Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by diverse clinical manifestations and autoantibody production, which is known to be strongly influenced by genetic factors. Previous studies have revealed the associations of SLE with HLA class II alleles and antiphospholipid antibody system (anticardiolipin antibody (aCL) and anti-β2 glycoprotein I antibody (anti-β2 GPI)). Therefore, we studied the associations of HLA class II alleles with SLE and anti-phospholipid antibody system.

The genotyping for HLA-DRB1 and DQB1 alleles were performed in 61 SLE patients and 100 controls by the polymerase chain reaction (PCR)-sequence specific oligonucleotide probe method. ELISA tests for aCL and anti-β2 GPI were performed in 39 of the 61 SLE patients. The results were evaluated statistically by Chi-square test.

The frequencies of the HLA-DRB1*15 and DQB1*06 in SLE patients were significantly higher than those in controls. HLA-DRB1*12 was significantly lower in SLE patients than controls. Nine of 39 patients were positive for aCL (IgG) and three were positive for aCL (IgM). One of 39 patients were positive for anti-β2 GPI (IgG) and none of them positive for anti-β2 GPI (IgM). Association of aCL with HLA class II alleles was not observed in our study.

According to our results, it was found that HLA-DRB1*15 and DQB1*06 were associated with genetic susceptiblility and DRB1*12 was associated with resistance to SLE in Korean population. No Association of aCL with HLA class II alleles was observed and the positive rate for anti-β2 GPI was very low.