‘Immunodeficiency with thymoma’ associated with leukocytopenia

Abstract

Two patients with “immunodeficiency with thymoma” associated with leukocytopenia were reported. Case 1 of a 55-year-old man and case 2 of a 62-year-old man were admitted to our hospital for examinating the cause of recurrent infections. They were diagnosed as immunodeficiency with thymoma because of the presence of thymoma and hypogammaglobulinemia. In addition, case 1 had neutropenia and case 2 lymphocytopenia. The immunophenotyping of the lymphocytes in the peripheral blood revealed that case 1 had an increase of CD 8⁺, CD 11 b^-, CD 57⁺ and DR^- cells, and case 2 had an increase of CD 8⁺, CD 11 b⁺, CD 57⁺ and DR⁺ cells, resulting in a decrease of CD 4⁺/CD 8⁺ ratio and B cell counts. On colony forming unit (CFU) assay of the bone marrow mononuclear cells, the formations of CFU-G and CFU-GM in case 1 and those of CFU-G, CFU-GM and CFU-E in case 2 were markedly suppressed. However, the removal of T cells resulted in an increase to subnormal level of the formations of CFU-G and CFU-GM in case 1, and CFU-G and CFU-E in case 2. These results suggest that leukocytopenia found in both patients was possibly due to bone marrow suppression by abnormal proportion of T cells.
In addition, abnormal proportion of T cells caused by unknown factors may induce thymoma, hypogammaglobulinemia and aberrant hematopoiesis in some patients with “immunodeficiency with thymoma”.