Experience Using Ustekinumab in Pediatric Patients With Medically Refractory Crohn Disease.

INTRODUCTION: Ustekinumab (UST), a human monoclonal antibody against interleukin-12 and 23, is approved to treat adult patients with psoriasis or Crohn disease (CD). Outcomes data for off-label use in pediatric patients with CD are limited. AIM: We conducted a retrospective cohort study to analyze the long-term efficacy of UST, including dose adjustments, in the treatment of pediatric patients with medically refractory CD. Adverse events were documented. METHODS: We identified 40 pediatric patients with CD treated with UST between January 1, 2016 and December 31, 2019. Electronic medical records were reviewed for demographics, Paris Classification, significant comorbidities, previous CD therapy, adverse events after initiation, and surveillance markers at the time of their first dose and most recent clinic visit. A validated abbreviated pediatric CD activity index (aPCDAI) was used to assess response to therapy. RESULTS: Thirty-eight pediatric patients with CD, including 34.2% with stricturing or penetrating disease, were analyzed after initiation of treatment with UST. Median age at diagnosis of CD was 12.5 years, and median age at UST induction was 17.2 years. No patients were anti-TNF-naive, and 34.2% were previously exposed to 2 or more anti-TNF agents. At time of last follow-up, 84.2% of patients remained on UST for a median duration on UST of 62.1 weeks, and 60.5% achieved clinical remission. Patients had significant improvement in aPCDAI scores, clinical remission rates, albumin, and hematocrit, and 89.5% of patients had no significant adverse events. Similar results were observed among those who required dose adjustment, including 61.1% achieving clinical remission, and among those with perianal disease, including 38.5% achieving clinical remission. CONCLUSIONS: Our data suggest that, within our cohort of pediatric patients with CD, UST has long-term efficacy with no observed safety concerns. Dose adjustment may be helpful in achieving clinical remission.

Non-catalytic ubiquitin binding by A20 prevents psoriatic arthritis-like disease and inflammation.

A20 is an anti-inflammatory protein that is strongly linked to human disease. Here, we find that mice expressing three distinct targeted mutations of A20's zinc finger 7 (ZF7) ubiquitin-binding motif uniformly developed digit arthritis with features common to psoriatic arthritis, while mice expressing point mutations in A20's OTU or ZF4 motifs did not exhibit this phenotype. Arthritis in A20ZF7 mice required T cells and MyD88, was exquisitely sensitive to tumor necrosis factor and interleukin-17A, and persisted in germ-free conditions. A20ZF7 cells exhibited prolonged IκB kinase activity that drove exaggerated transcription of late-phase nuclear factor-κB response genes in vitro and in prediseased mouse paws in vivo. In addition, mice expressing double-mutant A20 proteins in A20's ZF4 and ZF7 motifs died perinatally with multi-organ inflammation. Therefore, A20's ZF4 and ZF7 motifs synergistically prevent inflammatory disease in a non-catalytic manner.

Experience with corrective surgery for postburn contractures in Mumbai, India.

Postburn contracture is a source of significant morbidity in India, even though its occurrence can be reduced significantly by comprehensive postburn injury care, including surgical intervention. This study investigates whether limited access to initial medical care after burn injury has been associated with increased contracture formation among lower socioeconomic class patients in Mumbai, India. During a surgical mission in Mumbai, India, patients presenting with functionally debilitating burn contractures and minimal income were surveyed for initial care received immediately after burn injury. The survey consisted of questions regarding the history of burn injury and details of any initial treatment. Demographic data were collected by chart review. Thirty-eight patients from the state of Maharashtra participated in the study (mean age 28.1 years). The most common etiology of burn injury was from kerosene stove blasts (74%), and the most common morbidities were contractures of the neck and upper extremity. On average, time elapsed since the original injury was 2.8 years. Nearly all patients sought initial medical care at hospitals (97%) with the majority receiving only dressing changes for their full-thickness or deep-dermal burns (61%). The most common reason for not seeking out delayed burn reconstruction was perceived cost (65%). Ultimately, 60 operations were performed, of which 9 (15%) developed postsurgical complications. These data suggest that a subset of lower socioeconomic class burn patients in Maharashtra received suboptimal initial intervention. Comprehensive initial therapy after burn injury may provide better outcomes and limit the number of patients requiring delayed reconstruction.

Systemic signals regulate ageing and rejuvenation of blood stem cell niches.

Ageing in multicellular organisms typically involves a progressive decline in cell replacement and repair processes, resulting in several physiological deficiencies, including inefficient muscle repair, reduced bone mass, and dysregulation of blood formation (haematopoiesis). Although defects in tissue-resident stem cells clearly contribute to these phenotypes, it is unclear to what extent they reflect stem cell intrinsic alterations or age-related changes in the stem cell supportive microenvironment, or niche. Here, using complementary in vivo and in vitro heterochronic models, we show that age-associated changes in stem cell supportive niche cells deregulate normal haematopoiesis by causing haematopoietic stem cell dysfunction. Furthermore, we find that age-dependent defects in niche cells are systemically regulated and can be reversed by exposure to a young circulation or by neutralization of the conserved longevity regulator, insulin-like growth factor-1, in the marrow microenvironment. Together, these results show a new and critical role for local and systemic factors in signalling age-related haematopoietic decline, and highlight a new model in which blood-borne factors in aged animals act through local niche cells to induce age-dependent disruption of stem cell function.

The transcription factor EGR1 controls both the proliferation and localization of hematopoietic stem cells.

EGR1 is a member of the immediate early response transcription factor family and functions in cell growth, development, and stress responses in many tissues. Here we report an additional role for EGR1 in regulating homeostasis of hematopoietic stem cells (HSCs). HSCs normally express Egr1 at high levels, but dramatically downregulate its expression when induced to divide and migrate. Consistent with this finding, mice lacking Egr1 exhibit significant increases in steady-state levels of dividing HSCs in the bone marrow (BM), and a striking spontaneous mobilization of HSCs into the peripheral blood. These data identify EGR1 as a transcriptional regulator of stem cell migration that normally functions to promote HSC quiescence and retention in the niche. The ability of this single factor to regulate both proliferation and mobilization of HSCs suggests that EGR1 commands a genetic program that coordinates stem cell division and migration to maintain appropriate HSC number and function.