Increase of IgA in pharyngeal washings from patients with IgA nephropathy

The levels of IgA and total proteins in pharyngeal washings were examined in patients with IgA nephropathy and other glomerular diseases in order to determine whether secretory IgA, IgA1 and IgA2 were increased in these patients. Thirty patients with IgA nephropathy, 21 patients with other glomerular diseases and 15 healthy adults were examined. The levels of IgA were quantitated by radial immunodiffusion and laser nephelometry. The levels of total proteins in pharyngeal washings were quantitated by Tonein-TP. It was demonstrated that the levels of IgA in pharyngeal washings were significantly increased in patients with IgA nephropathy compared to those with other glomerular diseases and healthy adults. The levels of total proteins in pharyngeal washings were increased in patients with IgA nephropathy, and the ratio of IgA and total proteins in the washings from patients with IgA nephropathy was not significantly different from those healthy adults. There was a significant correlation between the levels of IgA in pharyngeal washings and those of IgA in sera from patients with IgA nephropathy. The IgA observed in pharyngeal washings contained secretory components, IgA1 and IgA2, in patients with IgA nephropathy. It is suggested that the increase of IgA in the pharyngeal washings in parallel with the increase of total proteins might be associated with local inflammation.