腎炎における流血中免疫グロブリン・クラス特異的免疫複合体の検討

―とくに腎組織所見との関連性について―

抄録

The relationship between the immunological characteristics of circulating immune complexes (CICS), the immunoglobulin (Ig) class of glomerular immune deposits and the degree of mesangial proliferation has not been studied in detail. Using enzyme-linked immunosorbent assays for Clq binding (Clq EIA) and anti-C₃ (a-C₃ EIA) and molecular analysis by sepharose column, sera from patients with IgA nephropathy (IgA GN, N=53), systemic lupus (SLE, n=41) and other renal diseases (n=65) were tested for the presence of CICS and their correlation with glomerular immunofluorescent and histological abnormalities. In IgA GN, 55% of pathents had CICS containing IgA, usually in association with IgG or IgM. The majority of CICS were medium-sized (approximately 500 KMW) but ranged from 150 K to 1000 K. The degree of mesangial proliferation correlated with the presence of IgG CICS or IgM CICS, but not IgA CICS. The Ig class of glomerular deposits correlated strongly with the Ig class of CICS. SLE patients had high levels of IgG CIC and IgA CIC, 76% showed more than one Ig class of CIC; CICS ranged in size from 150 K to 1000 K. Serial studied before and after treatment in 5 patients demonstrated a reduction in all size of CICs in all patiens; 3 of these showed the complete disappearance of large and small CICS. A high correlation between the Ig class of glomerular immune deposits and the Ig class of CICS. In conclusion. CICS may play a role in the pathogenesis of glomerular lesions seen in IgA nephropathy and SLE.