[The gamma delta T-cell receptors in sarcoidosis]

T-cells recognize specific antigen (s) through the T-cell antigen receptors (TCR). gamma delta T-cells compose a minor population of the peripheral blood lymphocytes (PBL). These lymphocytes play a central role in recognizing the mycobacterial antigens and granuloma formation in tuberculosis and leprosy. Significant increase of gamma delta T-cells in PBL is observed in a subgroup of sarcoidosis. The majority of gamma delta T-cells showed V gamma 9/V delta 2 recombination, which is common in normal blood. To evaluate the clonality of the increased gamma delta T-cells in PBL, several V gamma 9 and V delta 2 cDNA clones were established. Analysis of V-J junctional sequences of V gamma 9 clones revealed oligoclonal expansion in some cases. Most of V delta 2 clones showed unique sequences. Although no clonal expansion of gamma delta T-cells were observed, TCR-gamma chain might recognize limited numbers of putative antigens in sarcoidosis.