Henoch-Schonlein purpura nephritis: an update

Henoch-Schonlein purpura (HSP) is a form of systemic vasculitis characterised by vascular wall deposits of predominally IgA typically involving small vessels in skin, gut and glomeruli and associated with purpura, colic, haematuria and arthralgia or arthritis. HSP nephritis (HSPN) leads to chronic renal failure in up to 20% of paediatric patients after 20 years of followup in selected series. The risk is related to the initial clinical presentation and the percentage of glomeruli presenting with epithelial crescents. The pathogenesis of HSPN might be related to an increased production of abnormally glycosylated IgA, which is not sufficiently cleared by the liver and leads to the formation of IgA macromolecules, accumulating in the circulation with subsequent deposition in vessel walls and in the glomerular mesangium. HSPN is related to IgA nephropathy. These two diseases can be encountered consecutively in the same patient, have been described in identical twins and bear similar pathological and biological abnormalities. No consensus about treatment has been reached up to now. Recent studies indicate that early treatment with methylprednisolone or a combination of steroids and cytotoxic drugs might prevent evolution to chronic renal failure. Conclusion: despite numerous studies, the pathogeny of Henoch-Schonlein nephritis remains incompletely elucidated and controlled therapeutic trials are still needed.