Altered complement component C3A (beta-1C--beta-1A) in patients with glomerulonephritis.

1. The altered form of the complement component C'(β–β) was found in the fresh plasma of patients with acute glomerulo-nephritis (with or without low complement levels), and some patients with nephrotic syndrome due to proliferative glomerulonephritis and membranous glomerulonephritis. 2. This provides direct evidence that the complement has been involved in an immunological reaction. 3. The possible practical implications are discussed.