Late-onset myasthenia gravis - CTLA4(low) genotype association and low-for-age thymic output of naïve T cells.

Abstract Late-onset myasthenia gravis (LOMG) has become the largest MG subgroup, but the underlying pathogenetic mechanisms remain mysterious. Among the few etiological clues are the almost unique serologic parallels between LOMG and thymoma-associated MG (TAMG), notably autoantibodies against acetylcholine receptors, titin, ryanodine receptor, type I interferons or IL-12. This is why we checked LOMG patients for two further peculiar features of TAMG – its associations with the CTLA4 high/gain-of-function  +49A/A genotype and with increased thymic export of naive T cells into the blood, possibly after defective negative selection in AIRE-deficient thymomas. We analyzed genomic DNA from 116 …