Finally, in view of the level of IL-10 secreted by B10 in thymus tissues, CD19+B cells were purified by MACS, and after detection through real-time PCR and Western blot assay, the expression levels of CD19 and IL-10 in Tm+MG group were significantly higher than those in the Con and Tm groups, demonstrating that B10 was involved in thymoma progression and possibly involved in pathogenesis of thymoma with MG. This evidence concerns the gene CD19 and myasthenia gravis.