Interleukin-23 Receptor Variants Research Articles

Interleukin-23 Receptor Gene Variants in Acute Lymphoblastic Leukemia and Their Relation to Prognostic Factors.

Interleukin (IL)-23 has an important role in tumor immune regulation. To investigate the possible association of interleukin-23 receptor (IL23R) gene variants rs1884444, rs10889677 and rs11209026 with development of acute lymphoblastic leukemia (ALL). The IL23R variants were studied in 164 ALL patients and compared to 175 healthy controls by polymerase chain reaction-restriction fragment length polymorphism. The relationship between these variants and clinical and laboratory features of the patients and response to therapy were evaluated. No significant differences in genotype and allele frequencies existed between patients and controls. The rs1884444TG genotype was significantly lower in patients who relapsed (24.2%) compared to those without relapse (55.9%, p=0.006). Fewer patients who relapsed had evidence of the G allele (p=0.034). The TG genotype was associated with a longer complete remission at 1804±116 days compared to other genotypes (<1217 days, p=0.028), however, this result was not significant in multivariate analysis. The rs10889677 AA genotype and A allele were associated with age (p<0.041) and platelet number (p=0.03) in precursor-B cell ALL (B-ALL) patients. Both occurred more frequently in patients aged 2-10 years (63.6% and 66%, respectively) and in those with platelets >100×10ˆ3 μL (68.4% and 52.4%, respectively). Our findings showed a lack of association of the studied polymorphisms with the risk of ALL. The influence of the rs1884444 polymorphism on relapse rate and association of rs10889677 AA genotype with favorable prognostic factors suggest the effect of the studied polymorphisms on ALL response to therapy and prognosis.

Human and Murine Interleukin 23 Receptors Are Novel Substrates for A Disintegrin and Metalloproteases ADAM10 and ADAM17

IL-23 (interleukin 23) regulates immune responses against pathogens and plays a major role in the differentiation and maintenance of TH17 cells and the development of autoimmune diseases and cancer. The IL-23 receptor (IL-23R) complex consists of the unique IL-23R and the common IL-12 receptor β1 (IL-12Rβ1). Differential splicing generates antagonistic soluble IL-23R (sIL-23R) variants, which might limit IL-23-mediated immune responses. Here, ectodomain shedding of human and murine IL-23R was identified as an alternative pathway for the generation of sIL-23R. Importantly, proteolytically released sIL-23R has IL-23 binding activity. Shedding of IL-23R was induced by stimulation with the phorbol ester phorbol 12-myristate 13-acetate (PMA), but not by ionomycin. PMA-induced shedding was abrogated by an ADAM (A disintegrin and metalloprotease) 10 and 17 selective inhibitor, but not by an ADAM10 selective inhibitor. ADAM17-deficient but not ADAM10-deficient HEK293 cells failed to shed IL-23R after PMA stimulation, demonstrating that ADAM17 but not ADAM10 cleaves the IL-23R. Constitutive shedding was, however, inhibited by an ADAM10 selective inhibitor. Using deletions and specific amino acid residue exchanges, we identified critical determinants of ectodomain shedding within the stalk region of the IL-23R. Finally, interaction studies identified domains 1 and 3 of the IL-23R as the main ADAM17 binding sites. In summary, we describe human and murine IL-23R as novel targets for protein ectodomain shedding by ADAM10 and ADAM17.

IL23R (Interleukin 23 Receptor) Variants Protective against Inflammatory Bowel Diseases (IBD) Display Loss of Function due to Impaired Protein Stability and Intracellular Trafficking

Genome-wide association studies as well as murine models have shown that the interleukin 23 receptor (IL23R) pathway plays a pivotal role in chronic inflammatory diseases such as Crohn disease (CD), ulcerative colitis, psoriasis, and type 1 diabetes. Genome-wide association studies and targeted re-sequencing studies have revealed the presence of multiple potentially causal variants of the IL23R. Specifically the G149R, V362I, and R381Q IL23Rα chain variants are linked to protection against the development of Crohn disease and ulcerative colitis in humans. Moreover, the exact mechanism of action of these receptor variants has not been elucidated. We show that all three of these IL23Rα variants cause a reduction in IL23 receptor activation-mediated phosphorylation of the signal-transducing activator of transcription 3 (STAT3) and phosphorylation of signal transducing activator of transcription 4 (STAT4). The reduction in signaling is due to lower levels of cell surface receptor expression. For G149R, the receptor retention in the endoplasmic reticulum is due to an impairment of receptor maturation, whereas the R381Q and V362I variants have reduced protein stability. Finally, we demonstrate that the endogenous expression of IL23Rα protein from V362I and R381Q variants in human lymphoblastoid cell lines exhibited lower expression levels relative to susceptibility alleles. Our results suggest a convergent cause of IL23Rα variant protection against chronic inflammatory disease.

Smoking behaviour modifies IL23r‐associated disease risk in patients with Crohn's disease

The etiology of Crohn's disease (CD) implicates both genetic and environmental factors. Smoking behavior is one environmental risk factor to play a role in the development of CD. The study aimed to assess the contribution of the interleukin 23 receptor (IL23R) in determining disease susceptibility in two independent cohorts of CD, and to investigate the interactions between IL23R variants, smoking behavior, and CD-associated genes, NOD2 and ATG16L1. Ten IL23R single-nucleotide polymorphisms (SNPs) were genotyped in 675 CD cases, and 1255 controls from Brisbane, Australia (dataset 1). Six of these SNPs were genotyped in 318 CD cases and 533 controls from Canterbury, New Zealand (dataset 2). Case-control analysis of genotype and allele frequencies, and haplotype analysis for all SNPs was conducted. We demonstrate a strong increased CD risk for smokers in both datasets (odds ratio 3.77, 95% confidence interval 2.88-4.94), and an additive interaction between IL23R SNPs and cigarette smoking. Ileal involvement was a consistent marker of strong SNP-CD association (P ≤ 0.001), while the lowest minor allele frequencies for location were found in those with colonic CD (L2). Three haplotype blocks were identified across the 10 IL23R SNPs conferring different risk of CD. Haplotypes conferred no further risk of CD when compared with single SNP analyses. IL23R gene variants determine CD susceptibility in the Australian and New Zealand population, particularly ileal CD. A strong additive interaction exists between IL23R SNPs and smoking behavior resulting in a dramatic increase in disease risk depending upon specific genetic background.

IL23R and ATG16L1 variants in Moroccan patients with inflammatory bowel disease.

BackgroundInflammatory bowel diseases (IBD) are chronic diseases of the gastrointestinal tract. Although their pathogenesis is unclear, the combination of genetic predisposition and environmental components are believed to be the main cause of these diseases. Recently, many variants in interleukin 23 receptor (IL23R) and autophagy-related 16-like 1 (ATG16L1) genes have been associated with the disease. Our objective was to assess the frequency of ATG16L1 (T300A) and IL23R (L310P) variants in Moroccan IBD (Crohn’s disease and Ulcerative Colitis) patients and to evaluate a possible effect of these variants on disease’s phenotype and clinical course.Methods96 Moroccan IBD patients and 114 unrelated volunteers were genotyped for ATG16L1 (T300A) and IL23R (L310P) variants by PCR-restriction fragment length polymorphism.ResultsThis is the first report on the prevalence of ATG16L1 (T300A) and IL23R (L310P) variants in a Moroccan group. We found that IL23R (L310P) variant conferred a protective effect for crohn’s disease (CD) but not ulcerative colitis (UC) patients. The presence of ATG16L1 (T300A) mutated alleles was associated with CD type but not with disease onset. In addition, the carriage of T300A variant alleles conferred a protective effect in UC.ConclusionOur results showed that the prevalence of ATG16L1 and IL23R variants was not significantly different between patients and controls. However a possible role of ATG16L1 (T300A) on CD phenotype was suggested.Electronic supplementary materialThe online version of this article (doi:10.1186/1756-0500-7-570) contains supplementary material, which is available to authorized users.

Interleukin-23 receptor single nucleotide polymorphisms in ulcerative colitis. A study in Iranian populations

Genetic factors seem to play an important role in the pathogenesis of ulcerative colitis (UC). Genome wide association studies showed a highly significant association between interleukin 23 receptor (IL23R) single nucleotide polymorphisms (SNPs) and Crohn's disease; however, there are contrary results regarding the disease-modifying effects of IL23R variants in UC. This study was performed in a group of patients with UC to test the possible role of IL23R SNPs in conferring susceptibility or protection against the disease. The study was performed on 67 Iranian adult patients with UC and 78 healthy controls. Eight IL23R SNPs were genotyped, using real-time polymerase chain reaction (RT-PCR). The frequencies of alleles and genotype at each position were determined and compared between two groups of patients and controls. The frequency of the T allele at position rs1343151 was significantly higher in the patient group, compared to the controls (P=0.018). The TT genotype at the same position was also significantly overrepresented in the patient group (P=0.02). There was no significant difference in alleles and genotype frequencies of other SNPs between patients and controls. This study identified a new susceptibility locus associated with UC. Our findings provide further insight into the genetics of UC, which might be amenable to future therapeutic intervention.

PWE-106 Association Study Of Il23R And Atg16L1 Variants In Ibd Moroccan Patients

IntroductionIBD (Crohn’s disease and Ulcerative Colitis) is chronic and multifactorial disease of the gastrointestinal tract. Although several studies have tried to explore these diseases, their pathogenesis is still unclear. Recently,...

Protective effect of interleukin-23A (IL23A) haplotype variants on type 1A diabetes mellitus in a Brazilian population

The Interleukin 23 (IL-23) has a central role in autoimmunity. Allelic variants of p19 subunit of IL-23 (IL23A) and IL-23 receptor (IL23R) genes and increased IL-23 serum concentrations were associated with autoimmune diseases. We therefore searched for variants of IL23A and IL23R that could predispose to Type 1 diabetes (T1D). The coding regions and boundary intron sequences of IL23A were sequenced. Variants of IL23A and of IL23R were also genotyped. Pancreatic and extrapancreatic autoantibodies and IL-23 serum levels were determined. The cohort involved 370 patients with T1D and 351 healthy control subjects. We observed only one coding IL23A variant (rs11171806 G>A) out of the 6 described in databases. As the G alleles of rs11171806 and rs2066808 variants of IL23A gene were in strong linkage disequilibrium (D′=−0.825 for controls, p<2.0×10−6 and D′=−0.902, p<2.0×10−17 for patients), further analyses were performed with the haplotypes. The GG haplotype was more frequent in controls (16.7%) than in T1D patients (9.5%), conferring a protection to T1D (OR=0.53; pc=0.0003). No association was found between IL23A allelic variants with age at diagnosis of diabetes, C-peptide levels or frequency of autoantibodies. IL23R variants (rs10889677 and rs11209026) frequency and IL-23 serum concentrations were similar between groups. The GG haplotype of lL23A variants (rs11171806 and rs2066808) was protective against T1D. IL23R variants (rs11209026 and rs10889677) were not associated with T1D. IL-23 serum concentrations did not differ between groups.

O015 Unexpected complex STAT3 activation routes and lack of negative feedback inhibition by suppressor of cytokine signaling (SOCS) proteins in Interleukin 23 signal transduction

Introduction Signaling of Interleukin 23 (IL-23) via the IL-23 receptor (IL-23R) and the IL-12 receptor beta 1 (IL-12R β 1) controls innate and adaptive immune responses, and is involved in the proliferation of T H 17 cells. Activation of STAT3 appears to be the major signaling pathway of IL-23, and putative STAT binding sites were predicted in the IL-23R but not in the IL-12R β 1 chain. Methods To elucidate the IL-23 signaling pathway in vitro we generated various expression constructs with amino acid mutations using site-directed mutagensis and deletions within the intracellular domain (ICD) of the murine and human IL-23R. Proliferation of stably transduced Ba/F3-gp130 cells expressing the IL-12R β 1 and wild-type IL-23R or the mutated/truncated IL-23R variants has been investigated. Phosphorylation and activation of STAT3 was determined by Western blot and FACS analysis. Results We showed that the predicted STAT binding sites ((p)YXXQ; Y504, Y626 in murine IL 23R and Y484 , Y611 in human IL-23R) mediated STAT3 activation albeit with variable efficiency. Furthermore, we identified two uncommon STAT3 binding/activation sites within the IL-23R. Firstly, the murine IL-23R carried a YPNFQ (Y542) sequence, which acts as an additional activation site of STAT3. Secondly, we identified a phosphotyrosine-independent STAT3 binding motif within the murine and human IL-23R, indicating that pre-association of STAT3 with the IL-23R is required for IL-23 signal transduction. A fourth predicted site, Y416 in murine and Y399 in human IL-23R, was responsible for the activation of the MAPK pathway. In contrast to IL-6-induced short-term STAT3 phosphorylation, cellular activation by IL-23, resulted in long-term STAT3 phosphorylation, indicating that the IL-23R is not a target of negative feedback inhibition by suppressor of cytokine signaling (SOCS) proteins. Conclusion In summary, the uncommon STAT3 activation routes in combination with the lack of negative feedback inhibition by SOCS proteins of the IL-23R might explain why IL-6 is only a short-term differentiation factor, whereas IL-23 is a long-term proliferation factor of T H 17 cells.

IL-23R polymorphisms, HBV infection, and risk of hepatocellular carcinoma in a high-risk Chinese population

The interleukin-23 receptor (IL-23R) plays an important role in the T-helper 17 cell-mediated inflammatory process and is also involved in tumor immune surveillance, which may be linked to carcinogenesis in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). In this study, we hypothesized that potentially functional genetic variants of the IL-23R gene may modify HCC risk. We genotyped two single-nucleotide polymorphisms (SNPs) of IL-23R, rs6682925 and rs1884444, in a case-control study of 837 HCC cases, 899 HBV surface antigen (HBsAg)-positive controls, and 743 HBsAg-negative controls. A reporter gene assay was performed to evaluate the functional relevance of the rs6682925 SNP located at the promoter region of the IL-23R gene. We found that the two SNPs were associated with the risk of HCC when compared with both the HBsAg-positive and -negative controls. When compared with all controls, IL-23R rs6682925 and rs1884444 both increased the HCC risk in a recessive genetic model [rs6682925 CC vs. TT/TC: odds ratio (OR) 1.35, 95% confidence interval (CI) 1.07-1.70; rs1884444 GG vs. TT/TG: OR 1.36, 95% CI 1.05-1.77]. Furthermore, the variant C allele of rs6682925 in the promoter region of IL-23R was associated with increased reporter gene activity. These findings indicate that genetic variants in IL-23R may contribute to HCC development.

Potentially functional polymorphisms in IL-23 receptor and risk of esophageal cancer in a Chinese population

Interleukin-23 (IL-23)/IL-23 receptor (IL-23R) is essential for Th17 cell-mediated immune response, involved in autoimmune diseases and cancer pathogenesis. Two potentially functional genetic single nucleotide polymorphisms (SNPs; IL-23R rs6682925 T>C and rs1884444 T>G) were found to contribute to cancer susceptibility. In our study, we conducted a case-control study including 1,645 patients with esophageal cancer and 1,694 cancer-free controls in a Chinese population to assess the association between the two SNPs and the risk of esophageal cancer. We found that IL-23R rs6682925 TC/CC and rs1884444 TG/GG variant genotypes were associated with significantly increased risk of esophageal cancer [rs1884444: adjusted odds ratio (OR) = 1.16, 95% confidence intervals (CIs) =1.01-1.33; rs6682925: adjusted OR = 1.23, 95% CIs = 1.07-1.42], compared to their corresponding wild-type homozygotes. Furthermore, the increased risks associated with the two SNPs were independent from smoking and alcohol drinking status. These findings indicated that genetic variants in IL-23R may contribute to esophageal cancer risk in our Chinese population.

Polymorphisms of the IL23R Gene Are Associated with Psoriasis but not with Immunoglobulin A Nephropathy in a Hungarian Population

Recently, associations were found between autoimmune diseases and variants of interleukin-23 receptor (IL23R) gene; here, we analyzed the association of nine IL23R polymorphisms with psoriasis and with immunoglobulin A nephropathy (IgAN). Groups of patients with psoriasis, IgAN, and controls were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. We observed a significant increase in the carriage of the minor allele of rs11805303 in psoriasis patients compared to controls. Similarly, for rs2201841 prevalence of the CC genotype and for rs10889677, the AA genotype showed a more than two- and threefold increase, respectively in patients compared to controls. There was no difference in the distribution of IL23R variants between controls and IgAN patients. We confirmed the association of IL23R with psoriasis in a Hungarian population and demonstrated the effect of the rs11805303 SNP, which was tested so far only for other autoimmune diseases. We could not detect any association between the IL23R variants and IgAN.

Replication of association between interleukin-23 receptor (IL-23R) and its ligand (IL-12B) polymorphisms and psoriasis in the Chinese Han population

Psoriasis is an inflammatory skin disease with a multifactorial genetic basis. A recent genome-wide association study identified several psoriasis-predisposing loci, including IL-12B, which encodes the common p40 subunit of interleukin (IL)–12 and IL-23 and the IL-23 receptor gene (IL-23R). To investigate the relationships of these predisposing polymorphisms with psoriasis in the Chinese Han population, we genotyped three representative variants (rs6887695, rs11465817, and rs1343152) in 217 unrelated patients and 288 control subjects using direct sequencing, We further replicated the positive polymorphism, rs6887695, in a larger combined sample that included 578 patients and 1422 controls. We found the single nucleotide polymorphism, rs6887695 (odds ratio = 1.33, 95% confidence interval 1.03–1.73, p = 0.028) of IL-2B to be significantly associated with psoriasis, and a novel halotype A-A of rs11465817-rs1343152 also showed a positive association. Our study confirms the effects of IL-12B and IL-23R variants on psoriasis in East Asian populations, and provides a reference point for further investigation of the role of the IL-12/IL-23 pathway in chronic epithelial inflammation in Asian and other ethnic populations.

Interleukin-23 receptor genetic polymorphisms and Crohn’s disease susceptibility: a meta-analysis

This study was designed to evaluate whether interleukin-23 receptor (IL-23R) polymorphisms were associated with Crohn's disease (CD) susceptibility. PubMed, MEDLINE, and Embase were searched for studies that investigated the IL-23R variants and CD risk. Meta-analysis from all eligible case-control studies was performed to assess the purported associations. Our analysis found that variant minor alleles for single nucleotide polymorphisms (SNPs) rs11209026 (Arg381Gln) (P < 0.00001, OR = 0.43, 95% CI (0.37-0.50)) and rs7517847 (G/G vs. T/T, P < 0.00001, OR = 0.49, 95% CI (0.38-0.64); G/G vs. T/G + T/T, (P < 0.00001, OR = 0.56, 95% CI (0.44-0.72); T/G + G/G vs. T/T, (P < 0.00001, OR = 0.71, 95% CI (0.64-0.79) of IL-23R were inversely associated with CD risk; sensitivity analysis also indicated that Caucasian population with a variant of Arg381Gln has a decreased risk for developing CD (P < 0.00001, OR = 0.43, 95% CI (0.36-0.50)). Our meta-analysis supports that two polymorphisms (Arg381Gln and rs7517847) within the IL-23R gene may be considered to be protective factors against developing CD. Further large case-control studies especially concerning ethnicity differences and genotype-phenotype interaction should be performed to clarify possible roles of IL-23R in CD.

NOD2/CARD15,ATG16L1andIL23Rgene polymorphisms and childhood-onset of Crohn’s disease

To assess whether the polymorphisms of NOD2/CARD15, autophagy-related 16-like 1 (ATG16L1), and interleukin-23 receptor (IL23R) genes play a more critical role in the susceptibility of childhood-onset than in adult-onset Crohn's disease (CD). Polymorphisms R702W, G908R, and 3020insC of NOD2/CARD15; rs2241880 A/G of ATG16L1, and rs11209026 (R381Q) of IL23R gene were assessed in 110 childhood-onset CD, 364 adult-onset CD, and 539 healthy individuals. Analysis of polymorphisms R702W, G908R, and 3020insC of NOD2/CARD15 genotyping was performed by allele specific polymerase chain reaction (PCR) or by PCR-restriction fragment length polymorphism analysis. The polymorphisms rs2241880 A/G of the ATG16L1, and rs11209026 (R381Q) of the IL23R gene in the children's cohort were genotyped by PCR and melting curve analysis whereas adult group genotyping was performed using the Affymetrix Genome-Wide Human SNP Array 5.0 (500K). The 3020insC allele in NOD2/CARD15 was significantly higher in childhood than in adult-onset CD (P = 0.0067). Association with at least 1 NOD2/CARD15 variant was specific for ileal disease (with or without colonic involvement). Even if the frequency of G allele of the rs2241880 ATG16L1 polymorphism was increased in both paediatric and adult CD patients compared to controls (P = 0.017 and P = 0.001, respectively), no difference was observed between the childhood and the adult cohort. The rare Q allele of IL23R rs11209026 polymorphism was underrepresented in both paediatric and adult CD cases (P = 0.0018 and P = 0.04, respectively) and no difference was observed between the childhood and the adult cohort. The presence of the rs2241880 ATG16L1 and rs11209026 IL23R polymorphisms did not influence disease phenotype. Polymorphism 3020insC in NOD2/CARD15 occurs statistically significantly more often in patients with childhood-onset CD than in patients with adult-onset CD. The ATG16L1 and IL23R variants are associated with susceptibility to CD, but not early-onset disease.

Variants of the IL23R Gene are Associated with Ankylosing Spondylitis but not with Sjögren Syndrome in Hungarian Population Samples

Recently, associations were found between several autoimmune diseases and functional variants of interleukin-23 receptor (IL23R) gene; here, we studied the possible association of nine polymorphisms of IL23R with ankylosing spondylitis (AS) and with Sjögren syndrome (SS). In our study, we genotyped groups of patients with AS (n = 206), SS (n = 156) and healthy controls (n = 235) for rs11805303, rs10889677, rs1004819, rs2201841, rs11209032, rs11209026, rs10489629, rs7517847 and rs7530511 variants using PCR-RFLP methods. We observed significant increase in the carriage of the T allele of rs11805303 and the A allele of rs1004189 in the AS group compared with the controls. For the rs10889677 variant, the prevalence of the AA genotype and for the rs2201841, the CC genotype showed a more than two-fold increase in the AS group compared with the controls. By contrast, the GA heterozygous genotype of rs11209026 variant showed a significant decrease in AS patients compared with controls. Haplotype analysis revealed association of four IL23R haplotypes with AS. There was no difference in the distribution of any of the examined IL23R variants between controls and SS patients. In conclusion, we confirmed the susceptibility or protective associations of IL23R polymorphisms with AS in a Hungarian population and first demonstrated the involvement of the rs11805303 intronic single nucleotide polymorphisms, which was tested so far only for other autoimmune diseases.

IL23R in the Swedish, Finnish, Hungarian and Italian populations: association with IBD and psoriasis, and linkage to celiac disease

BackgroundAssociation of the interleukin-23 receptor (IL23R) with inflammatory bowel disease (IBD) has been confirmed in several populations. IL23R also associates with psoriasis, suggesting that the gene may be an important candidate for many chronic inflammatory diseases.MethodsWe studied association of single-nucleotide variants in IL23R with IBD in Swedish patients, in both Crohn's disease (CD) and ulcerative colitis (UC) subsets. The same genetic variants were also studied in Finnish patients with psoriasis or celiac disease, and in Hungarian and Italian patients with celiac disease.ResultsAssociation of IL23R with IBD was replicated in our Swedish patients, and linkage and association of the IL23R region with psoriasis was found in the Finnish population. The IL23R region was also linked to celiac disease in Finnish families, but no association of IL23R variants with celiac disease was found in the Finnish, Hungarian or Italian samples.ConclusionOur study is the first to demonstrate association of IL23R with CD and UC in Swedish patients with IBD. It is also the first study to report linkage and association of the IL23R region with psoriasis in the Finnish population. Importantly, this is the first report of linkage of the IL23R region to celiac disease, a chronic inflammatory condition in which IL23R has not been previously implicated.

OR.63. Functional Validation of Variants in Interleukin-23 Receptor (IL23R) Associated with Crohn's Disease

OR.63. Functional Validation of Variants in Interleukin-23 Receptor (IL23R) Associated with Crohn's Disease

Association of Interleukin 23 Receptor Variants with Psoriatic Arthritis

A recent genome-wide pooling study noted a significant association of interleukin 23 receptor (IL-23R) and psoriasis. Overxpression of IL-23 has been detected in lesional psoriatic skin, and induces epidermal proliferation. Given the interplay between psoriasis and PsA, we examined the association of IL-23R variants in 2 independent Canadian Caucasian cohorts of patients with psoriatic arthritis (PsA). We examined 496 PsA probands and 476 controls. Cases and controls were genotyped for a panel of 11 single-nucleotide polymorphisms (SNP) in IL-23R. Allele and haplotype associations were calculated using WHAP software. P values for haplotype associations were calculated using a permutation test. The 381Gln allele of the coding SNP Arg381Gln (rs11209026) was found to be protective in the Canadian population (p=0.004; corrected p=0.044). A 2-marker haplotype from SNP rs7530511 and rs11209026 was associated with PsA (p=0.011). All 3-marker sliding windows containing SNP rs11209026 were associated with PsA (p=0.02 for all 3 windows). The magnitude of effect of IL-23R association in PsA appears to be similar to that reported in uncomplicated psoriasis. Significant associations between Arg381Gln SNP and haplotypes encoding this variant were noted in PsA. It remains to be determined what contribution of this association, if any, is specifically due to the inflammatory arthritis (PsA) rather than psoriasis.

Insufficient Evidence for Association of NOD2/CARD15 or Other Inflammatory Bowel Disease-Associated Markers with Gvhd or Other Outcomes in T-Replete, Unrelated Donor Transplantation Facilitated by the NMDP

Genome wide association studies have identified more than 30 distinct loci linked with susceptibility to Crohn's disease (CD), a common idiopathic inflammatory bowel disease (IBD). Among these candidate genes, NOD2/CARD15 encodes a cytosolic protein that recognizes bacterial cell wall components and results in downstream activation of innate pathways of host defense. NOD2/CARD15 Variants are associated with increased susceptibility to CD. IRGM (immunity-related GTPase family, M) is involved in autophagy and intracellular pathogen clearance. Variations in or near the IRGM locus have been associated with increased susceptibility to CD. IL23R (interleukin 23 receptor) variants appear to have a protective role in the development of IBD although the mechanism for this is unknown. Initial studies in European cohorts described an association in which NOD2/CARD15 donor or recipient variants increased severe acute GvHD/transplant-related mortality and reduced survival in HLA-matched sibling transplants. In T cell depleted unrelated donor transplants for acute leukemia, an increased risk of relapse and death was observed in pairs with recipient NOD2/CARD15 variants. However, this association was not confirmed in a recent independent study in 101 unrelated Swedish subjects. No studies have yet evaluated IRGM or IL23R variants in GvHD or other transplant outcomes.Methods: Pre-transplant samples from 390 patients and their 10/10 HLA-A, B, C, DRB1 and DQB1-matched unrelated donors were provided by the National Marrow Donor Program Research Repository. Patients received T-replete transplants for early stage AML, ALL, CML, MDS using myeloablative conditioning and accrued between 1995–2004. Gut decontamination was not routinely used. Patients and donors were of predominately European American descent 92.2% and 94.5%, respectively with 6.7% racial/ethnic minorities. DNA was genotyped for three NOD2/CARD15 SNPs (rs2066844, rs2066845 and rs2066847), two IL23R SNPs (rs11209026 and rs11465804), and two IRGM SNPs (rs4958847 and rs13361189) using Sequenom and/or Taqman assays. Multivariate analyses were performed for overall (OS) and disease free survival (DFS), transplant-related mortality (TRM), relapse, and acute and chronic GvHD, adjusting for clinical variables.Results: Out of 390 donor recipient pairs, NOD2/CARD15 variant SNPs were found in 56 donors (14%) and 67 recipients (17%), with an overall frequency of 16% in this cohort. In 12 pairs (3%), both donor and recipient had a mutant SNP. These frequencies are lower than reported in the earlier European cohorts but our study population included 6.7% racial/ethnic minorities. For IL23R, 13% of donors and 16% of recipients had variant SNPs (n=353 pairs analyzed), with 11 pairs (3%) having both donor and recipient variants. For IRGM, variant SNPs were seen in 23% of both donors and recipients (n=353 pairs analyzed). The overall incidence of 100 day acute grade III–IV (21%) and 1-year chronic (53%) GvHD as well as OS and DFS at 100 days (85 and 84%), 6 months (77 and 74%) and 1 year (67 and 63%) were similar to published outcomes. For IRGM, there was a trend (0.01<p<0.05) for recipient mutations to be associated with higher OS, LFS, and lower TRM. However, none of the 3 IBD-associated alleles showed evidence of a statistically significant association with any of the aforementioned outcomes at p <0.01. In particular there was no association between the three NOD2/CARD15 SNPs (rs2066844, rs2066845 and rs2066847) and the incidence of acute or chronic GvHD.Conclusions: Our study finds insufficient evidence to support an association between the 3 examined IBD-associated SNPs and adverse outcomes following matched unrelated donor HCTs in a (predominately Caucasian) cohort of US patients. Several factors may contribute to this discrepancy from prior studies, including our larger cohort size, differences in patient characteristics, exclusion of sibling matched donor HCTs and T cell depletion procedures. Nevertheless, our findings do not support the use of IBD-associated allele mutation status in the donor/recipient selection process.