Mechanism of onset and exacerbation of chronic glomerulonephritis and its treatment

Immunoglobulin A nephropathy (IgAN) is one of the most common causes of chronic glomerulonephritis (CGN) in the world. The proliferative and crescentic forms of IgA are found in up to 30% of cases and are associated with nephritic‐range proteinuria, accelerated hypertension, and accelerated decline toward end‐stage renal disease. On the other hand, Henoch–Schönlein purpura (HSP) is a systemic disorder characterized by leukocytoclastic vasculitis involving the capillaries and the deposition of IgA immune complexes. Renal involvement is the principal cause of morbidity and mortality in children with HSP. Two entity diseases are important as renal diseases in childhood. We herein review the mechanism of the onset and exacerbation of IgAN and HSP nephritis (HSPN) and its treatment. As to the pathogenesis, we found that CB4 provoked exacerbation of renal pathologic findings in hyper IgA mice via endothelial injury, γ‐interferon production, and dysfunction of the mesangial pathway and could possibly become one of the factors involved in the mechanism of the onset or evolution of human IgAN. As to the treatment of IgAN and HSPN, we evaluated the efficacy of multidrug combination therapy (prednisolone, warfarin, and dipyridamole, including mizoribine) for diffuse IgAN and the efficacy of methylprednisolone and urokinase pulse therapy plus immunosuppressive drugs for severe HSPN in children. These therapies were effective in ameliorating the proteinuria and histologic severity of patients with IgAN or HSPN. In future, detailed investigations into the pathogenesis of CGN and double‐blind randomized control studies on children with IgAN or HSPN will be necessary.