Gamma delta T cell receptor subsets in the lung of patients with HIV-1 infection.

In this study the frequency of gamma delta+ cells and their subsets has been assessed in bronchoalveolar lavage (BAL) cell populations recovered from 51 patients at various clinical stages of HIV-1 infection. Thirteen out of the 51 HIV-1-infected patients showed an increase in the percentage of TCR delta 1+ BAL T cells (25.5%). BAL lymphocytes bearing pan-gamma delta antigens were also quantitatively increased in 10 patients (19.6%). A strict correlation was observed between the degree of CD8 alveolitis and the increase of gamma delta T cells. Phenotypic study of BAL gamma delta cells revealed that (a) V delta 2-related BB3+ cells accounted for the majority of lung gamma delta T cells; (b) these cells were CD45RO+ memory cells and expressed a series of adhesion molecules; and (c) 29% of BAL gamma delta T cells expressed CD8 surface molecules. We also compared the distribution of V delta 2 and V delta 1 subsets in paired samples of peripheral blood and BAL fluid. Patients who showed an increased number of BB3+ cells in the BAL fluid presented a reversal of the V delta 2 to V delta 1 cell ratio in the peripheral blood. By contrast, in the lung of normal subjects pulmonary BB3+ and A13+ cells were present in approximately the same proportions found in the peripheral blood. Taken together these data demonstrate that a redistribution of T cells expressing V delta 2 TCR takes place in the lung of a subset of patients with HIV-1 infection and CD8 alveolitis. In the pulmonary microenvironment these cells might play a role in the local immune response against HIV-1 and/or opportunistic infections.