UNUSUAL MORPHOLOGICAL FEATURES OF ADULT T-CELL LEUKEMIA-CELLS WITH ABERRANT IMMUNOPHENOTYPE

We describe 4 cases of adult T-cell leukemia (ATL) with unusual morpho logy and aberrant immunophenotype. All patients were Japanese and born in the Nagasaki district, an area endemic for HTLV-1. Peripheral bloo d and/or bone marrow films revealed bizarre giant cells with and witho ut large nucleoli; the cells were 5 to 6 times the diameter of erythro cytes, resembling Hodgkin's cells. Some peripheral blood cells were mo rphologically similar to prototypic ATL cells, while many other cells in the bone marrow showed unusual morphology. Furthermore, leukemic ce lls had aberrant immunophenotypes such as the CD8-positive type in pat ients 1 and 2, the CD4-. CD8-double-negative type in patient 3, and th e CD5 antigen defect in patient 4. All patients had marked elevations of the serum calcium and LDH and organomegaly, while all had a short s urvival. Anti-HTLV-1 antibodies and provirus DNA monoclonality were de monstrated in all patients. The results suggested that the unusual mor phology and aberrant ATL cell immunopheno-type may be indicative of a high grade malignant behaviour of ATL.