Restricted Vα2.3 gene usage by CD4+ T lymphocytes in bronchoalveolar lavage fluid from sarcoidosis patients correlates with HLA‐DR3

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Abstract
The α/β T cell receptor (TcR) V gene usage of bronchoalveolar lavage (BAL) lymphocytes and peripheral blood lymphocytes (PBL) from 11 sarcoidosis patients and 4 healthy controls was investigated, using eight α/β TcR V gene product‐specific monoclonal antibodies (mAb). Twenty‐seven percent (3/11) of the sarcoidosis patients had a highly significant increase in Vα2.3+CD4+ T lymphocytes in the bronchoalveolar space, while displaying normal frequencies of these T cells in peripheral blood. The reactivities with the remaining seven TcR mAb were normal. In the control group, no compartmentalization of any T cells was seen. Four of the patients expressed the HLA‐DR3 (w17), DQw2 haplotype. Interestingly, the three patients with distinct signs of compartmentalized Vα2.3+CD4+ T cells all expressed this HLA haplotype. Additionally, a fourth patient with pronounced, although less significant, accumulation of Vα2.3+CD4+ T cells in the lung, was also HLA‐DR3(w17), DQw2+. Expression of Vα2.3+CD4+ T cells in BAL of these patients correlated with clinical disease, as revealed on re‐analyzing the four patients after 6 months or longer. Predominant TcR Vα2.3 gene usage in compartmentalized CD4+ BAL T lymphocytes, linked to HLA‐DR3(w17), DQw2 haplotype, may thus indicate presence of a specific antigen localized to the lungs of sarcoidosis patients.