HLA-C and guttate psoriasis

Background Psoriasis is a heterogeneous disease in its clinical expression. Both genetic and environmental factors are thought to contribute to the pa thogenesis of the inflammatory and hyperproliferative components of the typ ical skin lesions. Predisposing genetic influences include associations wit h human leucocyte antigens (HLA) of which that with HLA-Cw6 is the stronges t. Guttate psoriasis is a specific clinical manifestation of psoriasis freq uently associated with group A beta -haemolytic streptococcal throat infect ion. Objectives We set out;to determine whether further clinical subdivision of psoriasis is associated with tighter correlation with HLA-C alleles. Patients/methods We determined the HLA-C locus genotype of 29 caucasian pat ients with guttate psoriasis presenting consecutively with guttate psoriasi s associated with a history of a sore throat and/or an antistreptolysin 0 t itre >200 IU mL(-1). Polymerase chain reaction typing using sequence-specif ic primers was used to detect all known HLA-C alleles. These data were comp ared with a control population of 604 random caucasian cadaver donors. Results All patients (100%) with guttate psoriasis carried the Cw*0602 alle le compared with 20% of the control population (odds ratio = infinity; 95% confidence limits 25.00-infinity; P-corrected < 0.0000002). Conclusions This result is consistent with HLA-Cw*0602 playing a part direc tly in the pathogenesis of guttate psoriasis.