Antigen identification in Goodpasture's syndrome

Abstract

Although there is unquestionable evidence that an anti-basement membrane antibody is involved in the development of the renal lesion in Goodpasture's syndrome the specific antigen has not been clearly identified. In an attempt to clarify this problem serum and antibody eluted from a patient with Goodpasture's syndrome was studied by fixation to normal human glomerular basement membrane (GBM) before and after treatment with collagenase, neuraminidase and 8 M urea. Controls for buffer, pH and temperature were employed. Absorption studies and spleen cell and lymphocyte transformation studies using GBM glycoproteins prepared by method of Kefalides were also performed. Double layer immunofiuorescent studies demonstrated that both serum and eluate fixed to the GBM of untreated normal human kidney and normal human kidney treated with 8 M urea, and neuraminidase. However they did not fix to collagenase treated kidney. This suggests that the collagen like glycoprotein rather than the non-collagenous or sialic acid rich glycoprotein is the antigen which induces autoimmune nephritis in Goodpasture's syndrome. Although cell transformation studies were inconclusive this finding was confirmed by absorption studies.