The prognostic significance in Goodpasture's disease of specificity, titre and affinity of anti-glomerular-basement-membrane antibodies.

BACKGROUND

The nephrotoxic potential of anti-glomerular-basement-membrane (GBM) antibodies has been demonstrated in numerous animal experiments. However, it is not known to what extent the properties of circulating anti-GBM antibodies in human disease reflect the severity of the disease and predict the outcome.

METHODS

Clinical data were collected for 79 Swedish patients for whom a positive result had previously been obtained with anti-GBM ELISA. In stored sera from the patients, we measured antibody concentration, specificity and affinity together with antineutrophil cytoplasmic antibodies and alpha(1)-antitrypsin phenotype.

RESULTS

Six months after diagnosis, 27 (34%) were dead, 32 (41%) were on dialysis treatment and only 20 (25%) were alive with a functioning native kidney. The best predictor for renal survival was renal function at diagnosis. In patients who were not dialysis dependent at diagnosis however, renal survival was associated with a lower concentration of anti-GBM antibodies, a lower proportion of antibodies specific for the immunodominant epitope and the histological severity of the renal lesion. The only factor that correlated with patient survival was age.

CONCLUSIONS

Immunochemical properties of autoantibodies do not affect patient survival in anti-GBM disease but seem to be a factor in renal survival in patients detected before renal damage is too advanced.