CCR9 and CCR7 are over-expressed in CD4(-) CD8(-) thymocytes of myasthenia gravis patients.

Introduction: Chemokine CC motif receptors 9 and 7 (CCR9 and CCR7) play a major role in the migration of T-cell precursors to the thymus to initiate T thymopoiesis. However, their role in development of T-cells in myasthenia gravis (MG) patients has not been fully elucidated. Methods: Expression and distribution of CCR9+ and CCR7+ cells were detected by flow cytometry and immunofluorescence. Real-time polymerase chain reaction was used to check the adhesion molecules on CD4–CD8– double-negative (DN) thymocytes. Results: CCR9 and CCR7 expression by DN thymocytes increased in the MG thymus; the levels of CCR9, CCR7, interleukin-7R mRNA increased, and CXCR4 levels decreased compared with levels in the non-MG thymus. More CCR7 and CCR9 double-positive (DP) thymocytes were gathered near the subcapsular region in MG thymus. Conclusions: Enhanced expression of CCR9 and CCR7 may complicate the differentiation of DP thymocytes from the DN stage in MG thymus. Muscle Nerve, 2016 Muscle Nerve 55: 84–90, 2017