Burns (1989) Vol. 151 No. 3 205

raised after burning injury. Studies were therefore carried out to determine if lactoferrin is the active agent in burn serum which inhibits the production of colony-stimulating factor.

In 18 patients with burns covering more than 30 per cent TBSA and within 24 h of injury the serum lactoferrin levels were elevated and associated with an absolute granulocytosis, which rapidly declined to a nadir between 3 and 5 days after injury. The same serum inhibited production in vitro of colony-stimulating factor by normal human peripheral blood mononuclear cells. Pre- incubation of the postburn serum with a lactoferrin antibody restored normal colony-stimulating factor production.

Peterson V. M., Ambruso D. R., Emmett M. et al. (1988) Inhibition of colony stimulating factor (CSF) production by postbum serum: negative feedback inhibition mediated by lacto- ferrin. 1. Trauma 28, (II), 1533-1540.

Much improved survival of burned children

The mortality rate of burned children has fallen in Boston, USA from an average of 9 per cent during 1968-1970 to an average of 1 per cent during 1981-1986. This dramatic decline was not the result of changes in the age of the patients nor their burn size, but to improvements in burn care and in particular prompt eschar excision. Logistic regression analysis showed that ages up to 19 years had no demonstrable effect on survival, that children survived at least as well, if not better than, adults between 20 and 29 years of age and that infants less than 12 months old survived as well as the 2-19-year-olds.

Since 1979 mortality has been essentially eliminated for patients with burn sizes of less than 70 per cent of the body surface (two deaths out of 296 patients). When the burn area covered > 80 per cent of the body surface area only eight out of 37 patients died (21.6 per cent).

Tompkins R. G., Remensnyder J. P., Burke J. F. et al. (1988)

Significant reductions in mortality for children with bum injuries through the use of prompt eschar excision. Ann. Surg. 208, (5), 577-585.

Impaired T-cell function has multiple causes

Bum sera contain factors which inhibit interleukin-2-mediated T-cell functions. These factors are heat labile and do not behave like endotoxins. However, treatment of burned patients with polymyxin B which neutralizes endotoxins reduces the levels of these factors, suggesting that they are generated in response to endotoxin exposure. Burn sera also contains soluble cell-free IL-2 receptors, the concentrations of which are not altered by treatment by polymyxin B and therefore do not appear to be endotoxin induced. Thus T-cell impairment postburn must have multiple causes.

Xiao G. X., Chopra R. K., Adler W. H. et al. (1988) Altered expression of lymphocyte IL-2 receptors in burned patients. J Trawm 28, (12) 1669-1672.

Leucocyte contamination of lymphocyte preparations

Mononuclear cells isolated by density gradient centrifugation from the peripheral blood of burn patients, but not healthy volunteers, are a mixture of lymphocytes which respond normally to phytohaemagglutinin and alloantigens and leucocytes that are not phenotypically or functionally lymphocytes. Thus assays of lymphocyte function using density gradient purified leucocytes may give spurious results unless the contaminating cells are first removed.

Xu D. H., Deitch E. A., Sittig K. et al. (1988) In vitro cell mediated immunity after thermal injury is not impaired: density gradient purification of mononuclear cells is associated with spurious (artifactual) immunosuppression. Ann. Surg. 208, (6), 768-775.