Iwona Wrobel

Serum Immune Responses Predict Rapid Disease Progression among Children with Crohn's Disease: Immune Responses Predict Disease Progression

BACKGROUND AND AIM:Crohns disease (CD) is a heterogeneous disorder characterized by diverse clinical phenotypes. Childhood-onset CD has been described as a more aggressive phenotype. Genetic and immune factors may influence disease phenotype and clinical course. We examined the association of immune responses to microbial antigens with disease behavior and prospectively determined the influence of immune reactivity on disease progression in pediatric CD patients.METHODS:Sera were collected from 196 pediatric CD cases and tested for immune responses: anti-I2, anti-outer membrane protein C (anti-OmpC), anti-CBir1 flagellin (anti-CBir1), and anti-Saccharomyces-cerevisiae (ASCA) using ELISA. Associations between immune responses and clinical phenotype were evaluated.RESULTS:Fifty-eight patients (28%) developed internal penetrating and/or stricturing (IP/S) disease after a median follow-up of 18 months. Both anti-OmpC (p < 0.0006) and anti-I2 (p < 0.003) were associated with IP/S disease. The frequency of IP/S disease increased with increasing number of immune responses (p trend = 0.002). The odds of developing IP/S disease were highest in patients positive for all four immune responses (OR (95% CI): 11 (1.5–80.4); p= 0.03). Pediatric CD patients positive for ≥1 immune response progressed to IP/S disease sooner after diagnosis as compared to those negative for all immune responses (p < 0.03).CONCLUSIONS:The presence and magnitude of immune responses to microbial antigens are significantly associated with more aggressive disease phenotypes among children with CD. This is the first study to prospectively demonstrate that the time to develop a disease complication in children is significantly faster in the presence of immune reactivity, thereby predicting disease progression to more aggressive disease phenotypes among pediatric CD patients.

Increased Immune Reactivity Predicts Aggressive Complicating Crohn’s disease in Children

BACKGROUND & AIMS The ability to identify children with CD who are at highest risk for rapid progression from uncomplicated to complicated phenotypes would be invaluable in guiding initial therapy. The aims of this study were to determine whether immune responses and/or CARD15 variants are associated with complicated disease phenotypes and predict disease progression. METHODS Sera were collected from 796 pediatric CD cases and tested for anti-Cbir1 (flagellin), anti-outer membrane protein C, anti-Saccharomyces cerevisiae, and perinuclear antineutrophil cytoplasmic antibody by using enzyme-linked immunosorbent assay. Genotyping (Taqman MGB) was performed for 3 CARD15 variants (single nucleotide polymorphisms 8, 12, and 13). Associations between immune responses (antibody sum and quartile sum score, CARD15, and clinical phenotype were evaluated. RESULTS Thirty-two percent of patients developed at least 1 disease complication within a median of 32 months, and 18% underwent surgery. The frequency of internal penetrating, stricturing, and surgery significantly increased (P trend < .0001 for all 3 outcomes) with increasing antibody sum and quartile sum score. Nine percent of seropositive groups had internal penetrating/stricturing versus 2.9% in the seronegative group (P = .01). Twelve percent of seropositive groups underwent surgery versus 2% in the seronegative group (P = .0001). The highest antibody sum group (3) and quartile sum score group (4) demonstrated the most rapid disease progression (P < .0001). Increased hazard ratio was observed for antibody sum group 3 (7.8; confidence interval, 2.2-28.7), P < .002 and quartile sum score group 4 (11.0; confidence interval, 1.5-83.0, P < .02). CONCLUSIONS The rate of complicated CD increases in children as the number and magnitude of immune reactivity increase. Disease progression is significantly faster in children expressing immune reactivity.

IL-23 Receptor (IL-23R) Gene Protects Against Pediatric Crohn’s Disease

Background The IL‐23 receptor (IL‐23R) has been found to be associated with small bowel Crohns disease (CD) in a whole genome association study. Specifically, the rare allele of the R381Q single nucleotide polymorphism (SNP) conferred protection against CD. It is unknown whether IL‐23R is associated with IBD in children. The aim was to examine the association of IL‐23R with susceptibility to IBD in pediatric patients. Methods DNA was collected from 609 subjects (151 CD and 52 ulcerative colitis [UC] trios). Trios were genotyped for the R381Q SNP of the IL‐23R gene and SNP8, SNP12, SNP13, of the CARD15 gene using Taqman. The transmission disequilibrium test (TDT) was used for association to disease using GENEHUNTER 2.0. Results The rare allele of R381Q SNP was present in 2.7% of CD and 2.9% UC probands. The CARD15 frequency was 31.5% (CD) and 18% (UC). The IL‐23R allele was negatively associated with inflammatory bowel disease (IBD): the R381Q SNP was undertransmitted in children with IBD (8 transmitted [T] versus 27 untransmitted [UT]; P = 0.001). This association was significant for all CD patients (6 T versus 19 UT; P = 0.009), especially for non‐Jewish CD patients (2 T versus 17 UT; P = 0.0006). TDT showed a borderline association for UC (2 T versus 8 UT; P = 0.06). As expected, CARD15 was associated with CD in children by the TDT (58 T versus 22 UT P = 0.00006), but not with UC. Conclusions The protective IL‐23R R381Q variant was particularly associated with CD in non‐Jewish children. Thus, the initial whole genome association study based on ileal CD in adults has been extended to the pediatric population and beyond small bowel CD. (Inflamm Bowel Dis 2007)

Age of diagnosis influences serologic responses in children with Crohn's disease: a possible clue to etiology?

Background: Crohns disease (CD) is often associated with antibodies to microbial antigens. Differences in immune response may offer clues to the pathogenesis of the disease. The aim was to examine the influence of age at diagnosis on the serologic response in children with CD. Methods: Data were drawn from 3 North American multicenter pediatric inflammatory bowel disease (IBD) research consortia. At or shortly after diagnosis, pANCA, ASCA IgA, ASCA IgG, anti‐ompC, and anti‐CBir1 were assayed. The results were compared as a function of age at CD diagnosis (0–7 years versus 8–15 years). Results: In all, 705 children (79 <8 years of age at diagnosis, 626 ≥8 years) were studied. Small bowel CD was less frequent in the younger group (48.7% versus 72.6%; P < 0.0001), while colonic involvement was comparable (91.0% versus 86.5%). ASCA IgA and IgG were seen in <20% of those 0–7 years old compared to nearly 40% of those 8–15 years old (P < 0.001), while anti‐CBir1 was more frequent in the younger children (66% versus 54%, P < 0.05). Anti‐CBir1 detected a significant number of children in both age groups who otherwise were serologically negative. Both age at diagnosis and site of CD involvement were independently associated with expression of ASCA and anti‐CBir1. Conclusions: Compared to children 8–15 years of age at diagnosis, those 0–7 years are more likely to express anti‐CBir1 but only half as likely to express ASCA. These age‐associated differences in antimicrobial seropositivity suggest that there may be different, and as yet unrecognized, genetic, immunologic, and/or microbial factors leading to CD in the youngest children.

Real‐time tool to display the predicted disease course and treatment response for children with Crohn's disease

Background: Immunomodulators and biologics are effective treatments for children with Crohns disease (CD). The challenge of communicating the anticipated disease course with and without therapy to patients and parents is a barrier to the timely use of these agents. The aim of this project was to develop a tool to graphically display the predicted risks of CD and expected benefits of therapy. Methods: Using prospectively collected data from 796 pediatric CD patients we developed a model using system dynamics analysis (SDA). The primary model outcome is the probability of developing a CD‐related complication. Input variables include patient and disease characteristics, magnitude of serologic immune responses expressed as the quartile sum score (QSS), and exposure to medical treatments. Results: Multivariate Cox proportional analyses show variables contributing a significant increase in the hazard ratio (HR) for a disease complication include female gender, older age at diagnosis, small bowel or perianal disease, and a higher QSS. As QSS increases, the HR for early use of corticosteroids increases, in contrast to a decreasing HR with early use of immunomodulators, early or late biologics, and early combination therapy. The concordance index for the model is 0.81. Using SDA, results of the Cox analyses are transformed into a simple graph displaying a real‐time individualized probability of disease complication and treatment response. Conclusions: We have developed a tool to predict and communicate individualized risks of CD complications and how this is modified by treatment. Once validated, it can be used at the bedside to facilitate patient decision making. (Inflamm Bowel Dis 2011;)

Immunogenicity and safety of influenza vaccination in children with inflammatory bowel disease.

Background: Protection against vaccine‐preventable diseases is important in inflammatory bowel disease (IBD) because of increased susceptibility and severity of infection with immunosuppressive therapy. However, immunosuppressive therapy may affect vaccine response. This study aimed to evaluate immunogenicity and safety of influenza vaccination in children with IBD. Methods: In this prospective cohort study, 60 children with IBD and 53 healthy controls had serum collected for preimmunization hemagglutination‐inhibition antibody titers to the 2008 inactivated influenza vaccine components. Three to 5 weeks following vaccine [A/Brisbane/10/2007(H3N2), A/Brisbane/59/2007(H1N1), B/Florida/4/2006] administration, all participants had serum collected for postimmunization titers. A 4‐fold or greater increase between pre‐ and postimmunization titers indicated an immunogenic response; a postimmunization titer ≥1:40 indicated serologic protection. Children with IBD were classified into immunosuppression status by therapy. Results: Seventy percent, 72%, and 53% of children with IBD mounted an immunogenic response to H3N2, H1N1, and influenza B components, respectively. Among children with IBD, serologic protection was achieved in 95%, 98%, and 85% to H3N2, H1N1, and influenza B components, respectively. For influenza B, children with IBD were less likely to mount an immunogenic response compared to controls (53% versus 81%, P = 0.0009), and immunosuppressed children with IBD were less likely to achieve serologic protection compared to nonimmunosuppressed children with IBD (79% versus 100%, P = 0.02). The majority (98%) tolerated the vaccine. Conclusions: Although children with IBD achieve appropriate immunogenicity to influenza A, immunogenicity to influenza B appears to be diminished, especially with immunosuppressive therapy. (Inflamm Bowel Dis 2011;)

Postoperative complications following colectomy for ulcerative colitis in children.

Background and Aims: Colectomy rates for ulcerative colitis (UC) and data on postcolectomy complications in children are limited. Thus, we assessed colectomy rates, early postcolectomy complications, and clinical predictors in children with UC undergoing a colectomy. Methods: Children (18 years old or older) with UC who underwent colectomy from 1983 to 2009 were identified (n = 30). All of the medical charts were reviewed. The diagnostic accuracy of International Classification of Diseases codes for UC and colectomy were validated. The primary outcome was postoperative complications defined as Clavien-Dindo classification grade II or higher. The yearly incidence of colectomies for pediatric UC was calculated and temporal trends were evaluated. Results: The sensitivity and positive predictive value of UC and colectomy International Classification of Diseases codes were 96% and 100%, respectively. The median ages at UC diagnosis and colectomy were 10.9 and 12.1 years, respectively. All of the children had pancolitis and 63% underwent emergent colectomy. Postoperatively, 33% experienced at least 1 complication. Patients with emergent colectomy were more likely to have a postoperative complication compared with patients with elective colectomy (90% vs 50%; P = 0.03). For emergent colectomy, postoperative complications were associated with a disease flare of ≥2 weeks before admission (60% vs 0%; P = 0.03) and >2 weeks from admission to colectomy (78% vs 22%; P = 0.04). The average annual rate of pediatric colectomy was 0.059/100,000 person-years and stable from 1983 to 2009 (P > 0.05). Conclusions: Colectomy UC was uncommon and rates have remained stable. Postcolectomy complications were common, especially in patients undergoing emergent colectomy. Optimizing timing of colectomy may reduce postoperative complications.

Multidimensional prognostic risk assessment identifies association between IL12B variation and surgery in Crohn's disease.

Background: The ability to identify patients with Crohn’s disease (CD) at highest risk of surgery would be invaluable in guiding therapy. Genome-wide association studies have identified multiple IBD loci with unknown phenotypic consequences. The aims of this study were to: (1) identify associations between known and novel CD loci with early resective CD surgery and (2) develop the best predictive model for time to surgery using a combination of phenotypic, serologic, and genetic variables. Methods: Genotyping was performed on 1,115 subjects using Illumina-based genome-wide technology. Univariate and multivariate analyses tested genetic associations with need for surgery within 5 years. Analyses were performed by testing known CD loci (n = 71) and by performing a genome-wide association study. Time to surgery was analyzed using Cox regression modeling. Clinical and serologic variables were included along with genotype to build predictive models for time to surgery. Results: Surgery occurred within 5 years in 239 subjects at a median time of 12 months. Three CD susceptibility loci were independently associated with surgery within 5 years (IL12B, IL23R, and C11orf30). Genome-wide association identified novel putative loci associated with early surgery: 7q21 (CACNA2D1) and 9q34 (RXRA, COL5A1). The most predictive models of time to surgery included genetic and clinical risk factors. More than a 20% difference in frequency of progression to surgery was seen between the lowest and highest risk groups. Conclusions: Progression to surgery is faster in patients with CD with both genetic and clinical risk factors. IL12B is independently associated with need and time to early surgery in CD patients and justifies the investigation of novel and existing therapies that affect this pathway.

Association of Mycobacterium avium subspecies paratuberculosis with Crohn Disease in pediatric patients.

Objectives: The aim of the present study was to determine the prevalence of Mycobacterium avium subsp paratuberculosis (MAP) DNA in intestinal biopsies from pediatric patients with granulomatous Crohn disease (CD) or ulcerative colitis (UC), and matched control subjects without inflammatory bowel disease (IBD). Patients and Methods: DNA was extracted from formalin-fixed paraffin-embedded colonic and ileal biopsies from patients with CD (n = 22) or UC (n = 20), and from controls without IBD (n = 21). IS900 nested polymerase chain reaction was performed in triplicate to determine the presence of MAP-specific DNA. Results: In mucosal biopsies from terminal ileum, IS900 amplicons were detected in 1 of 19 (5.2%) control subjects, 1 of 20 (5%) patients with UC, and 7 of 20 (35%) patients with CD (P < 0.05 vs controls, odds ratio 9.6). In colonic biopsies, IS900 amplicons were detected in 0 of 19 control subjects, 1 of 19 (5.2%) patients with UC, and 5 of 19 (26.3%) patients with CD (P < 0.05 vs controls, odds ratio 14.8). In patients with CD, there was no correlation between disease activity and the presence of IS900. Conclusions: Our technique enabled sensitive and specific detection of MAP DNA in archival endoscopic biopsy specimens. Although MAP-specific DNA can be detected in about 5% of intestinal biopsies from children with UC or controls without IBD, its presence was significantly associated with pediatric granulomatous CD, being particularly prevalent in ileal tissue. This easily defined clinical subset of patients may be useful for additional studies to determine the role of MAP in CD.

Immunogenicity of Influenza Vaccine for Patients with Inflammatory Bowel Disease on Maintenance Infliximab Therapy: A Randomized Trial.

Background:In patients with inflammatory bowel disease (IBD) on infliximab, data are limited on immune response to influenza vaccine and the impact of vaccine timing. The study aims were to evaluate immune responses to the influenza vaccine in IBD patients on infliximab and the impact of vaccine timing on immune responses. Methods:In this randomized study, 137 subjects with IBD on maintenance infliximab therapy were allocated to receive the 2012/2013 inactivated influenza vaccine at the time of infliximab infusion (n = 69) or midway between infusions (n = 68). Serum was collected before and after vaccination for hemagglutination inhibition titers. Serologic protection was defined by postvaccine titer of ≥1:40. Results:Comparing subjects vaccinated at the time of infliximab with those vaccinated midway, serologic protection was achieved in 67% versus 66% to H1N1 (P = 0.8), in 43% versus 49% to H3N2 (P = 0.5), and in 69% versus 79% to influenza B (P = 0.2). Although solicited adverse events were common (60%), no subject experienced a serious adverse event requiring additional medical attention. Only 6% of subjects had a clinically significant increase in disease activity score, not impacted by vaccine timing. Conclusions:Serologic protection to influenza vaccine is achieved in only approximately 45% to 80% of IBD patients on maintenance infliximab therapy varying by antigen. Yet, importantly, vaccine timing relative to infliximab infusion does not affect the achievement of serologic protection, and the influenza vaccine is well tolerated. Therefore, influenza vaccination at any point during infliximab scheduling is recommended for patients with IBD and opportunities to broaden the availability and convenience of influenza vaccine to optimize coverage should be explored.