HLA alloantigens in Greek patients with systemic lupus erythematosus

The frequency of the HLA-A, -B and -DR alloantigens was studied in 74 unselected, consecutive, unrelated Greek patients with systemic lupus erythematosus (SLE) and the results were compared with those of healthy controls (380 for the class I antigens and 154 for the class II antigens). No statistically significant differences were noted between patients and controls regarding the prevalence of any class II antigen. Furthermore, no such differences were observed between our 36 anti-Ro (SSA) positive and the rest of our SLE patients. However, the coexistence of anti-Ro (SSA) and anti-La (SSB) antibodies (9 patients) correlated significantly with HLA-B8, whereas the haplotype HLA-B8DR3 was more common in the anti-Ro (SSA) positive patients than in the rest-although the difference did not reach statistical significance. The combination of high anti-ds-DNA and low C4 serum levels correlated with absence of HLA-DR5. Our findings, while in agreement with those of certain previous studies, are somewhat different from those of others. The differences may at least partly be related to variations in the control populations employed. On the other hand some of the differences, in accordance with other peculiarities of Greeks with connective tissue disease, emphasize the role of racial and/or ethnic background in the HLA-association of various autoimmune diseases and the fact that the detectable HLA alloantigens in certain diseases modify disease and autoantibody expression rather than being responsible for the autoimmune process itself.