No evidence for pathogenic role of IgE in Henoch-Schoenlein purpura nephritis

Background. The incidence of increased plasma IgE levels was reported to be significantly higher in Henoch-Schoenlein purpura nephritis (HSPN) than in IgA nephropathy (IgAN), and IgE deposits were demonstrated on epidermal Langerhans cells and dermal mast cells in four of six patients with HSPN in two European studies. We designed this study to investigate whether levels of clinical and biological markers of atopy in children with HSPN were significantly higher than those in children with IgAN, non-IgA glomerulonephritis (non-IgAGN), or microhematuria. Methods. The incidence of atopic disease, increased IgE levels, and positive radioallergosorbent test (RAST) results was investigated in 28 children with HSPN, 26 with IgAN, 28 with non-IgAGN, and 30 with microhematuria, all aged 8-16 years. All patients except for those in the microhematuria group, had proteinuria greater than 100 mg/dl and had had a kidney biopsy. Results. The incidence of atopic disease, increased IgE levels, and positive RAST results in children with HSPN did not differ from findings in children with IgAN, non-IgAGN, or microhematuria. Conclusion. Our results in Japanese children do not support the idea (suggested by the two European studies) that IgE may play an important role in the pathogenesis of HSPN.