The involvement of type IV collagen in Goodpasture's syndrome.

Goodpasture's syndrome, involving lung and kidney, is considered to be caused by autoantibodies to basement membranes. This paper has described the isolation and identification of the antigen, which is isolated from collagenase digests of glomerular basement membrane, as a monomer protein of 26,000 daltons and two dimers of about 50,000 daltons. Further analyses indicated that the antigenic protein is derived from the globular domain of type IV collagen corresponding to the NCl peptide. All 22 patients with Goodpasture's syndrome studied had circulating antibodies to this antigen, a few had additional antibodies to laminin, and only one also had antibodies to the 7S collagen domain. No other patient with glomerulonephritis had circulating antibodies to the antigen. The isolated protein can therefore be used in an assay specific for Goodpasture's syndrome. Interestingly the protein antigen could be identified in glomerular, lung, and placenta basement membranes, although the components reacting with the antibodies represented different proportions of the preparations.