Henoch-Schoenlein syndrome: a clinical and morphological study of renal biopsies.

Twenty-four patients, 12 children and 12 adults, with the Henoch-Schoenlein syndrome had their renal biopsy specimens studied by light and electron microscopic and immunofluorescent antibody techniques. The principal glomerular lesion was a focal and segmental proliferative glomerulonephritis in 15, a diffuse proliferative glomerulonephritis in 6 and a animal or minor change lesion with mesangial hypertrophy in 3 cases. The proliferation of the cells was mainly mesangial. Renal biopsies taken earlier in the course of the disease showed a greater number with a focal lesion. Electron dense deposits with cellular proliferation and increased matrix were seen in the mesangium. Less frequent subendothelial and occasional subepithelial deposits were found. Capillary loop changes were seen more frequently in the later stages of the disease. Heavy deposits of IgA were found in the mesangium in all cases, and less intense deposits of IgG in 60%. beta 1 C globulin and fibrinogen were found in 80% and IgD and IgM less frequently. Complement activation was via the alternate pathway as early complement components C1q and C4 were absent. Overt allergies, streptococal infections and the HBsAg could not explain the pathogenesis of the disease. Henoch-Schoenlein syndrome is a chronic disease of the mesangium; only 5 patients showed complete recovery, 15 had persistent microscopic hematuria and 3 died or developed renal insufficiency within 8 years. The prognosis was worst with diffuse proliferative glomerulonephritis, widespread focal glomerulonephritis or epithelial cresents formation.