Association of HLA-A, -B, -C genes and TNF microsatellite polymorphism with psoriasis vulgaris: a study of genetic risk in Brazilian patients.

This study investigated the genetic association of HLA class I genes and TNF-alpha microsatellites. HLA-A, -B, -C typing was carried out in 92 psoriasis vulgaris patients and 160 healthy individuals using a PCR-SSP method. 70 patients and 71 controls were typed for five microsatellite polymorphisms, TNFa-e. HLA-B*13 Cw*06, HLA-B*57 Cw*06 and HLA-B*39 Cw*12 haplotypes were found to be increased in patients with psoriasis type I when compared to controls, which could determine the susceptibility to development of psoriasis. TNFa4, TNFb1, TNFe1 and TNFa2 b1 c2 d4 e1 haplotypes showed a decreased frequency (p < 0.05) in psoriasis patients when compared to controls. HLA-B*13 allele and HLA-B*13 Cw*06, TNFa11 b4 c1 d3 e3 haplotypes showed increased frequencies (p < 0.05) in patients with type II psoriasis, which suggests susceptibility to the onset of psoriasis. Our results detected polymorphisms of the HLA class I and microsatellite TNF locus which could be markers of genetic predisposition to the disease.