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Enhanced Contribution of HLA in Pediatric Onset Ulcerative Colitis.

ABSTRACT: Background:The genetic contributions to pediatric onset ulcerative colitis (UC), characterized by severe disease and extensive colonic involvement, are largely unknown. In adult onset UC, Genome Wide Association Study (GWAS) has identified numerous loci, most of which have a modest susceptibility risk (OR 0.84-1.14), with the exception of the human leukocyte antigen (HLA) region on Chromosome 6 (OR 3.59). Method:To study the genetic contribution to exclusive pediatric onset UC, a GWAS was performed on 466 cases with 2099 healthy controls using UK Biobank array. SNP2HLA was used to impute classical HLA alleles and their corresponding amino acids, and the results are compared with adult onset UC. Results:HLA explained the almost entire association signal, dominated with 191 single nucleotide polymorphisms (SNPs) (p = 5 x 10-8 to 5 x 10-10). Although very small effects, established SNPs in adult onset UC loci had similar direction and magnitude in pediatric onset UC. SNP2HLA imputation identified HLA-DRB1*0103 (odds ratio [OR] = 6.941, p = 1.92*10-13) as the most significant association for pediatric UC compared with adult onset UC (OR = 3.59). Further conditioning showed independent effects for HLA-DRB1*1301 (OR = 2.25, p = 7.92*10-9) and another SNP rs17188113 (OR = 0.48, p = 7.56*10-9). Two HLA-DRB1 causal alleles are shared with adult onset UC, while at least 2 signals are unique to pediatric UC. Subsequent stratified analyses indicated that HLA-DRB1*0103 has stronger association for extensive disease (E4: OR = 8.28, p = 4.66x10-10) and female gender (OR = 8.85, p = 4.82x10-13). Conclusion:In pediatric onset UC, the HLA explains almost the entire genetic associations. In addition, the HLA association is approximately twice as strong in pediatric UC compared with adults, due to a combination of novel and shared effects. We speculate the paramount importance of antigenic stimulation either by infectious or noninfectious stimuli as a causal event in pediatric UC onset.

SUBMITTER: Venkateswaran S

PROVIDER: S-EPMC6350448 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Project description:Ulcerative colitis in children can have a negative effect on quality of life (QOL).We included 16 of 31 patients who underwent colectomy for ulcerative colitis before 20 years of age between 1980 and 2005 at University of California in San Francisco Benioff Children's Hospital. A disease-specific QOL questionnaire (Inflammatory Bowel Disease Questionnaire-32), validated for adults, was used to determine QOL and an additional questionnaire addressing bowel function and reproductive health in long-term follow-up of these patients.Median age at the time of survey was 20.3 years (17.9-25.3), and time postcolectomy was 6.9 years (4.8-9.0). Mean total score was 159.7 ± 43.3 (58-210). Two patients (12.5%) had scores of ? 200, 12 (75.0%) had 101 to 199, and 2 (12.5%) had ? 100. Patients ages 18 years or younger at the time of survey showed higher QOL, particularly in emotional health (P=0.020), social function (P=0.014), and overall QOL (P=0.009). Social function scored highest of all of the systems (median 7; interquartile range 4-7). Patients with scores ? 100 had repeated episodes of pouchitis (16-30) compared with the other 14 patients (0-3). Children who were diagnosed ages 12 years or younger tended to have higher QOL (p=0.072). Years postcolectomy did not correlate to QOL. Eleven patients were sexually active. Two males had feelings of impotence and decreased libido, and 6 females experienced dyspareunia. Three women tried unsuccessfully to conceive after colectomy. One woman became pregnant 4 times, each leading to miscarriage.Younger age at time of colectomy, diagnosis, and survey show higher QOL. Highest satisfaction was found in ability to attend school, work, and social engagements. Pouchitis continued to be an issue for a small number of the patients, with 2 patients having recurring episodes that severely affected QOL. Patients reported decreased sexual activity and fertility at the time of survey due to colectomy, especially for females.

Project description:To investigate efficacy and safety for granulocyte, monocyte apheresis in a population of pediatric patients with ulcerative colitis.The ADAPT study was a prospective, open-label, multicenter study in pediatric patients with moderate, active ulcerative colitis with pediatric ulcerative colitis activity index (PUCAI) of 35-64. Patients received one weekly apheresis with Adacolumn(®) granulocyte, monocyte/macrophage adsorptive (GMA) apheresis over 5 consecutive weeks, optionally followed by up to 3 additional apheresis treatments over 3 consecutive weeks. The primary endpoint was the change in mean PUCAI between baseline and week 12; the secondary endpoint was improvement in PUCAI categorized as (Significant Improvement, PUCAI decrease of ? 35), Moderate Improvement (PUCAI decrease of 20 < 35), Small Improvement (PUCAI decrease of 10 < 20) or No change (PUCAI decrease of < 10).Twenty-five patients (mean age 13.5 years; mean weight 47.7 kg) were enrolled. In the intention-to-treat set (ITT), the mean value for PUCAI improvement was 22.3 [95%CI: 12.9-31.6; n = 21]. In the per-protocol (PP) set, the mean improvement was 36.3 [95%CI: 31.4-41.1; n = 8]. Significant Improvement was recorded for 9 out of 20 patients (45%); 5 out of 20 patients (25%) had Moderate Improvement and one patient (5%) had No Change in PUCAI score at week 12. In the PP set, six out of eight patients (75%) showed Significant Improvement; and in two out of eight patients (25%) Moderate Improvement was recorded. The endoscopic activity index (EAI) decreased by 3 points on average. Seven (7) out of 21 (33%) patients in ITT and 4 out of 8 (50%) patients in PP have used steroids during the clinical investigation. The mean steroid dosage for these patients in the ITT set decreased from a mean 12.4 mg to 10 mg daily on average from Baseline to week 12.Adacolumn(®) GMA apheresis treatment was effective in pediatric patients with moderate active Ulcerative Colitis. No new safety signals were reported. The present data contribute to considering GMA apheresis as a therapeutic option in pediatric patients having failed first line therapy.

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Enhanced Contribution of HLA in Pediatric Onset Ulcerative Colitis.

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