Increased numbers of T lymphocytes with γδ-positive antigen receptors in a subgroup of individuals with pulmonary sarcoidosis

Abstract

Individuals with sarcoidosis were evaluated for preferential usage of T cells with the γδ-positive (+) type of T cell antigen receptor. Compared with normal subjects (n = 19), the group with sarcoidosis had increased numbers of CD3+ αβ-negative (-) T cells in the blood (normal, 58±12 cells/μl; sarcoid, 192±45 cells/μl, P < 0.05) and in the epithelial lining fluid of the lung (normal, 78±14 cells/μl; sarcoid, 240±60 cells/μl, P < 0.04) and a concomitant elevated number of blood and lung CD3+ γδ+ T cells, owing to a striking increase in the number of CD3+ γδ+ T cells in a subgroup (7 of 20) of sarcoid individuals. The elevated numbers of sarcoid blood γδ+ T lymphocytes were mostly TiγA+ and δTCS1-, a pattern also seen in normal individuals, consistent with the majority of γδ+ T cells expressing one γ-chain variable region, Vγ9. The observation of an increase in the total γδ+ T cell numbers in a sarcoid subgroup suggests that various specific stimuli may trigger the expansion of different T cell subpopulations within different groups of individuals with sarcoidosis.