Unbalanced expression of membrane-bound and soluble inducible costimulator and programmed cell death 1 in patients with myasthenia gravis.

This study aimed to investigate the possible functions and mechanisms of positive and negative costimulatory molecules in the pathological process of myasthenia gravis (MG). The expression levels of membrane-bound inducible costimulator (ICOS) and programmed cell death 1 (PD-1) in peripheral blood T cells, their corresponding ligands ICOSL and PDL-1 on B cells, and their soluble forms (sICOS, sPD-1, sICOSL, and sPDL-1) in plasma were detected in patients with untreated-stage MG (USMG) and remission-stage MG (RSMG). The results showed that the expression levels of membrane-bound ICOS and PD-1 in the peripheral blood T cells of the USMG group and their corresponding ligands ICOSL and PD-L1 on B cells were significantly increased compared to those in the RSMG group and healthy controls (HCs). The levels of sICOSL and sPD-1 were significantly upregulated in USMG patients compared to those in the RSMG and HC groups, while the levels of sICOS and sPD-L1 were not different. The expression of PD-L1 on CD19+ B cells was positively correlated with the concentrations of AchR Ab in the USMG group. The expression of ICOS and PD-1 in CD4+ T cells and the expression of ICOSL and PD-L1 on CD19+ B cells were positively correlated with the quantitative myasthenia gravis (QMG) scores in the USMG group. Also, in the USMG group, the plasma levels of sICOSL and sPD-1 were positively correlated with the QMG scores. In addition, the percentage of peripheral blood follicular helper T (Tfh) cells in the USMG group was positively correlated with ICOS and PD-1 expression on CD4+ T cells and ICOSL and PD-L1 expression on CD19+ B cells. There were positive correlations between sICOSL and sPD-1 levels and the percentage of peripheral blood Tfh cells and plasma interleukin-21 (IL-21) levels in the USMG group. The results suggest that the positive ICOS/ICOSL and negative PD-1/PD-L1 costimulatory molecule pairs participate in the pathological process of MG. Abnormal sICOSL and sPD-1 expression might interfere with the normal signal transduction of ICOS and PD-1 on Tfh cells, causing excessive activation of Tfh cells and promotion of disease progression. sICOSL and sPD-1 have potential value in monitoring MG disease states.

Depletion of B7-H4 from C3H10 T1/2 Mesenchymal Stem Cells Attenuates their Immunomodulatory Therapy in Experimental Autoimmune Encephalomyelitis Mice.

Considering the controversial issue of whether MSC therapy is effective in the treatment of multiple sclerosis, it is important to seek more powerful data to clarify the effect of MSCs. B7-H4 is a unique costimulatory molecule that belongs to the B7 ligand family and is broadly expressed in both lymphoid and non-lymphoid tissues. Previous studies have shown that B7-H4 is involved in regulating the progression of autoimmune diseases. However, its role in MSCs and stem cell transplantation remains unclear. In this study, we focus on C3H10 T1/2 cells, which are mouse-derived mesenchymal stem cells. And we investigated the role of B7-H4 in C3H10 T1/2 cells and explored its underlying mechanisms. As a result, downregulation of B7-H4 induced apoptosis and impaired the cell proliferation of C3H10 T1/2 cells. Further results showed that cells were arrested in the G0/G1 phase after knockdown of B7-H4. Furthermore, an EAE model was induced in female C57BL/6 mice by injecting MOG 35-55, and we investigated the effect of C3H10 T1/2 cell transplantation for the EAE model after downregulation of B7-H4 in vivo. We found that C3H10 cells can migrate to the area of spinal cord lesions, and depletion of B7-H4 attenuated the immunoregulatory effect of C3H10 T1/2 cells in vivo. Together, our findings suggest that B7-H4 is important for C3H10 cells to exert neurorestoration and therefore may be a potential molecular target for stem cell transplant strategies.