Autoantigen-specific T cells are present in the blood of patients with thymoma-associated MG.

Scatter-bar plots showing the proliferative responses of peripheral T cells (PBL) and intratumorous T cells (Tm) harvested from patients with thymoma-associated MG. (A) Recombinant fragments of the acetylcholine receptor α subunit (αAChR, 301-398) and of the neurofilament protein (NF-M, 459-737) are used as stimulatory antigens, whereas tetanus toxoid (TT) is used as the recall antigen in panel B. Proliferative responses are given in terms of a stimulation index (SI) (see “Materials and methods”). Each triangle represents the SI of either PBL or Tm from an individual patient; bars indicate the mean SI among either PBL or Tm for each particular antigen. Autoantigen-specific T-cell responses in PBL and Tm are similar on stimulation with either αAChR (P = .3; n = 19) or NF-M (P = .4; n = 16); TT-specific responses, however, are significantly increased among PBL compared with Tm (P = .001; n = 14).