Altered Serum Cytokine Expression Profile In Idiopathic Inflammatory Myopathies And Its Clinical Significance

Objective:Idiopathic inflammatory myopathies(IIMs)are a set of infrequent autoimmune diseases characterized by affecting skeletal muscle and other organs including the skin and lungs.IIMs are mainly divided into dermatomyositis(DM),polymyositis(PM),immune-mediated necrotizing myositis(IMNM),inclusion body myositis(IBM),amyopathic dermatomyositis(ADM)and juvenile dermatomyositis(JDM).The pathogenesis of IIMs remains unknown,which may be related to genetics,environmental infection and immune factors.cytokines,as small molecule proteins,can regulate immunity,and play vital roles in the immune mechanism the and disease activities of IIMs.In recent years,a variety of myositis specific antibodies(MSAs)have been discovered,including anti-melanoma differentiation gene 5(MDA5),anti-transcription mediator 1-γ(TIF1γ),and anti-aminoacyl transfer RNA synthase(ARS,including Jo-1,EJ,OJ,PL7,PL12,KS),anti-signal recognition particle(SRP),anti-nuclear matrix protein 2(NXP2)and anti-nuclear small body weight structure deacetylase complex(MI-2),etc.Different MSAs group act different clinical phenomena.As yet,most studies mainly have focused on the changes of cytokines in DM and PM,there are few studies on cytokines in patients with different MSAs.Here,we studied the expression level of serum cytokine profile and its clinical significance in patients with untreated IIMs and different MSAs groups.Methods:1.The Human 48-Plex Luminex assay for cytokines was performed to detect 48 serum cytokines in IIMs patients,including 93 untreated and39 follow-up samples,and 32 healthy controls(HC).The changes of differentially expressed cytokines were analyzed before and after treatment.The correlation between differentially expressed cytokines and clinical indicators was compared.2.According to MSAs,IIMs patients were divided into anti-ARS(Jo-1,OJ,EJ,PL7,PL12)positive,anti-MDA5 positive and anti-TIF1γpositive antibodies,and the expression patterns of serum cytokines among the three groups were analyzed.3.The receptors of differentially expressed cytokines were matched by the ligand-receptor database(R-packet celltalker).The expression of cytokine receptors was explored using bioinformatics analysis for publicly available RNAseq or microarray datasets(muscle,blood,and skin).4.The expression of selected receptors in muscle tissue of IIMs patients was further verified by RT-q PCR,western blot and immunofluorescence.5.The expression of selected receptors in T lymphocytes of IIMs patients’peripheral blood was detected by flow cytometry.Results:1.The serum levels of Eotaxin,IL7,IL18,IP10,MCP1,MCSF,MIG and SCGFβwere elevated in the 93 untreated patients.Except for Eotaxin and IL7,all other cytokines were decreased after treatment.And except for IL7,the levels of other 7 cytokines were positively correlated with clinical indices such as LDH,ESR,CRP,ALT,Ig A,AST and Ig G while negatively correlated with albumin and MMT8.2.Compared with healthy controls,IP10 and MIG levels were increased in anti-TIF1γpositive patients;the expression levels of IL18,IP10,MIG and MSCF increased in anti-ARS positive patients;the expression levels of CTACK,Eotaxin,IL1Rα,IL7,IL18,MCP1,MCP3,MCSF,IP10,MIG and SCGFβwere up-regulated in anti-MDA5 positive patients.3.20 receptors of 8 differentially expressed cytokines(Eotaxin,IL7,IL18,IP10,MCP1,MCSF,MIG and SCGFβ)were identified based on the results of the ligand-receptor database.The expression of IL18R1 and CCR1 was found up-regulated in blood,muscle and skin tissues of IIMs patients from public datasets.4.The expression level of IL18R1 was significantly increased in the muscle tissue of DM patients.Immunofluorescence results showed that IL18R1 mainly distributed on inflammatory cells in the area of muscle necrosis.5.Compared with HC,the ratio of IL18R1~+CD4~+cells was increased while that of IL18R1~+CD8~+cells was decreased in peripheral blood of anti-MDA5 positive patients.Conclusion:1.Compared with healthy control group,serum cytokine profile in IIMs patients was significantly changed,and serum cytokine expression was different in anti-ARS positive,anti-MDA5 positive and anti-TIF1γpositive groups.2.Differentially expressed cytokines(Eotaxin,IL7,IL18,IP10,MCP1,MCSF,MIG and SCGFβ)were correlated with some clinical indicators.3.A total of 15 cytokine receptors were differentially expressed in blood,muscle or skin tissues of IIMs patients,and the expression levels of IL18R1 and CCR1 were significantly increased in three of them.4.The expression of IL18R1 was different in muscle tissue and peripheral blood cells of IIMs patients,suggesting that it may play an important role in IIMs.