BacteriophageλDNAを抗原とした抗二本鎖および抗一本鎖DNA抗体の測定

―ループス腎炎患者における抗DNA抗体とその親和性の検討―

抄録

IgG-class antibodies to double-stranded (ds) and single-stranded (ss) DNA in patients with collagen disease were measured by enzyme-linked immunosorbent assay (ELISA) using bacteriophage λ DNA as the antigen. Moreover, avidity of IgG-class antibodies to both dsDNA and ssDNA in patients with systemic lupus erythematosus (SLE) was evaluated by ELISA as salt-dependent binding activities. The results are as follows:1) Elevated IgG-class antibodies to dsDNA were largely restricted to patients with active SLE. Furthermore, the levels of IgG-class antibodies to dsDNA correlated with the disease activity of SLE. 2) Lupus nephritis (LN) patients with nephrotic syndrome (NS) or diffuse proliferative LN as determined by renal biopsy had high levels of IgG-class antibodies to both dsDNA and ssDNA. 3) LN patients with NS showed the highest means of avidity index of IgG-class antibodies to both dsDNA and ssDNA. These findings suggest that the present method of measuring IgG-class antibodies to dsDNA is useful for the diagnosis and management of patients with active SLE and that IgG-class antibodies to both dsDNA and ssDNA with high avidity may be an important factor in the pathogenesis of LN with NS.