Preparation of specific antisera against antigens from pharyngeal cells in patients with IgA nephropathy.

Rabbit antisera were produced against antigens obtained from pharyngeal cells of patients with IgA nephropathy (IgAN). Extracts of pharyngeal cells from patients with IgAN were frozen and thawed, and the supernatants were cocultured with fibroblasts (Vero and Hel cells). Pieces of renal biopsy specimens of the same patients were sectioned and centrifuged. The supernatants which contained IgA were incubated with the fibroblasts, and were stained with FITC-labeled anti human IgA antisera. Two positive (A and B) and one control Vero cell lines were destroyed and centrifuged. The precipitates were injected into rabbits, and rabbit antisera (A, B and control) were produced. Renal tissues from patients with IgAN and proliferative glomerulonephritis without IgA deposition (PGN) were stained with the FITC-labeled antisera. Positive stainings with FITC-labeled antiserum A was observed in 87% and that with FITC-labeled antiserum B in 55% of the patients with IgAN. No positive staining was detected with FITC-labeled control antiserum. There was also no positive staining with these antisera in renal tissues with PGN. The immunological specificity of the antisera was evaluated. It was found that these antisera did not react with complements components or immunoglobulins. The above findings suggested that some antigens from pharyngeal cells were deposited in the glomeruli from IgAN patients.