Altered glycosylation of circulatory IgA1 involved in Henoch-Schönlein purpura and IgA nephropathy

Abstract

Henoch-Schonlein purpura (HSP) is the most common type of systemic small vessel vasculitis in children. HSP most commonly affects children between 2 and 6 years of age. The presence of purpuric rash (100%) is essential to the diagnosis. Other clinical characteristics of HSP include abdominal pain or gastrointestinal bleeding (50e75%), arthralgia and/or arthritis (up to 82%), and hematuria and/ or proteinuria (20e60%). The disease generally has acute onset, and a benign and self-limiting course that lasts an average of 4 weeks. Immunoglobulin A nephropathy (IgAN), however, has an insidious onset and slow progressive nature. IgAN is the most common form of glomerulonephritis in both children and adults. It mostly affects young adults. Renal biopsy findings of IgAN and HSPN are indistinguishable due to the presence of IgA-containing immune complex deposits in the renal mesangium. It has been speculated that HSP is a systemic form of IgAN. The clinical features of children with IgAN are variable, going from asymptomatic microscopic hematuria with/ without proteinuria to gross hematuria. A small number of patients present with clinical signs of the nephrotic or nephritic syndrome. About 10e30% of pediatric patients have slow progressive disease, leading to end-stage renal disease in adulthood. Poor prognostic factors include older age, heavy proteinuria, renal insufficiency, hypertension and advanced renal histology, such as crescent