A Human T Lymphotropic Virus Type 1 Carrier Coinfected with Mycobacterium intracellulare and Pneumocystis jirovecii with a Characteristic Compositional Change of Bone Marrow Cells

Human T lymphotropic virus type 1 (HTLV-1) is endemic in the southern part of Japan. Infection of the virus can cause adult T cell leukemia/lymphoma (ATL), while most infected individuals remain in a carrier state for a long period of time. Although rare cases of carriers, like ATL patients, who developed opportunistic infections, have been reported, hematological changes of carriers who are prone to opportunistic infections have not been well defined. Here, we present a case of an HTLV-1 carrier who developed Mycobacterium intracellulare infection and Pneumocystis jirovecii pneumonia (PcP) simultaneously. Flow cytometric analysis of bone marrow cells revealed an aberrant compositional change similar to that in ATL patients. This suggests the presence of a pre-ATL state prior to the development of ATL, which is notable in terms of underlying cellular immunodeficiency.