Immunoglobulin A subclass-containing plasma cells in the jejunum in primary IgA nephropathy and in Henoch-Schönlein purpura.

We studied the distribution of IgA1- and IgA2-containing plasma cells in the jejunum of 5 patients with primary IgA nephropathy and of 2 patients with Henoch-Schönlein purpura. The percentage of IgA-containing cells (62.3 +/- 4.6) was below the level found in normal (79.4 +/- 5.1) (p less than 0.001). The percentage of IgA1-containing plasma cells relative to the total IgA-containing cells was too low in 2, normal in 3 and too high in 2 subjects (mean percentage 68.1 +/- 9.6; normal 69.0 +/- 3.8). Our data do not support an increased production of IgA1 in the jejunal mucosa of patients with primary IgA nephropathy or with Henoch-Schönlein purpura.