Ancestral diversity in pharmacogenomics affects treatment for Hispanic/Latine populations with inflammatory bowel disease.

BACKGROUND AND AIMS: The prevalence of inflammatory bowel disease (IBD) among Hispanic/Latine communities is increasing. Pharmacogenomic studies reveal genetic markers that influence treatment decisions. The aim of our study was to examine the frequency and impact of genetic polymorphisms on thiopurine-associated leukopenia (NUDT15, TPMT) and anti-TNF immunogenicity (HLA-DQA1*05) in a cohort of Hispanic patients of diverse ancestral backgrounds. METHODS: We performed a multicenter, retrospective cohort study comprised of 2225 Hispanic participants. We measured the frequency of variation affecting drug response in NUDT15, TPMT, and HLA-DQA1*05, their ancestral origin (European, African, or Amerindian), and the rate of development of myelosuppression and immunogenicity to thiopurines and anti-TNFs, respectively, in exposed patients. RESULTS: NUDT15 and TPMT variants were rare, except for rs116855232 in NUDT15 which was common only in alleles of Amerindian origin. All NUDT15 variant alleles were inherited on an Amerindian haplotype, and among the Amerindian allele subset, the variant frequency of NUDT15*4 (rs147390019) was a remarkable 23% in patients with leukopenia but only 3% in patients without leukopenia. HLA-DQA1*05 and its European tagging variant rs2097432 were common in alleles from all ancestral origins and demonstrated association with immunogenicity to anti-TNFs. However, rs2097432 was only correlated with HLA-DQA1*05 in the European allele subset. CONCLUSION: These findings indicate that NUDT15 testing should become standard clinical practice before prescribing thiopurines in individuals with Amerindian ancestry, including Hispanic individuals. Additionally, rs2097432 should not be used as a surrogate for HLA-DQA1*05 testing for diverse populations. Ultimately, incorporating ancestry in personalized therapeutic approaches is important for treatment of Hispanic patients with IBD.

Cathelicidin suppresses lipid accumulation and hepatic steatosis by inhibition of the CD36 receptor.

BACKGROUND AND OBJECTIVES: Obesity is a global epidemic which increases the risk of the metabolic syndrome. Cathelicidin (LL-37 and mCRAMP) is an antimicrobial peptide with an unknown role in obesity. We hypothesize that cathelicidin expression correlates with obesity and modulates fat mass and hepatic steatosis. MATERIALS AND METHODS: Male C57BL/6 J mice were fed a high-fat diet. Streptozotocin was injected into mice to induce diabetes. Experimental groups were injected with cathelicidin and CD36 overexpressing lentiviruses. Human mesenteric fat adipocytes, mouse 3T3-L1 differentiated adipocytes and human HepG2 hepatocytes were used in the in vitro experiments. Cathelicidin levels in non-diabetic, prediabetic and type II diabetic patients were measured by enzyme-linked immunosorbent assay. RESULTS: Lentiviral cathelicidin overexpression reduced hepatic steatosis and decreased the fat mass of high-fat diet-treated diabetic mice. Cathelicidin overexpression reduced mesenteric fat and hepatic fatty acid translocase (CD36) expression that was reversed by lentiviral CD36 overexpression. Exposure of adipocytes and hepatocytes to cathelicidin significantly inhibited CD36 expression and reduced lipid accumulation. Serum cathelicidin protein levels were significantly increased in non-diabetic and prediabetic patients with obesity, compared with non-diabetic patients with normal body mass index (BMI) values. Prediabetic patients had lower serum cathelicidin protein levels than non-diabetic subjects. CONCLUSIONS: Cathelicidin inhibits the CD36 fat receptor and lipid accumulation in adipocytes and hepatocytes, leading to a reduction of fat mass and hepatic steatosis in vivo. Circulating cathelicidin levels are associated with increased BMI. Our results demonstrate that cathelicidin modulates the development of obesity.

A validated web-based tool to display individualised Crohn's disease predicted outcomes based on clinical, serologic and genetic variables.

BACKGROUND: Early treatment for Crohn's disease (CD) with immunomodulators and/or anti-TNF agents improves outcomes in comparison to a slower 'step up' algorithm. However, there remains a limited ability to identify those who would benefit most from early intensive therapy. AIM: To develop a validated, individualised, web-based tool for patients and clinicians to visualise individualised risks for developing Crohn's disease complications. METHODS: A well-characterised cohort of adult patients with CD was analysed. Available data included: demographics; clinical characteristics; serologic immune responses; NOD2 status; time from diagnosis to complication; and medication exposure. Cox proportional analyses were performed to model the probability of developing a CD complication over time. The Cox model was validated externally in two independent CD cohorts. Using system dynamics analysis (SDA), these results were transformed into a simple graphical web-based display to show patients their individualised probability of developing a complication over a 3-year period. RESULTS: Two hundered and forty three CD patients were included in the final model of which 142 experienced a complication. Significant variables in the multivariate Cox model included small bowel disease (HR 2.12, CI 1.05-4.29), left colonic disease (HR 0.73, CI 0.49-1.09), perianal disease (HR 4.12, CI 1.01-16.88), ASCA (HR 1.35, CI 1.16-1.58), Cbir (HR 1.29, CI 1.07-1.55), ANCA (HR 0.77, CI 0.62-0.95), and the NOD2 frameshift mutation/SNP13 (HR 2.13, CI 1.33-3.40). The Harrell's C (concordance index for predictive accuracy of the model) = 0.73. When applied to the two external validation cohorts (adult n = 109, pediatric n = 392), the concordance index was 0.73 and 0.75, respectively, for adult and pediatric patients. CONCLUSIONS: A validated, web-based tool has been developed to display an individualised predicted outcome for adult patients with Crohn's disease based on clinical, serologic and genetic variables. This tool can be used to help providers and patients make personalised decisions about treatment options.

Clinical and demographic characteristics predictive of treatment outcomes for certolizumab pegol in moderate to severe Crohn's disease: analyses from the 7-year PRECiSE 3 study.

BACKGROUND: Clinical factors were previously identified as predictors of short-term treatment efficacy in Crohn's disease (CD). The PRECiSE 3 (P3) 7-year trial provides an opportunity to study predictors of short- and long-term clinical remission among CD patients treated with certolizumab pegol (CZP). AIM: To identify factors that influence long-term remission of CD with CZP treatment. METHODS: Patients who had completed placebo-controlled studies (PRECiSE 1/PRECiSE 2, P1/P2) enrolled in P3 and received open-label CZP 400 mg every 4 weeks up to 7 years. Baseline predictors included, but were not limited to, smoking status, disease duration, prior inflammatory bowel disease (IBD) surgery, Harvey-Bradshaw Index (HBI), albumin, haematocrit and CZP exposure; association with time to initial remission (HBI ≤4) was tested for patients who received CZP in P1/P2; time to loss of remission/frequency of maintenance of remission was also tested. Univariate analyses and multivariate Cox or logistic regression models were used. RESULTS: Predictors for initial remission (N = 377) included age, haematocrit, prior IBD surgery and entry HBI (P < 0.05 for all). Predictors for loss of remission (N = 437) included HBI, serum albumin concentration, haematocrit, smoking status and exposure. Predictors of maintenance of remission (N = 437) included haematocrit, IBD surgery, HBI, disease duration, serum albumin concentration and exposure. Significant predictors were confirmed with stepwise multivariate regression models. CONCLUSIONS: These analyses identified several influential parameters for short-and long-term remission of Crohn's disease with certolizumab pegol treatment. The data yield valuable hypotheses regarding factors that influence certolizumab pegol treatment. More investigation is needed. (ClinicalTrials.gov identifier NCT00552058).

Linkage of Crohn's disease-related serological phenotypes: NFKB1 haplotypes are associated with anti-CBir1 and ASCA, and show reduced NF-kappaB activation.

BACKGROUND AND AIMS: Genetics studies of the serum expression of antibodies to microbial antigens may yield important clues to the pathogenesis of Crohn's disease. Our aim was to conduct a linkage study using expression of anti-CBir1, anti-I2, anti-OmpC and ASCA as quantitative traits. METHODS: Expression of antibodies to microbial antigens was measured by enzyme-linked immunosorbant assay (ELISA) and a standard approximately 10 cM whole genome microsatellite study was conducted. Single nucleotide polymorphism genotyping was performed using either Illumina or TaqMan MGB technology. Nuclear factor Kappa B (NF-kappaB) activation in cells from Epstein-Barr virus (EBV)-transformed cell lines was assessed using an electrophoretic mobility shift assay and protein was measured using ELISA and western blotting. RESULTS: Evidence for linkage to anti-CBir1 expression was detected on human chromosome 4 (logarithm of odds (LOD) 1.82 at 91 cM). We therefore directly proceeded to test the association of haplotypes in NFKB1, a candidate gene. One haplotype, H1, was associated with anti-CBir1 (p = 0.003) and another, H3, was associated with ASCA (p = 0.023). Using cell lines from Crohn's disease patients with either H1 or H3, NF-kappaB activation and NF-kappaB p105 and p50 production were significantly lower for patients with H1 compared to patients with H3. CONCLUSIONS: These results suggest that NFKB1 haplotypes induce dysregulation of innate immune responses by altering NF-kappaB expression. The results also show the use of EBV-transformed lymphoblastoid cell lines to conduct phenotypic studies of genetic variation.

Risks and benefits of azathioprine therapy.

The risk of lymphoma may be increased by about fourfold in patients with inflammatory bowel disease treated with thiopurines. The increased risk could be a result of the medications, the severity of the underlying disease, or a combination of the two.

Analysis of the IBD5 locus and potential gene-gene interactions in Crohn's disease.

BACKGROUND AND AIMS: Genetic variation in the chromosome 5q31 cytokine cluster (IBD5 risk haplotype) has been associated with Crohn's disease (CD) in a Canadian population. We studied the IBD5 risk haplotype in both British and Japanese cohorts. Disease associations have also been reported for CARD15/NOD2 and TNF variants. Complex interactions between susceptibility loci have been shown in animal models, and we tested for potential gene-gene interactions between the three CD associated loci. METHODS: Family based association analyses were performed in 457 British families (252 ulcerative colitis, 282 CD trios) genotyped for the IBD5 haplotype, common CARD15, and TNF-857 variants. To test for possible epistatic interactions between variants, transmission disequilibrium test analyses were further stratified by genotype at other loci, and novel log linear analyses were performed using the haplotype relative risk model. Case control association analyses were performed in 178 Japanese CD patients and 156 healthy controls genotyped for the IBD5 haplotype. RESULTS: The IBD5 haplotype was associated with CD (p=0.007), but not with UC, in the British Caucasian population. The CARD15 variants and IBD5 haplotype showed additive main effects, and in particular no evidence for epistatic interactions was found. Variants from the IBD5 haplotype were extremely rare in the Japanese. CONCLUSIONS: The IBD5 risk haplotype is associated with British CD. Genetic variants predisposing to CD show heterogeneity and population specific differences.

Treatment of intestinal Behçet's syndrome with chimeric tumour necrosis factor alpha antibody.

Few patients with Behçet's syndrome have gastrointestinal ulceration. Such patients are difficult to treat and have a higher mortality. Faced with refractory symptoms in two patients with intestinal Behçet's, we used the tumour necrosis factor alpha (TNF-alpha) monoclonal antibody infliximab to induce remission. Both women (one aged 27 years, the other 30 years) presented with orogenital ulceration, pustular rash, abdominal pain, bloody diarrhoea due to colonic ulceration, weight loss, and synovitis. One had thrombophlebitis, digital vasculitis, perianal fistula, and paracolic abscess; the other had conjunctivitis and an ulcer in the natal cleft. Treatment with prednisolone, methyl prednisolone, and thalidomide in one and prednisolone, colchicine, and cyclosporin in the other was ineffective. After full discussion, infliximab (3 mg/kg, dose reduced because of recent sepsis in one, and 5 mg/kg in the other) was administered. Within 10 days the ulcers healed, with resolution of bloody diarrhoea and all extraintestinal manifestations. A second infusion of infliximab was necessary eight weeks later in one case, followed by sustained (>15 months) remission on low dose thalidomide. Remission was initially sustained for 12 months in the other but thalidomide had to be stopped due to intolerance, and a good response to retreatment lasted only 12 weeks without immunosuppression, before a third infusion. The cause of Behçet's syndrome is unknown but peripheral blood CD45 gammadelta T cells in Behçet's produce >50-fold more TNF-alpha than controls when stimulated with phorbol myristate acetate and anti-CD3. Infliximab could have a role for inducing remission in Behçet's syndrome.