GAMMA-DELTA T-LYMPHOCYTOSIS ASSOCIATED WITH COMMON VARIABLE IMMUNODEFICIENCY

We present the case of a 28-year-old Caucasian female with common vari able immunodeficiency (CVID) since age 5 who had a long history of hos pitalizations for unexplained fevers and pulmonary infiltrates. The pa tient developed mild lymphocytosis 7 months prior to our evaluation. F low cytometry of peripheral blood revealed an expansion of gamma delta T lymphocytes, mild CD4 T lymphocytopenia, and a reduced CD4/CD8 rati o (0.2). Two subpopulations of gamma delta T lymphocytes were found (C D3(+)/CD4(-)/CD8(+), 47%; CD3(+)/CD4(-)/CD8(-), 53%), the vast majorit y of which expressed V-delta 1. An infections cause for the patient's gamma delta T lymphocytosis could not be found. The sputum was chronic ally colonized with Staphylococcus aureus, and the organism produced T SST-1 in vitro. A bronchoalveolar lavage (BAL) revealed marked lymphoc ytosis, but gamma delta T lymphocytes were not overrepresented in the BAL. Lymphocyte functional studies revealed poor proliferative respons es to mitogens and staphylococcal superantigens and diminished cytokin e production. V-delta 1 T lymphocytes from the patient's blood were no t expanded in vitro in response to staphylococcal superantigens. TCR g ene rearrangement studies confirmed the presence of J gamma and J beta 1 clonal rearrangements accounting for only a small subpopulation of the gamma delta T lymphocytes. These studies were repeated 5 months la ter and were unchanged. A bone marrow biopsy was negative for leukemia . Hence, the cause of the patient's gamma delta T lymphocytosis could not be determined despite evaluation for underlying malignancy. occult infection, or superantigen-driven stimulation. The patient ultimately died of progressive respiratory insufficiency. The state of current k nowledge regarding gamma delta T lymphocytosis, decreased production o f alpha beta T lymphocytes, and a low CD4/CD8 ratio in association wit h CVID is discussed.