The familial Mediterranean fever (MEFV) gene may be a modifier factor of inflammatory bowel disease in infancy

High frequency of MEFV disease-causing variants in children with very-early-onset inflammatory bowel disease

BACKGROUND

Biological similarities between inflammatory bowel disease (IBD) and familial Mediterranean fever (FMF) have been described in humans and animal models suggesting a possible common genetic basis. FMF is caused by variants in the MEFV gene which encodes pyrin, an immune regulator. This study aimed to investigate the carrier rate of disease-causing MEFV variants in children of different ethnicities diagnosed with very-early-onset IBD (VEO-IBD).

METHODS

The study included 23 children diagnosed with VEO-IBD who had undergone whole exome sequencing. The exomes were evaluated for MEFV monoallelic and biallelic disease-causing variants and compared to exome sequencing data of 250 probands with suspected monogenic diseases other than IBD.

RESULTS

Of the 23 children diagnosed with VEO-IBD, 12 (52%) were carriers of at least one MEFV disease-causing variant, which was threefold higher than in individuals without IBD. The most frequent variants identified were p.M694V and p.E148Q (42% each). The allelic frequency of MEFV variants was found to be higher across the VEO-IBD group in 13 of 14 ethnicities compared to the control group.

CONCLUSION

The study suggests that disease-causing variants in the MEFV gene should be sought in cases of VEO-IBD. However, the clinical importance of this finding is yet to be defined.

IMPACT

There are biological similarities between inflammatory bowel disease and familial Mediterranean fever, suggesting a possible genetic relationship. Children less than 6 years old clinically diagnosed with inflammatory bowel disease have a threefold higher rate of disease-causing variants in the MEFV gene than controls. Monogenic testing in children with very-early-onset inflammatory bowel disease should include a search for MEFV variants.

Familial Mediterranean fever in Armenian children with inflammatory bowel disease

Inflammatory bowel disease (IBD) and familial Mediterranean fever (FMF) are inflammatory diseases with complex interactions among genetic, immune, and environmental factors. FMF is a monogenic autoinflammatory disease, characterized by recurrent febrile attacks and polyserositis, and is manifested mainly in childhood. FMF is widespread in Armenia. There are reports on the concurrent occurrence of FMF and IBD. MEFV gene mutations may have a disease-modifying effect on IBD. We have investigated the frequency of MEFV mutations and FMF in Armenian children with IBD and their influence on the clinical course. A total of 69 untreated IBD patients under 18 years of age were enrolled: 52.1% (36) had ulcerative colitis (UC), 21.7% (15) had Crohn's disease (CD), and 26.0% (18) had unclassified colitis (IBD-U). The frequency of FMF among them was 36.2% (25/69), and MEFV mutations were identified in 53.6% (37/69). The highest rate of MEFV mutations and FMF was in UC patients (61.1% and 41.6% respectively). In all, 56.7% (21/37) of IBD patients with MEFV mutations had M694V mutated alleles, mainly in compound heterozygous and heterozygous states. There were no associations in the group of IBD patients with coexisting FMF (25), either between any MEFV mutation and type of IBD or coexistence of FMF. Overall, 36.0% (9/25) of them developed VEO IBD and carried mainly the M694V mutation. We concluded that the carrier frequency of MEFV mutations among Armenian pediatric IBD patients was rather high (53.6%), especially for UC. It was suggested that the MEFV gene is not necessarily a susceptibility gene but most likely modifies the course of IBD. MEFV genetic testing was recommended for Armenian pediatric IBD patients, especially for VEO UC and IBD-U, atypical IBD course, or resistance to the conventional treatment. They should also be asked for isolated febrile attacks, recurrent arthritis, and family history, even in the absence of FMF typical symptoms, to rule out FMF and its complications.

The Influence of Coexisting Familial Mediterranean Fever on Crohn's Disease: Data From an FMF Endemic Area

GOAL

The goal of this study was to evaluate the impact of coexisting familial Mediterranean fever (FMF) on Crohn's disease (CD) patients' phenotype and disease course in an endemic region for FMF.

BACKGROUND

CD and FMF are inflammatory diseases characterized by recurrent abdominal pain and fever attacks. The impact of coexisting FMF on CD patients' phenotype and disease course is currently unknown.

MATERIALS AND METHODS

We reviewed the medical records of 210 adult CD patients who were regularly followed up at a tertiary gastroenterology clinic between November 2006 and April 2018. The patients were divided into FMF positive (CD-FMF) and FMF negative (CD-control) groups. The severity of CD was assessed by the rate of hospitalization because of CD, the need for biological therapy, and whether surgery was performed for CD.

RESULTS

Eight (3.8%) of 210 CD patients have concomitant FMF, which is 35 to 40 times higher than expected in an endemic region for FMF. Baseline demographic parameters, location/behavior of the CD, and initial therapeutic regimens were similar between the 2 groups. The prevalence of peripheral arthritis was significantly higher in CD-FMF group (37.5% vs. 10.4%, respectively, P =0.04). A significantly greater proportion of the CD-FMF patients had received biological therapy (50% vs. 11.9%; P =0.012). Steroid dependence and CD-related hospitalization rates in the CD-FMF group were relatively higher but were not statistically significant (37.5% vs. 15.3 and 62.5% vs. 41.1%).

CONCLUSIONS

Our findings indicate that the disease course of CD tends to be more severe in patients with coexisting FMF.

Next generation sequencing (NGS)-based approach to diagnosing Algerian patients with suspected inborn errors of immunity (IEIs)

The advent of next-generation sequencing (NGS) technologies has greatly expanded our understanding of both the clinical spectra and genetic landscape of inborn errors of immunity (IEIs). Endogamous populations may be enriched for unique, ancestry-specific disease-causing variants, a consideration that significantly impacts molecular testing and analysis strategies. Herein, we report on the application of a 2-step NGS-based testing approach beginning with targeted gene panels (TGPs) tailored to specific IEI subtypes and reflexing to whole exome sequencing (WES) if negative for Northwest Algerian patients with suspected IEIs. Our overall diagnostic yield of 57% is comparable to others broadly applying short-read NGS to IEI detection, but data from our localized cohort show some similarities and differences from NGS studies performed on larger regional IEI cohorts. This suggests the importance of tailoring diagnostic strategies to local demographics and needs, but also highlights ongoing concerns inherent to the application of genomics for clinical IEI diagnostics.

Very Early Onset Inflammatory Bowel Disease: A Clinical Approach With a Focus on the Role of Genetics and Underlying Immune Deficiencies

Very early onset inflammatory bowel disease (VEO-IBD) is defined as IBD presenting before 6 years of age. When compared with IBD diagnosed in older children, VEO-IBD has some distinct characteristics such as a higher likelihood of an underlying monogenic etiology or primary immune deficiency. In addition, patients with VEO-IBD have a higher incidence of inflammatory bowel disease unclassified (IBD-U) as compared with older-onset IBD. In some populations, VEO-IBD represents the age group with the fastest growing incidence of IBD. There are contradicting reports on whether VEO-IBD is more resistant to conventional medical interventions. There is a strong need for ongoing research in the field of VEO-IBD to provide optimized management of these complex patients. Here, we provide an approach to diagnosis and management of patients with VEO-IBD. These recommendations are based on expert opinion from members of the VEO-IBD Consortium (www.VEOIBD.org). We highlight the importance of monogenic etiologies, underlying immune deficiencies, and provide a comprehensive description of monogenic etiologies identified to date that are responsible for VEO-IBD.

Fecal calprotectin in children with familial Mediterranean fever in the attack-free period

BACKGROUND

Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent episodes of fever and serosal inflammation. The aim of this study was to evaluate fecal calprotectin (FC) in children with FMF during the non-attack period.

METHODS

A retrospective evaluation was made of the data of a total 66 patients diagnosed with FMF in an attack-free period and without amyloidosis or inflammatory bowel disease (IBD). FC level in the FMF patients was compared with that in the patients with IBD and healthy control subjects.

RESULTS

The FMF patients consisted of 37 boys (56.1%) with a mean age of 10.1 ± 3.9 years. Mean FC was 192.5 μg/g (range, 19.5-800 μg/g) in the FMF group, 597.9 μg/g (range, 180-800 μg/g) in the IBD group, and 43.8 μg/g (range, 19.5-144 μg/g) in the control group. The FC level in the children with FMF was higher than in the control group (P < 0.001), and the FC level of the IBD patients was higher than both the FMF and the control groups (P = 0.020, P < 0.001, respectively).

CONCLUSIONS

FC was higher in FMF patients compared with healthy children even in the absence of IBD/amyloidosis. Even though colonoscopy is the gold standard in identifying intestinal inflammation in FMF patients, FC, a non-invasive and inexpensive method, can be used for screening. The presence of subclinical intestinal inflammation was also quantitatively identified in children with FMF.

The Role of Familial Mediterranean Fever Gene Mutation in Treatment of Infantile Colitis With Resistant Perianal Fistula

Symptoms of infantile inflammatory bowel disease (I-IBD) can be life-threatening and associated with poor prognosis. The presence of Mediterranean fever (MEFV) gene mutations play an important role in treatment of I-IBD. In this article, we describe a case of I-IBD with a resistant fistula, in which remission occurred following colchicine therapy. The patient was a six-month-girl with complaints of bloody diarrhea and a perianal abscess of three months duration. Laboratory tests revealed elevated inflammatory parameters, hypoalbuminemia, and anemia. Results of repeated viral, bacterial and parasitic analyses were negative. Endoscopic and histopathological examinations confirmed a diagnosis of I-IBD. Although diarrhea episodes decreased following intensive conventional treatment with immunosuppressive therapy and anti-tumor necrosis factor, the perianal abscess and fistula did not resolve. Molecular genetic analysis to identify causes of infantile disease revealed the MEFV gene mutation. Thus, colchicine was added to the treatment regimen. Following treatment with colchicine, defecation returned to normal, and the fistula resolved. The MEFV gene mutation should be investigated in children with infantile colitis and resistant fistulas, particularly in Mediterranean countries. In patients with infantile colitis who have the MEFV gene mutation, colchicine treatment may be an alternative to intensive immunosuppressive therapy.

Inflammatory bowel diseases and primary immunodeficiency diseases

Recent advances in molecular biology have provided important insights into the genetic background of various inflammatory diseases. In particular, genome-wide association studies of inflammatory diseases have revealed genetic loci that play critical roles in the pathology of inflammation. Whole-exome and whole-genome sequencing analyses have also identified more than 300 causative genes for primary immunodeficiency diseases (PIDs). Some genetic loci that are associated with inflammatory diseases are mutated in PIDs, suggesting close relationships between inflammation and PIDs. Inflammatory diseases for which genetic associations have been described include inflammatory bowel disease (IBD), multiple sclerosis, rheumatoid arthritis, type 1 diabetes mellitus, and systemic lupus erythematosus. Herein, I discuss about the genetic interactions between IBD and PIDs.

Early-onset inflammatory bowel disease as a model disease to identify key regulators of immune homeostasis mechanisms

Rare, monogenetic diseases present unique models to dissect gene functions and biological pathways, concomitantly enhancing our understanding of the etiology of complex (and often more common) traits. Although inflammatory bowel disease (IBD) is a generally prototypic complex disease, it can also manifest in an early-onset, monogenic fashion, often following Mendelian modes of inheritance. Recent advances in genomic technologies have spurred the identification of genetic defects underlying rare, very early-onset IBD (VEO-IBD) as a disease subgroup driven by strong genetic influence, pinpointing key players in the delicate homeostasis of the immune system in the gut and illustrating the intimate relationships between bowel inflammation, systemic immune dysregulation, and primary immunodeficiency with increased susceptibility to infections. As for other human diseases, it is likely that adult-onset diseases may represent complex diseases integrating the effects of host genetic susceptibility and environmental triggers. Comparison of adult-onset IBD and VEO-IBD thus provides beautiful models to investigate the relationship between monogenic and multifactorial/polygenic diseases. This review discusses the present and novel findings regarding monogenic IBD as well as key questions and future directions of IBD research.

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.

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.

Neonatal ulcerative colitis associated with Familial Mediterranean fever: a case report

Neonatal inflammatory bowel disease (IBD) is a subclass of very early onset IBD that includes children younger than 1 month. It is characterized by more colonic involvement and monogenetic etiology, resistance to classical anti-inflammatory/immunomodulatory treatments and associated with colitis in first-degree family members. Herein we report a 3 month-old girl who was admitted with bloody diarrhea since 10 days of age. Her symptoms persist despite diet elimination. She was diagnosed with neonatal ulcerative colitis (UC) based on clinical, laboratory and histopathological examination. But, she was unresponsive to the immunosuppressive therapy. On the follow-up, she was hospitalized for the high fever two times. Genetic analysis revealed homozygote M694 V mutation. Bloody diarrhea and other clinical findings were improved after colchicine therapy. Neonatal UC associated with Familial Mediterranean fever is an extremely rare condition and to the best of our knowledge our case is the first case in literature. Early diagnosis autoinflammatory disease may prevent complications related to unnecessary immunosuppressive drug usage and the risk of development of amyloidosis associated with autoinflammatory disorders.

Inflammatory bowel disease in Turkish children

BACKGROUND

This study was undertaken to evaluate demographics, clinical manifestations, laboratory findings and outcomes of children with inflammatory bowel disease (IBD) in Turkey.

METHODS

We analyzed the medical records of 127 children diagnosed with IBD (under 18 years old) between January 2004 and January 2012 in 8 pediatric gastroenterology centers.

RESULTS

Of the 127 patients, 90 (70.9%) suffered from ulcerative colitis (UC), 29 (22.8%) from Crohn's disease (CD), and 8 (6.3%) from IBD unclassified. The mean age of the 127 patients was 11.6 ± 4.1 years, and 11.8% of the patients were below 5 years old. Of the patients, 49.6% were male, and males were more predominant in patients with CD than in those with UC (72.4% vs. 42.2%, P = 0.008; a male/female ratio of 2.62 in CD, P = 0.0016). Approximately one fifth of the patients had extra-intestinal manifestations and 13.3% of the patients had associated diseases. Extraintestinal manifestations and associated diseases were more common in early onset disease [P = 0.017, odds ratio (OR) = 4.02; P = 0.03, OR = 4.1]. Of the patients, 15% had normal laboratory parameters including anemia, high platelet count, hypoalbuminemia, hypoferritinemia, and high sedimentation rate. Area under receiver operation characteristics was used to predict pancolitis in patients with UC. The values of C-reactive protein, sedimentation rate and pediatric ulcerative colitis activity were 0.61 (P = 0.06), 0.66 (P = 0.01) and 0.76 (P = 0.0001), respectively. Four (4.4%) patients with UC underwent colectomy, and finally two (1.5%, 95% confidence interval: 0-3.7%) patients died from primary disease or complications.

CONCLUSIONS

IBD is an increasing clinical entity in Turkey. Features of IBD are similar to those in other populations, but prospective multicenter studies are needed to analyze the true incidence of IBD in Turkish children.

The diagnostic approach to monogenic very early onset inflammatory bowel disease

Patients with a diverse spectrum of rare genetic disorders can present with inflammatory bowel disease (monogenic IBD). Patients with these disorders often develop symptoms during infancy or early childhood, along with endoscopic or histological features of Crohn's disease, ulcerative colitis, or IBD unclassified. Defects in interleukin-10 signaling have a Mendelian inheritance pattern with complete penetrance of intestinal inflammation. Several genetic defects that disturb intestinal epithelial barrier function or affect innate and adaptive immune function have incomplete penetrance of the IBD-like phenotype. Several of these monogenic conditions do not respond to conventional therapy and are associated with high morbidity and mortality. Due to the broad spectrum of these extremely rare diseases, a correct diagnosis is frequently a challenge and often delayed. In many cases, these diseases cannot be categorized based on standard histological and immunologic features of IBD. Genetic analysis is required to identify the cause of the disorder and offer the patient appropriate treatment options, which include medical therapy, surgery, or allogeneic hematopoietic stem cell transplantation. In addition, diagnosis based on genetic analysis can lead to genetic counseling for family members of patients. We describe key intestinal, extraintestinal, and laboratory features of 50 genetic variants associated with IBD-like intestinal inflammation. In addition, we provide approaches for identifying patients likely to have these disorders. We also discuss classic approaches to identify these variants in patients, starting with phenotypic and functional assessments that lead to analysis of candidate genes. As a complementary approach, we discuss parallel genetic screening using next-generation sequencing followed by functional confirmation of genetic defects.

Clinical and genetic profile of children with periodic fever syndromes from a single medical center in South East Michigan

OBJECTIVE

To report a cohort of children with periodic fever syndromes (PFS) from Southeast Michigan.

METHODS

A retrospective review of medical records for patients referred for periodic fever over 5 years.

RESULTS

Sixty-six patients including 21 FMF, 15 PFAPA, four TRAPS and one patient with combined HIDS and FMF were included. In addition, 25 patients were categorized as clinical PFS (cPFS) based on their clinical features however their genetic workup was either negative or inconclusive. Majority of the patients with FMF were from Middle Eastern background (88 %), but positive family history was noted in only 55 % of cases. Mean age at diagnosis was 40.8 months with a mean delay in diagnosis of 24 months. Most common MEFV mutations were p.M694V and p.M694I. Four patients with TRAPS were from mixed European descent and age at onset of symptoms was 6, 12, 12, and 84 months respectively. TNFRSF1A sequence variants in the TRAPS patients included p.R121Q (R92Q) and p.C99G (C70G); one patient had a rare occurrence of a concurrent p.V726A/-MEFV mutation. One patient with HIDS and FMF presented with atypical overlapping PFS clinical manifestations and genetic evaluation showed a unique combination of p.I268T/p.V377I MVK mutations and p.E230K/-MEFV variant. All patients with PFAPA group were from mixed European descent, symptoms started at a mean age of 34.6 months with a mean delay in diagnosis of 23.3 months. Symptoms started during infancy in six patients. All patients fulfilled the diagnostic criteria for PFAPA. The mean age of onset of symptoms in cPFS group was 17.2 months. Empiric colchicine and glucocorticosteroids controlled flares in majority of patients with cPFS. No evidence of amyloidosis was found in this entire cohort of 66 patients after a mean of 29.2 months of follow-up.

CONCLUSION

PFS can present with atypical manifestations and should not be excluded based on a negative family history. Concomitant mutations in different autoinflammatory disorders genes can be present and possibly explain atypical manifestations. Various therapies may be considered even if genetic testing is inconclusive or negative.

Association of familial Mediterranean fever in Turkish children with inflammatory bowel disease

AIM

Familial Mediterranean fever (FMF) and inflammatory bowel disease (IBD) carry similar clinical and biological properties. Both are characterized with chronic inflammation attacks and neutrophil migration and impaired apoptosis mechanism are present in the areas of damage in both conditions. In our study, we aimed to determine the frequency of association of FMF in patients with IBD, to compare the demographic, clinical, laboratory and treatment response properties in these patients with the ones in other IBD patients and to determine association of FMF especially in treatment-resistant patients.

MATERIAL AND METHODS

Fifty-three patients who were being followed up with a diagnosis of IBD aged between 0 and 18 years were included in the study. The patient group included the patients who were diagnosed with IBD according to clinical, serological, endoscopic and histopathological criteria, who were being followed up and whose therapies were continuing. Genetic analysis in terms of MEFV gene mutations was performed in all patients with a diagnosis of IBD. Acute phase reactants, complete blood count, immunoglobulin levels, stool analysis, "perinuclear anti-neutrophil cytoplasmic antibodies" (pANCA) and "anti-Saccharomyces cerevisiae antibodies" (ASCA) were studied at the time of diagnosis. The diagnosis of FMF was made according to detailed history, physical examination findings, laboratory tests and the results of genetic analyses in terms of MEFV gene mutations in accordance with the criteria defined in 2009.

RESULTS

We found that FMF accompanied in 14 (26.4%) of the patients who had a diagnosis of IBD. 3 of these 14 patients in whom FMF accompanied were being followed up with a diagnosis of Crohn disease and 11 were being followed up with a diagnosis of ulcerative colitis. All of these patients had MEFV gene mutation. These mutations included M694V (50%), K695R (21.4%), M680I (14.3%) and R202Q (14.3%) in order of frequency. When the laboratory data were compared between the patients who had a diagnosis of IBD alone and who had a diagnosis of IBD plus FMF, it was observed that the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) values were statistically significantly higher in the IBD+FMF group.

CONCLUSIONS

FMF is a common condition in the Turkish population and M694V mutation is found most commonly. In our study, this status did not change in cases where FMF accompanied IBD, but K695R mutation was found more frequently compared to FMF alone. We think that it should be kept in mind that other inflammatory conditions including mainly FMF may accompany IBD, if a case of IBD does not have an expected course or is resistant to treatment.

Inflammatory bowel diseases: Current problems and future tasks

Current knowledge on inflammatory bowel disease (IBD) is mainly endorsed by controlled trials and epidemiologic studies. Yet, we seldom look at the messages from real-world practice. Among a patient population followed since 2008, we looked at an unselected sample of 64 IBD patients [26 Crohn’s disease (CD) and 38 ulcerative colitis (UC)] who had been seen as out-patients in the last year. Inducing remission, mesalamines (86% for UC/69% for CD/33%-16% as MMX formulation) prevailed as prescriptions; steroids (55%/19% for UC/CD) ranked second. Prescription of third-party drugs (antibiotics, NSAIDs, biologics) and adherence, were issues in the maintenance. 34% of CD, and 23% of UC patients showed accompanying immunologic diseases: CD-associated familiar psoriasis (4:9) ranked first. Main Message. The association between IBD (CD mainly) and psoriasis, now found in our practice, matches current basic science gathering IBD together with psoriasis (and perhaps chronic respiratory disease) under the comprehensive term “barrier organ disease” wherein an epithelial surface with sensor systems rules contacts between outer antigens and a reactive underneath tissue, with the balance between inflammation and quiescence kept at any time by mucosal permeability. IBD is thus viewed as a polyfactorial/polygenic/syndromic disorder, embedded into a galaxy of immune conditions offering multiple points of attack. This mindset of splitting the IBDs into pathogenic categories may allow overcoming the uniformly targeting of a single cytokine by biological drugs, in favor of demarcating the boundaries between different disease-subtype-specific indications, and paving the way to future personalized strategies.

Inflammatory bowel disease: An archetype disorder of outer environment sensor systems

The pathogenesis of the two inflammatory bowel diseases (IBDs) phenotypes ulcerative colitis (UC) and Crohn's disease (CD) has remained elusive, thus frustrating attempts at defining a cure. IBD often presents as a complex inflammatory process wherein colon lesions (UC) or widespread ulceration and fissure (CD) might be accompanied by ancillary extra-intestinal manifestations involving the eye, skin, joints or liver, but also by full-blown "autoimmune" disorders from psoriasis and multiple sclerosis to rheumatoid arthritis; attempts at unraveling a link or a hierarchical order in these entities have proven almost fruitless. More recently, the input of genetics has suggested that the IBDs might be multi-organ inflammatory processes, elicited by a large number of low-penetrance susceptibility genes, with environmental factors needed to induce full-blown disease. At a noteworthy exception to this rule, the description of the nucleotide-oligomerization domain (NOD) gene mutations in CD came at the beginning of the 2000s: the NOD-LRR are part of a highly conserved microbial sensor system which respond to bacterial peptidoglycans by mounting an inflammatory response. At least in Caucasian patients, the prevalently loss-of-function mutation of NOD permitted to unexpectedly define CD as an immune deficiency state, and upon its recent description in apparently unrelated disorders such as the Blau syndrome (a granulomatous pediatric syndrome), and perhaps in psoriasis and chronic obstructive pulmonary disorders, has contributed to revolutionize our view of IBD and CD in particular. The latter affection, together with psoriasis and chronic pulmonary disease can now be included into a newly identified category named "barrier organ disease", wherein a barrier organ is defined as a large mucosal or epithelial surface with an abundant metagenomic microbial population and an underneath reactive tissue, the whole structure being in contact with the outer environment and capable to react to it. Personalized treatments and empowerment of research across different disease phenotypes should be the advantages of this novel mindset.

Inflammatory bowel disease: An archetype disorder of outer environment sensor systems

The pathogenesis of the two inflammatory bowel diseases (IBDs) phenotypes ulcerative colitis (UC) and Crohn's disease (CD) has remained elusive, thus frustrating attempts at defining a cure. IBD often presents as a complex inflammatory process wherein colon lesions (UC) or widespread ulceration and fissure (CD) might be accompanied by ancillary extra-intestinal manifestations involving the eye, skin, joints or liver, but also by full-blown "autoimmune" disorders from psoriasis and multiple sclerosis to rheumatoid arthritis; attempts at unraveling a link or a hierarchical order in these entities have proven almost fruitless. More recently, the input of genetics has suggested that the IBDs might be multi-organ inflammatory processes, elicited by a large number of low-penetrance susceptibility genes, with environmental factors needed to induce full-blown disease. At a noteworthy exception to this rule, the description of the nucleotide-oligomerization domain (NOD) gene mutations in CD came at the beginning of the 2000s: the NOD-LRR are part of a highly conserved microbial sensor system which respond to bacterial peptidoglycans by mounting an inflammatory response. At least in Caucasian patients, the prevalently loss-of-function mutation of NOD permitted to unexpectedly define CD as an immune deficiency state, and upon its recent description in apparently unrelated disorders such as the Blau syndrome (a granulomatous pediatric syndrome), and perhaps in psoriasis and chronic obstructive pulmonary disorders, has contributed to revolutionize our view of IBD and CD in particular. The latter affection, together with psoriasis and chronic pulmonary disease can now be included into a newly identified category named "barrier organ disease", wherein a barrier organ is defined as a large mucosal or epithelial surface with an abundant metagenomic microbial population and an underneath reactive tissue, the whole structure being in contact with the outer environment and capable to react to it. Personalized treatments and empowerment of research across different disease phenotypes should be the advantages of this novel mindset.

Association of inflammatory bowel disease with familial Mediterranean fever in Turkish children

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) and familial Mediterranean fever (FMF) share common clinical and biological features. The prevalence of other inflammatory diseases, including IBD, is increased in FMF. We investigated the presence of IBD accompanying FMF in patients who were being followed up with a diagnosis of FMF and the relation of IBD with the MEFV gene mutation.

METHODS

A total of 78 children with FMF were enrolled in the study. The patients were included in the study independent of the presence of complaints. Colonoscopy for IBD was performed if any of the following was present: blood mixed with mucus in the stool; chronic diarrhea (loose and frequent stools lasting >4 weeks); abdominal pain incompatible with FMF (localized in a certain part of the abdomen, not occurring during attacks, >3 days); and positive IgA and IgG anti-Saccharomyces cerevisiae antibodies and perinuclear antineutrophil cytoplasmic antibodies. MEFV gene mutations were analyzed in patients diagnosed as having IBD and FMF.

RESULTS

Of the 78 patients with a diagnosis of FMF, colonoscopy was performed and biopsy samples were taken in 20 patients (25.6%) who had abdominal pain incompatible with FMF, chronic diarrhea, bloody stools, and/or positive perinuclear anti-neutrophil cytoplasmic antibody or anti-Saccharomyces cerevisiae antibody. Histopathological examination resulted in a diagnosis of IBD in 12 of the 78 patients (15.4%). MEFV gene mutations were present in all 12 patients diagnosed as having IBD. We observed M694 V mutations in 5 of 12 patients (41.7%), M680I mutations in 3 (25%), K695R mutations in 3 (25%), and E148Q mutations in 1 (8.3%).

CONCLUSIONS

We found that the number of patients with FMF was higher than the number with IBD in the general population. When IBD accompanied FMF, the most common mutation was M694 V; however, the high rate (25%) of K695R mutation in our patients with FMF and IBD was not observed in previous studies.

Association of the MEFV gene variations with inflammatory bowel disease in Turkey

BACKGROUND

Association of NOD2 (CARD15) gene mutations with inflammatory bowel diseases (IBD) is well known. We herein aimed to investigate the role of familial Mediterranean fever-associated MEFV variations in IBD patients as additional regional-specific risk factor.

STUDY

One hundred thirty-seven (78 female, 56.9%) IBD patients [62 Crohn's disease (CD), 75 ulcerative colitis (UC)] were enrolled into the study. The diagnosis of all patients was confirmed by colonoscopy, histopathology, and the clinical findings. One hundred one healthy donors' samples were used as healthy controls. All patients were genotyped for the most common E148Q, M608I, M694V, and V726A variations of the MEFV and R702W, G908R, and 1007fs of the NOD2.

RESULTS

The overall MEFV variation frequency was found to be higher in the IBD (25.5%) patients (28% in UC, 22.6% in CD) compared with controls (9.9%, P=0.006). This association was stronger with the penetrant exon 10 variations (M694V, M680I, V726A; odds ratio =4.5, P=0.001). Contribution of M694V was higher compared with the other variations (14.5% in CD, 17.3% in UC and 3% in controls, odds ratio =6.039, 95% confidence intervals, 1.7-20.7, P=0.002). The overall frequency of 3 NOD2 variants in the IBD group was not different from that of controls.

CONCLUSIONS

The results of this study suggest that the MEFV variations may be an additional susceptibility factor for IBD in certain parts of the world where the carrier rate is high, and the genetic background of the IBD patients may show regional changes.

The association of inflammatory bowel disease and Mediterranean fever gene (MEFV) mutations in Turkish children

BACKGROUND AND AIMS

Familial Mediterranean fever (FMF) and inflammatory bowel disease (IBD) concordance has been investigated in a few studies. We investigated MEFV mutations and prevalence of FMF disease in Turkish children with IBD and their relationship with the disease severity.

METHODS

Sixteen patients with ulcerative colitis (UC), 14 with Crohn's disease (CD) and three with indeterminate colitis (IC) were enrolled in the study (median age 13 years, range 0.6-16 years, n = 19 boys). Demographic, clinical and laboratory characteristics of the patients were evaluated as well as the parameters of disease severity. All patients were screened for 12 common MEFV mutations.

RESULTS

MEFV mutations were detected in 17 of 66 (25.7%) alleles. Seven patients (four patients with CD, two with IC, and one with UC) were also diagnosed as FMF. FMF disease was found in seven of all IBD patients (21.2%) and four of them had CD. M694V was the leading mutation, and as a disease-causing mutation, it was found to be significantly more frequent in CD patients than UC patients (Fisher's exact test P = 0.03). Demographics, laboratory evaluations, growth parameters, extraintestinal manifestations, and treatment with immunosuppressive agents other than steroids were comparable between the patients with and without FMF in most aspects.

CONCLUSIONS

Although this is a small cohort, disease-causing MEFV mutations and FMF disease rate were increased among our patients with IBD. The increase was prominent among CD patients, whereas in UC the rate was similar to the Turkish healthy control population.

An infant with severe refractory Crohn's disease and homozygous MEFV mutation who dramatically responded to colchicine

Previous studies have suggested that inflammatory bowel disease is particulary frequent and severe in familial Mediterranean fever (FMF) families. An 8-month-old boy was admitted to our hospital with chronic bloody diarrhea, failure to thrive and high-grade fever. He was diagnosed as Crohn's disease (CD) based on clinical, laboratory and histological findings and, corticosteroid therapy was started. The patient did not respond to intensive medical therapy including intravenous corticosteroid, mesalazine, azathioprine, intravenous cyclosporine and enteral feeding. MEFV gene mutation analysis revealed homozygous M694V mutation. In addition to azathioprine and cyclosporine therapy, with the diagnosis of FMF, colchicine therapy was started and partial remission was observed within 2 weeks. To the best of our knowledge, this is the first report of association of CD and FMF in an infant. In cases of CD resistant to medical therapy, possibility of underlying FMF should be considered, especially in countries where FMF is prevalent.

Genetic variation in the familial Mediterranean fever gene (MEFV) and risk for Crohn's disease and ulcerative colitis

BACKGROUND AND AIMS

The familial Mediterranean fever (FMF) gene (MEFV) encodes pyrin, a major regulator of the inflammasome platform controlling caspase-1 activation and IL-1beta processing. Pyrin has been shown to interact with the gene product of NLRP3, NALP3/cryopyrin, also an important active member of the inflammasome. The NLRP3 region was recently reported to be associated with Crohn's disease (CD) susceptibility. We therefore sought to evaluate MEFV as an inflammatory bowel disease (IBD) susceptibility gene.

METHODOLOGY AND RESULTS

MEFV colonic mucosal gene expression was significantly increased in experimental colitis mice models (TNBS p<0.0003; DSS p<0.006), in biopsies from CD (p<0.02) and severe ulcerative colitis (UC) patients (p<0.008). Comprehensive genetic screening of the MEFV region in the Belgian exploratory sample set (440 CD trios, 137 UC trios, 239 CD cases, 96 UC cases, and 107 healthy controls) identified SNPs located in the MEFV 5' haplotype block that were significantly associated with UC (rs224217; p = 0.003; A allele frequency: 56% cases, 45% controls), while no CD associations were observed. Sequencing and subsequent genotyping of variants located in this associated haplotype block identified three synonymous variants (D102D/rs224225, G138G/rs224224, A165A/rs224223) and one non-synonymous variant (R202Q/rs224222) located in MEFV exon 2 that were significantly associated with UC (rs224222: p = 0.0005; A allele frequency: 32% in cases, 23% in controls). No consistent associations were observed in additional Canadian (256 CD trios, 91 UC trios) and Scottish (495 UC, 370 controls) sample sets. We note that rs224222 showed marginal association (p = 0.012; G allele frequency: 82% in cases, 70% in controls) in the Canadian sample, but with a different risk allele. None of the NLRP3 common variants were associated with UC in the Belgian-Canadian UC samples and no significant interactions were observed between NLRP3 and MEFV that could explain the observed flip-flop of the rs224222 risk allele.

CONCLUSION

The differences in association levels observed between the sample sets may be a consequence of distinct founder effects or of the relative small sample size of the cohorts evaluated in this study. However, the results suggest that common variants in the MEFV region do not contribute to CD and UC susceptibility.

An integrated classification of pediatric inflammatory diseases, based on the concepts of autoinflammation and the immunological disease continuum

Historically, pediatric inflammatory diseases were viewed as autoimmune but developments in genetics of monogenic disease have supported our proposal that "inflammation against self" be viewed as an immunologic disease continuum (IDC), with genetic disorders of adaptive and innate immunity at either end. Innate immune-mediated diseases may be associated with significant tissue destruction without evident adaptive immune responses and are designated as autoinflammatory due to distinct immunopathologic features. However, the majority of pediatric inflammatory disorders are situated along this IDC. Innate immunity has been demonstrated in polygenic disorders, particularly Crohn's disease (CD). A genetic overlap exists between CD and some major histocompatibility complex (MHC) class I-associated diseases, including psoriasis; these diseases seem to represent a true intermediate between autoinflammation and autoimmunity. Conversely, classical autoimmune diseases, with autoantibody and MHC class II associations, including celiac disease and rheumatoid arthritis (RA), have adaptive immune genetic associations, including Cytotoxic T-Lymphocyte Antigen-4 (CTLA4) and PTPN22. This proposed classification is clinically relevant, because innate immune-mediated disorders may respond to cytokine antagonism whereas autoimmune-mediated diseases respond better to anti-T and B cell therapies. Furthermore, the etiopathogenesis of poorly defined "autoimmune" diseases, such as juvenile idiopathic arthritis, may be inferred to have substantial innate immune involvement, based on response to IL-1 antagonism.

NOD-like receptors and inflammation

The nucleotide-binding and oligomerization domain, leucine-rich repeat (also known as NOD-like receptors, both abbreviated to NLR) family of intracellular pathogen recognition receptors are increasingly being recognized to play a pivotal role in the pathogenesis of a number of rare monogenic diseases, as well as some more common polygenic conditions. Bacterial wall constituents and other cellular stressor molecules are recognized by a range of NLRs, which leads to activation of the innate immune response and upregulation of key proinflammatory pathways, such as IL-1beta production and translocation of nuclear factor-kappaB to the nucleus. These signalling pathways are increasingly being targeted as potential sites for new therapies. This review discusses the role played by NLRs in a variety of inflammatory diseases and describes the remarkable success to date of these therapeutic agents in treating some of the disorders associated with aberrant NLR function.

Autoinflammatory diseases: mimics of autoimmunity or part of its spectrum? Case presentation

INTRODUCTION

Autoinflammatory diseases are very rare diseases presenting within a wide clinical spectrum. Recognition of the main clinical features are challenging due to overlapping or mimicking with autoimmune diseases.

DISCUSSION

A case series is reviewed to illustrate typical and atypical features and the difficulties of these diagnoses in the low prevalence areas--a typical unrecognized case of familial Mediterranean fever (FMF) in a youngster, an atypical adult case with overlapping of FMF with Behçet disease, and an early presentation of FMF in infant presenting with inflammatory colitis, as well as the overlapping features within the cryopirin diseases spectrum in an 8-year-old boy who presented with systemic onset arthritis.

CONCLUSION

These cases may represent examples of a very puzzling relationship among disorders of innate and adaptive immune systems and inflammation.