The most common form of the kidney disease called glomerulonephritis is IgA nephropathy. Now a study published in the Journal of the American Society of Nephrology by researchers at the University of Alabama at Birmingham largely validates the hypothesis that a second immunoglobulin, IgG, is a crucial part of the pathogenic immunodeposits in glomeruli of patients with IgA nephropathy. Up to now, routine immunofluorescence microscopy — which identifies the presence of IgA in all cases of IgA nephropathy — failed to show IgG in 50 to 80 percent of kidney biopsies. In addition, IgG found in those positive tests had never been tested for antigenic specificity, such as specificity against the IgA1. Read the full article.