Decreased LAG3 expression on T effector cells and regulatory T cells in SAA.

To investigate the expression of lymphocyte activation gene 3(LAG3) on CD8+T effector cells (Teffs), CD4+ Teffs and regulatory T cells (Tregs) in patients with severe aplastic anemia (SAA). We detected the expression of LAG3 on CD8+ Teffs, CD4+ Teffs and Tregs in SAA patients and healthy controls (HC) by flow cytometry, and analyzed its correlation with the immune status and severity of the disease. ELISA was used to detect soluble LAG3(sLAG3). The expression of LAG3 on CD8+ Teffs, CD4+ Teffs and Tregs in untreated SAA patients were significantly lower than those in HC group (P < 0.05). After IST, the LAG3 expression of target cells increased to a level even higher than that in HC group (P < 0.05). LAG3 on T cell subsets was closely related to immune status and severity of the disease. The concentration of sLAG3 in these groups showed similar trends. LAG3 was not a prognostic factor of response. The decreased expression of LAG3 on CD8+ Teffs, CD4+ Teffs and Tregs may be involved in the pathogenesis of SAA. LAG3 intervention may have therapeutic potential in treating SAA.