IgA-containing plasma cells in the intestinal mucosa of children with selective IgA deficiency.

In 8 children with selective IgA deficiency (serum IgA less than 5 mg/dl, secretory IgA less than 0.5 mg/dl in unstimulated saliva) immunofluorescent staining of intestinal biopsy specimens revealed the presence of IgA-containing plasma cells. This finding supports the hypothesis that in the intestinal mucosa of patients with IgA deficiency B lymphocytes undergo "sterile" differentiation into IgA-containing plasma cells probably incapable of secreting the IgA synthesized.