Bilineage hematopoietic inhibitor and T lymphocyte dysfunction in a patient with pure red cell aplasia, myasthenia gravis and thymoma.

The case history, laboratory findings and clinical course of a patient with pure red cell aplasia (PRCA) combined with myasthenia gravis and thymoma are reported herein. In vitro study revealed bilineage complement-dependent IgG inhibitor(s) in both the granulocyte-macrophage and erythroblastic progenitor cells. His serum showed high anti-acetylcholine receptor antibody levels associated with activity of myasthenia gravis as well as PRCA. Patient history of thymectomy 7 years previously followed by extensive cutaneous candidiasis with abnormal T lymphocyte subsets (decreased T4/T8 ratio and increased number of activated T lymphocytes) in both the bone marrow and peripheral blood suggested primary T lymphocyte dysfunction, whereas the erythropoiesis was not inhibited by T lymphocytes. This case is of interest in the context of a possible immunological pathogenesis for other hematopoietic disorders, including some cases of aplastic anemia.