A teenage boy with both secretory component deficiency and selective serum immunoglobulin A deficiency also developed pernicious anemia, insulin-dependent diabetes mellitus, pancreatic insufficiency, lymphopenia, intestinal candidiasis, and anti-intestinal antibody. The patient's father had pernicious anemia and diabetes mellitus while the paternal grandfather also had pernicious anemia. Because the patient had inherited the paternal grandmother's human leukocyte antigen complex, there was no direct association between pernicious anemia and the genetic markers. The presence of multiple immunologic abnormalities in a single patient supports the concept of an underlying defect in immune regulation as a central factor in the pathogenesis of these disorders.