Chronic Clonal Proliferative Disease of Gamma-Delta (γδ) T-cells in a Patient with Rheumatoid Arthritis and Neutropenia: Lack of the Morphology and the Immunophenotype of Large Granular Lymphocytes

Normal gd T-lymphocytes have the morphology of large granular lymphocytes (LGL) and, as the LGL of ab 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 gd 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 gd T proliferations such as the hepatosplenic gd T-cell lymphoma.