Henoch-Schönlein anaphylactoid purpura nephropathy: electron microscopic lesions mimicking acute poststreptococcal nephritis.

The clinical, laboratory, and histologic features of a patient with Henoch-Schönlein syndrome are presented. The skin biopsy examination showed "leucocytoclastic vasculitis." Kidney tissue demonstrated deposits of IgG, C3, and fibrinogenfibrin by fluorescence microscopy in the mesangium and the peripheral glomerular basement membrane in a granular-nodular pattern. These correlated well with areas of mesangial hyperplasia and polymorphonuclear leucocyte infiltration seen by light and electron microscopy. Several well delineated, variably sized, subepithelial electron dense deposits flanked by polymorphonuclear leucotytes adherent to the glomerular basement membrane were seen in two of the four glomeruli examined by electron microscopy. The significance of these findings is discussed. A detailed ultrastructural evaluation of patients with Henoch-Schönlein nephropathy may yield information about the frequency of subepithelial deposits and perhaps may help to clarify the pathogenesis of this syndrome.