Antiglomerular basement membrane antibodies in human sera: detection by a modified micro-ELISA.

An enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to human glomerular basement membrane has been developed. Special emphasis has been put on the choice of microtiter plates which were coated with a collagenase digest of human glomerular basement membrane. Results differed markedly between the different microtiter plates. Best results were obtained with a flexible polyvinylchloride microtiter plate with flat wells (Dynatec). This plate exhibited the highest positive/negative ratio and the lowest intraassay standard deviation. Optimal conditions for each step in the ELISA have been determined. The assay proved to be specific, sensitive, and reproducible. Circulating antibodies in each of 11 patients with active antiglomerular basement membrane disease were detected by the ELISA, while sera from patients with various renal and nonrenal diseases were negative by the test.