IL23R Genotype Research Articles

Associations between IL-17A G/A-rs2275913 and IL 23R A/G-rs11209026 gene polymorphisms and severe coronavirus disease 2019 (COVID-19)

Severe COVID-19 disease was linked to a severe proinflammatory response and cytokine storm interleukin 17 (IL-17) is one of these cytokines, was associated with severe acute lung injury and multiorgan dysfunction. Single nucleotide polymorphisms (SNPs) in genes coding IL-17 can affect level of IL-17 hence its role in diseases. Also, SNPs in IL-23 R which control IL-23 is the main activator of IL-17 production. This study aimed to determine whether the IL-17A (G/A-rs2275913), IL-23R (A/G rs11209026) SNPs and serum levels of IL-17 were related to the risk of severe COVID-19. This case-control study included 120 confirmed COVID-19 patients, divided into two categories according to the severity of the disease and 74 normal subjects as controls. COVID-19 patients were SARS-CoV-2 positive by a reverse transcription-polymerase chain reaction and subjected to full clinical examinations, routine laboratory tests, and radiographic evaluations. The IL-17 levels were assessed using ELISA method, and genotyping of IL-17A (197 A/G; rs2275913) and IL-23R rs11209026 (A/G) was performed by the TaqMan Genotyping Assay. There were no differences in the distribution of IL-17A or IL-23R genotypes between COVID-19 groups and the control group (p=0.93 and p=0.84, respectively). Severe COVID-19 patients had significantly higher IL-17 serum levels than non-severe COVID-19 (p=0.0001). The GG genotypes of IL-17A were significantly higher in severe COVID-19 patients (p=0.004). Multivariate logistic regression analysis revealed that AG, GG genotypes of IL-17 and IL-17A were independent predictors of COVID-19 disease severity (p < 0.0001, p=0.06 and p=0.04, respectively). ROC curve analysis for IL-17, as predictor of severe COVID-19 disease revealed a sensitivity of 87.9% and specificity of 66.1% at a cutoff point of 114 pg/ml with AUC = 0.799. In conclusion, these findings indicated that IL-17 may be considered a marker of severe COVID-19. IL-17A SNPs may have a role in COVID-19 severity. IL-23R SNPs had no role in COVID-19.

IL23R-Protective Coding Variant Promotes Beneficial Bacteria and Diversity in the Ileal Microbiome in Healthy Individuals Without Inflammatory Bowel Disease.

This study aimed to characterize the mucosa-associated microbiota in ileal Crohn's disease [CD] patients and in healthy controls in terms of host genotype and inflammation status. The mucosa-associated microbiotas of intestinal pinch biopsies from 15 ileal CD patients with mild and moderate disease and from 58 healthy controls were analysed based on 16S ribosomal sequencing to determine microbial profile differences between [1] IL23R, NOD2 and ATG16L1 genotypes in healthy subjects, [2] ileal CD patients and control subjects, and [3] inflamed and non-inflamed mucosal tissue in CD patients. The protective variant of the IL23R gene [rs11209026] significantly impacted the microbial composition in the ileum of healthy subjects and was associated with an increased abundance of phylotypes within the family Christensenellaceae as well as increases in diversity and richness. Comparative analysis of healthy and non-inflamed CD microbiome samples indicated a notable decrease in the abundance of Faecalibacterium prausnitzii as well as Shannon diversity and richness. Inflamed and non-inflamed ileal samples of CD subjects had high intra-individual stability and inter-individual variability, but no significant alterations in diversity, richness or taxa were identified. Calprotectin correlated positively with the abundance of Proteobacteria and negatively with diversity in the samples from healthy subjects. The observation of low diversity and low abundance of beneficial bacteria in healthy control subjects carrying the IL23R [rs11209026] wild-type GG genotype indicates that the gut microbiome is influenced by host genetics and is altered prior to disease diagnosis. Faecal calprotectin may be a potential non-invasive screening tool for dysbiosis in subjects without disorders of intestinal inflammation.

IL23R gene variants in relation to IL17A levels and clinical phenotype in patients with ankylosing spondylitis.

BackgroundIL23 receptor (IL23R) binding by IL23 is required for the maturation of CD4+ cells into Th17 cells and subsequent generation of IL17A and TNF. As IL23R variations contribute to AS susceptibility, we investigated the effect of IL23R variants on cytokine levels and disease measures in an AS cohort.MethodsThis was a cross-sectional study of AS patients (n = 334, 90% B27+, age 45 years). IL23R genotyping for three non-synonymous single-nucleotide polymorphisms (rs11209026, protective allele A; rs10489629, protective allele A; and rs11209032, risk allele A) was done by Taqman RT-PCR. IL23, IL17A, TNF and IL6 concentrations were determined by sandwich ELISA. Genotypic associations were analysed with non-parametric methods.ResultsTwenty-two AS patients (6.6%) carried the protective rs11209026 A allele, whereas 206 (61.7%) carried the rs11209032A risk allele (P = 0.03). Two patients homozygous for rs11209026A had late onset, no co-morbidity and undetectable cytokine levels. IL23R genotypes and five common haplotypes were unrelated with age at onset, BASFI or co-morbidity (all P >0.2). There was no overall difference in the concentration of IL17A (184 vs 233 pg/ml, P > 0.2) or IL23 (276 vs 262 pg/ml, P > 0.4) between AS patients and controls, but a global haplotype association (P = 0.01) was observed for IL23 concentrations.ConclusionHomozygosity for rs11209026A is rare in AS patients, but may ameliorate the clinical presentation. IL17A and IL23 levels are similar in controls and AS patients. IL23R variants influence IL23 levels but not IL17A levels in AS patients, suggesting that IL23R impacts more on cell types other than Th17 cells.

Intestinal neuroendocrine cells and goblet cells are mediators of IL-17A-amplified epithelial IL-17C production in human inflammatory bowel disease.

Interleukin (IL)-17C is a novel member of the IL-17 cytokine family. Its function in human inflammatory bowel disease (IBD) remains elusive as its role in colonic inflammation is entirely derived from murine models. We aimed to analyze the role of IL-17C in human IBD, focusing on T helper type 17 (Th17) cell- and intestinal epithelial cell (IEC)-dependent mechanisms. IL-17C mRNA (P=0.005), serum levels (P=0.008), and colonic staining intensity (P=0.004) is increased in active IBD. Serum IL-17C levels are modified by IL23R genotypes and IL-17C mRNA correlates (r>0.5, P<0.001) with IL-17A, tumor necrosis factor (TNF)-α, C-C motif chemokine ligand 20 (CCL20) and IL-23 mRNA in the inflamed colon of IBD patients. In the inflamed colon, IL-17C is produced by enteroendocrine and goblet cells, with contrary polar cytosolic localization of IL-17C within the cellular axis. In these two cell types, IL-17A strongly amplifies TNF-α-induced IL-17C production. On the molecular level, IL-17C production in IECs is dependent on TNF-α-activated nuclear factor-κB, extracellular signal-regulated kinase-1/2 and p38, and IL-17A-activated Akt, monocyte chemotactic protein-induced protein 1, and C/EBPδ. IL-17C upregulates the Th17 chemoattractant CCL20 in IECs. In summary, our findings support the involvement of IL-17A-amplified IL-17C production by enteroendocrine and goblet cells in the pathogenesis of active IBD, revealing an interaction between the neuroendocrine system and the Th17 pathway in human IBD.

A non-synonymous polymorphism in IL-23R Gene (rs1884444) is associated with reduced risk to schistosomiasis-associated Immune Reconstitution Inflammatory Syndrome in a Kenyan population.

BackgroundHuman Immunodeficiency Virus (HIV) and Schistosomiasis co-infection is common among residents at the shores of Lake Victoria in Kenya. About 36% of this population initiating antiretroviral therapy (ART) experience Immune Reconstitution Inflammatory Syndrome (IRIS) that complicates recovery. Several IL-23R alleles have been associated with susceptibility to both autoimmune and inflammatory diseases through T-helper type 17 (TH17) cells. However, whether or not variants within the IL-23R increase susceptibility to IRIS in western Kenya is unknown. The objective of the current study was to determine the association between IL-23R gene polymorphisms, CD4+ cell counts and HIV RNA levels and IRIS in HIV and Schistosoma mansoni co-infected patients undergoing highly active anti-retroviral therapy (HAART).MethodsA three-month case–control study was conducted on antiretroviral naïve schistosomiasis/HIV co-infected fishermen starting HAART in Uyoma Rarieda, Siaya County, Kenya. Seventy one patients were sampled at baseline and followed up for three months, to establish if they developed Schistosoma-related IRIS. In addition, the CD4+ cell counts and HIV RNA levels were determined in pre- and post-administration of HAART. Variations at five polymorphic sites of IL-23R (rs1884444, rs11465754, rs6682925, rs7530511 and rs7539625) based on >10% minor allele frequency in Yoruban reference population was determined using Allelic Discrimination Assay. The association between the five variants and susceptibility to IRIS was determined using logistic regression while controlling for potential confounders. In addition, the functional differences between the baseline CD4 + Cell counts and viral loads were determined using medians while across IL-23R genotypes were determined using Kruskal-Wallis tests.ResultsOverall, 26 (36.6%) patients developed schistosomiasis-associated IRIS at a median age of 35.5 years. Carriage of the TT genotype at the non-synonymous rs1884444 T > G relative to GG, was associated with a decreased risk of schistosomiasis-associated IRIS (OR, 0.25, 95% CI, 0.07-0.96, P = 0.043) while both baseline CD4+ cell counts and viral loads had no association with IRIS.ConclusionThese findings indicate that the non-synonymous variant rs1884444 T > G of IL-23R is associated with a decreased risk to schistosomiasis-associated IRIS. However, additional studies in a larger cohort and with an all inclusive polymorphic variants in the synonymous and non-synonymous regions need to be evaluated.

Interaction between IL23R gene and IBD5 locus in Hungarian ulcerative colitis patients

In previous single-locus association studies, the IBD5 loci were found not to confer susceptibility to UC, while the rs2201841 and rs1004819 IL23R were not investigated in Hungarian UC patients. The aim of our current work was to study two IL23R SNPs (rs1004819 and rs2201841) in Hungarian UC population and to test for possible statistical interaction, stratifying the IL23R genotypes by IBD5 genotypes. 320 unrelated subjects with ulcerative colitis and 316 healthy controls were genotyped. Interactions and specific genotype combinations of a total of seven variants were tested. The variants of IBD5 locus (IGR2198a_1 rs11739135, IGR2096a_1 rs12521868, IGR2230a_1 rs17622208 and SLC22A5 rs2631367) and IL23R (rs1004819, rs2201841) gene were genotyped by PCR-RFLP, the SLC22A4 rs1050152 was determined by direct sequencing. For the IL23R rs1004819 A allele we found significantly higher allele frequency (P = 0.032) in UC patients compared to control subjects. The SNP rs1004819 showed significant association with UC risk for carriers (P = 0.004, OR = 1.606; 95% CI:1.160 – 2.223) and the SNP rs2201842 for homozygotes (P = 0.030, OR = 1.983; 95% CI:1.069 – 3.678). There was no evidence for statistical interaction between IBD5 loci and IL23R genes using logistic regression analysis. After genotype stratification, we could detect a positive association on the background of rs1004819 A allele for SLC22A4 T allele, SLC22A5 C, IGR2198a_1 C or IGR2096_a T allele, the highest OR was calculated in the presence of SLC22A4 T allele (P = 0.005, OR = 2.015; 95% CI:1.230 – 3.300). There was no association with UC for any combinations of rs1004819 and IGR2230a_1. The IL23R rs2201841 homozygous genotype and IBD5 carrier status together did not confer susceptibility for ulcerative colitis. The present study has shown that UC susceptibility genes are likely to act in a complex interactive manner similar to CD.

Tu1712 Analysis of the IL-17C-IL-17RE Cytokine Ligand-Receptor Pair in Human Inflammatory Bowel Disease Reveals Chromogranin a-Positive Epithelial Cells As Major Producers of IL-17C and IL-17RE-Positive Lamina Propria Mononuclear Cells As Main Colonic IL-17C Targets

Background: To date, the role of IL-17C and its specific receptor subunit IL-17RE in inflammatory bowel disease (IBD) settings is entirely based on murine models. Therefore, the aim of this study was to analyze the role of the novel IL-17 family member IL-17C and its receptor IL-17RE in human IBD. Methods: IL-17C expression in intestinal epithelial cells (IEC) was analyzed by qPCR, immunoblotting, immunohistochemistry, EMSA, RNA interference and pharmacological or antibody-mediated inhibition. IL-17C protein and mRNA expression in IBD patient samples was assessed by ELISA, qPCR and immunohistochemistry. IL-17C serum levels were correlated to IL23R genotype status. Results: IL-17A amplifies IL-17C expression in human IEC upon TNF-α stimulation; this depends on TNFα-activated NF-κB, ERK-1/2 and p38 MAP kinases, and IL-17A-activated Akt kinase, MCPIP and C/EBP-δ pathways. IL-17C serum levels are elevated in patients with ulcerative colitis (UC) (P=0.008). IL-17C mRNA is increased in inflamed colonic sections of IBD patients (P=0.005) and correlates significantly with the mRNA expression of Th1 cytokines (e.g., IFN-γ; P<0.01) and Th17 cytokines (e.g., IL-17A, IL-23, CCL20; P<0.01). Genotyping revealed that UC patients carrying a minor allele of the IL23R SNP rs134351 have decreased IL-17C serum levels (P=0.037). Immunohistochemistry displayed increased IL-17C and IL17RE staining in IBD patients with active disease, compared to IBD patients in remission and healthy controls. Chromogranin A-positive IEC are major producers of IL-17C in the colon, whereas the IL-17RE subunit was only present on lamina propria mononuclear cells but not in IEC. In vitro experiments suggested that IEC lines are not responsive to IL-17C stimulation, even when combined with other cytokines, such as IL-22. Conclusions: This is the first comprehensive study involving human IBD patients which demonstrates an upregulation of the novel IL-17C-IL-17RE cytokine ligand-receptor pair during active human IBD. In contrast to murine models, IL-17RE expression is confined to lamina propria leukocytes and not epithelial cells; specialized chromogranin A-positive cells are among the major producers of IL-17C in the epithelium. Our data indicate that serum IL-17C is modulated by IL23R genotype status. In addition, our data reveal potential novel targets for the pharmacological modulation of epithelium-derived IL-17C.

Tu1713 Role of miR-19b-Targeting SOCS3 in Modulating Production of Chemokine in Colonic Epithelial Cells and Is Associated With the Pathogenesis of Crohn's Disease

Background: To date, the role of IL-17C and its specific receptor subunit IL-17RE in inflammatory bowel disease (IBD) settings is entirely based on murine models. Therefore, the aim of this study was to analyze the role of the novel IL-17 family member IL-17C and its receptor IL-17RE in human IBD. Methods: IL-17C expression in intestinal epithelial cells (IEC) was analyzed by qPCR, immunoblotting, immunohistochemistry, EMSA, RNA interference and pharmacological or antibody-mediated inhibition. IL-17C protein and mRNA expression in IBD patient samples was assessed by ELISA, qPCR and immunohistochemistry. IL-17C serum levels were correlated to IL23R genotype status. Results: IL-17A amplifies IL-17C expression in human IEC upon TNF-α stimulation; this depends on TNFα-activated NF-κB, ERK-1/2 and p38 MAP kinases, and IL-17A-activated Akt kinase, MCPIP and C/EBP-δ pathways. IL-17C serum levels are elevated in patients with ulcerative colitis (UC) (P=0.008). IL-17C mRNA is increased in inflamed colonic sections of IBD patients (P=0.005) and correlates significantly with the mRNA expression of Th1 cytokines (e.g., IFN-γ; P<0.01) and Th17 cytokines (e.g., IL-17A, IL-23, CCL20; P<0.01). Genotyping revealed that UC patients carrying a minor allele of the IL23R SNP rs134351 have decreased IL-17C serum levels (P=0.037). Immunohistochemistry displayed increased IL-17C and IL17RE staining in IBD patients with active disease, compared to IBD patients in remission and healthy controls. Chromogranin A-positive IEC are major producers of IL-17C in the colon, whereas the IL-17RE subunit was only present on lamina propria mononuclear cells but not in IEC. In vitro experiments suggested that IEC lines are not responsive to IL-17C stimulation, even when combined with other cytokines, such as IL-22. Conclusions: This is the first comprehensive study involving human IBD patients which demonstrates an upregulation of the novel IL-17C-IL-17RE cytokine ligand-receptor pair during active human IBD. In contrast to murine models, IL-17RE expression is confined to lamina propria leukocytes and not epithelial cells; specialized chromogranin A-positive cells are among the major producers of IL-17C in the epithelium. Our data indicate that serum IL-17C is modulated by IL23R genotype status. In addition, our data reveal potential novel targets for the pharmacological modulation of epithelium-derived IL-17C.

Association of IL-12B Genetic Polymorphism with the Susceptibility and Disease Severity of Ankylosing Spondylitis

Interleukin 23 (IL-23) stimulates the differentiation of T helper 17 (Th17) cells, which are involved in the pathogenesis of ankylosing spondylitis (AS). Binding of IL-23 to the IL-23 receptor complex activates Janus kinases 2 and tyrosine kinase 2, which phosphorylate IL-23R and subsequently promote the transcription of the IL-17 gene. IL-12B encodes a p40 subunit common to IL-12 and IL-23. We evaluated the effects of IL-12B and IL-23R genotype on the occurrence and clinical features of AS. A total of 362 patients with AS and 362 healthy controls were enrolled in the study. Genotypes of IL-12B A1188C (rs3212227) and IL-23R C2370A (rs10889677) were identified by polymerase chain reaction/restriction fragment-length polymorphism. Disease activity and functional status were assessed by Bath AS indices. Subjects carrying IL-12B CC [matched relative risk (RR(m)) 1.93, 95% CI 1.23-3.03] and IL-12B AC (RR(m) 1.73, 95% CI 1.21-2.46) genotypes had a significantly greater risk of developing AS than subjects with the IL-12B AA genotype. Subjects carrying both IL-12B CC and IL-23R AA genotypes also had a significantly higher risk (RR(m) 2.98, 95% CI 1.51-5.89) of developing AS compared to those with IL-12B AA and IL-23R CC/CA genotypes, and this interaction between IL-12B and IL-23R was significant. Patients with AS who had IL-12B CC and IL-12B AC genotypes had an obviously increased Bath Ankylosing Spondylitis Disease Activity Index score compared to those who carried the IL-12B AA genotype (4.3 vs 3.7). The IL-12B A1188C genotype was associated with the development and disease severity of AS.

Association between interleukin 23 receptor polymorphism and kidney transplant outcomes: A 10-year Taiwan cohort study

ObjectiveInterleukin 23 receptor (IL-23R) plays a role in the pathogenesis of multiple autoimmune processes. The relationship between allograft outcomes and the IL-23Rvariant genotypes has not been reported on previously. Therefore, we examined the relationship between this genetic polymorphism and kidney transplant outcomes. MethodsThis is an observational cohort study and 422 renal transplant recipients (RTRs) were enrolled. Polymerase chain reaction-restriction fragment length polymorphism was used for the measurement of IL-23R genetic polymorphisms. We used a composite end-point incorporating serum creatinine (SCr) doubling, graft failure and death as the primary outcome. Secondary outcomes included biopsy-proven acute rejection (BPAR), biopsy-proven interstitial fibrosis/tubular atrophy (IF/TA) and individual primary outcome. The risks of developing primary and secondary outcomes were compared between the different IL-23R genotypes and alleles. ResultsWith a mean follow-up of 79.3±28.8months, 26 patients in the IL-23R genotype AA group and 32 patients in the IL-23R genotype AC/CC group reached the primary outcome (p=0.061). RTRs who carried the IL-23R AC/CC genotype (aHR 1.78; 95% CI. 1.01–3.12; p=0.046) and C allele (aHR 1.48; 95% CI. 0.96–2.28; p=0.075) had a higher risk of developing primary outcome as compared to those with IL-23R AA genotype and A allele, respectively. Moreover, RTRs who carried the IL-23R AC/CC genotype and C allele had a higher risk of developing biopsy-proven IF/TA (p=0.012; p=0.012) and SCr doubling (p=0.024; p=0.042) as compared to those with IL-23R AA genotype and A allele, respectively. The risk of BPAR, graft failure and death between the IL-23R genotypes and alleles were comparable. ConclusionIL-23R polymorphism may have a potential immuno-modulating role in long-term allograft outcome.

Genetic Variations of Interleukin-23R (1143A>G) and BPI (A645G), but Not of NOD2, Are Associated with Acute Graft-versus-Host Disease after Allogeneic Transplantation

Single nucleotide polymorphisms (SNPs) in genes of the immune system predict for aGVHD and mortality after allo-SCT. We investigated the effect of SNPs in the NOD2, BPI, and IL-23R genes on posttransplantation outcome in a cohort of 304 patients. NOD2 patient and donor genotype and BPI recipient genotype were not associated with the occurrence of aGVHD. However, IL-23R-SNP in the donor was correlated with less aGVHD. This association could be confirmed in multivariate analysis (odds ratio [OR], 0.39; P = .039), which identified in vivo T cell depletion (OR, 0.32; P < .001) and multiagent GVHD prophylaxis (OR, 0.51; P = .031) as other independent factors predicting for less-severe aGVHD. This multivariate model also revealed a trend toward less aGVHD in patients receiving a BPI G allele transplant (OR, 0.60; P = .067) and in those receiving a transplant from an HLA-matched donor (OR, 0.57; P = .058). Incontrast, relapse was more frequent in patients with NOD2-SNPs (46.2% for SNP vs 33.2% for wild-type; P= .020). This association was found to be of borderline significance in multivariate analysis. Neither BPI nor IL-23R genotype predicted for relapse, and none of the investigated SNPs was correlated with 5-year overall survival. In our analysis, NOD2 SNPs did not predict aGVHD, but IL-23R(1142A>G) and BPI(A645G) SNPs appeared to be promising markers in this regard. The importance of these markers in prediction models for GVHD and relapse remain to be defined in large prospective clinical trials.

The presence of fistulas and NOD2 homozygosity strongly predict intestinal stenosis in Crohn’s disease independent of the IL23R genotype

We analyzed the prevalence of concomitant intestinal stenosis in patients with fistulizing Crohn's disease (CD), including the NOD2/CARD15 and IL23R genotype status. Medical records of n = 1,110 patients with inflammatory bowel diseases were screened for patients with fistulizing and stricturing CD. Study inclusion required diagnosis of stenosis made within 6 months of diagnosing fistulas. CD-associated NOD2 and IL23R variants were genotyped. Similarly, we prospectively investigated 42 patients presenting with fistulizing CD. In the retrospective study (n = 333 CD patients), fistulas were found in 145 (43.5%) patients and stenoses in 223 (67.0%) patients. Concomitant stenosis was diagnosed in 125 patients with fistulas resulting in a positive predictive value (PPV) of 86.2% for fistulas predicting intestinal stenosis (p = 5.53 x 10(-11); OR 5.74, 95% CI 3.22-10.50). In logistic regression analysis, presence of fistulas (OR 4.51; 95% CI 2.54-8.01, p = 2.68 x 10(-7)) and disease duration (OR 1.09; 95% CI 1.05-1.13; p = 3.19 x 10(-6)) were strongly associated with intestinal stenosis. NOD2 genotype information, but not IL23R status, increased the PPV for the correct diagnosis of stenosis (PPV = 89.9%). All homozygous carriers (100%) of NOD2 variants with fistulizing CD were diagnosed with stenosis; 1007fs homozygotes were found more often among patients with fistulas and stenoses than in patients without stenoses and fistulas (p = 0.00037). Similar results were found in the prospective analysis, in which 83.3% of the patients with fistulizing CD had concomitant stenosis. Fistulizing CD is strongly associated with concomitant intestinal stenosis, particularly in homozygous carriers of NOD2 mutations.

Disease Activity, ANCA, and IL23R Genotype Status Determine Early Response to Infliximab in Patients With Ulcerative Colitis

We analyzed the efficacy and safety of the antitumor necrosis factor-alpha antibody infliximab (IFX) for induction therapy in patients with moderate-to-severe ulcerative colitis (UC) in a large single-center cohort. A total of 90 UC patients treated with IFX for 14 weeks were analyzed retrospectively. Colitis activity index (CAI) and markers of inflammation were measured during IFX induction therapy. Genotyping for UC-associated variants in the IL23R gene and in the IL2/IL21 region was performed. At week 2 (after the first IFX infusion), 64.1% of IFX-treated patients had clinical response to IFX and 52.6% were in remission. At week 14 (after three infusions), 61.0% showed clinical response and 52.5% were in remission. The mean CAI decreased significantly from 10.4 points at week 0 to 5.1 at week 2 (P<0.001), to 4.4 at week 6 (P<0.001), and to 5.0 at week 14 (P<0.001). Similarly, IFX therapy significantly decreased C-reactive protein levels and leukocyte counts (P=0.01 and P=0.001 at week 2 and week 0, respectively). Multivariate regression analysis identified high CAI before IFX therapy (P=0.01) and negative antineutrophil cytoplasmatic autoantibody (ANCA) status (P=0.01) as independent positive predictors for response to IFX. Homozygous carriers of inflammatory bowel disease (IBD) risk-increasing IL23R variants were more likely to respond to IFX than were homozygous carriers of IBD risk-decreasing IL23R variants (74.1 vs. 34.6%; P=0.001). No serious adverse IFX-related events requiring hospitalization were recorded. Our findings suggest that IFX therapy is safe and effective in patients with moderate-to-severe UC. A high CAI before IFX therapy, ANCA seronegativity, and the IL23R genotype were predictors of early response to IFX.

Disease activity, pANCA and IL23R genotype status determine early response to infliximab in patients with ulcerative colitis

Introduction: We analysed efficacy and predictors of response to anti-TNF-α antibody induction therapy using infliximab (IFX) in patients with moderate-to-severe ulcerative colitis (UC) in a large single center cohort.

NOD2/CARD15 genotype influences MDP-induced cytokine release and basal IL-12p40 levels in primary isolated peripheral blood monocytes

The functional link between mutations in NOD2 and Crohn's disease (CD) has not been entirely elucidated. The 1007fs mutation results in loss of NF-kappaB activation in response to muramyl dipeptide (MDP) but has also been linked to an increased IL-1beta processing and IL-12 release. We investigated the basal and MDP-triggered mRNA expression and protein release for TNF-alpha, IL-10, IL-1beta, and IL-12p40 in peripheral blood monocytes from 40 CD patients and 15 healthy individuals with different NOD2 genotypes. Monocytes from individuals with 2 mutated NOD2 alleles (homozygous and compound-heterozygous individuals) displayed an impaired release of TNF-alpha and IL-10 but also of IL-1beta and IL-12p40 in response to MDP. In contrast to other NOD2 variants, the presence of at least 1 1007fs allele in double-mutated individuals completely abrogated NOD2 receptor function. Interestingly, monocytes from CD patients with 2 mutated NOD2 alleles displayed significantly higher basal levels of IL-12p40 in cell culture supernatants compared to wildtype CD patients and control individuals (P = 0.002 and P = 0.008, respectively). This was regardless of the IL23R genotype and was not mirrored by increased IL-12p40 plasma levels in these individuals. The CD-associated NOD2 variants lead, in a dose- and mutation-dependent manner, to an impaired release of TNF-alpha, IL-10, IL-1beta, and IL-12p40 in response to MDP. The finding of increased basal levels for IL-12p40-related cytokines in monocytes with 2 mutated NOD2 alleles is likely to set a new link between NOD2 mutations and the inflammatory mechanisms underlying CD.

Reduced Incidence of Severe Acute GVHD in Patients Transplanted from Donors with IL23R (Arg381Gln) Gene Variant.

Background. Recently, a gene polymorphism of the IL23R gene (Arg381Gln), which is a subunit of the receptor of the pro-inflammatory cytokine interleukin-23, was found to be strongly associated with Crohn's disease (Duerr et al.Science 2006). The exchange of arginine with glutamine at position 381 of IL23R causes a blockade of the IL-23 signaling pathway, which confers strong protection against Crohn's disease. Because IL-23 activity is participated in autoimmune diseases, we hypothesized that it might also be important in the development of GVHD reaction post allogeneic transplantation.Methods .Here we evaluated 401 patients with their donors for the occurrence of the IL23R gene variant (Arg381Gln, 1142 G>A) by real-time PCR who underwent allogeneic transplantation.Results. We analyzed the IL23 gene variant 1142 G>A in a cohort of 221 transplant recipients and their HLA-identical sibling donors and in a second cohort of 186 transplant recipients and their HLA- identical unrelated donors. A heterozygous Arg381Gln gene variant was found in 13,1% of patients and in 11,3% of donors. The donor's IL-23R genotype was significantly associated with a reduced risk of severe acute GVHD in both cohorts for patients after transplant. Analysis of all 407 transplant recipients showed that IL-23R (1142G>A, Arg381Gln) genotype of the donor were associated with a decreased risk of grade II-IV acute GVHD (31.6% compared to 51.0%, p=0.02) and severe acute GVHD III or IV (3.91% compared 23.4%, p=0.003). Death in remission was significantly lower in patients transplanted from donors with variante of IL23-R (11.7% versus 27.7%, p=0.028), whereas overall survival or relapse rates were not influenced significantly by the IL-23R genotype. The multivariate analysis including factors which influence the occurrence of severe acute GVHD as disease stage, age of patients (>or <40 years, gender constellation of recipient and donor, graft source, HLA-status (HLA-identical versus non-identical), donor constellation (sibling versus unrelated) confirmed that the gene variant of IL23R at the donor site confers protection against the occurrence of acute GVHD grade II-IV or severe acute GVHD grade III-IV. The association of IL23R mutation to GVHD was stronger than NOD2 mutations.Conclusions. The results presented here suggest that IL-23 signaling pathway may play an important role in development of acute GVHD after transplant. Blockade of IL-23 signaling could be a rational therapeutic strategy for GVHD.

Linking genetic susceptibility to Crohnʼs disease with Th17 cell function: IL-22 serum levels are increased in Crohnʼs disease and correlate with disease activity and IL23R genotype status

We analyzed the influence of Crohn's disease (CD)-associated IL23R gene variants on IL-22 that is expressed in IL-23R+ Th17 cells. IL-22 serum levels were measured in 242 CD patients and in 31 healthy controls. Subanalyses included serum levels of IL-6, TNF-alpha, IL-17A, IL-17F, C-reactive protein (CRP), and leukocyte count. In all patients, genotyping for 10 CD-associated IL23R single nucleotide polymorphisms (SNPs) and the 3 main CD-associated CARD15 variants was performed. There was a highly significant increase in IL-22 serum expression in CD patients compared to healthy controls (P = 2.53 x 10(-9)). IL-22 serum levels correlated with disease activity: IL-22 levels in patients with a Crohn's disease activity index (CDAI) >150 were significantly higher than in patients with a CDAI <150 (P = 0.001), while TNF-alpha and IL-6 were not significantly different between these 2 groups. Analyzing the effect of 10 IL23R variants on IL-22 serum levels, we demonstrated that the quotients of mean IL-22 serum levels of carriers of the minor allele to the mean serum IL-22 in wildtype carriers correlated highly with the corresponding CD susceptibility risk for each gene variant (r = 0.807). The IL-22 levels in carriers of CD risk-increasing IL23R variants were significantly higher than in carriers of CD risk-decreasing IL23R variants (P = 0.008). The Th17 cytokine IL-22 is expressed at high levels in CD and correlates with disease activity, offering a better separation between active and inactive CD than IL-6 and TNF-alpha. IL23R genotypes influence IL-22 serum expression, linking genetic CD susceptibility to Th17 cell function for the first time.

IL23R R381Q and ATG16L1 T300A Are Strongly Associated With Crohn's Disease in a Study of New Zealand Caucasians With Inflammatory Bowel Disease

Recently, separate genome-wide association analyses have identified nonsynonymous SNPs in IL23R and ATG16L1 (rs11209026; c1142G>A, R381Q, and rs2241880; c1338A>G, T300A, respectively) as strong candidate susceptibility factors for Crohn's disease (CD) in whites. The aim of our study was to test whether these SNPs are associated with CD in a population-based cohort of New Zealand Caucasian inflammatory bowel disease (IBD) patients. Allele frequencies of rs11209026 and rs2241880 were determined in 496 CD patients, 466 ulcerative colitis (UC) patients, and 591 controls. Distribution of the relevant alleles was compared between controls and IBD patients. rs11209026 and rs2241880 genotype distributions were examined both within IBD clinical subphenotypes and CARD15 genotypes. rs11209026 and rs2241880 were both associated with CD (P valuers11209026=0.0026, OR 0.54, 95% CI 0.36-0.81; P valuers2241880=0.0001, OR 1.41, 95% CI 1.18-1.67). In addition, there was evidence for association of rs11209026 with UC (P value=0.037, OR 0.66, 95% CI 0.45-0.98). No significant association was observed between IL23R genotype or ATG16L1 genotype and IBD subphenotypes. IL23R was associated with CD and UC only in the absence of CARD15 mutations, whereas ATG16L1 was associated with CD in the presence and absence of CARD15 mutations. We replicated the previously reported associations between CD and rs11209026 and rs2241880, confirming that IL23R and ATG16L1 are susceptibility loci for CD in the New Zealand population. We also provide further evidence for association of rs11209026 with UC and a report of an additive effect between IL23R and CARD15 genotypes in CD.