The Level Of IL-38 In Peripheral Blood Of Patients With Ankylosing Spondylitis And Its Correlation With Th17/treg Cell Balance

Objective:To investigate the level of interleukin（IL）-38 in peripheral blood of patients with ankylosing spondylitis（AS）,and its correlation with helper T cells 17（Th17）,regulatory T cells（Treg）and their secreted cytokines.Methods:A total of 44 patients with AS who visited tthe Affiliated Hospital of Guizhou Medical University from October 2020 to February 2022 were selected as the observation group,and 30 healthy subjects during the same period were selected as the healthy control（HC）group.Clinical data such as gender,age,disease course and Bath AS disease activity index（BASDAI）were collected from all patients,and AS patients were further divided into active group and stable group according to BASDAI score.Enzyme-linked immunosorbent assay was used to detect the levels of IL-38,IL-17 and IL-10 in peripheral blood of all subjects,and flow cytometry was used to detecttheproportionofCD3⁺CD8^-IL-17⁺Th17cellsand CD3⁺CD4⁺CD25^hiCD127^loTreg cells.Clinical laboratory indicators such as serum C-reactive protein（CRP）,IL-6,immunoglobulin（Ig）G,M,A,complement C3,C4levels and erythrocyte sedimentation rate（ESR）were recorded from all patients.Compare the differences of each index among groups,and analyze the correlation between each index.Results:1.The comparison between groups showed:（1）The levels of IL-38,IL-10 and the percentage of Treg cells in peripheral blood in the AS group were significantly lower than those in the HC group,while the levels of IL-17 and the percentage of Th17 cells in the AS group were significantly higher than those in the HC group（P<0.05）;（2）The level of IL-38 and the percentage of Treg cells in the peripheral blood of patients with AS active group were significantly lower than those in the stable group,and the level of IL-17 was significantly higher than that in the stable group（P<0.05）;（3）ESR and serum levels of CRP,IL-6,Ig G,and C3 in the AS active group were significantly higher than those in the stable group（P<0.05）.2.Correlation analysis showed:（1）The level of IL-17 in peripheral blood of patients with AS was positively correlated with the percentage of Th17 cells（r was 0.360,P<0.05）,the level of IL-10 was positively correlated with the percentage of Treg cells（r=0.338,P<0.05）;（2）The level of IL-38and the percentage of Treg cells in the peripheral blood of AS patients were negatively correlated with the BASDAI score（r were-0.365 and-0.313,P<0.05）,and the level of IL-17 was positively correlated with the BASDAI score（r was0.425,P<0.05）;（3）The level of IL-38 in peripheral blood of AS patients was significantly negatively correlated with the level of IL17,the percentage of Th17 cells and the ratio of Th17/Treg cells（r were-0.381,-0.376 and-0.309,P<0.05）,and was no significant correlation with the level of IL-10 and the percentage of Treg cells（P>0.05）;（4）The level of IL-38 was negatively correlated with ESR and serum levels of complement C3（r were 0.396 and-0.323,P<0.05）,and the level of IL-17 was positively correlated with the serum levels of serum CRP,IL-6 and Ig G（r were 0.329,0.346 and 0.446,P<0.05）,the percentage of Th17 cells was positively correlated with serum IL-6 level（r=0.320,P<0.05）.Conclusions:1.Abnormal levels of IL-38 in peripheral blood and imbalance of Th17/Treg cell ratio may be involved in the occurrence of AS,mainly manifested as decreased levels of IL-38,Treg cells and related cytokines IL-10,increased levels of Th17 cells and related cytokines IL-17.2.The levels of IL-38 and Treg cells in peripheral blood were negatively correlated with BASDAI,and the levels of IL-17 were positively correlated with BASDAI,which may be used as indicators to help assess the disease activity of AS.3.The decreased level of IL-38 in peripheral blood of patients with was closely related to the increased levels of Th17 cells and related cytokines IL-17 and the imbalance of Th17/Treg cell ratio.