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Growth failure remains a common complication of pediatric Crohn's disease (CD) and has been associated with small bowel involvement and need for surgery. We have reported that patients with elevated (≥ 1.6 μg/mL) granulocyte macrophage colony stimulating factor autoantibodies (GM-CSF Ab) are more likely to experience complicated ileal disease requiring surgery. We hypothesized that concurrent GM-CSF Ab and CARD15 risk allele carriage (C15(+) GMAb(+) ) would be associated with growth failure in CD and growth hormone (GH) resistance in murine ileitis.We enrolled 229 pediatric CD patients at two sites and determined CARD15 genotype, serum GM-CSF Ab, and GH binding protein (GHBP), and height (HTz) and weight (WTz) z-scores at diagnosis. Ileitis was induced in card15-deficient mice by GM-CSF neutralization and nonsteroidal antiinflammatory drug (NSAID) exposure. Hepatic GH receptor (GHR) abundance and GH-dependent Stat5 activation were determined by western blot and Igf-I mRNA expression by real-time polymerase chain reaction (PCR).Mean (95% confidence interval [CI]) HTz at diagnosis was reduced to -0.48 (-4.2, 2.3) in C15(+) GMAb(+) patients, compared to -0.07 (-4.9, 3.4) in disease controls (P ≤ 0.05). Circulating GHBP, as a marker for tissue GHR abundance, was reduced in C15(+) GMAb(+) patients. Hepatic GHR abundance, GH induction of Stat5 tyrosine phosphorylation, and Igf-I mRNA expression were reduced in male card15-deficient mice with ileitis due to GM-CSF neutralization and NSAID exposure.Innate dysfunction due to concurrent genetic variation in CARD15 and neutralizing GM-CSF Ab is associated with linear growth failure in pediatric CD, and hepatic GH resistance in murine ileitis.

BACKGROUND: Alterations in intestinal permeability have been implicated in the pathogenesis of Crohn disease (CD). We have reported that granulocyte macrophage-colony-stimulating factor (GM-csF) is required for mucosal barrier function in mice, and elevated neutralizing GM-CsF autoantibodies (Ab) are associated with stricturing ileal disease and surgery in patients with CD. We hypothesized that children with CD with elevated GM-CSF Ab would exhibit increased intestinal permeability. PATIENTS AND METHODS: Subjects were divided into 3 groups: 15 with CD andhigh GM-CSF Ab (≥1.6 μg/mL, GM-CSF Ab Hi), 12 with CD and low GM-CSF Ab (

Systemic exposure to lipopolysaccharide (LPS) has been linked to clinical disease activity in adults with inflammatory bowel disease (IBD). We hypothesized that markers of LPS exposure and the acute phase response (APR) would be increased in pediatric IBD patients with growth failure, and that LPS signaling would be required for induction of the APR in murine colitis.Serum markers of LPS exposure, endotoxin core IgA antibody (EndoCAb), and the APR, LPS binding protein (LBP) were quantified in pediatric IBD patients and controls. LBP and cytokine production were determined after administration of trinitrobenzene sulfonic acid (TNBS) enemas to mice with genetic deletion of Toll-Like receptor 4 (TLR4), and wildtype (WT) controls.Serum EndoCAb and LBP were significantly elevated in patients with Crohn's disease (CD), compared to disease controls with ulcerative colitis (UC) and healthy controls (P0.001). This was independent of disease activity or location. CD patients with elevated serum EndoCAb and LBP exhibited linear growth failure which persisted during therapy. Serum LBP increased in WT mice following TNBS administration, in conjunction with increased serum TNF-alpha, IL-6, and IL-10, and expansion of regulatory T-cell numbers. Both the APR and expansion of foxp3+ T cells were abrogated in TLR4-deficient mice, in conjunction with a reduction in acute weight loss.LPS exposure and a persistent APR are associated with growth failure in pediatric CD. LPS signaling is required for the APR in murine colitis. Therapies targeting this pathway may benefit the subset of patients with refractory growth failure.