Association of complement C4 and HLA-DR alleles with systemic lupus erythematosus in Koreans

Objective. To examine the association of complement C4 and HLA-DR to systemic lupus erythematosus (SLE) susceptibility in Korea. Methods. Complement C4 protein typing was carried out by immunofixation and immunoblotting methods using EDTA-plasma from 60 patients with SLE and 12 healthy controls. Restriction fragment length polymorphism analysis of C4 genes was also carried out using TaqI or HindIII for restriction enzymes. HLA-DR was determined by polymerase chain reaction amplification with sequence specific primers using genomic DNA from 61 patients with SLE and 12 healthy controls. Results. The frequency of the C4AQ0 allele was significantly higher in the patients with SLE than in controls (41.1 vs 25.0%, p<0.05)