepresentation of their risk-taking roles in patient-oriented bedside decisions that de- termine requests for cytapheresis blood products. It is the responsibility of the pheresis unit physician as donor-advocate to ensure that complete information is available in the decision-making process so that the risks to the cytapheresis donor will be appropriately weighed.

References

1 Seidl, S.: Ethical aspects of cytapheresis; in Proc. Symp. on Ethics and Blood Transfusions. XVII Congr. Int. SOC. Hematology and XV

Congr. Int. SOC. Blood Transfusion, Paris 1978, p. 58.

2 Wieckowicz, M.: Single donor platelet transfusions: scientific, legal and ethical considerations. Transfusion, Philad. 16: 193 (1976).

3 Higby, D. J. and Burnett, D.: Granulocyte transfusions: current status. Blood 55: 2 (1980).

4 Schiffer, C. A.; Aisner, J., and Wiernik, P. H.: Platelet transfusion therapy for patients with leukemia; in Greenwalt and Jamieson, The blood platelet in transfusion therapy, p. 281 (Liss, New York 1978).

5 Graw, R. G.; Herzig, R. H.; Langston, M. G., et al.: National donor registry and computer transfusion programs for platelet transfusions. Transplant. Proc. 9: 225 (1977).

6 Blood Services Operations Report, Fiscal Year 1978-79 (ARC 591), p. 18 (American Red Cross, Washington, D.C.).

S. Gerald Sandler, MD, Associate Director, Blood Services, Headquarters, American Red Cross, Washington, D C 20006 (USA)

Documents

Which Are the Principal Established or Potential Risks for Donors Undergoing Cytapheresis Procedures and How Can They Be Prevented