γδ T Cell Receptor Subsets in the Lung of Patients with HIV-1 Infection

In this study the frequency of γδ+ 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 TCRδ1+ BAL T cells (25.5%). BAL lymphocytes bearing pan-γδ 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 γδ T cells. Phenotypic study of BAL γδ cells revealed that (a) Vδ2-related BB3+ cells accounted for the majority of lung γδ T cells; (b) these cells were CD45RO+ memory cells and expressed a series of adhesion molecules; and (c) 29% of BAL γδ T cells expressed CD8 surface molecules. We also compared the distribution of Vδ2 and Vδ1 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 Vδ2 to Vδ1 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 Vδ2 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.