Circulating antiinflammatory cytokine IL-10 in patients with inflammatory bowel disease (IBD).

IBD is characterized by increased serum concentrations of different cytokines. IL-10 inhibits the production of proinflammatory cytokines such as IL-1, tumour necrosis factor-alpha (TNF-a), interferon-gamma (IFN-gamma) and IL-6 through inhibitory action on Th1 cells and macrophages, and it is thought to be a suppressor type cytokine. In the present study we determined serum concentrations of IL-10 in patients with ulcerative colitis (UC) and Crohn's disease (CD). We measured human IL-10 by our own newly established ELISA system using PharMingen antibodies. Serum antibodies were assessed in 44 patients with UC, 40 patients with CD, and in 30 healthy controls. Human IL-10 serum levels were significantly increased in patients with active UC (144 +/- 34 pg/ml (mean +/- s.e.m.), P < 0.001) and in active CD (132 +/- 32 pg/ml, P < 0.001) compared with healthy controls (44 +/- 9.5 pg/ml). Only patients with active CD and active UC presented with significantly increased IL-10 serum levels, while patients with inactive disease did not show any significant increase. There was no statistically significant difference between IL-10 serum levels in patients with CD or UC. Compared with clinical disease activity indices there was a significant correlation between IL-10 serum concentration and CDAI in patients with CD (r = 0.45, P < 0.01) and CAI in UC patients (r = 0.39, P < 0.05). Comparing IL-10 serum levels with serum concentrations of other proinflammatory cytokines there was a significant correlation to serum levels of sIL-2R (r = 0.417, P < 0.05) and IL-6 (r = 0.387, P < 0.05) in patients with CD. Serum cytokine levels in patients with UC did not show any significant correlation to IL-10 serum concentration. IL-10 is elevated in serum of patients with active CD and UC, suggesting that IL-10 acts as a naturally occurring damper in the acute inflammatory process of IBD.     

IL-4, IL-10 and IL-13 down-regulate monocyte-chemoattracting protein-1 (MCP-1) production in activated intestinal epithelial cells

Several studies have demonstrated that intestinal epithelial cells play a major role in the initiation and perpetuation of intestinal inflammation by secreting proinflammatory cytokines and chemokines. MCP-1 is suggested to be a chemokine that plays a major part during intestinal inflammation in inflammatory bowel disease (IBD). Immunoregulatory cytokines such as IL-4, IL-10 and IL-13 have been described to exert anti-inflammatory properties on various cell types. The aim of our study was to determine the effect of Th2 cytokines on the production of MCP-1 by activated intestinal epithelial cells. We examined Caco-2 cells as well as intestinal epithelial cells which were isolated from surgical specimens. Production of the chemokine MCP-1 was determined under stimulated and non-stimulated conditions. IL-4, IL-10 and IL-13 were added to stimulated epithelial cells under various culture conditions. Supernatants were analysed for cytokine concentrations using ELISAs. Under stimulation with physiological agents like IL-1β or tumour necrosis factor-alpha (TNF-α), we observed markedly increased concentrations of MCP-1 in supernatants of Caco-2 cells and intestinal epithelial cells. IL-4, IL-10 and IL-13 all had the capacity to down-regulate the production of MCP-1 in Caco-2 cells as well as in freshly isolated epithelial cells. Caco-2 cells which were primed with Th2 cytokines 24 h before stimulation were subsequently decreased in their ability to be stimulated by IL-1β or TNF-α for MCP-1 production. As MCP-1 has been shown to play a major role during intestinal inflammation, the in vitro suppression of MCP-1 in enterocytes suggests the in vivo use of regulatory cytokines in patients with active IBD.     

Mannose-capped lipoarabinomannan-induced B10 cells decrease severity of dextran sodium sulphate-induced inflammatory bowel disease in mice

Inflammatory bowel disease (IBD) is a chronic, non-specific, inflammatory gastrointestinal disease that mainly consists of Crohn's disease and ulcerative colitis. However, the aetiology and pathogenesis of IBD are still unclear. B10 (IL-10 producing regulatory B) cells, a subset of regulatory B cells, are known to contribute to intestinal homeostasis and the aberrant frequency of B10 cells is associated with IBD. We have recently reported that B10 cells can be induced by ManLAM (mannose-capped lipoarabinomannan), a major cell-wall lipoglycan of M tb (Mycobacterium tuberculosis). In the current study, the ManLAM-induced B10 cells were adoptively transferred into IL(interleukin)-10^−/− mice and the roles of ManLAM-induced B10 cells were investigated in DSS (dextran sodium sulphate)-induced IBD model. ManLAM-induced B10 cells decrease colitis severity in the mice. The B10 cells downregulate Th1 polarization in spleen and MLNs (mesenteric lymph nodes) of DSS-treated mice. These results suggest that IL-10 production by ManLAM-treated B cells contributes to keeping the balance between CD4⁺ T cell subsets and protect mice from DSS-induced IBD.     

Very early onset inflammatory bowel disease: Investigation of the IL-10 signaling pathway in Iranian children

Background & aimComparing to adult inflammatory bowel disease (IBD), those with early onset manifestations have different features in terms of the underlying molecular pathology, the course of disease and the response to therapy. We investigated the IL-10 signaling pathway previously reported as an important cause of infantile (Very Early Onset) IBD to find any possible variants.MethodWith the next generation sequencing technique we screened IL-10, IL-10RA and IL10RB genes of 15 children affected by very early onset-GI (gastrointestinal) disorders. Additionally, we analyzed them based on Thermo Fisher immune deficiency panel for genes either having a known role in IBD pathogenesis or cause the disorders with overlapping manifestations. We performed multiple functional analyses only for the cases showing variants in IL-10- related genes.ResultIn 3 out of 15 patients we identified variants including a homozygous and heterozygote mutations in IL-10RA and a novel homozygous mutation in IL-12RB1. Our functional studies reveal that in contrast to the IL-10RA heterozygote mutation that does not have deleterious effects, the homozygous mutation abrogates the IL-10 signaling pathway.ConclusionOur study suggests we need to modify the classical diagnostic approach from functional assays followed by candidate- gene or genes sequencing to the firstly parallel genomic screening followed by functional studies.     

子宫内膜异位症并不孕患者IL-10，IL13含量变化及其临床意义

目的检测IL-10和IL-13在子宫内膜异位症并不孕患者腹腔液及外周血中含量并探讨其意义。方法电视腹腔镜手术中采集EMS并不孕及对照组的腹腔液,术前空腹抽取外周血,采用ELISA法检测细胞因子水平。EMS并不孕组及对照组中,分别抽取38份腹腔液、外周血测IL-10及IL-13。结果EMS并不孕组和对照组腹腔液IL-10的含量分别为（15.8±12.9）pg/ml和（10.6±5.7）pg/ml,外周血中分别为（13.8±9.9）pg/ml和（8.6±5.7）pg/ml,两组比较均无统计学意义（P〉0.05）;EMS并不孕组和对照组腹腔液IL-13的含量分别为（93±9.6）pg/ml和（114±26）pg/ml,外周血中分别为（78±7.6）pg/ml和（102±29）pg/ml,两组比较均有统计学意义（P〈0.05）。结论异位子宫内膜细胞可抑制IL-13的产生,进而营造免疫抑制微环境,干扰免疫调节功能。     

Activation antigens on colonic T cells in inflammatory bowel disease: effects of IL-10

Activated T cells that express activation antigens are termed nonprofessional antigen‐presenting cells (T‐APCs). This study evaluates the ability of lamina propria lymphocytes (LPLs) in inflammatory bowel disease (IBD) to become T‐APCs. LPLs were stained by two‐colour immunofluorescence to determine the expression of activation antigens on T cells. Those from actively inflamed IBD mucosa expressed greater amounts of MHC class II (DR) and CD86 than did LPL T cells from disease controls or normal individuals. After culture in IL‐2 with or without IL‐10, the ability of the T‐APCs from IBD colon to stimulate allogeneic peripheral blood T cell proliferation was measured. The T‐APCs from IBD stimulated an allogeneic mixed lymphocyte reaction, particularly through their expression of DR and CD86, as demonstrated by antibody blocking. Normal LPLs acquired these properties only if repeatedly stimulated with allogeneic peripheral blood lymphocytes (PBLs) used as cell lines in the presence of IL‐2. Addition of IL‐10 reduced expression of activation antigens and the stimulatory ability of LPLs from either IBD patients or from these cell lines. In summary, LPLs from active IBD, but not from disease controls, express activation antigens that stimulate naïve T cells, a process that is reduced by IL‐10. This may contribute to perpetuation of the inflammation.     

Contribution of the IL-2 and IL-10 genes to inflammatory bowel disease (IBD) susceptibility

Although the importance of genetic susceptibility to IBD has been established by epidemiological studies, the genes involved remain poorly characterized. Important candidate genes include those encoding the immunoregulatory cytokines IL-2 and IL-10. The aim of this study was to assess the contribution of the IL-2 and IL-10 genes to IBD susceptibility. One hundred and ninety-eight pairs of siblings with IBD were genotyped at dinucleotide repeat polymorphisms within the IL-2 and IL-10 genes, and data analysed by the affected sib-pair method of linkage analysis and the transmission disequilibrium test (TDT). A subset of 89 affected sibling pairs was genotyped at markers flanking the IL-2 gene as part of a genome-wide search. The IL-2 polymorphism showed no linkage to IBD overall, but modest evidence for linkage to the ulcerative colitis (UC) data set (P = 0.028). A microsatellite 4 cM distal to the IL-2 gene showed a similar distortion in the ulcerative colitis subgroup (P = 0.006). The TDT showed some distortion of allelic transmission for the IL-2 polymorphism in the UC group, but this did not reach statistical significance (P = 0.09). Results for the IL-10 polymorphism were not significant. Thus the gene encoding IL-2 may contribute to UC susceptibility, but the effect is modest and must await replication in other data sets. The IL-10 gene does not appear to contribute to the risk of developing UC or Crohn's disease.     

IL-13和IL-4在哮喘发病中的作用及相互关系

目的　探讨IL 13在哮喘发病中的作用及其与IL 4的相互关系。方法　哮喘组 2 4例 ,男 17例 ,女 7例 ;健康对照组 2 4例 ,男 12例 ,女 12例。用ELISA法检测不同时段PBMC培养上清IL 13和IL 4水平及加IL 13单克隆抗体 (McAb)和IL 4McAb干预后PBMC培养上清IL 4、IL 12、IL 13和IFN γ水平。结果　 (1)IL 13动态变化 :①对照组PBMC培养 3d、5d、7d水平均较培养 1d水平高 ,差异有显著性 ,培养 3d的水平较培养 5d、7d的高 ,差异有显著性 ;②哮喘组PBMC培养 3d、5d、7d的水平均较培养 1d的水平高 ,差异有显著性 ,培养 5d的水平均较培养 3d、7d的水平高 ,但之间差异无显著性 ;③哮喘组PBMC培养 3d、5d、7d的IL 13水平均较对照组高 ,差异有显著性。 (2 )IL 4动态变化 :①对照组和哮喘组PBMC培养 1d后 ,IL 4水平明显上升 ,第 3天仍保持较高水平 ,第 5、7天明显下降 ;②哮喘组 1d、3d、5d和 7d水平均较对照组高 ,差异有显著性。 (3)IL 4McAb干预后 ,哮喘组和正常组IL 13水平与对应小鼠IgG组相比有显著性降低 ,哮喘组IFN γ水平与对应小鼠IgG组相比有显著性增高。 (4)IL 13McAb干预后IL 12水平在哮喘组和正常组均提高 ,与对应小鼠IgG组相比差异有显著性。 (5 )IL 13McAb和IL 4McAb联合干预后哮喘组I     

Allelic polymorphism in IL-1 beta and IL-1 receptor antagonist (IL-1Ra) genes in inflammatory bowel disease.

Recent reports have shown that allele 2 of the IL-1 receptor antagonist (IL-1Ra) gene is over-represented in ulcerative colitis (UC). Healthy individuals carrying allele 2 of this gene have increased production of IL-1Ra protein. Since the final outcome of the biological effects of IL-1 beta may depend on the relative proportion of these two cytokines, we have studied if a TaqI polymorphism in the IL-1 beta gene, which is relevant to IL-1 beta protein production, may be involved in the genetic susceptibility to UC and Crohn's disease (CD), in association with the established IL-1Ra gene polymorphism. Polymorphisms in the closely linked genes for IL-1 beta and IL-1Ra were typed in 100 unrelated Dutch patients with UC, 79 with CD, and 71 healthy controls. The polymorphic regions in exon 5 of the IL-1 beta gene and in intron 2 of the IL-1Ra gene, were studied by polymerase chain reaction (PCR)-based methods. The IL-1 beta allele frequencies in UC and CD patients did not differ from those in healthy controls. In order to study if the IL-1 beta gene polymorphism might participate synergistically with the IL-1Ra gene polymorphism in susceptibility to UC and CD, individuals were distributed into carriers and non-carriers of allele 2 of the genes encoding IL-1 beta and IL-1Ra, in each of the patient groups and controls. Results indicated a significant association of this pair of genes, estimated by the odds ratio (OR) after performing Fisher's exact test, in the UC group (P = 0.023, OR = 2.81), as well as in the CD group (P = 0.01, OR = 3.79). Thus, non-carriers of IL-1 beta allele 2 were more often present in the subgroup of patients carrying the IL-1Ra allele 2. By contrast, no association of these alleles was detected in the group of healthy controls (P = 1.00, OR = 0.92). These results suggest that the IL-1 beta/IL-1Ra allelic cluster may participate in defining the biological basis of predisposition to chronic inflammatory bowel diseases.     

IL-13对成纤维细胞IL-13受体和IL-4受体表达的影响

目的研究IL-13对人肺成纤维细胞株HFL-1和人肝星状细胞株LX-2 IL-13受体和IL-4受体表达的调节作用。方法 RT-PCR法检测HFL-1细胞株和LX-2细胞株IL-13Rα1、IL-4R和IL-13Rα2 mRNA的表达;凝胶电泳定量软件Image Tool2.0对RT-PCR电泳条带进行光密度分析;ELISA法检测HFL-1细胞株和LX-2细胞株分泌可溶型IL-13Rα2以及检测细胞裂解液总IL-13Rα1、IL-4R和IL-13Rα2含量。结果 IL-13(5～100 ng/ml)对HFL-1细胞株和LX-2细胞株表达IL-13Rα1和IL-4R无影响;IL-13为5、10、20 ng/ml时能诱导HFL-1细胞株表达IL-13Rα2并呈现剂量依赖,当IL-13为50 ng/ml时,对HFL-1细胞株IL-13Rα2表达的诱导作用明显减弱,IL-13 100 ng/ml组没有检测到HFL-1细胞株IL-13Rα2的表达;LX-2细胞株IL-13Rα2表达缺失且IL-13不能诱导LX-2细胞株表达IL-13Rα2。结论 IL-13不能上调人肺成纤维细胞株HFL-1和人肝星状细胞株LX-2表达功能型受体IL-13Rα1和IL-4R,表明IL-13不能通过上调IL-13Rα1和IL-4R表达量来放大自身作用;一定浓度的IL-13能诱导人肺成纤维细胞株HFL-1表达抑制型受体IL-13Rα2,表明IL-13的自身负调控。     

Anti-inflammatory effects of probiotic yogurt in inflammatory bowel disease patients

Our aim was to assess anti-inflammatory effects on the peripheral blood of subjects with inflammatory bowel disease (IBD) who consumed probiotic yogurt for 1 month. We studied 20 healthy controls and 20 subjects with IBD, 15 of whom had Crohn's disease and five with ulcerative colitis. All the subjects consumed Lactobacillus rhamnosus GR-1 and L. reuteri RC-14 supplemented yogurt for 30 days. The presence of putative regulatory T (T(reg)) cells (CD4(+) CD25(high)) and cytokines in T cells, monocytes and dendritic cells (DC) was determined by flow cytometry from peripheral blood before and after treatment, with or without ex vivo stimulation. Serum and faecal cytokine concentrations were determined by enzyme-linked immunosorbent assays. The proportion of CD4(+) CD25(high) T cells increased significantly (P = 0.007) in IBD patients, mean (95% confidence interval: CI) 0.84% (95% CI 0.55-1.12) before and 1.25% (95% CI 0.97-1.54) after treatment, but non-significantly in controls. The basal proportion of tumour necrosis factor (TNF)-alpha(+)/interleukin (IL)-12(+) monocytes and myeloid DC decreased in both subject groups, but of stimulated cells only in IBD patients. Also serum IL-12 concentrations and proportions of IL-2(+) and CD69(+) T cells from stimulated cells decreased in IBD patients. The increase in CD4(+) CD25(high) T cells correlated with the decrease in the percentage of TNF-alpha- or IL-12-producing monocytes and DC. The effect of the probiotic yogurt was confirmed by a follow-up study in which subjects consumed the yogurt without the probiotic organisms. Probiotic yogurt intake was associated with significant anti-inflammatory effects that paralleled the expansion of peripheral pool of putative T(reg) cells in IBD patients and with few effects in controls.     

IL-4、IL-13蛋白表达及抗IL-4、IL-13人源单链抗体的筛选

目的:表达IL-4和IL-13蛋白,从人源单链抗体文库中分别筛选抗IL-4和抗IL-13单链抗体.方法:采用RT-PCR从健康志愿者外周血单核细胞(PBMC) mRNA中扩增IL-4和IL-13 cDNA;构建硫氧还蛋白融合表达载体,转化大肠杆菌BL21,IPTG诱导表达并对表达产物进行纯化鉴定.以生物素化的IL-4和IL-13为抗原从前期构建的人源抗体文库中采用噬菌体展示技术分别筛选抗IL-4和抗IL-13人源单链抗体(scFv).结果:扩增的IL-4 cDNA大小为280 bp,表达的融合蛋白大小为27 kD左右.扩增的IL-13 cDNA大小为252 bp,表达的融合蛋白大小为25 kD左右.分别以生物素化的IL-4和IL-13蛋白为抗原,采用噬菌体展示技术对人源抗体文库进行3轮富集后,分别有大约37％的scFvs与IL-4有结合特性,有约27％的scFvs与IL-13有结合特性.筛选了4株分别与IL-4和IL-13结合能力强的单链抗体进行了Westem blot鉴定和测序.结论:成功筛选到抗IL-4和抗IL-13人源性单链抗体.     

Therapeutic targeting of IL-4-and IL-13-responsive cells in pulmonary fibrosis

Severe forms of idiopathic interstitial pneumonia (IIP), such as usual interstitial pneumonia (UIP), can be impervious to modern steroid and immunosuppressive treatment regimens, thereby emphasizing the need for novel effective therapies. Understanding the cytokine networks that may affect immune and structural cell activation and, hence, the progression of these fatal fibrotic diseases, has been a focus in our research. In this regard, we have examined the role of interleukin (IL)-4 and IL-13 and their respective receptor subunits in this process. Examination of clinical surgical lung biopsies (SLBs) showed that IIP is characterized by the abnormal, heightened expression of the receptor subunits that bind IL-4 and IL-13. Specifically, IL-4Rα and IL-13Rα2 (the high-affinity IL-13 receptor subunit) was present in greater abundance in SLBs and fibroblasts from IIP patients compared with normal patients, who exhibited no evidence of pulmonary fibrosis. These clinical findings prompted us to investigate whether the targeting of pulmonary cell types that were highly responsive to IL-4 and IL-13 was a viable therapeutic option in IIP. Using a chimeric protein comprised of human IL-13 and a truncated version of an exotoxin from Pseudomonas (abbreviated IL13-PE), we observed that IL13-PE selectively targeted human pulmonary fibroblasts grown from IIP SLBs, whereas it had a minimal effect on fibroblasts grown from biopsies from normal patients. In murine models characterized by abnormal airway or interstitial fibrotic responses, the intranasal administration of IL13-PE significantly attenuated the fibrotic response through the targeting of IL-4Rα-and IL-13Rα2-expressing pulmonary cells, including monocytes, macrophages, and pulmonary fibroblasts. Together, these data demonstrate that IL-4 and IL-13 are required for the initiation and maintenance of pulmonary fibrosis, and highlight the importance of further investigation of anti-fibrotic therapeutics that prevent the action of both cytokines during clinical pulmonary fibrosis.     

HIV-1 induces IL-10 production in human monocytes via a CD4-independent pathway

In HIV-infected patients, increased levels of IL-10, mainly produced by virally infected monocytes, were reported to be associated with impaired cell-mediated immune responses. In this study, we investigated how HIV-1 induces IL-10 production in human monocytes. We found that CD14(+) monocytes infected by either HIV-1(213) (X4) or HIV-1(BaL) (R5) produced IL-10, IL-6, tumor necrosis factor-alpha (TNF-alpha), and to a lesser extent, IFN-gamma. However, the capacity of HIV-1 to induce these cytokines was not dependent on virus replication since UV-inactivated HIV-1 induced similar levels of these cytokines. In addition, soluble HIV-1 gp160 could induce CD14(+) monocytes to produce IL-10 but at lower levels. Cross-linking CD4 molecules (XLCD4) with anti-CD4 mAbs and goat anti-mouse IgG (GAM) resulted in high levels of IL-6, TNF-alpha and IFN-gamma but no IL-10 production by CD14(+) monocytes. Interestingly, neither anti-CD4 mAbs nor recombinant soluble CD4 (sCD4) receptor could block IL-10 secretion induced by HIV-1(213), HIV-1(BaL) or HIV-1 gp160 in CD14(+) monocytes, whereas anti-CD4 mAb or sCD4 almost completely blocked the secretion of the other cytokines. Furthermore, HIV-1(213) could induce IL-10 mRNA expression in CD14(+) monocytes while XLCD4 by anti-CD4 mAb and GAM failed to do so. As with IL-10 protein levels, HIV-1(213)-induced IL-10 mRNA expression in CD14(+) monocytes could not be inhibited by anti-CD4 mAb or sCD4. Taken together, HIV-1 binding to CD14(+) monocytes can induce CD4-independent IL-10 production at both mRNA and protein levels. This finding suggests that HIV induces the immunosuppressive IL-10 production in monocytes and is not dependent on CD4 molecules and that interference with HIV entry through CD4 molecules may have no impact on counteracting the effects of IL-10 during HIV infection.     

瘦素通过免疫调节对炎症性肠病的影响

炎症性肠病是指一组以胃肠道慢性炎症为特征的慢性、复发和缓解交替的疾病,严重影响患者的生活质量,其发病机制复杂,其中免疫因素被认为是主导因素。瘦素是一种脂肪细胞来源的激素,近年来的研究表明瘦素具有调控免疫细胞和炎症信号通路等多重功能。本综述通过总结近年来有关炎症性肠病发病机制、瘦素调节免疫机制以及免疫调节剂的相关研究进展...     

Influence of Toll-like receptor 2 and interleukin 10 on the intestinal epithelial barrier and their roles in inflammatory bowel disease

Different polymorphisms in key genes of innate and adaptive immunity disrupt the intestinal host-microbiotic balance in inflammatory bowel disease (IBD). In most cases these alterations affect the maintenance of the intestinal epithelium. Because of this, actions taken in order to reinforce or help intestinal epithelium recovery can provide benefits to idiopathic illnesses such as IBD. With this in mind, several studies support the idea that actions derived from the Toll-like receptor (TLR) 2 of the epithelial cells may help to maintain the epithelial barrier. However, in inflammatory conditions TLR-2 disappears from the intestinal epithelium and acquires a pivotal role in dendritic cells. In this event, the interleukin (IL)-10 production by sub-epithelial dendritic cells mediated by TLR-2 activation, thus leading to T-reg phenotypes in the lamina propria, may favour the recovery from epithelial damage. Therefore, the TLR-2/IL-10 axis can help to reinforce and recover the epithelial lining in IBD. In this way, several data suggest that early epithelial repair diminishes the antigen load reaching the lamina propria, which reduces inflammation and improves therapeutic performance. However, there is currently a lack of knowledge regarding molecular regulation of epithelial barrier by TLR-2 and IL-10.     

Interleukin-4 and Interleukin-10 Gene Polymorphisms in Patients with Inflammatory Bowel Disease

Background: Changes in cytokine expression have been frequently found in patients with inflammatory bowel disease (IBD). Cytokine values outside the normal range may be somewhat related to common polymorphisms within cytokine genes.

Objective: The present study was designed to investigate the possible association between polymorphisms within Interleukin IL-4 and IL-10 genes and susceptibility to and clinical features of IBD.

Methods: The study population was composed of 140 healthy controls and 75 patients with IBD (40 patients with Crohn’s disease (CD) and 35 patients with ulcerative colitis (UC)). Genotyping was performed using polymerase chain reaction with sequence-specific primers.

Results: Higher frequencies for the C allele of IL-4–590 polymorphism (P < 0.0001; odds ratio [OR], 5.68; 95% confidence interval [95% CI], 3.28–9.83) and for the T allele of IL-4–1098 polymorphism (P = 0.016; OR, 1.83; 95% CI, 1.11–3.02) were observed in the whole group of IBD patients. The IL-4–590 C allele was also significantly overrepresented when IBD patients were subdivided into CD and UC (P < 0.0001; OR, 5.2–6.28). While the IL-4–1098 T allele was present at higher frequencies in patients with UC (P = 0.05; OR, 1.95), but not in CD (P = 0.09). Multiple pairwise comparisons indicated that genotypes of all polymorphisms investigated within IL-4 gene are correlated with IBD, CD, and UC. Haplotype analysis showed that the IL-4–1098/-590 TC haplotype might predispose individuals to IBD, CD, and UC whereas the IL-4–1098/-590 TT and GC haplotypes have a protective effect. On the contrary, neither allele nor genotype frequencies of IL-10 polymorphisms (IL-10–1082 A > G, IL-10–592 A > C, and IL-10–819 T > C) were associated with IBD, CD, or UC.

Conclusions: The present study suggests that IL-4 polymorphisms might play a role in susceptibility to IBD and its major subtypes in the Iranian population.