Colonization during a key developmental window reveals microbiota-dependent shifts in growth and immunity during undernutrition.

BACKGROUND: Childhood undernutrition is a major global health challenge with devastating lifelong consequences. Linear growth stunting due to undernutrition has been linked to poor health outcomes, and mothers who experience growth stunting in childhood are more likely to give birth to stunted children later in life. Based on these findings, we hypothesized that intergenerational colonization of mice with microbiota from human donors with undernutrition may recapitulate certain immune and growth changes observed in this disorder. RESULTS: To test this hypothesis, we developed a gnotobiotic murine model of undernutrition using microbiota from human infants with healthy or stunted growth trajectories. Intergenerational colonization with microbiota derived from children with growth stunting lead to less linear growth and the development of immune features of undernutrition and enteropathy, including intestinal villus blunting, lower liver IGF-1 and accumulation of intraepithelial lymphocytes and plasma cells in the small intestine. In contrast, colonization after weaning lead to fewer host phenotypic changes between these distinct microbial communities. CONCLUSIONS: These results are broadly consistent with previous findings demonstrating that exposure of the immune system to microbial products during the weaning phase is a critical determinant of later life immune function. Overall, our results suggest intergenerational colonization with human microbiota samples is a useful approach with which to investigate microbiota-dependent changes in growth and immunity in early life. Murine models that capture the intergenerational and multifactorial nature of undernutrition are critical to understanding the underlying biology of this disorder. Video Abstract.

Colonization during a key developmental window reveals microbiota-dependent shifts in growth and immunity during undernutrition.

Childhood undernutrition is a major global health challenge with devastating lifelong consequences. Linear growth stunting due to undernutrition has been linked to poor outcomes, and mothers who experience stunting are more likely to give birth to stunted children. Murine models that capture the intergenerational and multifactorial nature of undernutrition are critical to understanding the underlying biology of this disorder. Here we report a gnotobiotic mouse model of undernutrition using microbiota from human infants with healthy or stunted growth trajectories. Intergenerational transmission of microbiota from parents to offspring leads to the development of growth and immune features of undernutrition and enteropathy, including reduced linear growth, intestinal villus blunting and accumulation of intraepithelial lymphocytes. In contrast, colonization after weaning reduces sensitivity to detect changes driven by distinct microbial communities. Overall, these results suggest intergenerational colonization is a useful approach with which to investigate microbiota-dependent growth and immunity in early life.

Hypersensitivity Reaction to Ustekinumab in Pediatric and Young Adult Inflammatory Bowel Disease Patients: A Case Series.

Ustekinumab (UST) is a human IgG1K monoclonal antibody that binds to the p40 receptor subunit bound by cytokines IL-12 and IL-23. It is indicated in both Crohn's disease and ulcerative colitis as a second-line agent. The safety and efficacy of UST in children and young adults has not been thoroughly studied. We report a case series of six pediatric patients and young adults who developed hypersensitivity reactions during intravenous infusion with UST. These reactions ranged from mild allergic reactions to anaphylaxis, with no detectable antibodies if tested. We hypothesize the reaction could be secondary to ethylenediaminetetraacetic acid, which is present solely in the intravenous preparation. Patients who experience hypersensitivity reactions during their UST infusion may safely receive subcutaneous preparations of UST, as demonstrated by some patients who received it based on physician discretion. Further investigation is required to establish the etiology of infusion reactions.

Antitumor Necrosis Factor-Alpha (TNF-α) Infliximab-Induced Pleural Effusion and Pericarditis in Crohn's Disease.

Crohn's disease (CD) is a chronic inflammatory disease that can be associated with intestinal and extraintestinal manifestations. Some patients are treated with infliximab, an antitumor necrosis factor-alpha (TNF-α) agent, to help them achieve and maintain clinical and biochemical remission. However, some patients with CD can present severe adverse effects such as drug-induced lupus and rarely present with pleural space and pericardium involvement. We report a case of an 18-year-old Hispanic male with CD who acquired anti-TNF-α-induced lupus after infliximab therapy presenting with pleural effusion and pericarditis. The patient presented with a 2-week history of pleuritic chest pain. Initial laboratory workup was remarkable for leukocytosis and increased inflammatory markers. Imaging and cardiovascular studies were consistent with pericarditis and pleural effusions. Serositis was initially thought to be reactive secondary to the current Mycoplasma pneumoniae infection. He was treated with colchicine 0.6 mg PO TID for six weeks and azithromycin 500 mg PO for seven days. Pain improved after discharge but resurfaced on the day of infliximab infusion. Imaging and cardiovascular studies demonstrated the persistence of pleural effusions and pericarditis. Ultrasound-guided thoracentesis was consistent with exudative pleural effusions. Rheumatological workup was remarkable for increased antihistone antibodies, consistent with drug-induced lupus. Infliximab-induced pericarditis and pleural effusions are rarely reported in the literature. It is thought that infliximab may have a proinflammatory activity or have a delayed type III hypersensitivity reaction. The first line of therapy of anti-TNF-α-induced lupus is the withdrawal of the offending drug. Our patient is unique as few cases of anti-TNF-α-induced pleural effusion and pericarditis in CD are reported. After discontinuing the offending drug, ustekinumab was started, and maintaining a steroid and colchicine regimen, the patient's chest pain improved. Antihistone antibodies have returned to normal one month after starting ustekinumab.

Very Early-Onset Inflammatory Bowel Disease (VEO-IBD) Presenting with Recurrent Leukocytoclastic Vasculitis Preceded by Streptococcal Pharyngitis.

Inflammatory bowel disease (IBD) that presents in children <6 years of age is known as very early-onset IBD (VEO-IBD). Extraintestinal manifestations in IBD, such as erythema nodosum (EN), pyoderma gangrenosum (PG), and, less likely, leukocytoclastic vasculitis (LV), are more commonly present in Crohn's disease. Association between LV and ulcerative colitis (UC) is not commonly seen. We report a case of a 6-year-old female with a VEO-IBD UC phenotype presenting with multiple episodes of leukocytoclastic vasculitis, each preceded by streptococcal pharyngitis. Prior to the diagnosis of VEO-IBD, a skin biopsy was obtained and had shown leukocytoclastic vasculitis with a negative IgA stain. Initial laboratory results were remarkable for leukocytosis and increased anti-strep O and anti-DNase B titers. Gastrointestinal panel PCR demonstrated Clostridium difficile toxin A/B. Treatment for LV consisted of methylprednisolone IV 20 mg for four days with a weaning schedule of prednisolone for two weeks and naproxen 250 mg BID for three days. Clostridium difficile was treated with metronidazole 250 mg TID for ten days. She remained stable for three years until she presented with continuous bloody stools, newly onset chest pain, and shortness of breath. Computed tomography angiogram (CTA) was normal. Stool calprotectin was elevated at 658 mcg/gm. Abdominal magnetic resonance enterography (MRE), esophagogastroduodenoscopy, and colonoscopy confirmed a VEO-IBD ulcerative colitis phenotype. She was started on infliximab 10 mg/kg every four weeks after infliximab titers, and antibodies were obtained. Currently, the patient remains on clinical and biochemical remission, with no recent LV episodes or recurrence of streptococcal pharyngitis. Our patient is unique as no case report has been published with multiple episodes of leukocytoclastic vasculitis in association with a VEO-IBD UC phenotype.