Long-term persistence of clonally expanded T cells in patients with polymyositis

Polymyositis is a CD8+ T‐cell–mediated disease. T‐cell clonal expansions are observed at disease onset, but little is known about their persistence over time. Qualitative and quantitative spectratyping demonstrated that PM relapse features dramatically perturbed blood T‐cell repertoires but is not associated with the emergence of new T‐cell clones. It is striking that patients in remission also maintained all their T‐cell repertoire abnormalities. The clonally expanded T‐cells displayed a memory phenotype, expressed intracellular perforin, and dramatically responded to IL‐2, showing a potential to be reactivated upon appropriate conditions. These results indicate that persistent T‐cell clonal expansion is an important feature of polymyositis. Ann Neurol 2004