C5b-9 deposition in children with glomerular diseases.

Kidney biopsies were obtained in 28 children with glomerular diseases and studied using indirect immunofluoreoscence and immunoperoxidase for the detection of IgG, IgA, IgM, Clq, C3c, C4, Fibrinogen and the neoantigens of the terminal C5b-9 complement complex. An affinity-purified rabbit IgG was used to recognize the neoantigens of the assembled terminal components of the complement system into the C5b-9 complex. The immunohistochemical studies were correlated to the clinical data and laboratory investigations. Fourteen of the 28 patients presented specific C5b-9 glomerular deposits; they were also present at the tubular sites in 8 patients and at the vascular sites in 12 patients. An unfavourable evolution was observed for patients presenting C5b-9 deposits in contrast to those without such deposits, even of the same histopathological pattern of glomerulonephritis. The presence of C5b-9 complex at the site of glomerular injury suggests a pathological involvement of the "in situ" complement activation and could be a marker in the prognosis of the glomerular diseases.