Antigen-presenting-cell-associated programs in thymoma-associated myasthenia gravis: public transcriptomic reanalysis and archived cell-model observations

Thymoma-associated myasthenia gravis (TAMG) involves a complex thymic immune environment, but tissue antigen-presenting-cell (APC) programs do not by themselves establish a soluble-signal mechanism. We re-analyzed public single-cell and spatial transcriptomic data and examined archived records from one Thy0517 AB-thymoma line and a THP-1-derived dendritic cell-like preparation. Donor-resolved single-cell summaries showed antigen-presentation-associated expression across several APC compartments, whereas IL21 transcripts were sparse and most evident in Tfh-like CD4+T cells. IL21R/IL2RG-containing modules were exploratory tissue annotations, not validation of IL-21R signaling in the culture model. In two TAMG sections, unadjusted APC antigen-presentation and maturation/costimulation correlations attenuated after covariate adjustment; associations with migratory DC, Tfh/IL-21 and GC-like B-cell programs differed between sections. A single normal adult thymus sample provided a descriptive, unmatched reference. The retained morphology and CD11c panels document induction of the THP-1-derived preparation, not an effect of subsequent Thy0517 conditioning. A separate cytokine worksheet contained IL-21- and IL-6-labeled entries, but concentration units and calibration could not be verified. Unverified quantitative marker endpoints were removed. Representative CD4+T-cell plots document the assay format only and do not establish frequency or ratio changes. These observations provide descriptive human tissue context and archived cell-model documentation; they do not establish a Thy0517-conditioning effect or an IL-21-specific TAMG mechanism.