associated genetic regions account for only approximately

14% of the total variance of psoriasis risk or approximately

22% of its estimated heritability.2 Psoriasis is most strongly

associated with the human leucocyte-associated antigen, HLA-

Cw0602 allele (PSORS1) of the HLA-Cw6 antigen, which con-

fers a relative risk of developing psoriasis of approximately 20

in homozygotes and approximately 10 in heterozygotes.3 HLA-

Cw*0602 is associated with psoriasis of young onset (type 1)

and interacts genetically with endoplasmic reticulum amino-

peptidase-1 (ERAP1) such that variants of ERAP1 are only asso-

ciated with psoriasis in the presence of HLA-Cw6 risk alleles.4

More recently, an interaction has also been found between

LCE3C_LCE3B deletion and HLA-Cw6 as risk factors for psoriasis.

The report by Talamonti et al.5 in this issue of the BJD showing

that the HLA-Cw*0602 allele, but not the LCE3C_LCE3B dele-

tion, is associated with a clinical response to ustekinumab is

therefore of significant interest.

Studies in pharmacogenetics have shown that certain genetic

variations may be associated with either a clinical response or

an adverse side-effect of a drug, and could therefore allow clini-

cians to select the most appropriate therapies for their patients;

this has already become reality. For example, HLA-B*5701 test-

ing is recommended prior to prescribing abacavir, used to treat

human immunodeficiency virus infection; patients who test

positive should be given an alternative therapy due to the strong

association of this allele with hypersensitivity to the drug.6 In

patients with late-stage melanoma, vemurafenib should be pre-

scribed only to those who carry the BRAF V600E mutation. The

field of pharmacogenetics is rapidly expanding; in this issue of

the BJD, Talamonti et al.5 link the major psoriasis susceptibility

genetic polymorphism HLA-Cw6 to the clinical response with

the interleukin (IL)-23/IL-12 blocking agent ustekinumab.

Their results show that HLA-Cw6-positive patients had a signifi-

cantly greater response to ustekinumab therapy [primary end-

point: Psoriasis Area and Severity Index (PASI) 75 at 12 weeks

96�4% vs. 65�2% in the HLA-Cw6-negative patients, OR 13�4,95% confidence interval 1�6–12�6]. Furthermore, HLA-Cw6-

positive patients responded significantly faster to ustekinumab

therapy (PASI 50 was reached by 89�3% at week 4 vs. 60�9% in

the HLA-Cw6-negative patients). Notably, multivariate analysis

indicates that age at onset, for example, is unlikely to be a con-

founder. This, however, was a relatively small retrospective

study with limited power and should therefore be interpreted

with caution. In addition, as acknowledged by the authors, the

majority of patients had previously received antitumour necro-

sis factor-a therapy. Replication of these results in a prospective

larger cohort will be important. Nevertheless, this study pro-

vides proof-of-principle evidence that genetic polymorphisms

could, in future, be used to predict response to biologic therapy

in patients with psoriasis.7 Although we would need to con-

sider the potential positive and negative predictive value of

genotyping and how to introduce rapid, cost-effective genotyp-

ing into the healthcare system, personalized medicine could

potentially lead to improved resource allocation and reduce

exposure of patients to unnecessary toxicity.

Conflicts of interest

N.J. Reynolds has acted as a Consultant to Abbott and Pfizer

and received travel support to attend conferences from Abbott.

K.C.P.W. is a Wellcome Trust Clinical Research Fellow.

K .C .P . WU

N. J . REYNOLD S

Dermatological Sciences, Institute of Cellular

Medicine, William Leech Building,

Newcastle University, Newcastle Upon Tyne,

NE2 4HH, U.K.

E-mail: nick.reynolds@ncl.ac.uk

References

1 Meggitt SJ, Anstey AV, Mohd Mustapa MF et al. British Association

of Dermatologists’ guidelines for the safe and effective prescribingof azathioprine 2011. Br J Dermatol 2011; 165:711–34.

2 Tsoi LC, Spain SL, Knight J et al. Identification of 15 new psoriasissusceptibility loci highlights the role of innate immunity. Nat Genet

2012; 44:1341–8.3 Gudjonsson JE, Karason A, Antonsdottir A et al. Psoriasis patients

who are homozygous for the HLA-Cw*0602 allele have a 2.5-foldincreased risk of developing psoriasis compared with Cw6 hetero-

zygotes. Br J Dermatol 2003; 148:233–5.4 Strange A, Capon F, Spencer CC et al. A genome-wide association

study identifies new psoriasis susceptibility loci and an interactionbetween HLA-C and ERAP1. Nat Genet 2010; 42:985–90.

5 Talamonti M, Botti E, Galluzzo M et al. Pharmacogenetics ofpsoriasis: HLA-Cw6 but not LCE3B/3C deletion or TNFAIP3

polymorphism predisposes to clinical response to interleukin-12/23blocker ustekinumab. Br J Dermatol 2013; 169:458–63.

6 Hetherington S, Hughes AR, Mosteller M et al. Genetic variations inHLA-B region and hypersensitivity reactions to abacavir. Lancet

2002; 359:1121–2.7 Tejasvi T, Stuart PE, Chandran V et al. TNFAIP3 gene polymorphisms

are associated with response to TNF blockade in psoriasis. J InvestDermatol 2012; 132:593–600.

Patient empowerment increases capacity andwidens access to phototherapy

DOI: 10.1111/bjd.12496

ORIGINAL ARTICLE, p 464

A course of ultraviolet (UV) B phototherapy typically requires

patients to attend their local phototherapy unit three times per

week for up to 10 weeks. For many patients this represents a

significant undertaking involving time, money and inconve-

nience. Yule and colleagues from Dundee have practised

patient-centred care for phototherapy for many years, recog-

nizing and responding to the need for some patients to receive

phototherapy at home with home phototherapy devices.

Having gained experience in this model of care, a natural

development was to apply the same principles of patient

empowerment to hospital-based phototherapy services. Their

© 2013 British Association of Dermatologists British Journal of Dermatology (2013) 169, pp239–242

Commentaries 241

rationale for this involved patients taking a more active role in

shared decision-making, thereby encouraging self-management

of disease. Yule states that for some patients, shift work and

demanding lifestyles make it difficult to fit in with treatment

appointment times. Self-administration of phototherapy pro-

vides patients with more flexibility and may help to reduce

time spent in the department.

The study Yule et al.1 carried out aimed to assess the feasibil-

ity of self-administration of phototherapy as a potential service

development. Using a training programme and monitoring

system developed for their home phototherapy service, they

conducted a pilot study on 20 patients with psoriasis. They

conclude that self-administration of UVB phototherapy is ‘prac-

ticable, safe and effective for most selected patients’.

What needs to be done to turn this pilot study into routine

clinical practice? A larger study is now required to develop

this concept further. Importantly, clarity is needed around

training of patients, case selection and monitoring of patients.

This service development seems to work well as part of a

comprehensive approach to providing high quality photother-

apy services to patients. Indeed, the authors are correct in

claiming that this self-administration of UVB phototherapy

represents a new intermediate level of care between nurse-

administered hospital phototherapy and self-administered

home phototherapy.

Should other phototherapy units embrace this new concept?

Not until the clinical governance frame work has been fully

established to ensure that such a service is safe and effective.

Dermatologists who are interested in adopting self-adminis-

tered UVB as a service development would do well to consider

patient access issues for their existing phototherapy services.

Yule et al. report giving phototherapy to 1500 patients per

year for a population of 500 000. This high rate of photother-

apy usage reflects a long tradition of excellence in photothera-

py and a strong focus on addressing patient access issues. The

mantra for those interested in developing their phototherapy

services should be to provide a service that allows access to all

patients who would benefit from phototherapy. Most depart-

ments have a long way to go before reaching this level and

require significant investment and expansion of their conven-

tional phototherapy services before considering novel

approaches such as home phototherapy and self-administration

of hospital-based phototherapy.

A . ANS T EYAneurin Bevan Health Board, Academic

Dermatology Unit, St Woolos Hospital,

Newport, NP20 4SZ, U.K.

E-mail: alex.anstey@wales.nhs.uk

Reference

1 Yule S, Sanyal S, Ibbotson S et al. Self-administration of hospital-based narrowband ultraviolet B (TL-01) phototherapy: a feasibility

study in an outpatient setting. Br J Dermatol 2013; 169:464–68.

© 2013 British Association of DermatologistsBritish Journal of Dermatology (2013) 169, pp239–242

242 Commentaries