Nonmalignant monoclonal immunoglobulinemia, pernicious anemia and gastric carcinoma. A model of immunologic dysfunction. Report of two cases and review of the literature.

The association of an autoimmune disease with a monoclonal immunoglobulin is not exceptional and most probably results from a dysfunction of the immunologic apparatus. This study describes two patients with monoclonal immunoglobulin A (IgA) and M (IgM) gammopathy, respectively, in whom pernicious anemia and finally gastric carcinoma developed. One patient had autoantibodies to gastric parietal cell and to thyroid microsomal antigen which could not be identified with the M-component. This observation, together with the fact that pernicious anemia occurred in one case before and in the other case after the discovery of M-component, suggests that different clones of cells were responsible for both disorders. Sixteen cases in which the patients had the same association have been collected from the literature and the data are compared with ours.