AUTOAGGRESSIVE MYOCYTOTOXIC LYMPHOCYTES-T EXPRESSING AN UNUSUAL GAMMA-DELTA T-CELL RECEPTOR

Polymyositis mediated by gamma/delta T cells is a unique disease in which autoaggressive T lymphocytes surround, invade, and destroy muscle fibers. Histochemically, the vast majority of muscle-infiltrating T cells in a patient with polymyositis were reactive with a pan-gamma/delta T cell receptor (TCR)-specific monoclonal antibody (TCR-delta1+), but unlike >90% of peripheral blood gamma/beta T cells, these lymphocytes did not react with Vdelta1- or Vgamma9-specific antibodies (A13- and TigammaA-, respectively). Differential reactivity with two different Vdelta2-specific monoclonal antibodies (BB3-/T(i)V-delta2+) indicated that the infiltrating T cells express a Vdelta2-containing TCR with unusual additional structural features. Using conventional and anchored polymerase chain reaction for the analysis of TCR transcripts, we found a striking predominance of one unusual Vdelta2-Jdelta3 recombination and one Vgamma3-Jgamma1 recombination. Both the unusual phenotype (TCR-delta1+/A13-/TigammaA-/BB3-/T(i)V-delta2+) and the dominance of distinct TCR transcripts are compatible with the assumption that one T cell clone, which expresses a Vgamma3-Jgamma1-Cgamma1/Vdelta2-Jdelta3-Cdelta disulfide-linked TCR, dominates among the infiltrating T cells of the polymyositis muscle specimen analyzed.