T-LYMPHOCYTES WITH GAMMA-DELTA+ V-DELTA-2+ ANTIGEN RECEPTORS ARE PRESENT IN INCREASED PROPORTIONS IN A FRACTION OF PATIENTS WITH TUBERCULOSIS OR WITH SARCOIDOSIS

T-lymphocytes with T-cell antigen receptor (TCR) comprising a gamma chain and a delta chain (gamma delta+ T cells) are believed to be involved in the immune reaction to mycobacterial antigens, and they have been found in increased proportions in sarcoid patients. We evaluated the proportions of gamma delta+ T-lymphocytes and of two major gamma delta+ subpopulations, the V delta 1+ and the V delta 2+ T-cell subsets, in 10 normal blood donors, in 15 patients with tuberculosis (TB), seven of whom had pleural effusion (PE), and in 12 patients with pulmonary sarcoidosis (PS), nine of whom underwent bronchoalveolar lavage (BAL). T-cell subsets were evaluated in peripheral blood (PBL) of all subjects and in PE from patients with TB and in BAL from patients with PS. Compared with normal blood donors, patients with TB had increased proportions of PBL CD3+ gamma delta+ T cells (6 +/- 1% versus 14 +/- 3% of CD3+ T cells, p < 0.05) because of the presence of four patients who had an increase (respectively, 18.3, 22.0, 24.2, and 35.4% of CD3+ T cells) of gamma epsilon+ T cells. In patients with TB and PE, gamma delta+ T cells were 7.9 +/- 2.7%, a value not different from that in the tubercular PBL and in normal PBL. Although patients with PS had proportions of PBL gamma delta+ T cells (9.2 +/- 3.4%) similar to those in normal PBL, two patients had increased (35 and 31%) PBL gamma delta+ T-lymphocytes. The proportions of gamma delta+ T cells in sarcoid lung recovered by BAL were similar to those in PBL from patients with PS (3.0 +/- 0.8% of CD3+ T cells, p > 0.05). Among gamma delta+ T-cell subsets, V delta 2+ T-lymphocytes were 73 +/- 9% of total gamma delta+ T cells in PBL of normal subjects, similar to PBL and PE of patients with TB and to PBL and BAL of patients with PS. However, in the patients with TB or PS with an expansion of PBL gamma delta+ T cells, V delta 2+ T cells were > 90% of gamma delta+ T cells, and they were increased also as absolute numbers of cells/mu l of PBL, whereas the proportions of V delta 1+ T cells were similar to normal values. The expansion of gamma delta+ T cells with identical variable regions in some patients with PS and TB may be due to similar immunopathogenetic processes and/or it may represent a type of immune reaction of a subgroup of patients.