Flow cytometric immunophenotypic profiles of mature gamma delta T-cell malignancies involving peripheral blood and bone marrow.

BACKGROUND

In this study we compared clinical findings with flow cytometric immunophenotypic results in a series of patients with aggressive and indolent gamma delta T-cell malignancies with peripheral blood and/or bone marrow involvement.

METHODS

Gamma delta T-cell malignancies were detected based on flow cytometric demonstration of an abnormal T-cell population staining positive with T-cell receptor gamma delta and confirmed by morphologic and clinical reviews. Clinical data were obtained through chart review and discussion with the patients' physicians.

RESULTS

Blood or bone marrow involvement was present in all patients. Hepatosplenic and cutaneous gamma delta T-cell lymphomas had an aggressive clinical course, whereas the gamma delta T-cell large granular lymphocyte (LGL) leukemias had an indolent course. Expressions of CD5, CD8, CD16, and CD57 differed in gamma delta T-cell LGL leukemia compared with hepatosplenic and cutaneous gamma delta T-cell lymphomas.

CONCLUSIONS

Gamma delta T-cell malignancies have a poor prognosis with the exception of gamma delta T-cell LGL leukemia (indolent process). Because CD57 expression is specific for gamma delta T-cell LGL leukemias, expression of this antigen may be associated with a more indolent clinical course. Because cutaneous gamma delta T-cell lymphoma can present with peripheral blood involvement, flow cytometric evaluation of peripheral blood is important in staging these patients.