HLA-C locus alleles may modulate the clinical expression of psoriatic arthritis
1 Rheumatology Service, Hospital Universitario Central de Asturias (HUCA), C/Celestino Villamil s/n. 33006, Oviedo, Spain
2 Department of Functional Biology, University of Oviedo, C/Julian Claveria s/n. 33006, Oviedo, Spain
3 Immunology Department, Hospital Universitario Central de Asturias (HUCA), C/Celestino Villamil s/n. 33006, Oviedo, Spain
4 Clinical Epidemiology Unit, Complejo Hospitalario Donostia, P° del Dr Beguiristain 111, 20014, San Sebastian, Basque Country, Spain
Arthritis Research & Therapy 2006, 8:R185 doi:10.1186/ar2097Published: 13 December 2006
The aim of the present study was to evaluate the relative contribution of human leukocyte antigen (HLA)-C locus alleles in determining the risk and the clinical expression of psoriatic arthritis (PsA). One hundred PsA patients were randomly selected and grouped into three disease subsets: oligoarthritis (n = 40), polyarthritis (n = 25) and spondylitis (n = 35). The HLA-C locus profile of this cohort was studied by methods based on molecular biology and was compared with that of 45 patients with psoriasis vulgaris and 177 healthy blood donors from the same ethnic origin. HLA-Cw*0602 was found associated with both psoriasis (odds ratio (OR) 6.2; 95% confidence interval (CI) 3.1 to 12.5; p < 0.0001) and PsA (OR 6.2; 95% CI 3.6 to 10.8; p < 0.0001); however, this allele was equally found among the PsA subsets. HLA-Cw6-positive patients showed a longer psoriasis-arthritis latency period (p = 0.012). HLA-Cw*0701 was found under-represented in PsA in comparison with controls (OR 0.5; 95% CI 0.3 to 0.9; p = 0.04), as was HLA-Cw*0802 (OR 0.3; 95% CI 0.08 to 1; p = 0.05). A positive association was found between psoriatic spondylitis and HLA-Cw*0702 (OR 5.0; 95% CI 1.4 to 25; p = 0.01). HLA-Cw*0602 seems to confer a general risk for psoriasis, but the presence of other HLA-C locus alleles may explain an additional arthritogenic risk. HLA-C alleles may modulate some aspects of the clinical expression of PsA, but these findings need confirmation.