Use of a monoclonal antibody in differential diagnosis of children with haematuria and hereditary nephritis.

In a retrospective, double-blind study, paraffin-embedded renal biopsy sections from 44 children with haematuria were examined to see whether a mouse monoclonal antibody (MCA-P1) against glomerular basement membrane (GBM) could identify a subgroup of patients with hereditary glomerulonephritis (Alport's syndrome) in whom the Goodpasture antigen was abnormal. There was strong linear binding of MCA-P1 to GBM in all of 29 patients with no evidence of hereditary nephritis and in 2 patients in whom the diagnosis of hereditary nephritis was thought possible but not definite on available clinicopathological evidence. In contrast, 12 of 13 patients with strong evidence of hereditary nephritis showed no binding (9) or greatly reduced binding (3). These findings suggest that a major subgroup of patients with hereditary glomerulonephritis have biochemical abnormalities of the GBM involving Goodpasture antigen and that MCA-P1 is useful in the differential diagnosis of children with haematuria.