OLIGOCLONAL EXPANSION OF MUSCLE INFILTRATING T-CELLS IN INCLUSION-BODY MYOSITIS

Inclusion body myositis (IBM) is the most common muscle disease affect ing individuals over 50 years of age. An important feature of IBM is i nvasion of muscle fibers by T cells. The muscle infiltrating T cells s how a restricted usage of variable (V) alpha/beta gene families. In th is study we have investigated the clonality of T cells using two of th e predominant VP families i.e. V beta 3 and V beta 8 in three patients with IBM. The study was performed by reverse transcription and polyme rase chain reaction (RT-PCR) analysis, followed by cloning and sequenc ing of the T cell receptor complementarity determining region 3. We fo und oligoclonal expansion of V beta 3 bearing muscle infiltrating T ce lls in two patients and of V beta 8 in one patient, supporting the con cept that antigen stimulated T cells are important in the pathogenesis of IBM. Results of HLA typing indicated a genetic predisposition for the disease by the presence of DR3, DR52 and DQB 10201/0202 in all th ree patients. (C) 1997 Elsevier Science B.V.