Objective: To investigate the predisposing role of major histocompatibility complex (MHC) genes to autoantibody production and clinical manifestations comparing French Canadian and Non-French Canadian Caucasians with systemic lupus erythematosus (SLE)

Methods: Ninety-one Caucasian patients with SLE were studied. Clinical manifestations, autoantibody expression and HLA-A, B, (serology), DR, DQ and C4A gene deletion (restriction fragment length polymorphism [RFLP] typing) were determined.

Results: Photosensitivity was present in all SLE subjects with anti-Ro antibodies (P = 0.001, RR = 13.1, Cl = 1.8, 564). Photosensitivity was further associated with the HLA-A1, C4A gene deletion haplotype. More strikingly, C4A gene deletion was associated with anti-Ro (P = 0.008, RR = 4.6, Cl = 1.4, 16.2) and anti-La (P = 0.02, RR = 11.7, Cl = 1.4, 549) autoantibodies. This relationship was also significant for anti-Ro antibody in the French Canadian patients (P = 0.01, RR = 21.3, Cl = 1.7, 105.3). In contrast, anti-dsDNA autoantibodies were negatively associated with photosensitivity (P = 0.02, RR = 0.3, Cl = 0.07, 0.8) and correlated with HLA-DR15 (P = 0.006, RR = 4.2, Cl = 1.5, 12.8) and Dw2 (P = 0.009, RR = 3.9, Cl = 1.4, 11.9).

Conclusion: C4A gene deletion has a previously unrecognized powerful association with anti-Ro and anti-La autoantibodies. These results support the concept of divergent MHC gene associations with autoantibody expression and emphasize the influence of ethnicity on the immunogenetic study of SLE.

Search results

Clinical correlates,serum autoantibodies and the role of the major histocompatibility complex in French Canadian and non-French Canadian Caucasians with SLE