Interleukin-21 triggers effector cell responses in the gut

In the gut of patients with Crohn's disease and patients with ulcerative colitis,the major forms of inflammatory bowel diseases(IBD) in humans,the tissue-damaging immune response is mediated by an active cross-talk between immune and non-immune cells.Accumulating evidence indicates also that cytokines produced by these cells play a major role in initiating and shaping this pathologic process.One such cytokine seems to be interleukin(IL)-21,a member of the common γ-chainreceptor family.IL-21 is produced in excess in the in-flamed intestine of patients with IBD mostly by activated CD4+ T helper cells co-expressing interferon-γ and follicular T helper cells.Moreover,both in vitro and in vivo studies indicate that excessive IL-21 production leads to the activation of multiple signaling pathways that expand and sustain the ongoing mucosal inflammation.In this article,we review the available data supporting the pathogenic role of IL-21 in IBD.

Involvement of interleukin-15 and interleukin-21, two γ-chain-related cytokines, in celiac disease

Celiac disease (CD), an enteropathy caused by dietary gluten in genetically susceptible individuals, is histologically characterized by villous atrophy, crypt cell hyperplasia, and increased number of intra-epithelial lymphocytes. The nature of CD pathogenesis remains unclear, but recent evidence indicates that both innate and adaptive immune responses are necessary for the phenotypic expression and pathologic changes characteristic of CD. Extensive studies of molecules produced by immune cells in the gut of CD patients have led to identification of two cytokines, namely interleukin (IL)-15 and IL-21, which are thought to play a major role in orchestrating the mucosal inflammatory response in CD. Here we review the current knowledge of the expression and function of IL-15 and IL-21 in CD.

Association between interleukin-21 gene rs907715 polymorphism and gastric precancerous lesions in a Chinese population

BACKGROUND The single nucleotide polymorphisms of interleukin-21(IL-21)gene were confirmed to be related to various diseases,but no studies have examined the possible role of IL-21 single nucleotide polymorphisms(SNPs)(rs907715,rs2221903,and rs12508721)in gastric precancerous lesions.AIM To explore the associations between SNPs of IL-21 gene(rs907715,rs2221903,and rs12508721)and gastric precancerous lesions in a Chinese population.METHODS Three SNPs of IL-21 were genotyped using polymerase chain reaction–ligase detection reaction in 588 cases and 290 healthy controls from May 2013 to December 2016 in northwestern China.Gastric precancerous lesions were confirmed by endoscopic examination and categorized as non-atrophic gastritis,atrophic gastritis,and intestinal metaplasia.Descriptive statistic and logistic regression were used for data analyses.RESULTS IL-21 rs907715 genotype CC and C frequencies were higher in in patients with gastric precancerous lesions than in the controls(OR=1.59,95%CI:1.06-2.38,P=0.013;OR=1.28,95%CI:1.01-2.22,P=0.044,respectively)after adjusting for confounding factors.For SNP rs907715 in intestinal metaplasia patients,significant differences between cases and controls were observed in the frequencies of genotype CC and C(OR=1.92,95%CI:1.24-2.98,P=0.004;OR=1.53,95%CI:1.04-2.24,P=0.028,respectively);for non-atrophic gastritis and atrophic gastritis patients,the CC and C genotypes showed no significant association with risk in all models.No association between either rs2221903 or rs12508721 and gastric precancerous lesions was found in the present study.In the haplotype analysis,the TC haplotype(rs907715 and rs12508721)and TT haplotype(rs2221903 and rs907715)were more frequent in the case group than control group(P<0.05).CONCLUSION Our findings indicate that SNP rs907715 of IL-21 gene is associated with gastric precancerous lesions.The TC haplotype(rs907715 and rs12508721)and TT haplotype(rs2221903 and rs907715)increased the risk of gastric precancerous lesions.If confirmed,these findings will shed light on the etiology of precancerous lesions.

mIL-21基因转染的Sp2/0瘤苗细胞的抗肿瘤机制探讨

目的:探讨小鼠IL-21瘤苗-Sp2/0-mIL-21抗肿瘤效应的机制。方法:用流式细胞术检测Sp2/0-mIL-2瘤苗细胞表面MHC-Ⅰ类分子及CD80分子的表达。以瘤苗细胞接种BALB/c小鼠,以CFSE,7-AAD标记,用流式细胞术检测NK细胞、CTL的细胞毒活性。观察肿瘤组织中淋巴细胞的浸润。用RT-PCR检测肿瘤组织中CXC家族趋化因子I-TAC的表达。结果:与对照组相比,瘤苗细胞膜表面MHC-Ⅰ类分子的表达明显上调。瘤苗接种组小鼠NK细胞、CTL的细胞毒活性明显增强。病理分析发现,肿瘤组织中有较多的淋巴细胞浸润并检测到干扰素诱导的T细胞α趋化因子(I-TAC)的表达上调。结论:肿瘤细胞瘤苗Sp2/0-mIL21可增强小鼠的细胞免疫作用,其抗肿瘤机制可能与T细胞的增殖、活化,促进NK细胞的分化成熟,淋巴细胞向肿瘤组织浸润,以及增强NK细胞和CTL的细胞毒活性有关。

小鼠白细胞介素21瘤苗的构建及其抗肿瘤效应研究

目的:建立稳定表达小鼠白细胞介素21(mIL-21)的肿瘤细胞瘤苗,观察其在小鼠体内是否能够诱导有效的抗肿瘤免疫反应及免疫记忆效应。方法:将已鉴定的重组质粒pcDNA3.1/mIL-21用脂质体法转染Sp2/0细胞制备瘤苗,RT-PCR法鉴定瘤苗中mIL-21的表达。通过流式细胞仪检测细胞周期来反映瘤苗体外增殖活性,再将其接种BALB/c小鼠,监测肿瘤生长情况,观察mIL-21瘤苗诱导的抗肿瘤效应;用ELISA法检测血清IFN-γ和IL-4含量。结果:得到稳定表达mIL-21的瘤苗Sp2/0-mIL-21。与对照组相比,体外增殖活性无差异。皮下接种BALB/c小鼠后,肿瘤生长缓慢,部分小鼠无瘤体生长并长期存活;用野生株Sp2/0瘤细胞再次攻击未长肿瘤的实验小鼠,4周后亦未见肿瘤生长。接种瘤苗小鼠血清中IFN-γ水平明显上升,IL-4无明显增高。结论:成功构建了mIL-21瘤苗Sp2/0-mIL-21,其能诱导有效的抗肿瘤免疫反应及免疫记忆效应。

酒精性肝病患者血浆白细胞介素-21水平及重组IL-21对LX-2肝星状细胞增殖和活化的影响

目的：分析酒精性肝病患者血浆白细胞介素-21（IL-21）水平及重组IL-21体外对LX-2肝星状细胞增殖和活化的影响。方法采用ELISA法检测17例酒精性肝炎、51例酒精性肝硬化患者和20例健康人血浆IL-21水平；体外培养LX-2肝星状细胞，以IL-21（1ng/ml或10ng/ml）处理24 h或48 h，检测LX-2细胞增殖及α-平滑肌肌动蛋白表达。结果与健康对照人群比，酒精性肝炎和酒精性肝硬化患者血浆IL-21水平均显著升高（P＆lt;0.05），但酒精性肝炎和肝硬化患者之间无显著性差异，不同Child分级的肝硬化患者之间也无显著性差异；在IL-21作用24～48 h后，LX-2细胞增殖水平与对照组比无显著性差异，但α-平滑肌肌动蛋白表达均较对照组显著升高。结论血浆IL-21可能通过促进肝星状细胞活化参与了酒精性肝病患者肝纤维化的发生和发展。

小鼠白细胞介素-21基因重组腺病毒可控制慢性HBV感染

目的观察小鼠白细胞介素-21基因重组腺病毒(Ad-GFP-mIL-21)在慢性HBV感染小鼠中的表达以及其对病毒清除和HBV特异性抗体产生的作用。方法 Ad-GFP-mIL-21体外感染HepG2.2.15细胞后分别采用ELISA和Western blot检测上清和细胞mIL-21的表达;尾静脉注射rAAV8-1.3HBV至野生型C57BL/6小鼠体内建立HBV持续表达模型,12周后实验组尾静脉注射Ad-GFP-mIL-21,以注射空载GFP重组腺病毒或PBS为对照组,荧光显微镜观察Ad-GFP-mIL-21在小鼠体内各器官的表达情况,ELISA检测各组小鼠血清HBsAg、HBsAb、HBcAb和mIL-21的水平。结果 Ad-GFP-mIL21可在体外感染HepG2.2.15细胞,且上清mIL-21水平与重组载体的滴度和感染时间相关。注射Ad-GFP-mIL21至HBV持续表达小鼠后第4天观察到绿色荧光主要在肝细胞表达;与处理前相比,注射第4天血清mIL-21水平显著升高(P<0.05),而HBsAg滴度则明显下降;实验组和对照组小鼠在注射第13天血清HBsAb均为阴性;与对照组相比,实验组小鼠血清HBcAb水平显著升高(P<0.05)。结论 AdGFP-mIL-21在HBV持续感染小鼠体内可表达mIL-21,并能下调血清HBsAg滴度和促进HBcAb产生,提示其在体内具有控制慢性HBV感染的作用。

Interleukin-34 deficiency aggravates development of colitis and colitis-associated cancer in mice

BACKGROUND Although expression of interleukin(IL)-34 is upregulated in active ulcerative colitis(UC),the molecular function and underlying mechanism are largely unclear.AIM To investigate the function of IL-34 in acute colitis,in a wound healing model and in colitis-associated cancer in IL-34-deficient mice.METHODS Colitis was induced by administration of dextran sodium sulfate(DSS),and carcinogenesis was induced by azoxymethane(AOM).Whether the impact of IL-34 on colitis was dependent on macrophages was validated by depletion of macrophages in a murine model.The association between IL-34 expression and epithelial proliferation was studied in patients with active UC.RESULTS IL-34 deficiency aggravated murine colitis in acute colitis and in wound healing phase.The effect of IL-34 on experimental colitis was not dependent on macrophage differentiation and polarization.IL-34-deficient mice developed more tumors than wild-type mice following administration of AOM and DSS.No significant difference was shown in degree of cellular differentiation in tumors between wild-type and IL-34-deficient mice.IL-34 was dramatically increased in the active UC patients as previously reported.More importantly,expression of IL-34 was positively correlated with epithelial cell proliferation in patients with UC.CONCLUSION IL-34 deficiency exacerbates colonic inflammation and accelerates colitis-associated carcinogenesis in mice.It might be served as a potential therapeutic target in UC.

Review of the potential value of serum interleukin levels as prognostic biomarkers of liver failure

Liver failure(LF)is prevalent in China and is characterized by complex path-ogenesis,challenging clinical management,poor prognosis,and rising incidence and mortality rates.The immune status is an important factor affecting LF prognosis.Interleukins(Ils)are a type of cytokine that act and interact with multiple cells,including immune cells.These signaling molecules play important roles in intercellular information transmission,including the regulation of immune cells;mediation of the activation,proliferation,and differentiation of T and B cells;and orchestration of the inflammatory response.To date,many studies have explored the correlation between IL expression and liver disease prognosis,but few studies have evaluated Ils as the prognostic biomarkers of LF.This article reviews the potential use of Ils as the prognostic biomarkers of LF.Particularly,it evaluates the predictive values of IL-21,IL-22,and IL-31,the three often overlooked yet promising prognostic biomarkers,in predicting suscept-ibility to LF.Harnessing biomarkers for early prognostic insights can facilitate tailored treatment strategies and enhance patient survival.Thus,this article focuses on the identification of IL-21,IL-22,and IL-33 as biomarkers in preclinical and clinical studies on LF and reviews their role as biomarkers in the pathogenesis and diagnosis of LF.

Role of interleukin-21 in HBV infection： friend or foe？

I nterleukin （I L）-21, a cytokine produced by activated CD4＋ T cells, has broad pleiotropic actions that affect the functions of a variety of lymphoid cells. The roles of IL-21 in modulating immunity to infections are currently being defined. Notably, IL-21-mediated cellular and humoral immune responses play an important role in determining the outcome of viral infection. This article reviews the current knowledge on the critical role of IL-21 in hepatitis B virus （HBV） infection. As a competent intermediary, IL-21 derived from virus-specific CD4＋ T cells plays key roles in sustaining CD8＋ T cells and promoting B-cell responses that are essential for effective viral control. However, as a mediator of inflammation, I L-21 is also involved in the development of HBV-induced liver cirrhosis and exacerbating liver injury. Overall, the current data point to IL-21 as an immunomodulatory cytokine in HBV infection. Immunotherapeutic strategies aimed at optimizing the beneficial effects of IL-21 in HBV infection may prove to be a rigorous challenge in the future, as they should foster the strengths of IL-21 while circumventing potential drawbacks.

Gene polymorphisms of interleukin-28, p21-activated protein kinases 4, and response to interferon-α based therapy in Chinese patients with chronic hepatitis B

Background Peg-lnterferon-a treatment is expensive and associated with considerable adverse effects, selection of patients with the highest probability of response is essential for clinical practice. The objective of this study was to assess the relationship between the gene polymorphisms of interleukin-28 （IL-28）, p21-activated protein kinase 4 （PAK4） and the response to interferon treatment in chronic hepatitis B patients. Methods Two hundred and forty interferon-naive treatment HBeAg seropositive chronic hepatitis B patients were enrolled in the present prospective nested case-control study. Peripheral blood samples were collected, including 92 with favorable response and 148 without response to the interferon treatment. Rs8099917, rs12980602, and rs9676717 SNP was genotyped using matrix assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF MS）. Results IL-28 genotype was not associated with response to interferon treatment （OR for GT/GG vs. TT, 0.881 （95% CI 0.388-2.002）; P=0.762; OR for CT/CC vs. TT, 0.902 （95% CI 0.458-1.778）; P=-0.766）. Rs9676717 in PAK4 genotype was independently associated with the response （OR for CT/CC vs. TT, 0.524 （95% CI 0.310-0.888）; P=0.016）. When adjusting for age, gender, smoking, drinking, levels of hepatitis B virus DNA, and alanine aminotransferase （ALT）, rs9676717 genotype TT appeared to be associated with a higher probability of response for interferon treatment （OR, 0.155 （95% CI 0.034-0.700）; P=0.015）. Conclusion Genotype TTfor rs9676717 in PAK4 gene and no drinking may be predictive of the interferon-a treatment success.

Correlation between thrombopoietin and inflammatory factors,platelet indices,and thrombosis in patients with sepsis:A retrospective study

BACKGROUND Thrombopoietin(TPO)is a primary regulator of thrombopoiesis in physiological conditions.TPO,in combination with its specific cytokine receptor c-Mpl,drives platelet production by inducing the proliferation and differentiation of megakaryocytes.However,the role of TPO in sepsis is not well determined.The elevated levels of TPO are often accompanied by a decrease of platelet count(PLT)in systemic infected conditions,which is contrary to the view that TPO promotes platelet production under physiological conditions.In addition,whether TPO mediates organ damage in sepsis remains controversial.AIM To explore the relationships between TPO and inflammatory factors,platelet indices,and thrombotic indicators in sepsis.METHODS A total of 90 patients with sepsis diagnosed and treated at the emergency medicine department of The First People’s Hospital of Foshan between January 2020 and March 2021 were enrolled in this study.In addition,110 patients without sepsis who came to the emergency medicine department were included as controls.Clinical and laboratory parameters including age,gender,TPO,blood cell count in peripheral blood,platelet indices,inflammatory factors such as high-sensitivity Creactive protein(hs-CRP),interleukin(IL)-21,and IL-6,organ damage indicators,and thrombotic indicators were collected and analyzed by using various statistical approaches.RESULTS The results showed that the TPO levels were higher in the sepsis group than in controls[86.45(30.55,193.1)vs 12.45(0.64,46.09)pg/mL,P<0.001],but PLT was lower(P<0.001).Multivariable analysis showed that white blood cell count(WBC)[odds ratio(OR)=1.32;95%confidence interval(CI):1.01-1.722;P=0.044],TPO(OR=1.02;95%CI:1.01-1.04;P=0.009),IL-21(OR=1.02;95%CI:1.00-1.03;P=0.019),troponin I(OR=55.20;95%CI:5.69-535.90;P=0.001),and prothrombin time(PT)(OR=2.24;95%CI:1.10-4.55;P=0.027)were independent risk factors associated with sepsis.TPO levels were positively correlated with IL-21,IL-6,hs-CRP,creatinine,D-dimer,PT,activated prothrombin time,international normalized ratio,fibrinogen,WBC count,and neutrophil count,and negatively correlated with PLT,thrombin time,red blood cell count,and hemoglobin concentration(P<0.05).Receiver operating characteristic analysis showed that TPO had fair predictive value in distinguishing septic patients and non-septic patients(the area under the curve:0.788;95%CI:0.723-0.852;P<0.001).With an optimized cutoff value(28.51 pg/mL),TPO had the highest sensitivity(79%)and specificity(65%).CONCLUSION TPO levels are independently associated with sepsis.High TPO levels and low PLT suggest that TPO might be an acute-phase response protein in patients with infection.

Follicular helper T lymphocytes in health and disease

A correct antibody response requires the participation of both B and T lymphocytes and antigen presenting cells. In this review we address the role of follicular helper T lymphocytes(T FH) in this reaction. We shall focus on the regulation of their development and function in health and disease. T FH can be characterized on the basis of their phenotype and the pattern of secretion of cytokines. This fact is useful to study their participation in the generation of antibody deficiency in primary immunodeficiency diseases such as common variable immunodeficiency, X-linked hyper Ig M syndrome orX-linked lymphoproliferative disease. Increased numbers of T FH have been demonstrated in several autoimmune diseases and are thought to play a role in the development of autoantibodies. In chronic viral infections caused by the human immunodeficiency virus, hepatitis B or C virus, increased circulating T FH have been observed, but their role in the protective immune response to these agents is under discussion. Likewise, an important role of T FH in the control of some experimental protozoan infections has been proposed, and it will be important to assess their relevance in order to design effective vaccination strategies.

IL-21对LPS诱导的巨噬细胞中细胞因子IL-1β、IL-10、IL-12 mRNA表达的影响

通过分离并培养BALB/c小鼠腹腔巨噬细胞,采用SqRT-PCR的方法检测IL-21对LPS诱导的巨噬细胞中细胞因子IL-1β、IL-10、IL-12mRNA表达的影响。结果表明,与NT组相比,单独LPS处理组IL-1β、IL-10、IL-12mRNA表达明显增加,差异极显著;与LPS组相比,在IL-21+LPS组中,IL-21显著抑制LPS诱导的巨噬细胞中IL-1β、IL-10、IL-12mRNA表达,差异显著。以上结果表明,IL-21通过抑制LPS诱导的巨噬细胞中IL-10、IL-12、IL-1β的表达,在固有免疫应答中发挥一定的作用。

C-X-C chemokine receptor type 5+CD8+T cells as immune regulators in hepatitis Be antigen-positive chronic hepatitis B under interferonalpha treatment

BACKGROUND C-X-C chemokine receptor type 5(CXCR5)^(+)CD8^(+)T cells represent a unique immune subset with dual roles,functioning as cytotoxic cells in persistent viral infections while promoting B cell responses.Despite their importance,the specific role of CXCR5^(+)CD8^(+)T cells in chronic hepatitis B(CHB),particularly during interferon-alpha(IFN-α)treatment,is not fully understood.This study aims to elucidate the relationship between CXCR5^(+)CD8^(+)T cells and sustained serologic response(SR)in patients undergoing 48 weeks of pegylated IFN-α(peg-IFN-α)treatment for CHB.AIM To elucidate the relationship between CXCR5^(+)CD8^(+)T cells and sustained SR in patients undergoing 48 weeks of peg-IFN-αtreatment for CHB.METHODS This study enrolled 60 patients with hepatitis Be antigen(HBeAg)-positive CHB undergoing 48 weeks of peg-IFN-αtreatment.Participants were assessed for eligibility based on criteria such as persistent HBsAg-positive status for at least six months,HBeAb-negative,hepatitis B virus DNA levels exceeding 2×10^(4) copies/mL,and alanine aminotransferase(ALT)levels between 2 and 10 times the upper limit of normal.Blood samples were collected at baseline and at weeks 12,24,48,and a 24-week treatment-free follow-up(week 72)to measure serum interleukin(IL)-21 concentration via ELISA and to analyze CXCR5 and programmed death-ligand 1(PD-L1)expression on CD8^(+)T cells by flow cytometry,CXCR5 is a chemokine receptor that directs immune cells to specific tissues,while PD-L1 is a protein that regulates immune responses by inhibiting T cell activity.RESULTS Patients with CHB exhibited significantly lower levels of circulating CXCR5^(+)CD8^(+)T cells compared to healthy controls(P<0.01).Notably,CXCR5^(+)CD8^(+)T cells were prominently expressed in patients who achieved sustained SR compared to non-SR(NSR).A significant correlation was observed between CXCR5 and PD-L1 expression(r=-0.189,P=0.002).However,there was no significant correlation between serum IL-21 levels and CXCR5+CD8+lymphocytes(r=-0.03,P=0.625)or serum ALT levels(r=0.026,P=0.678).CONCLUSION The enhanced expression of CXCR5^(+)CD8^(+)T cells in patients achieving HBeAg seroconversion during IFN-αtreatment suggests that these cells play a crucial role in antiviral immune responses against hepatitis B.This study highlights the potential of CXCR5^(+)CD8^(+)T cells as immune regulators in CHB,which may inform future therapeutic strategies to optimize antiviral treatments.

Advances in the role of follicular T helper cells in graft versus host diseases

Graft versus host disease(GVHD)is a refractory complication of allogeneic hematopoietic stem cell transplantation for the treatment of malignant and non-malignant hematopoietic diseases.Inflammatory cascade responses and cellular immune reactions are the major factors underlying GVHD pathogenesis.Cells producing the cytokine,interleukin(IL)-21 are crucial players involved in injured tissues in GVHD patients.Besides T helper 17 cells,follicular T helper(Tfh)cells are a new source of IL-21 and play a vital role in GVHD pathogenesis.Tfh cell function is mostly regulated by T-follicular regulatory(Tfr)cells that are also located in the germinal center.This review highlights recent advances in the role of Tfh and Tfr cell function in GVHD pathogenesis.New insights are provided into the potential for clinical application in GVHD prevention and treatment.