T cell receptor beta-chain repertoire in inclusion body myositis

Inclusion body myositis (IBM) is the most common muscle disease affecting i ndividuals over 50 years of age. The inflammatory reaction is characterized by cell infiltrates predominated by CD8(+) cytotoxic T cells. To analyze c lonality of muscle infiltrating lymphocytes, we studied the complementarity determining region 3 (CDR3) length distribution of the T cell receptor (TC R). Muscle infiltrating lymphocytes were studied in three IBM patients and compared with peripheral blood lymphocytes (PBL) in two of these patients. The study was performed by reverse transcription polymerase chain reaction (RT-PCR) of RNA extracted from muscle tissue and PBL followed by analysis o f fragment length distribution of the CDR3 region in each of 24 different V beta families. There was a restricted usage of TCR V beta gene families in muscle infiltrating T cells in all three patients. Some of the TCR V beta gene families showed oligoclonal expansions but polyclonal patterns were do minating. The CDR3 distribution of most V beta families differed between mu scle infiltrating lymphocytes and PBL indicating that T cells have expanded locally or selectively accumulated in muscle. (C) 1998 Elsevier Science B. V. All rights reserved.