HLA-CW-ASTERISK-0602 AND HIV-ASSOCIATED PSORIASIS

The aetiopathogenesis of psoriasis is unknown, but, genetic and enviro nmental factors may be involved. Psoriasis may not be one disease but a cutaneous inflammatory reaction pattern consequent upon several diff erent independent or related stimuli in susceptible individuals, There are controversial issues regarding the immunological basis of psorias is and the role of CD4 vs. CD8 T lymphocytes. Psoriasis has been assoc iated with HLA-Cw6 and Cw7 by serology and specifically with HLA-Cw06 02 by polymerase chain reaction (PCR) typing. Psoriasis is probably no more common in HIV infection than in the general population; however, it may appear for the first time or pre-existing psoriasis may worsen and be difficult to treat in HIV disease. We have investigated the pr evalence of HI,A-C alleles, in the specific clinical context of HIV in fection complicated by type 1 psoriasis, in a case control study of 14 men with HIV disease and type 1 psoriasis and 147 HIV-infected patien ts without psoriasis. Typing was performed using PCR with sequence-spe cific amplification primers, Eleven of 14 patients (79%) with psoriasi s carried the HLA-Cw0602 allele compared with 24.5% of those without psoriasis (odds ratio = 11.31; 95% confidence limits 2.73 to 65.36; P = 0.0001). Two patients without the HLA-Cw0602 allele carried instead the closely related Cw0401/3 allele. The results confirm the previou sly reported association between the HLA-Cw0602 allele and type 1 pso riasis, and suggest that the association with HLA-Cw0602 is stronger in HIV-associated psoriasis although this trend needs to be supported by a larger sample. The immunodysregulation resulting from HIV infecti on may trigger psoriasis in those genetically predisposed by the Cw06 02 allele, As CD8 T cells recognize antigens in the context of class I major histocompatibility complex, the identification of an HLA class I association in HIV-associated psoriasis strengthens the argument for an important role for CD8 + T lymphocytes in the immunopathogenesis o f psoriasis. Investigations of the pathogenesis of psoriasis should ta ke account of clinical and other subtypes already identified.