Adult T-cell leukemia: clinical and immunologic characterization of a nonendemic case

A 56-year-old black man with nonendemic adult T-cell leukemia is reported, who presented with severe hypercalcemia and leukemic leptomeningeal infiltration but had no evidence of bone marrow involvement. His malignant cells were characterized by light and transmission electron microscopy, cytogenetics, and flow cytometry. The cells demonstrated the deeply indented or convoluted nuclei characteristic of endemic human T-cell lymphoma virus-associated cases. Surface phenotyping indicated the cells' origin to be from the mature, helper/inducer subset of T-lymphocytes. However, there was no clinical or laboratory evidence that the malignant cells retained immunoregulatory function. The clinical and immunologic features of this and other nonendemic cases are compared with those of patients from the endemic regions of Japan, the Caribbean islands, and the southeastern United States.