A COMMON TCR BETA-CHAIN EXPRESSED BY CD8(-MUCOSA T-CELLS IN ULCERATIVE-COLITIS() INTESTINAL)

The human intestine contains two populations of anatomically distinct T cells, intraepithelial lymphocytes and lamina propria lymphocytes (L PLs), both of which preferentially use the TCR-alpha beta. Recent stud ies of TCR alpha- and beta-chain usage by intestinal intraepithelial l ymphocytes, which are predominantly CD8(+) T cells, have demonstrated that these cells are oligoclonal in normal intestine. This report exam ined the TCR beta-chains expressed by purified CD4(+) and CD8(+) T cel ls from normal colonic lamina propria and from the intestinal mucosa o f patients with active ulcerative colitis (UC). The selective expansio n of CD8(+) T cell clones, and to a lesser extent CD4(+) T cell clones , was observed among both normal LPLs and mucosal T cells in UC. These expanded LPL clones from normal donors were all distinct, but the muc osal T cells isolated from five of nine patients with UC contained CD8 (+) T cells expressing related V beta 3-J beta 1.6 TCRs. These observa tions provide evidence for an Ag-specific mucosal T cell response in U C. Further studies will be required to identify this Ag and address wh ether the T cell response to it plays a primary role in initiating the disease or is secondary to the inflammatory response.