MPO and IgA glomerulonephritis: Some authors suggest that the presence of IgA antibodies is secondary to an increase in circulating immune complex cells of the IgA-fibronectin type [9]; others believe it is because the IgA-MPO reaction is mediated by abnormal composition in carbohydrates of the IgA2 molecule [10]; this was described in isolated cases of IgA nephropathy other than patients diagnosed with Henoch–Shönlein purpura, suggesting that these are clinical forms with a poor prognosis [6].