Study of the major phenotype of large granular T-cell lymphoproliferative disorder.

Six cases of large granular T-cell lymphoproliferative disorder with a selected immunophenotype (CD3+, CD4-, CD8+, CD16+) were studied to characterize a homogeneous group of patients. It was found that most of these patients did not exhibit the clinical features frequently described in large granular T-cell lymphoproliferative disorder--recurrent infection, rheumatoid arthritis, and splenomegaly. The laboratory tests usually positive in large granular T-cell lymphoproliferative disorder, including rheumatoid factor and anti-nuclear antibodies, also were frequently negative. The pathognomonic features were found to be neutropenia and large granular lymphocytosis with positive killer cell markers. All six cases showed T-cell receptor gene rearrangement that indicated a monoclonal proliferation of lymphoid cells, which were natural killer-like T cells by immunophenotyping. B cells were essentially absent in all cases. It should be emphasized that bone marrow aspirates are as informative as peripheral blood samples for the diagnosis of large granular T-cell lymphoproliferative disorder; indeed, phenotypes of blood and marrow in one case were identical in terms of percentages of markers. In this selected group of patients, the clinical courses were indolent with uncomplicated outcomes. In three patients, chemotherapy did not induce an obvious clinical response, but all patients' conditions remained stable with only supportive care.