POSSIBLE PATHOGENIC ROLE OF IGE IN HENOCH-SCHONLEIN PURPURA

The incidences of clinical and biological markers of atopy were invest igated in 16 children with IgA nephropathy (IgAN) (group A) and in 22 with Henoch-Schonlein purpura nephritis (HSPN) (group B). The incidenc e of increased plasma IgE levels according to age-matched normal value s was significantly higher in group B (17/22, 77%) than in group A (7/ 16, 44%) (P <0.05). Although not significant, the incidences of positi ve RAST tests and of a history of typical atopic symptoms were also hi gher in group B [10/22 (45%) and 11/22 (50%), respectively] than in gr oup A [4/16 (25%) and 5/16 (31%), respectively]. Moreover, IgE deposit s were demonstrated by a peroxidase/anti-peroxidase method on cutaneou s Langerhans and mast cells in 4 of 6 patients with HSPN. Thus immunoa llergy might account, in some cases, for the cutaneous, intestinal and pulmonary signs observed in HSPN, but not in IgAN. We postulate stimu lation of IgE-sensitized mast cells by specific antigens in the presen ce of IgA circulating immune complexes (CIC), release of vasoactive su bstances, increased capillary permeability and perivascular deposition of IgA CIC.