Objective: To investigate the association of HLA DRB1 alleles with beta 2 glycoprotein I (beta 2 GPI)-dependent anticardiolipin antibodies (aCL) in Japanese patients with systemic lupus erythematosus (SLE).
Methods: One hundred and forty-five Japanese patients with SLE were studied. beta 2 GPI-dependent aCL was measured by enzyme-linked immunosorbent assays. DNA typing of the DRB1 alleles was performed by the polymerase chain reaction sequence specific oligonucleotide probe method.
Results: beta 2 GPI-dependent aCL was positive in 29 (20.0%) out of 145 SLE patients. SLE patients with beta 2 GPI-dependent aCL had a significantly higher frequency or one or more of the clinical manifestations assumed to be associated with aCL, compared to those without beta 2 GPI-dependent aCL (p < 0.05). The frequency of DRB1*0901 was lower in SLE patients than in healthy subjects. SLE patients with beta 2 GPI-dependent aCL were significantly associated with DRB1*0901 as compared to those without beta 2 GPI-dependent aCL (41.4% vs 15.5%, p < 0.005, R.R. = 3.8), although the corrected P value was not significant.
Conclusion: A possible association of DRB1*0901 with Japanese SLE patients with beta 2 GPI-dependent aCL was found. This association indicates an association between the disease and the HLA-DR53 (DRB4)-bearing haplotypes in different ethnic groups.