Chronic clonal proliferative disease of gamma-delta (gammadelta) T-cells in a patient with rheumatoid arthritis and neutropenia: lack of the morphology and the immunophenotype of large granular lymphocytes.

Normal gammadelta T-lymphocytes have the morphology of large granular lymphocytes (LGL) and, as the LGL of alphabeta T-cells, they express pan-T antigens, NK-associated antigens and the cytotoxic molecules, perforin and granzime B. In this report we describe an unusual patient with rheumatoid arthritis and neutropenia who has a chronic gammadelta T-cell proliferation with a chronic, indolent clinical course and atypical lymphocytes, lacking the classical LGL morphology, not expressing NK-associated antigens, and not expressing perforin or granzyme B. In spite of the atypical morphological features of the clonal cells, which were suggestive of a more malignant process, the patient has been followed for 4 years without aggressive therapy. It is important to recognize this entity and to distinguish it from other gammadelta T proliferations such as the hepatosplenic gammadelta T-cell lymphoma.