DNA POLYMORPHISM OF HLA CLASS-II GENES IN SYSTEMIC LUPUS-ERYTHEMATOSUS

We investigated the DNA restriction fragment length polymorphism (RFLP) of the major histocompatibility complex (MHC) genes: HLA-DRB, -DQA, -DQB, -DPB in 24 Danish patients with systemic lupus erythematosus (SLE) and in 102 healthy Danes. A highly significant increase of the frequency of the DR3- and DRw6-associated 7.00 kb DRB TaqI DNA fragment was found in SLE patients compared to normal controls (83.3% vs 35.5%; RR=9.1, p < 10(-4)). The frequencies of the DQA1*0501-associated 4.56 kb DQA TaqI fragment and the DRB3*01/03-associated 9.79 kb TaqI fragment were also found to be significantly increased in SLE patients (70.8% vs 29.7%; RR=5.8, p < 10(-2) for the DQA fragment and 70.8% vs 36.1%; RR=4.3, p<0.05 for the DRB3 fragment). Less extensive and insignificant increases of the frequencies of the DR3-associated DQB and DPB fragments were observed. The frequencies of the DR2-associated DRB, DQA, and DQB fragments were comparable to those found in normal controls.