ASSOCIATION OF HLA-DR5 (DR11) WITH SYSTEMIC-SCLEROSIS (SCLERODERMA) IN MEXICAN PATIENTS

Objective: To study the association between Major Histocompatibility C omplex (MHC) haplotypes and systemic sclerosis (SSc) in Mexican mestiz o patients. Methods: Class I, II and III MHC antigens were determined in 41 Mexico mestizo patients with SSc, 113 of their first degree rela tives, and 85 ethnically matched controls. The significance of differe nces between patients and controls was tested by chi-square analysis w ith Yates' correction. Results: Frequencies of HLA-DR5 and HLA-DRw52 w ere found to be higher in SSc patients compared to ethnically matched healthy controls (p = 0.007, RR = 3.31; 95% confidence interval: 1.3-8 .3 and p = 0.04, RR = 2.4; 95% confidence interval: 1.0-5.7, respectiv ely). Sequence-specific oligotyping in DR5 positive individuals showed that 10 out of 41 patients had the DRB11104 subtype (24.3%) as compa red to only 6 of the 85 healthy controls (7.0%) (p = 0.01, RR = 4.25). Subdividing patients according to their clinical features showed a si gnificant increase of HLA-DR5 in diffuse (p = 0.013, RR = 3.89, 95% co nfidence interval: 1.27-12.0) and limited scleroderma (p = 0.0008), bu t not in the CREST syndrome. Segregation analysis obtained from the fa milies showed that in the patients, DR5 was mostly part of the [HLAB35 ;DR5] haplotype as opposed to healthy controls. Conclusion: These data support the role of DRS (DRB11104) in the genetic susceptibility to develop scleroderma in Mexican patients mid also sustain the notion of genetically determined clinical subgroups of SSc.