Lack of IgG in a healthy adult: a rare case of dysgammaglobulinemia with undetectable serum IgG, IgA2, and IgE.

No IgG of any subclass could be detected in the serum of a normal healthy male adult (E.E.) who had no recent history of repeated infections. Markedly increased concentrations of both IgM and IgA were present although no IgA2 nor IgE could be demonstrated. No anti-immunoglobulin antibodies were present in the serum; when used as supplement in in vitro cultures, the serum supported differentiation of IgG-producing cells to an equal extent as that of normal serum. No cells with surface or intracellular IgG were found in the peripheral blood although low numbers of IgG-secreting cells could be induced in vitro after mitogen stimulation. No increase in suppressor cell activity was found in cocultivation experiments. T-Cell-enriched populations from E.E. were poor inducers of immunoglobulin synthesis in allogeneic B cells, and B-cell-enriched populations from E.E. could not be triggered to synthesize IgG with the aid of allogeneic T cells. Thus, it seems that lack of IgG does not necessarily lead to a highly increased susceptibility to bacterial infections.