Differential association of polymorphisms in the TNFalpha region with psoriatic arthritis but not psoriasis.

To investigate the potential association of tumour necrosis factor alpha (TNFalpha) microsatellite and promoter alleles with psoriatic arthritis (PsA).DNA from 89 white patients with PsA, 65 patients with psoriasis, and 99 healthy white controls was investigated for two TNFalpha promoter (-238 and -308) and three microsatellite polymorphisms (TNFa, c, and d). Patients had previously been studied by serology for HLA class I antigens and by sequence-specific polymerase chain reaction for DRB1* alleles. In addition, TNFalpha production of Ficoll separated peripheral blood mononuclear cells (PBMC) into culture supernatants after stimulation with lipopolysaccharide, alphaCD3 antibodies, phytohae…