The Preliminary Study Of Co-Stimulatory Molecules ICOS And OX40 In Neuromyelitis Optica

Background and objectiveNeuromyelitis Optica(NMO)is a rare demyelinating inflammatory central nervous system disease,the global incidence of which is between 0.34 and 10/100,000 person-years and commonly found in female aged 20-40 years old.Recurrent attacks of disease can lead to the accumulation of neurological deficits,causing a huge physical and economic burden.It is believed that NMO is a humoral immune-mediated autoimmune disease with extensive involvement of cellular immunity.Excessive activation of T cells plays an important role in the pathogenesis of NMO,which cannot be achieved without the involvement of costimulatory molecules.Inducible costimulatory molecule(ICOS)is a member of the CD28-B7 superfamily.ICOS interacts with the ICOS ligand can promote CD4+ T cell proliferation,differentiation to T helper cell phenotypes and regulate T cell receptor(TCR)signaling to cytokines production.OX40 is a type 1 transmembrane protein belonging to tumor necrosis factor receptor superfamily.OX40-OX40L interactions can enhance the proliferation of CD4+T cells in response to antigen and differentiation of Th cell subpopulations,promote the production of effector memory T cells,maintain the cellular activation state and play an important role in maintaining the late stage of the immune response.ICOS/ICOSL and OX40/OX40L have been found to act in a cooperative manner to maximize and prolong T follicular helper(Tfh)differentiation to regulate immune responses.ICOS/ICOSL and OX40/OX40L are classical positive co-stimulatory axes.Several previous studies have shown that they are involved in the pathogenesis of various autoimmune diseases such as Systemic Lupus Erythematosus(SLE),Rheumatoid Arthritis,and Myasthenia Gravis,but there are a handful of studies in NMO.In this study,we analyze the expression of co-stimulatory molecules ICOS,OX40 and their corresponding ICOS ligand and OX40 ligand on peripheral blood mononuclear cell(PBMC)and their clinical implications to study the pathogenesis of NMO and provide reference for the treatment of NMO.MethodsSixty patients with optic neuromyelitis optica who visited the Department of Neurology of the First Affiliated Hospital of Zhengzhou University from January 2021 to January 2022 were recruited,including 28 patients in the acute phase and 32 patients in remission phase.All patients were interviewed in detail and general demographic data and clinical data were recorded by two neuroimmunologists in our hospital.Thirty healthy volunteers during the same period were selected as the healthy control group.Flow cytometry was applied to analyze the expression of co-stimulatory molecules ICOS,OX40 and their corresponding ICOS ligand and OX40 ligand in peripheral blood of each group.Quantitative data were described using the mean ± standard deviation for normal distribution and median(P25,P75)for non-normal distribution.Categorical data were compared using chi-square test three groups of normally distributed quantitative data were compared between groups using LSD-t test or Bonferroni method,non-normally distributed quantitative data were compared among groups using non-parametric test,and correlation analysis was performed using Pearson or Spearman correlation coefficients.P<0.05 was considered statistically significant.Results1.The expression level of ICOS on CD4+T cells was significantly higher in the acute phase of NMO than in the remission phase and control group,with statistically significant differences(P<0.001,P=0.001).The expression level of ICOSL on CD14+ monocytes was significantly higher in the acute phase than in the remission phase and control group(P<0.001,P<0.001),and in the acute phase ICOSL expression levels on CD19+B cells were significantly higher than in the remission and control groups(P=0.002,P<0.001).2.The expression level of OX40 on CD4+ T cells was significantly higher in the acute phase of NMO than in the remission patients and control group,and the difference was statistically significant(P<0.001,P=0.003),the expression level of CD14+ monocytes OX40L was significantly higher in the acute phase than in the remission and control group(P<0.001,P<0.001),and OX40L expression levels of CD19+ B cells were significantly higher in both acute and remission groups than in healthy control group(P<0.001,P=0.001).3.The proportion of Tfh cells was significantly higher in the acute group than in the remission group and healthy control group.The difference was statistically significant(P<0.001,P<0.001),and the expression level of OX40 on Tfh was significantly higher in both the NMO acute and remission groups than in the healthy control group(P<0.001,P=0.003).4.In the acute group,there was a non-significant correlation between ICOS and OX40 expression levels on CD4+ T cells(r=-0.2375,P=0.225),a positive correlation between ICOS expression levels on CD4+T cell and EDSS scores,between Tfh cell ratio and EDSS scores(r=0.508,P=0.006;r=0.465,P=0.013),OX40 expression levels of Tfh cells and CD4+T cells were not significantly correlated with EDSS scores(r=0.508,P=0.006;r=0.211,P=0.281).Conclusion1.Compared with healthy controls,the costimulatory molecules ICOS/ICOSL and OX40/OX40L were significantly increased in patients in acute phase,suggesting that ICOS/ICOSL and OX40/OX40L may be involved in the pathogenesis of NMO2.The proportion of Tfh in the acute phase of NMO patients was significantly higher than in remission phase of patients and healthy controls,which was positively correlated with the EDSS scores and is expected to be a biological marker reflecting the disease activity.