V gamma 9-V delta 2+ gamma delta T cells from a patient with Felty syndrome that exhibit aberrant response to triggering of the CD3 molecule can regulate immunoglobulin secretion by B cells.

Expanded populations of T lymphocytes bearing gamma delta T cell receptors have been detected in several patients with Felty syndrome. The goal of this study was to functionally characterize these lymphocytes in a newly described patient with this disease. For this, fluorescence-activated cell sorter analysis of T cell surface antigens, proliferation, and tumor necrosis factor alpha enzyme-linked immunosorbent assays, as well as quantitative assays of immunoglobulins secreted by pokeweed mitogen-driven B cells were performed. The gamma delta cells, that expressed a CD3+CD4-V gamma 9-V delta 2+C delta + phenotype, and constituted 60% of the peripheral blood T cells, did not proliferate after triggering with anti-CD3, but did secrete tumor necrosis factor alpha and the addition of these cells to pokeweed mitogen-stimulated B cells from the patient decreased their secretion of immunoglobulin M while augmenting IgG secretion. These data suggest that the expanded anergic V gamma 9-V delta 2+ gamma delta cells can play an immunoregulatory role in the patient.