Martin Wetzke

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

Background: We analyzed the influence of Crohns disease (CD)‐associated IL23R gene variants on IL‐22 that is expressed in IL‐23R+ Th17 cells. Methods: IL‐22 serum levels were measured in 242 CD patients and in 31 healthy controls. Subanalyses included serum levels of IL‐6, TNF‐&agr;, 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. Results: There was a highly significant increase in IL‐22 serum expression in CD patients compared to healthy controls (P = 2.53 × 10−9). IL‐22 serum levels correlated with disease activity: IL‐22 levels in patients with a Crohns disease activity index (CDAI) >150 were significantly higher than in patients with a CDAI <150 (P = 0.001), while TNF‐&agr; 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). Conclusions: 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‐&agr;. IL23R genotypes influence IL‐22 serum expression, linking genetic CD susceptibility to Th17 cell function for the first time.

639 Anti-TNF Antibody-Induced Psoriasiform Skin Lesions in Patients With Inflammatory Bowel Disease Are Characterized by Interferon-y-Expressing TH1 Cells and IL-17A/IL-22-Expressing TH17 Cells and Respond to Anti-IL-12/IL-23 Antibody Treatment

Background We analysed incidence, predictors, histological features and specific treatment options of anti-tumour necrosis factor α (TNF-α) antibody-induced psoriasiform skin lesions in patients with inflammatory bowel diseases (IBD). Design Patients with IBD were prospectively screened for anti-TNF-induced psoriasiform skin lesions. Patients were genotyped for IL23R and IL12B variants. Skin lesions were examined for infiltrating Th1 and Th17 cells. Patients with severe lesions were treated with the anti-interleukin (IL)-12/IL-23 p40 antibody ustekinumab. Results Among 434 anti-TNF-treated patients with IBD, 21 (4.8%) developed psoriasiform skin lesions. Multiple logistic regression revealed smoking (p=0.007; OR 4.24, 95% CI 1.55 to 13.60) and an increased body mass index (p=0.029; OR 1.12, 95% CI 1.01 to 1.24) as main predictors for these lesions. Nine patients with Crohns disease and with severe psoriasiform lesions and/or anti-TNF antibody-induced alopecia were successfully treated with the anti-p40-IL-12/IL-23 antibody ustekinumab (response rate 100%). Skin lesions were histologically characterised by infiltrates of IL-17A/IL-22-secreting T helper 17 (Th17) cells and interferon (IFN)-γ-secreting Th1 cells and IFN-α-expressing cells. IL-17A expression was significantly stronger in patients requiring ustekinumab than in patients responding to topical therapy (p=0.001). IL23R genotyping suggests disease-modifying effects of rs11209026 (p.Arg381Gln) and rs7530511 (p.Leu310Pro) in patients requiring ustekinumab. Conclusions New onset psoriasiform skin lesions develop in nearly 5% of anti-TNF-treated patients with IBD. We identified smoking as a main risk factor for developing these lesions. Anti-TNF-induced psoriasiform skin lesions are characterised by Th17 and Th1 cell infiltrates. The number of IL-17A-expressing T cells correlates with the severity of skin lesions. Anti-IL-12/IL-23 antibody therapy is a highly effective therapy for these lesions.

rs1004819 Is the Main Disease-Associated IL23R Variant in German Crohn's Disease Patients: Combined Analysis of IL23R, CARD15, and OCTN1/2 Variants

Background The IL23R gene has been identified as a susceptibility gene for inflammatory bowel disease (IBD) in the North American population. The aim of our study was to test this association in a large German IBD cohort and to elucidate potential interactions with other IBD genes as well as phenotypic consequences of IL23R variants. Methods Genomic DNA from 2670 Caucasian individuals including 833 patients with Crohns disease (CD), 456 patients with ulcerative colitis (UC), and 1381 healthy unrelated controls was analyzed for 10 IL23R SNPs. Genotyping included the NOD2 variants p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008 and polymorphisms in SLC22A4/OCTN1 (1672 C→T) and SLC22A5/OCTN2 (–207 G→C). Results All IL23R gene variants analyzed displayed highly significant associations with CD. The strongest association was found for the SNP rs1004819 [P = 1.92×10−11; OR 1.56; 95 % CI (1.37–1.78)]. 93.2% of the rs1004819 TT homozygous carriers as compared to 78% of CC wildtype carriers had ileal involvement [P = 0.004; OR 4.24; CI (1.46–12.34)]. The coding SNP rs11209026 (p.Arg381Gln) was protective for CD [P = 8.04×10−8; OR 0.43; CI (0.31–0.59)]. Similar, but weaker associations were found in UC. There was no evidence for epistasis between the IL23R gene and the CD susceptibility genes CARD15 and SLC22A4/5. Conclusion IL23R is an IBD susceptibility gene, but has no epistatic interaction with CARD15 and SLC22A4/5. rs1004819 is the major IL23R variant associated with CD in the German population, while the p.Arg381Gln IL23R variant is a protective marker for CD and UC.

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

OBJECTIVES:We analyzed the efficacy and safety of the antitumor necrosis factor-α antibody infliximab (IFX) for induction therapy in patients with moderate-to-severe ulcerative colitis (UC) in a large single-center cohort.METHODS: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.RESULTS: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.CONCLUSIONS: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.

The ATG16L1 gene variants rs2241879 and rs2241880 (T300A) are strongly associated with susceptibility to Crohn's disease in the German population.

OBJECTIVES:We analyzed ATG16L1, a recently identified Crohns disease (CD) susceptibility gene, in a large cohort with inflammatory bowel disease (IBD) including potential interactions with other IBD genes as well as factors regulating its gene expression.METHODS:Genomic DNA from 2,890 Caucasians including 768 patients with CD, 507 patients with ulcerative colitis (UC), and 1,615 healthy controls was analyzed for 9 different ATG16L1 single nucleotide polymorphisms (SNPs). Genotyping included CARD15/NOD2 variants p.Arg702Trp, p.Gly908Arg, and p.Leu1007fsX1008 and polymorphisms in SLC22A4/OCTN1 (1672 C→T) and SLC22A5/OCTN2 (−207 G→C) as well as 10 CD-associated IL23R variants. The transcriptional regulation of ATG16L1 was studied in intestinal epithelial cells following stimulation with Toll-like receptor (TLR) ligands and proinflammatory cytokines and in a murine ileitis model and CD biopsies.RESULTS:All nine ATG16L1 gene variants analyzed displayed highly significant associations with CD demonstrating a CD-protective effect for the minor allele. The strongest associations were found for rs2241879 and the coding SNP rs2241880 (T300A); P = 3.6 × 10−6 and 3.7 × 10−6, respectively (OR 0.74, 95% CI 0.65–0.84 for both variants). The genotype-phenotype analysis revealed no significant associations. In UC, only rs6431660 was weakly disease-associated. There was no evidence for epistasis between the ATG16L1 gene and other susceptibility genes (IL23R, CARD15, SLC22A4/5). ATG16L1 mRNA expression was not upregulated in CD and murine ileitis, and was less than threefold increased in cells stimulated with proinflammatory cytokines and TLR ligands.CONCLUSION:ATG16L1 is a CD susceptibility gene without epistatic interaction with other CD susceptibility genes and is not upregulated in intestinal inflammation.

Novel Genetic Risk Markers for Ulcerative Colitis in the IL2/IL21 Region Are in Epistasis With IL23R and Suggest a Common Genetic Background for Ulcerative Colitis and Celiac Disease

OBJECTIVES:Recently, a genome-wide association study showed that single-nucleotide polymorphisms (SNPs) in the chromosome 4q27 region containing IL2 and IL21 are associated with celiac disease. Given the increased prevalence of inflammatory bowel disease (IBD) among celiac disease patients, we investigated the possible involvement of these SNPs in IBD.METHODS:Five SNPs strongly associated with celiac disease within the KIAA1109/TENR/IL2/IL21 linkage disequilibrium block on chromosome 4q27 and one coding SNP within the IL21 gene were analyzed in a large German IBD cohort. The study population comprised a total of 2,948 Caucasian individuals, including 1,461 IBD patients (ulcerative colitis (UC): n=514, Crohns disease (CD): n=947) and 1,487 healthy unrelated controls.RESULTS:Three of the five celiac disease risk markers had a protective effect on UC susceptibility, and this effect remained significant after correcting for multiple testing: rs6840978: P=0.0082, Pcorr=0.049, odds ratio (OR) 0.77, 95% confidence interval (CI) 0.63–0.93; rs6822844: P=0.0028, Pcorr=0.017, OR 0.73, 95% CI 0.59–0.90; rs13119723: P=0.0058, Pcorr=0.035, OR 0.75, 95% CI 0.61–0.92. A haplotype consisting of the six SNPs tested was markedly associated with UC susceptibility (P=0.0025, Pcorr=0.015, OR 0.72, 95% CI 0.58–0.89). Moreover, in UC, epistasis was observed between the IL23R SNP rs1004819 and three SNPs in the KIAA1109/TENR/IL2/IL21 block (rs13151961, rs13119723, and rs6822844).CONCLUSIONS:Similar to other autoimmune diseases such as celiac disease, rheumatoid arthritis, type 1 diabetes, Graves’ disease, and psoriatic arthritis, genetic variation in the chromosome 4q27 region predisposes to UC, suggesting a common genetic background for these diseases.

Epistasis Between Toll-Like Receptor-9 Polymorphisms and Variants in NOD2 and IL23R Modulates Susceptibility to Crohn's Disease

OBJECTIVES:Recent data suggest functional interactions between NOD2 and other receptors of the innate immune system modulating inflammatory responses. Here we analyzed the role of Toll-like receptor 9 (TLR-9) gene variants with respect to susceptibility to inflammatory bowel disease (IBD) and tested for genetic interactions with NOD2 and other susceptibility genes for Crohns disease (CD).METHODS:The single-nucleotide polymorphisms (SNPs) –1237T/C (rs5743836) and 2848A/G (rs352140=p.Pro545Pro) in TLR9, the main CD-associated variants within the genes for NOD2, IL23R, ATG16L1, and variants in the IBD5 locus and in the DLG5 gene were assessed in 956 patients with IBD (606 CD and 350 ulcerative colitis) and in 792 healthy controls. The associations with disease susceptibility and phenotype, and epistatic gene–gene interactions, were analyzed.RESULTS:The TLR9 −1237T/C polymorphism showed significant interactions with NOD2 mutations. The frequency of −1237C was significantly higher in CD patients with at least one NOD2 mutation (P=0.004 vs. controls, odds ratio (OR) 1.60, 95% confidence interval (CI) (1.15–2.21)) and further increased in CD patients with two mutated NOD2 alleles (P=0.002 vs. controls, OR 2.37, 95% CI (1.35–4.15)). Significant gene–gene interactions were also observed for the TLR9 polymorphism −1237T/C with IL23R variants (most significantly with rs1004819, P=0.0007), with a particular high frequency of –1237C in CD patients carrying CD-protective IL23R variants. Epistatic interactions of the TLR9 −1237T/C SNP were also noted with the DLG5 113G/A variant (P=0.0007).CONCLUSIONS:Our results provide evidence for genetic interactions between polymorphisms in TLR9 and CD-associated variants in NOD2, IL23R, and DLG5, differentially modulating CD susceptibility.

Pulmonary transplantation of macrophage progenitors as effective and long-lasting therapy for hereditary pulmonary alveolar proteinosis

Macrophage progenitors are an effective and long-lasting therapy of hereditary pulmonary alveolar proteinosis. Macrophages Treat Rare Lung Disease Innate immune cell transplant into the lung could be an effective treatment for a rare lung disease. Happle et al. report that transplanting macrophage progenitors into lungs of a mouse model of hereditary pulmonary alveolar proteinosis (herPAP) improved lung function for up to 9 months after transplant. herPAP is caused by mutations in the granulocyte-macrophage colony-stimulating factor receptor genes, resulting in disturbed alveolar macrophage differentiation and life-threatening respiratory problems. A single transplantation of macrophage progenitors into a mouse model of herPAP resulted in differentiation into functional alveolar macrophages. If these data hold true in humans, this could not only provide a new treatment modality for herPAP but also serve as a proof of principle for other genetic diseases. Hereditary pulmonary alveolar proteinosis (herPAP) is a rare lung disease caused by mutations in the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor genes, resulting in disturbed alveolar macrophage differentiation, massive alveolar proteinosis, and life-threatening respiratory insufficiency. So far, the only effective treatment for herPAP is repetitive whole-lung lavage, a merely symptomatic and highly invasive procedure. We introduce pulmonary transplantation of macrophage progenitors as effective and long-lasting therapy for herPAP. In a murine disease model, intrapulmonary transplanted macrophage progenitors displayed selective, long-term pulmonary engraftment and differentiation into functional alveolar macrophages. A single transplantation ameliorated the herPAP phenotype for at least 9 months, resulting in significantly reduced alveolar proteinosis, normalized lung densities in chest computed tomography, and improved lung function. A significant and sustained disease resolution was also observed in a second, humanized herPAP model after intrapulmonary transplantation of human macrophage progenitors. The therapeutic effect was mediated by long-lived, lung-resident macrophages, which displayed functional and phenotypical characteristics of primary human alveolar macrophages. Our findings present the concept of organotopic transplantation of macrophage progenitors as an effective and long-lasting therapy of herPAP and may also serve as a proof of principle for other diseases, expanding current stem cell–based strategies toward potent concepts using the transplantation of differentiated cells.

IRGM variants and susceptibility to inflammatory bowel disease in the German population.

Background & Aims Genome-wide association studies identified the autophagy gene IRGM to be strongly associated with Crohns disease (CD) but its impact in ulcerative colitis (UC), its phenotypic effects and potential epistatic interactions with other IBD susceptibility genes are less clear which we therefore analyzed in this study. Methodology/Principal Findings Genomic DNA from 2060 individuals including 817 CD patients, 283 UC patients, and 961 healthy, unrelated controls (all of Caucasian origin) was analyzed for six IRGM single nucleotide polymorphisms (SNPs) (rs13371189, rs10065172 = p.Leu105Leu, rs4958847, rs1000113, rs11747270, rs931058). In all patients, a detailed genotype-phenotype analysis and testing for epistasis with the three major CD susceptibility genes NOD2, IL23R and ATG16L1 were performed. Our analysis revealed an association of the IRGM SNPs rs13371189 (p = 0.02, OR 1.31 [95% CI 1.05–1.65]), rs10065172 = p.Leu105Leu (p = 0.016, OR 1.33 [95% CI 1.06–1.66]) and rs1000113 (p = 0.047, OR 1.27 [95% CI 1.01–1.61]) with CD susceptibility. There was linkage disequilibrium between these three IRGM SNPs. In UC, several IRGM haplotypes were weakly associated with UC susceptibility (p<0.05). Genotype-phenotype analysis revealed no significant associations with a specific IBD phenotype or ileal CD involvement. There was evidence for weak gene-gene-interaction between several SNPs of the autophagy genes IRGM and ATG16L1 (p<0.05), which, however, did not remain significant after Bonferroni correction. Conclusions/Significance Our results confirm IRGM as susceptibility gene for CD in the German population, supporting a role for the autophagy genes IRGM and ATG16L1 in the pathogenesis of CD.

Gene Correction of Human Induced Pluripotent Stem Cells Repairs the Cellular Phenotype in Pulmonary Alveolar Proteinosis

RATIONALE Hereditary pulmonary alveolar proteinosis (hPAP) caused by granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor α-chain (CSF2RA) deficiency is a rare, life-threatening lung disease characterized by accumulation of proteins and phospholipids in the alveolar spaces. The disease is caused by a functional insufficiency of alveolar macrophages, which require GM-CSF signaling for terminal differentiation and effective degradation of alveolar proteins and phospholipids. Therapeutic options are extremely limited, and the pathophysiology underlying the defective protein degradation in hPAP alveolar macrophages remains poorly understood. OBJECTIVES To further elucidate the cellular mechanisms underlying hPAP and evaluate novel therapeutic strategies, we here investigated the potential of hPAP patient-derived induced pluripotent stem cell (PAP-iPSCs) derived monocytes and macrophages. METHODS Patient-specific PAP-iPSCs were generated from CD34(+) bone marrow cells of a CSF2RA-deficient patient with PAP. We assessed pluripotency, chromosomal integrity, and genetic correction of established iPSC lines. On hematopoietic differentiation, genetically corrected or noncorrected monocytes and macrophages were investigated in GM-CSF-dependent assays. MEASUREMENTS AND MAIN RESULTS Although monocytes and macrophages differentiated from noncorrected PAP-iPSCs exhibited distinct defects in GM-CSF-dependent functions, such as perturbed CD11b activation, phagocytic activity, and STAT5 phosphorylation after GM-CSF exposure and lack of GM-CSF uptake, these defects were fully repaired on lentiviral gene transfer of a codon-optimized CSF2RA-cDNA. CONCLUSIONS These data establish PAP-iPSC-derived monocytes and macrophages as a valid in vitro disease model of CSF2RA-deficient PAP, and introduce gene-corrected iPSC-derived monocytes and macrophages as a potential autologous cell source for innovative therapeutic strategies. Transplantation of such cells to patients with hPAP could serve as a paradigmatic proof for the potential of iPSC-derived cells in clinical gene therapy.