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+ TCRVβ-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, ~ 25% of the expanded cells initially showed a naïve 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-α2 (p < 0.03). The CD8+ TCRVβ expansions were stable over 5 years, but RTE markers declined.