Disordered balance of IgA subclass production in the tonsils of some IgA nephropathy patients.

Background: There are reports concerning the relationship between tonsillectomy and immunoglobulin A nephropathy (IgAN). Two reports on the biochemical analysis of over-produced IgA1 from IgAN patients were recently published. On the other hand, histochemical analysis of tonsillar tissue indicated the disordered balance in IgG and IgA producing cells and in the IgA subclass producing cells in IgAN patients.

Methods: IgA in tonsillar extracts and serum was separated into passed fraction (IgA2) and bound fraction (IgA1) by a jacalin-agarose column. Isoelectric focusing (IEF) analysis was carried out using an IPGphor instrument. The IgA content in each sample was analyzed by enzyme-linked immunosorbent assay (ELISA).

Results: The IgA1/IgA2 ratio of the tonsillar extracts from controls and IgAN patients was compared. The ratio distribution indicated statistically significant differences. The mean ratio for the control tonsil was 61/39. However, the ratio from eight out of thirty-two IgAN patients exhibited a higher value than the mean + 2SD (standard deviation) of the controls. Among them, three patients exhibited 92/8. Meanwhile, the ratios for serum by this method were close to the previously reported 89/11. There were no differences in the IgA1 IEF profile between the representative lowand high-IgA1 producing patients.

Conclusions: This is the first report concerning IgA subclass distribution in tonsillar tissue. The ratio 61/39 for tonsillar IgA differ from the value (>90% of IgA1) in the previous histochemical report. The value is similar to the previous report for colostrum, whole saliva, jejunal fluid and bronchial fluid. The IgA1/IgA2 ratio distribution in the tonsillar extracts from the patients with chronic tonsillitis is significantly different from that of the IgAN patients.