Expanded TCR Vβ subsets of CD8+ T-cells in late-onset myasthenia gravis: Novel parallels with thymoma patients

Little is known about pathogenesis - and especially about involvement of CD8(+) T-cells - in late-onset myasthenia gravis (LOMG). Remarkably, outstanding CD8(+) TCRV beta-subset expansions were found in 64% and 72% of recent onset LOMG or thymoma-associated MG (vs. 16% with early-onset MG (p<0.0002); 21% in older controls (p<0.001)). In LOMG, similar to 25% of the expanded cells initially showed a naive CD62L(+hi)/CD45RA(+) recent thymic emigrant (RTE)-like phenotype. These expansions associated significantly with IgG antibodies against cytomegalovirus (p<0.036), IL-12 and/or IFN-alpha 2 (p<0.03). The CD8(+) TCRV beta expansions were stable over 5 years, but RTE markers declined. (C) 2009 Elsevier B.V. All rights reserved.