Expansion of selected V delta 1+ gamma delta T cells in systemic sclerosis patients.

We have previously shown an increased percentage of gamma delta T cells expressing the TCR V delta 1 gene segment in the peripheral blood and bronchoalveolar lavage fluid of patients with systemic sclerosis (SSC). To estimate clonality of these V delta 1+ T cells, the diversity of V delta 1 junctional regions (V-D-J) was examined using a reverse transcriptase-PCR to amplify TCR delta-chain transcripts isolated from PBMC, lung, esophagus, stomach, or skin of patients and controls. Limited diversity of V delta 1-J delta junctional regions in SSC patients was demonstrated by comparing the size distribution of PCR-amplified junctional region cDNA from patients with that of controls. Sequence analyses confirmed that V delta 1-J delta junctional regions from the blood of SSc patients had less diversity than those from controls, in that a significantly higher proportion of sequences were repeated in patients (54.4 vs 19.4% in controls). Evidence for selection of the V delta 1+ T cells in the tissues of SSC patients came from the findings that the same V delta 1-J delta junctional sequences persisted in an individual patient over time and that identical junctional sequences were isolated from multiple sites. Analysis of deduced amino acid sequences revealed two clusters of similarities among the junctional regions from patients. These data suggest that expansion of V delta 1+ gamma delta T cells may be Ag driven in SSC patients.