LIMITED T-CELL RECEPTOR-V GENE USAGE IN INCLUSION-BODY MYOSITIS

Inclusion body myositis (IBM) is a chronic, progressive inflammatory m yopathy. The inflammatory infiltrates are dominated by T cells, which frequently invade muscle fibres. The present study was performed to ch aracterize the usage of the variable (V) segment of the T-cell recepto r of muscle infiltrating cells in IBM. Using the reverse transcriptase polymerase chain reaction (RT-PCR) technique the authors analysed the expression of 22 V alpha and 24 V beta families in muscle tissue from six patients with IBM displaying intense inflammatory cell infiltrati on. The following V alpha/V beta families appeared in at least 50% of the patients: V alpha 1, 5, 7, 15, 16, 17, 20, 21, 22 and V beta 3, 5. 2, 8, 12, 14, 22. In all patients V alpha 7, 16 and V beta 8 were expr essed in muscle tissue. Furthermore, in two of the patients peripheral blood lymphocytes (PBL) were investigated in parallel. There was a re stricted usage of V alpha and V beta families in muscle in comparison to PBL, indicating a selective homing or local proliferation of T lymp hocytes in the inflammatory lesions in IBM.