To study the influence MHC class II and TAP2 alleles exert on systemic lupus erythematosus (SLE) susceptibility and on the clinical and serological manifestations of the disease, in a cohort of Spanish patients.Methods
HLA-DR serological typing and HLA-DQA, DQB, and TAP2 DNA sequence specific oligotyping, were carried out in 85 unrelated Spanish SLE patients and 186 healthy controls. Autoantibodies detection was carried out by indirect immunofluorescence and counter immunoelectrophoresis.Results
Total SLE group: the frequency of HLA-DR3 and HLA-DQA1[black star]0501 is significantly increased in this group (pc <0.005, delta=0.34 and pc <0.005, delta= 0.45, respectively) although the highest delta value (delta=0.87) is obtained when the TAP2[black star]01 alleles are considered. No DQB allele shows significant deviation from the control group. Renal damage: it mainly occurs in HLA-DR3 patients (pc <0.0005 and delta=0.72). HLA-DQA1[black star]0501 (pc <0.05, delta=0.57) and DQB1[black star]0201 (pc NS, delta=0.56) are weaker susceptibility factors. Ro+ (but not La) group: this autoantibody response is associated with TAP2[black star]01 alleles in homozygosity (p<0.05, delta=0.81). Ro/La+ group: it has a different genetic background as HLA-DQA1[black star]0501 (delta=1) and HLA-DQB1[black star]0201 (delta=1) are the main susceptibility factors.Conclusions
A differential association between HLA-DR, DQA1, and DQB1 alleles and SLE or its clinical and serological manifestations are found. Furthermore, the associations are different to the ones reported in other ethnic groups. Finally, TAP2[black star]01 group of alleles are associated with the highest susceptibility to SLE (higher than HLA-DR3) and may influence Ro (but not La) autoantibodies production, whereas HLA-DQA1[black star]0501 and DQB1[black star]0201 mediates concomitant Ro and La production.