HISTONE-REACTIVE IGA ANTIBODIES IN ADULT IGA NEPHROPATHY AND OTHER PRIMARY GLOMERULONEPHRITIS

The levels of histone-reactive IgA antibodies in the sera of adult pat ients with IgA mesangial glomerulonephritis, membranous glomerulonephr itis, membranoproliferative glomerulonephritis and idiopathic nephroti c syndrome (minimal change disease + segmental glomerulosclerosis + Ig M nephropathy) were evaluated by an enzyme-linked immunosorbent assay. Increased levels of IgA antibodies to all five major histones (H1, H2 A, H2B, H3, H4) were found in all four disease groups when compared to normal controls. These histone-reactive IgA antibodies were restricte d to the IgA1 subclass and their levels did not correlate with the lev els of total serum IgA, nor with serum creatinine, creatinine clearanc e, and 24-hour proteinuria. Increasing ionic strength resulted in only partial inhibition of the binding to histones and, in individual pati ents, levels of reactivity with individual histones were usually corre lated. This study shows that elevated levels of IgA antibodies reactiv e with self antigens are present in primary glomerulonephritis and ext ends previous observations indicating that anomalies of the IgA system occur in various forms of primary glomerulonephritis and are not limi ted to IgA nephropathy.