Interleukin-10 receptor mutations in children with neonatal-onset Crohn's disease and intractable ulcerating enterocolitis

Thromboembolic Events in Patients with Inflammatory Bowel Disease: A Comprehensive Overview

Inflammatory bowel disease (IBD), Crohn’s disease and ulcerative colitis are chronic inflammatory disorders of the intestines. The underlying inflammation activates the coagulation cascade leading to an increased risk of developing arterial and venous thromboembolic events such as deep vein thrombosis and pulmonary embolism. Patients with IBD are at a 2–3-fold increased risk of developing thromboembolism. This risk increases in patients with active IBD disease, flare-ups, surgery, steroid treatment, and hospitalization. These complications are associated with significant morbidity and mortality making them important in clinical practice. Clinicians should consider the increased risk of thromboembolic events in patients with IBD and manage them with appropriate prophylaxis based on the risk. In this review, we discuss the literature associated with the pathophysiology of thromboembolism in patients with IBD, summarize the studies describing the various thromboembolic events, and the management of thromboembolism in patients with IBD.

Harnessing the Biology of Canine Intestinal Organoids to Heighten Understanding of Inflammatory Bowel Disease Pathogenesis and Accelerate Drug Discovery: A One Health Approach

In a recent issue of the Lancet, the prevalence of Inflammatory Bowel Disease (IBD) was estimated at 7 million worldwide. Overall, the burden of IBD is rising globally, with direct and indirect healthcare costs ranging between $14.6 and $31.6 billion in the U.S. alone in 2014. There is currently no cure for IBD, and up to 40% of patients do not respond to medical therapy. Although the exact determinants of the disease pathophysiology remain unknown, the prevailing hypothesis involves complex interplay among host genetics, the intestinal microenvironment (primarily bacteria and dietary constituents), and the mucosal immune system. Importantly, multiple chronic diseases leading to high morbidity and mortality in modern western societies, including type II diabetes, IBD and colorectal cancer, have epidemiologically been linked to the consumption of high-calorie, low-fiber, high monosaccharide, and high-fat diets (HFD). More specifically, data from our laboratory and others have shown that repeated consumption of HFD triggers dysbiotic changes of the gut microbiome concomitant with a state of chronic intestinal inflammation and increased intestinal permeability. However, progress in our understanding of the effect of dietary interventions on IBD pathogenesis has been hampered by a lack of relevant animal models. Additionally, current in vitro cell culture systems are unable to emulate the in vivo interplay between the gut microbiome and the intestinal epithelium in a realistic and translatable way. There remains, therefore, a critical need to develop translatable in vitro and in vivo models that faithfully recapitulate human gut-specific physiological functions to facilitate detailed mechanistic studies on the impact of dietary interventions on gut homeostasis. While the study of murine models has been pivotal in advancing genetic and cellular discoveries, these animal systems often lack key clinical signs and temporal pathological changes representative of IBD. Specifically, some limitations of the mouse model are associated with the use of genetic knockouts to induce immune deficiency and disease. This is vastly different from the natural course of IBD developing in immunologically competent hosts, as is the case in humans and dogs. Noteworthily, abundant literature suggests that canine and human IBD share common clinical and molecular features, such that preclinical studies in dogs with naturally occurring IBD present an opportunity to further our understanding on disease pathogenesis and streamline the development of new therapeutic strategies. Using a stepwise approach, in vitro mechanistic studies investigating the contribution of dietary interventions to chronic intestinal inflammation and "gut leakiness" could be performed in intestinal organoids and organoid derived monolayers. The biologic potential of organoids stems from the method's ability to harness hard-wired cellular programming such that the complexity of the disease background can be reflected more accurately. Likewise, the effect of therapeutic drug candidates could be evaluated in organoids prior to longitudinal studies in dog and human patients with IBD. In this review, we will discuss the value (and limitations) of intestinal organoids derived from a spontaneous animal disease model of IBD (i.e., the dog), and how it can heighten understanding of the interplay between dietary interventions, the gut microbiota and intestinal inflammation. We will also review how intestinal organoids could be used to streamline the preclinical development of therapeutic drug candidates for IBD patients and their best four-legged friends.

Characterization of novel and large fragment deletions in exon 1 of the IL10RA gene in Chinese children with very early onset inflammatory bowel diseases

BACKGROUND

Defects in interleukin 10 (IL10) and its receptors are particularly involved in very early onset inflammatory bowel disease (VEOIBD). However, large fragment deletions of IL10 receptor A (IL10RA) are rare.

METHODS

VEOIBD patients with confirmed mutations in the IL10RA gene were enrolled from January 1, 2019 to June 30, 2020. The clinical features and endoscopic-radiological findings of the patients with large fragment deletions of the IL10RA gene were determined and followed up.

RESULTS

Thirty-five patients with IL10RA gene mutations, namely, 28 compound heterozygous mutations and 7 homozygote mutations, were enrolled in this study. Six patients carried the reported point mutation c.301C > T (p. R101RW) or c.537 G > A (p. T179T) in one locus and a large fragment deletion in exon 1 in another locus, which were novel mutations in this gene. A 333-bp deletion of exon 1 (117857034-11857366 del) was the main mutation in this locus in 85.7% of the patients with large fragment deletions. The time of disease onset ranged from birth to 4 years, and diarrhea was the main initial symptom. In total, 6/7 patients had perianal complications, including perianal abscess, fistula and skin tags. Six patients accepted thalidomide treatment, 5/7 accepted mesalamine, 3/7 accepted hematopoietic stem cell transplantation (HSCT), and 3/7 were waiting for HSCT.

CONCLUSIONS

We identified a novel large deletion of exon 1 involving the IL10RA gene for the first time and showed the characteristics of VEOIBD patients. This study expands the spectrum of Chinese VEOIBD patients with IL0RA gene mutations.

Case Report: A Novel Compound Heterozygous Mutation in IL-10RA in a Chinese Child With Very Early-Onset Inflammatory Bowel Disease

Very early-onset inflammatory bowel disease (VEO-IBD) is defined as IBD diagnosed in children younger than 6 years of age. VEO-IBD is often associated with a monogenic etiology or primary immune deficiency. Here, we report the case of a 7-month-old Chinese girl diagnosed with VEO-IBD who had a variant in the interleukin-10 receptor A (IL-10-RA) gene. The patient presented with recurrent fevers, abdominal pain, diarrhea, perianal abscesses, and oral ulcers. Whole-exome sequencing (WES) identified a novel compound heterozygote mutation, c.395T>G (p.Leu132Arg)/ex.1del (p.?), in the IL-10RA gene of the patient. The missense mutation c.395T>G (p.Leu132Arg) was inherited from her mother, and ex.1del (p.?) was inherited from her father. Neither mutation has been reported previously. The IL-10RA function of the patient was defective, as demonstrated by a failure of signal transducer and activator of transcription 3 (STAT3) activation in peripheral blood mononuclear cells (PBMCs) stimulated with recombinant IL-10. The patient underwent matched unrelated peripheral blood hematopoietic stem cell transplantation (HSCT), and the clinical manifestations were dramatically improved. In summary, we identified a novel compound heterozygote mutation, c.395T>G (p.Leu132Arg)/ex.1del (p.?), in IL-10RA that caused VEO-IBD in a Chinese child, which further expands the mutational spectrum of IL-10RA.

A Case of a Two-Month-Old Boy Diagnosed with Infantile Crohn's Disease Based on an Atypical Perianal Lesion

Inflammatory bowel disease is rare in infants, and the early diagnosis is very important. We herein report an infant who received an early diagnosis of infantile Crohn's disease (CD). A two-month-old boy presented with bloody stool. He developed a poor sucking tendency and a painful perianal lesion at three months of age. He was suspected of having infantile CD because of his atypical perianal lesion. Colonoscopy revealed that his perianal lesion had induced rectal longitudinal ulcers. Histology showed no granulomas but patchy inflammation reaching the submucosal layer. He was diagnosed with infantile CD based on the Japanese criteria. CD should be suspected in infants with atypical perianal lesions, irrespective of their age. Early colonoscopy with histology should be considered in these cases in order to prevent adverse outcomes in children.

Monogenic autoinflammatory diseases in children: single center experience with clinical, genetic, and imaging review

Purpose

1. To review the contemporary literature and present a list of the imaging findings for patients with autoinflammatory diseases from our hospital. All these patients are found to have a genetic mutation that is responsible for their disease.

2. To present follow-up imaging findings, when available, and correlate those with symptoms and type of treatment administered in approximately 40 patients with autoinflammatory diseases of a single tertiary pediatric health care center including familial Mediterranean fever, Cryopyrin-associated autoinflammatory syndrome, PAPA (pyogenic arthritis, pyoderma gangrenousum, and acne) syndrome, and more. These findings are related to disease progression, treatment response, or treatment-induced changes.

Conclusion

Autoinflammatory diseases are relatively rare entities that can affect any system of the body. Given the many nonspecific imaging features, awareness of these diseases and good communication with clinicians aid in reaching an accurate diagnosis.

Neonatal Crohn's disease with Oral ulcer as the first symptom caused by a compound heterozygote mutation in IL-10RA: a case report

Objective

To investigate the clinical and genetic characteristics of neonatal Crohn's disease (CD), improve recognition of neonatal CD, and reduce the number of patients that are missed or misdiagnosed.

Methods

A 10-day-old Chinese girl with oral ulcers was admitted to the Department of Neonatology. She later developed a rash and perianal disease, but without diarrhea and stool abnormalities. The patient and her parents underwent next-generation sequencing.

Results

The results showed that the patient carries a compound heterozygous mutation in the interleukin-10 receptor A (IL-10RA) (NM_001558.3) gene. One heterozygous mutation was c.301 c > T, P. (Arg 101 Trp) in exon 3 of IL-10RA (a missense mutation), and the other was c. 537G > A, P. (Thr 179 =) in exon 4 of IL 10RA (a synonymous mutation). The patient's father also carries the c.301 c > T, P. (Arg 101 Trp) heterozygous mutation in exon 3 of IL-10RA, whereas her mother carries the c.537G > A, P. (Thr 179 =) heterozygous mutation in exon 4 of IL-10RA.

Conclusions

The results show that a compound heterozygous mutation in IL-10RA is associated with neonatal CD. Oral ulcers with a rash and perianal disease may be an early symptom of neonatal CD; therefore, such patients should undergo genetic identification as soon as possible.

Targeting IL-10 Family Cytokines for the Treatment of Human Diseases

Members of the interleukin (IL)-10 family of cytokines play important roles in regulating immune responses during host defense but also in autoimmune disorders, inflammatory diseases, and cancer. Although IL-10 itself primarily acts on leukocytes and has potent immunosuppressive functions, other family members preferentially target nonimmune compartments, such as tissue epithelial cells, where they elicit innate defense mechanisms to control viral, bacterial, and fungal infections, protect tissue integrity, and promote tissue repair and regeneration. As cytokines are prime drug targets, IL-10 family cytokines provide great opportunities for the treatment of autoimmune diseases, tissue damage, and cancer. Yet no therapy in this space has been approved to date. Here, we summarize the diverse biology of the IL-10 family as it relates to human disease and review past and current strategies and challenges to target IL-10 family cytokines for clinical use.

Clinical aspects and treatments for pediatric inflammatory bowel disease

The incidence of pediatric inflammatory bowel disease (IBD) is increasing worldwide, especially in the developing countries. It differs from adult disease in clinical manifestations, especially with regard to genetic predisposition in monogenic IBD. Pediatric disease also have a tendency to show more aggressive inflammation and greater extent of lesion. Newer drugs such as antitumor necrosis factor-α have been known to make a difference in treating pediatric IBD. Recent studies suggested that the patients with high risk factors might have some benefits from earlier use of biologics. To achieve treatment goals such as relieving symptoms, optimizing growth, and improving quality of life while minimizing drug toxicity, more research is needed to develop tools for risk stratification in the use of biologics for pediatric IBD.

Clinical Aspects and Treatments for Pediatric Inflammatory Bowel Diseases

The incidence of pediatric inflammatory bowel disease (IBD) is increasing worldwide, especially in the developing countries. It differs from adult disease in clinical manifestations, especially with regard to genetic predisposition in monogenic IBD. Pediatric disease also have a tendency to show more aggressive inflammation and greater extent of lesion. Newer drugs such as anti-tumor necrosis factor α have been known to make a difference in treating pediatric IBD. Recent studies suggested that the patients with high risk factors might have some benefits from earlier use of biologics. To achieve treatment goals such as relieving symptoms, optimizing growth, and improving quality of life while minimizing drug toxicity, more research is needed to develop tools for risk stratification in the use of biologics for pediatric IBD.

Recent Advance in Very Early Onset Inflammatory Bowel Disease

Recent studies on pediatric inflammatory bowel disease (IBD) have revealed that early-onset IBD has distinct phenotypic differences compared with adult-onset IBD. In particular, very early-onset IBD (VEO-IBD) differs in many aspects, including the disease type, location of the lesions, disease behavior, and genetically attributable risks. Several genetic defects that disturb intestinal epithelial barrier function or affect immune function have been noted in these patients from the young age groups. In incidence of pediatric IBD in Korea has been increasing since the early 2000s. Neonatal or infantile-onset IBD develops in less than 1% of pediatric patients. Children with "neonatal IBD" or "infantile-onset IBD" have higher rates of affected first-degree relatives, severe disease course, and a high rate of resistance to immunosuppressive treatment. The suspicion of a monogenic cause of VEO-IBD was first confirmed by the discovery of mutations in the genes encoding the interleukin 10 (IL-10) receptors that cause impaired IL-10 signaling. Patients with such mutations typically presented with perianal fistulae, shows a poor response to medical management, and require early surgical interventions in the first year of life. To date, 60 monogenic defects have been identified in children with IBD-like phenotypes. The majority of monogenic defects presents before 6 years of age, and many present before 1 year of age. Next generation sequencing could become an important diagnostic tool in children with suspected genetic defects especially in children with VEO-IBD with severe disease phenotypes. VEO-IBD is a phenotypically and genetically distinct disease entity from adult-onset or older pediatric IBD.

Genomic and Immunologic Drivers of Very Early-Onset Inflammatory Bowel Disease

PURPOSE OF REVIEW

Inflammatory bowel disease (IBD) is a multifactorial disease caused by dysregulated immune responses to commensal or pathogenic intestinal microbes, resulting in chronic intestinal inflammation. However, a subset of patients with IBD diagnosed <6 years of age, known as very early-onset (VEO)-IBD, can be phenotypically and genetically distinct from older onset IBD. We aim to review the clinical presentation of children with VEO-IBD and recent discoveries that point to the underlying genomic and immunologic drivers of disease, and the significant impact on our therapeutic decisions.

RECENT FINDINGS

VEO-IBD is increasing in incidence and is associated with more severe disease, aggressive progression, and poor response to most conventional therapies. This article will review some of the genetic findings in this population and the subsequent impact on therapy, with targeted approaches.

SUMMARY

Children with VEO-IBD may present with a different phenotype and more severe disease than older children and adults. An integrated approach combining genetics, immunology, and traditional IBD evaluations can lead to the identification of causal defects that directly impact management. These strategies can also be employed in older onset refractory IBD.

Recent advance in very early-onset inflammatory bowel disease

Recent studies on pediatric inflammatory bowel disease (IBD) have revealed that early-onset IBD has distinct phenotypic differences compared with adult-onset IBD. In particular, very early-onset IBD (VEO-IBD) differs in many aspects, including the disease type, location of the lesions, disease behavior, and genetically attributable risks. Neonatal or infantile-onset IBD develops in less than 1% of pediatric patients. Children with infantile-onset IBD have high rates of affected first-degree relatives and severe disease course. The suspicion of a monogenic cause of VEO-IBD was first confirmed by the discovery of mutations in the genes encoding the interleukin 10 (IL-10) receptors that cause impaired IL-10 signaling. Patients with such mutations typically presented with perianal fistulae, shows a poor response to medical management, and require early surgical interventions in the first year of life. To date, 60 monogenic defects have been identified in children with IBD-like phenotypes. The majority of monogenic defects presents before 6 years of age, and many present before 1 year of age. Next generation sequencing could become an important diagnostic tool in children with suspected genetic defects especially in children with VEO-IBD with severe disease phenotypes. VEO-IBD is a phenotypically and genetically distinct disease entity from adult-onset or older pediatric IBD.

CD11b-activated Src signal attenuates neuroinflammatory pain by orchestrating inflammatory and anti-inflammatory cytokines in microglia

Neuroinflammation plays an important role in the induction and maintenance of chronic pain. Orchestra of pattern-recognition receptor-induced pro-inflammatory and anti-inflammatory cytokines is critical for inflammation homeostasis. CD11b on macrophages could inhibit toll-like receptor (TLR) activation-induced inflammatory responses. However, the function of CD11b on microglia remains unknown. In the current study, we demonstrated that CD11b-deficient microglia cells produced more inflammatory cytokines, such as interleukin-6 and tumor necrosis factor alpha, while less anti-inflammatory cytokines. Signal transduction assay confirmed that nuclear factor-κB activation was increased in CD11b-deficient microglia cells, which resulted from decreased activation of Src. Inhibition of Src by PP1 increased inflammation in wild-type microglia cells significantly, but not in CD11b-deficient microglia cells. In vivo, CD11b-deficient mice were more susceptible to chronic constrictive injury-induced allodynia and hyperalgesia with significantly more inflammatory cytokines expression. All these results indicated that the regulatory function of CD11b-Src signal pathway on both inflammatory and anti-inflammatory cytokines in microglia cells is a potential target in neuropathic pain treatment.

Computational Protein Phenotype Characterization of IL10RA Mutations Causative to Early Onset Inflammatory Bowel Disease (IBD)

The deleterious amino acid substitution mutations in IL-10 receptor alpha gene are most frequently reported in several autoimmune diseases including early onset-inflammatory bowel disease (IBD). Despite the important role of IL-10 RA in maintaining immune homeostasis, the specific structural and functional implications of these mutations on protein phenotype, stability, ligand binding and post translational characteristics is not well explored. Therefore, this study performed the multidimensional computational analysis of IL10RA missense variations causative to pediatric or early onset inflammatory bowel disease (<5 years of age). Our computational algorithmic screening identified the deleterious nature of p. W45G, p. Y57C, p. W69G, p.T84I, p.Y91C, p.R101W, p.R117C, and p.R117H, IBD causative IL10-RA mutations. The sensitivity and specificity analysis of different computational methods showed that CADD outperform SIFT, PolyPhen 2.0, FATHMM, LRT, MetaLR, MetaSVM, PROVEAN and Condel in predicting the pathogenicity of IL10RA mutations. Our three-dimensional protein modeling assays showed that the point mutations cause major drifts in the structural plasticity of IL10 RA molecule and negatively influence its stability. Findings from molecular docking analysis have shown that these point mutations decrease the binding affinity of IL10RA toward IL10 and may likely to disturb the IL10 signaling pathway. This study provides an easy frame work for phenotypic characterization of mutant IL10RA molecule in terms of structure, flexibility and stability aspects. Our approach may also add a new dimension to conventional functional biology assays in quickly studying IL10 RA mutations and also for designing and developing inhibitors for mutant IL10RA molecule.

The role of monogenic disease in children with very early onset inflammatory bowel disease

PURPOSE OF REVIEW

Inflammatory bowel disease (IBD) is a multifactorial disease caused by dysregulated immune responses to commensal or pathogenic intestinal microbes, resulting in chronic intestinal inflammation. Patients diagnosed with IBD occurring before the age of 5 are a unique population, known as very early onset (VEO)-IBD and can be phenotypically and genetically distinct from older-onset IBD. We aim to review the clinical presentation of children with VEO-IBD and recent discoveries that point to genomic drivers of disease that may impact our therapeutic decisions.

RECENT FINDINGS

VEO-IBD is increasing in incidence and is associated with more severe disease, aggressive progression and poor response to most conventional therapies. This article will review the advances in sequencing technology that have led to identification of novel gene variants associated with disease and potentially new targeted therapeutic options.

SUMMARY

Children with VEO-IBD may present with a different phenotype and more severe disease than older children and adults. Identification of the causal gene or pathways, these children may allow for true precision medicine with targeted therapy and improved disease course.

Genetic association and epistatic interaction of the interleukin-10 signaling pathway in pediatric inflammatory bowel disease

AIM

To study the genetic association and epistatic interaction of the interleukin (IL)-10 and IL-10/STAT3 pathways in pediatric inflammatory bowel disease (IBD).

METHODS

A total of 159 pediatric inflammatory IBD patients (Crohn’s disease, n = 136; ulcerative colitis, n = 23) and 129 matched controls were studied for genetic association of selected single nucleotide polymorphisms (SNPs) of the IL-10 gene and the genes IL10RA, IL10RB, STAT3, and HO1, from the IL-10/STAT3 signaling pathway. As interactions between SNPs from different loci may significantly affect the associated risk for disease, additive (a) and dominant (d) modeling of SNP interactions was also performed to examine high-order epistasis between combinations of the individual SNPs.

RESULTS

The results showed that IL-10 rs304496 was associated with pediatric IBD (P = 0.022), but no association was found for two other IL-10 SNPs, rs1800872 and rs2034498, or for SNPs in genes IL10RA, IL10RB, STAT3, and HO1. However, analysis of epistatic interaction among these genes showed significant interactions: (1) between two IL-10 SNPs rs1800872 and rs3024496 (additive-additive P = 0.00015, Bonferroni P value (Bp) = 0.003); (2) between IL-10RB rs2834167 and HO1 rs2071746 (dominant-additive, P = 0.0018, Bp = 0.039); and (3) among IL-10 rs1800872, IL10RB rs2834167, and HO1 rs2071746 (additive-dominant-additive, P = 0.00015, Bp = 0.005), as well as weak interactions among IL-10 rs1800872, IL-10 rs3024496, and IL-10RA (additive-additive-additive, P = 0.003; Bp = 0.099), and among IL10RA, IL10RB, and HO1 genes (additive-dominant-additive, P = 0.008, Bp = 0.287).

CONCLUSION

These results indicate that both the IL-10 gene itself, and through epistatic interaction with genes within the IL-10/STAT3 signaling pathway, contribute to the risk of pediatric IBD.

IL-10 and IL-10 Receptor Mutations in Very Early Onset Inflammatory Bowel Disease

Very early onset inflammatory bowel disease (VEO-IBD) is a unique disease entity with a complex genetic susceptibility in affected patients. Next-generation gene sequencing techniques have revealed various monogenetic mutations contributing to the pathogenesis of VEO-IBD, including interleukin 10 (IL-10) and IL-10 receptor (IL-10R) mutations. In this article, we reviewed the features of and effective therapeutic options for VEO-IBD with IL-10 and/or IL-10R mutations. The IL-10 signal pathway inhibits the release of several key cytokines and thereby has a significant anti-inflammatory effect in the gastrointestinal tract. Mutations of the genes encoding IL-10 and/or IL-10R have been detected in VEO-IBD patients among myriad populations throughout the world. VEO-IBD patients with IL-10 or IL-10R mutations often present with repeated bouts of bloody diarrhea, marked weight loss, growth retardation, and recurrent perianal problems, including abscesses, fistulas, and significant fissures. Moreover, some patients may have folliculitis and present with pulmonary infections. While the therapeutic efficacy of immunosuppressants is typically poor in these patients, allogeneic hematopoietic stem cell transplantation (HSCT) has been reported to improve symptoms significantly. However, the long-term prognosis of VEO-IBD patients with IL-10 or IL-10R gene mutations treated with HSCT requires further exploration to verify the efficacy and safety of this treatment. We concluded that clinicians should recognize the clinical phenotype of VEO-IBD, as mutational analysis of the IL-10 pathway can support the diagnosis and prompt early treatment of this complicated disease.

Targeted Sequencing and Immunological Analysis Reveal the Involvement of Primary Immunodeficiency Genes in Pediatric IBD: a Japanese Multicenter Study

PURPOSE

Pediatric inflammatory bowel disease (IBD) is a heterogeneous disorder caused by multiple factors. Although genetic and immunological analyses are required for a definitive diagnosis, no reports of a comprehensive genetic study of a Japanese population are available.

METHODS

In total, 35 Japanese patients <16 years of age suffering from IBD, including 27 patients aged <6 years with very early-onset IBD, were enrolled in this multicenter study. Exome and targeted gene panel sequencing was performed for all patients. Mutations in genes responsible for primary immunodeficiency diseases (PID) and clinical and immunological parameters were evaluated according to disease type.

RESULTS

We identified monogenic mutations in 5 of the 35 patients (14.3 %). We identified compound heterozygous and homozygous splice-site mutations in interleukin-10 receptor A (IL-10RA) in two patients, nonsense mutations in X-linked inhibitor of apoptosis protein (XIAP) in two patients, and a missense mutation in cytochrome b beta chain in one patient. Using assays for protein expression levels, IL-10 signaling, and cytokine production, we confirmed that the mutations resulted in loss of function. For each patient, genotype was significantly associated with clinical findings. We successfully treated a patient with a XIAP mutation by allogeneic cord blood hematopoietic stem cell transplantation, and his symptoms were ameliorated completely.

CONCLUSIONS

Targeted sequencing and immunological analysis are useful for screening monogenic disorders and selecting curative therapies in pediatric patients with IBD. The genes responsible for PID are frequently involved in pediatric IBD and play critical roles in normal immune homeostasis in the gastrointestinal tract.

Comprehensive mutation screening for 10 genes in Chinese patients suffering very early onset inflammatory bowel disease

AIM

To perform sequencing analysis in patients with very early-onset inflammatory bowel disease (VEO-IBD) to determine the genetic basis for VEO-IBD in Chinese pediatric patients.

METHODS

A total of 13 Chinese pediatric patients with VEO-IBD were diagnosed from May 2012 and August 2014. The relevant clinical characteristics of these patients were analyzed. Then DNA in the peripheral blood from patients was extracted. Next generation sequencing (NGS) based on an Illumina-Miseq platform was used to analyze the exons in the coding regions of 10 candidate genes: IL-10, IL-10RA, IL-10RB, NOD2, FUT2, IL23R, GPR35, GPR65, TNFSF15, and ADAM30. The Sanger sequencing was used to verify the variations detected in NGS.

RESULTS

Out of the 13 pediatric patients, ten were diagnosed with Crohn's disease, and three diagnosed with ulcerative colitis. Mutations in IL-10RA and IL-10RB were detected in five patients. There were four patients who had single nucleotide polymorphisms associated with IBD. Two patients had IL-10RA and FUT2 polymorphisms, and two patients had IL-10RB and FUT2 polymorphisms. Gene variations were not found in the rest four patients. Children with mutations had lower percentile body weight (1.0% vs 27.5%, P = 0.002) and hemoglobin (87.4 g/L vs 108.5 g/L, P = 0.040) when compared with children without mutations. Although the age of onset was earlier, height was shorter, and the response to treatment was poorer in the mutation group, there was no significant difference in these factors between groups.

CONCLUSION

IL-10RA and IL-10RB mutations are common in Chinese children with VEO-IBD. Patients with mutations have an earlier disease onset, lower body weight and hemoglobin, and poorer prognosis.

Integrin CD11b attenuates colitis by strengthening Src-Akt pathway to polarize anti-inflammatory IL-10 expression

Interleukin-10 (IL-10) plays a central role in regulation of intestinal mucosal homeostasis and prevention of inflammatory bowel disease (IBD). We previously reported that CD11b(hi) regulatory dendritic cells (DCs) can produce more IL-10, and CD11b can negatively regulate Toll-like receptors (TLRs)-induced inflammatory responses in macrophages. However whether CD11b and its signaling can control autoimmunity via IL-10 production remains unclear. Here we found that CD11b deficient (Itgam(-/-)) mice were more susceptible to dextran sulfate sodium (DSS)-induced colitis, with more tumor necrosis factor α (TNF-α) while less IL-10 production. CD11b inhibited nuclear factor-kappa B (NF-κB) while promoted activator protein 1 (AP-1) activation through activating sarcoma oncogene (Src), leading to decreased TNF-α while increased IL-10 production. Src interacted with and promoted c-casitas B lineage lymphoma proto-oncogene (c-Cbl)-mediated degradation of the inhibitory subunit p85 of phosphatidylinositol 3-kinase (PI3K). Importantly, Src inhibitor dasatinib aggravated DSS-induced colitis by decreasing IL-10 while increasing TNF-α in vivo. Therefore, CD11b promotes IL-10 production by activating Src-Akt signal pathway. An axis of CD11b-Src pathway is important in balancing homeostasis of TLR-induced pro-inflammatory and anti-inflammatory responses.

Very early-onset inflammatory bowel disease (IBD) in infancy is a different disease entity from adult-onset IBD; one form of interleukin-10 receptor mutations

Infantile periods may have stronger genetic influences. Recently, studies on genetic defects in the interleukin-10 (IL-10) signaling pathway have provided new insights into inflammatory bowel disease (IBD). This study is to reveal whether mutations of IL-10 signaling pathway genes contribute to the phenotypes of IBD. Forty children who were diagnosed with IBD below the age of 10 years were enrolled. We sequenced the genes interleukin-10 receptor A (IL-10RA), IL-10RB and IL-10, and analyzed the clinical characteristics of very early-onset IBD (VEO-IBD). In total, 14 out of the 40 children developed their symptoms within 1 year of age. We found mutations in IL-10RA in 7 out of the 40 children (17.5%). All seven children had developed symptoms within the first year of life. Particularly, half of the children with infantile-onset IBD had IL-10RA mutations. None of the remaining 26 children diagnosed above 1 year of age had IL-10RA mutations. No mutations were found in IL-10RB and IL-10. Identified IL-10RA mutations were p.(R101W), p.(Y91C), p.(R262C), p.(R117H) and p.(W69R). IL-10RA mutations were associated with onset of infancy (P<0.001), perianal fistulae (P<0.001), poor response to medical management (P=0.017) and early surgical interventions (P<0.001). VEO-IBD in infancy is phenotypically and genetically different disease entity from adult-onset or older child-onset IBD. It has a strong association with IL-10 receptor gene. We should consider the genotyping of genes of the IL-10 signaling pathway including IL-10RA in patients with VEO-IBD, especially in whom with onset of perianal fistulae and severe colitis.

Characterisation of enterocolitis in the piroxicam-accelerated interleukin-10 knock out mouse--a model mimicking inflammatory bowel disease

BACKGROUND

In inflammatory bowel disease a defective mucosal barrier, a dysregulated immune response and an excessive reactivity against the gut microbiota are assumed to cause a breakdown of the intestinal homeostasis and lead to chronic inflammation. Piroxicam treatment is a method for induction of colitis in IL-10 k.o. mice, which integrates a dysfunction of both the intestinal barrier and the immune system. However, the translational value of this model has not been thoroughly clarified.

AIM

To characterise the piroxicam-accelerated colitis (PAC) IL-10 k.o. model with respect to clinical features, pathogenic mechanisms and its ability to respond to existing therapies.

METHODS

The PAC IL-10k.o. model was established on a C57BL/6J background and the clinical manifestations, immunological mechanisms and efficacy of ampicillin and anti-IL-12/23p40 treatment were assessed.

RESULTS

The PAC IL-10 k.o. mice developed weight loss and diarrhoea, and colonoscopy revealed a thickened granulomatous mucosa. Histological evaluation of ileum and colon showed Crohn's disease-like changes with pronounced hyperplasia and focal transmural inflammation. Ileitis was also observed in piroxicam treated wild type mice. The total number of neutrophils, monocytes and natural killer cells was elevated in the blood compared to IL-10 k.o. and wild type mice, indicating a role of the innate immune system in the pathogenesis. These findings were supported by analyses of the intestinal cytokine profile. Ampicillin and anti-IL-12/23p40 treatment significantly suppressed disease in the model.

CONCLUSION

The PAC IL-10 k.o. model resembles several features of Crohn's disease and could be a useful in vivo model in preclinical research.