Human leukocyte antigen DQ2/8 prevalence in non-celiac patients with gastrointestinal diseases

HLA-DQ and alcohol in the pathogenesis of irritable bowel syndrome in college students: a case-control study

Some researchers have shown that genetics contribute to the incidence of IBS. However, no research has focused on the interaction between HLA-DQ and living habits in the pathogenesis of IBS. The present study explored the risk factors for IBS in college students of Guangxi Han nationality and explored the interaction between HLA-DQ and living habits on the pathogenesis of IBS. Univariate and multivariate analyses were used to determine the risk factors for IBS. Logistic interaction analysis and the Excel table made by Andersson were used to explore the interaction between genes and living habits in the context of IBS. We found that low expression of HLA-DQ2 and DQ8 were associated with the pathogenesis of IBS, while mild to moderate alcohol consumption was associated with the occurrence of IBS symptoms. Only the HLA-DQ8 gene and alcohol consumption had additive interactions in the context of the occurrence of IBS. In other words, for college students of Guangxi Han nationality, HLA-DQ2 and HLA-DQ8 might be protective against IBS, while alcohol consumption might be an independent risk factor. There was an additive interaction between HLA-DQ8 and alcohol consumption in the occurrence of IBS.

Gluten Degradation by the Gut Microbiota of Ulcerative Colitis Patients

Several studies have reported improved disease symptomatology in ulcerative colitis (UC) patients consuming a gluten free diet. This observation coupled with diversity depletion in the gut microbiota of UC patients led us to hypothesize that UC-associated enteric microbes differentially metabolize dietary gluten to produce immunogenic products that promote inflammation. Gluten concentration in stool was determined using gluten-specific ELISA, and gluten intake was assessed by food frequency questionnaire (FFQ) in UC (n = 12) and healthy controls (HC; n = 13). Gluten-metabolizing bacteria were isolated on minimal media supplemented with 1% gluten from UC and HC and identified by 16S rRNA profiling. Cell-free culture media from gluten metabolizing gut bacterial isolates was assessed for immunogenicity in vitro using HT29 colonocytes. Compared to HC, UC patients did not consume gluten differently (Mann−Whitney; p > 0.10) and exhibited equivalent levels of gluten in their feces (Mann−Whitney; p = 0.163). The profile of gluten-degrading bacteria isolated from UC stool was distinct (Chi-square; p ≤ 0.0001). Compared with Enterococcus isolates, products of gluten degradation by Bacillus strains induced higher IL8 and lower occludin (Mann−Whitney; p = 0.002 and p = 0.059, respectively) gene expression in colonocytes irrespective of whether they originated from UC or healthy gut. Members of HC and UC microbiota exhibit gluten-degrading ability, metabolites of which influence genes involved in inflammation and barrier function in enteric colonocyte cultures. Preliminary findings of this study warrant further investigations into the mechanisms by which gut microbiota contribute to UC pathogenesis through gluten degradation.

Patients With Inflammatory Bowel Disease on Treatment Have Lower Rates of Celiac Disease

BACKGROUND

The association between celiac disease and inflammatory bowel disease (IBD) has been studied; however, the impact of IBD therapy on celiac disease is not known. Using a large database, we sought to describe the association of celiac disease and IBD and the impact of IBD treatment.

METHODS

We queried a large multicenter database (Explorys Inc.), an electronic health record data aggregate from 26 American health care systems. We identified a cohort of patients with celiac disease and IBD between 1999 and 2020 and conducted a statistical analysis using a multivariate model.

RESULTS

Of the 72,965,940 individuals in the database, 133,400 had celiac disease (0.18%), 191,570 (0.26%) had ulcerative colitis (UC), and 230,670 (0.32%) had Crohn disease (CD). Patients with IBD were more likely to have a diagnosis of celiac disease (odds ratio [OR], 13.680), with a greater association with CD. Treated patients with UC and with CD, respectively, had a lower risk association with celiac disease compared to those not undergoing IBD treatment, specifically corticosteroids (OR, 0.407 and 0.585), 5-aminosalicylates (OR, 0.124 and 0.127), immunomodulators (OR, 0.385 and 0.425), and anti-tumor necrosis factor drugs (OR, 0.215 and 0.242). There was no lower risk association in the vedolizumab group, but there was a higher risk association among the ustekinumab group.

CONCLUSIONS

In this large dataset, we showed a bidirectional association between celiac disease and IBD that was stronger with CD. Patients with IBD treated using corticosteroids, 5-aminosalicylates, immunomodulators, or anti-tumor necrosis factor drugs had a lower association with celiac disease. Additional studies are required to determine the underlying mechanisms for IBD therapy-related modification of celiac disease incidence.

Evaluation of the Utility of Amino Acid Citrulline as a Surrogate Metabolomic Biomarker for the Diagnosis of Celiac Disease

INTRODUCTION

Citrulline is regarded as a biomarker for celiac disease (CD). Its utility for assessment and evaluation of additive predictive value for latent, potential CD and first degree relatives (FDRs) needs exploration.

METHOD

Consecutive 558 index cases diagnosed as per European Society for Pediatric Gastroenterology and Nutrition (ESPGHAN) 2012 guidelines and their 1565 FDRs were evaluated over five and half year period. Serology negative FDRs at initial visit and follow ups were served as controls. HLA typing for DQ2 and DQ8 genotypes, along with plasma and dried blood spot (DBS) filter paper citrulline were evaluated.

RESULTS

Median plasma citrulline values were 20.1 and 37.33 µMol/l in cases and controls (P < .001). Cut off values for Marsh grade 3a, 3b, and 3c were 35.0, 32.8, 25.26 µMol/l in CD patients and 36.51, 30.10, 25.26 µMol/l in biopsy proven FDR. Increasing trends of plasma citrulline levels with decreasing tTG-IgA levels were observed on follow up. Low plasma citrulline levels were observed with HLA DQ 2.5 genotype (P < .05). Agreement between DBS and plasma citrulline was 94.8%.

CONCLUSION

Citrulline is a good surrogate biomarker for identification of histopathological grade of damage, extent of mucosal recovery and has negative correlation with tTG-IgA. It identifies the silent and latent phase of CD. DBS citrulline provides adequate information and can be used for monitoring CD patients at remote locations.

Approach to the adult patient with chronic diarrhea: A literature review

Chronic diarrhea is defined by symptoms lasting longer than 4 weeks. It is a common problem that affects up to 5% of the adult population. Different pathophysiologic mechanisms involve numerous causes, including drug side effects, postoperative anatomic and physiologic alterations, intestinal and colonic wall abnormalities, inflammatory or malabsorption causes, pancreatobiliary diseases, and functional or gut-brain axis disorders associated with dysbiosis or gastrointestinal motility alterations. Due to such a broad differential diagnosis, it is important to categorize chronic diarrhea into five main groups: drug side effect, postoperative, postinfectious, malabsorptive, inflammatory, and functional. The present review is a narrative analysis of the diagnostic approach, emphasizing key aspects of the clinical history, the utility of biomarkers (in breath, stool, urine, and serology) and malabsorption and motility tests, the role of radiologic and endoscopic studies, and the most common histologic findings. A diagnostic algorithm aimed at determining etiology and personalizing therapy is also proposed.

Approach to the adult patient with chronic diarrhea: a literature review

Chronic diarrhea is defined by symptoms lasting longer than 4 weeks. It is a common problem that affects up to 5% of the adult population. Different pathophysiologic mechanisms involve numerous causes, including drug side effects, postoperative anatomic and physiologic alterations, intestinal and colonic wall abnormalities, inflammatory or malabsorption causes, pancreatobiliary diseases, and functional or gut-brain axis disorders associated with dysbiosis or gastrointestinal motility alterations. Due to such a broad differential diagnosis, it is important to categorize chronic diarrhea into five main groups: drug side effect, postoperative, postinfectious, malabsorptive, inflammatory, and functional. The present review is a narrative analysis of the diagnostic approach, emphasizing key aspects of the clinical history, the utility of biomarkers (in breath, stool, urine, and serology) and malabsorption and motility tests, the role of radiologic and endoscopic studies, and the most common histologic findings. A diagnostic algorithm aimed at determining etiology and personalizing therapy is also proposed.

Prevalence of HLA DQ 2, 8 in children with celiac disease

OBJECTIVE

Celiac disease is a chronic disease that affect small bowel by making its villi become atrophic. Various environmental and genetic factors have been identify as inducing factors for celiac disease. Most of the patients has one of the HLA DQ forms. Although the prevalence of these genes are variable in different areas of the world, we do not have a comprehensive information about this issue in our region. Thus the aim of present study is to investigate the prevalence of HLA DQ typing of patients who visited Emam Reza Gastroenterology clinic of Shiraz(IRAN).

METHODS

In this case-control study all under 18 years old children who were diagnosed with celiac disease and have visited Emam Reza gastroenterology clinic were investigated. The diagnosis of celiac disease was made by history, physical exam, serologic test, and histopathology of duodenal biopsy. Blood sample was taken and HLA typing performed using PCR method at Motahari clinic cytology laboratory. Also those people who neither them self nor their first degree relatives were not case of celiac disease and underwent HLA typing for other reason were identified as control group. The statistical analysis was done using SPSS 18 software. The p value < 0.05 was identified as statistically significant.

RESULTS

A total of 139 patients with celiac disease and 146 normal children were studied. The mean age of the patient with celiac disease were 9.1 years old with standard deviation of 3.4 years old. 64% of the celiac patients were girls and 36% were boys. While this proportion was 54.4% for boy and 48.6% for girls in control group. The most common HLA in celiac patients group were HLA DQ2 and 8 but the most common ones in control group were HLA DQ 8 and 5. Failure to Thrive were the most common signs of the celiac patients with a prevalence of 60 children. Total IgA titer were normal in 98.6% of the patients and TTG IgA titer were positive in 93.5% of the patients. The most common co existing disease with the celiac disease were diabetes with a prevalence of 30 children (66.7%).

CONCLUSION

present study reveals that the prevalence of the HLA DQ2 and 8 among patients with celiac disease is 72.6% and 53% in our normal population.

The frequency of HLA-DQ2/DQ8 haplotypes and celiac disease among the first-degree relatives of patients with celiac disease

AIM

We evaluated the frequency of human leukocyte antigen (HLA) DQ2/DQ8 haplotypes as well as celiac disease (CD) among the first-degree relatives (FDRs) of CD patients, compared with healthy controls, and compared the HLA typing with serologic tests in this population.

BACKGROUND

Until now, no study has examined the frequency of HLA-DQ2/DQ8 haplotypes among the FDRs of Iranian patients with CD.

METHODS

In the current case-control study, 100 FDRs of CD patients and 151 healthy controls were included. Demographic characteristics were assessed using a research-made questionnaire. A blood sample was collected from each participant for HLA-DQ typing and measuring serum levels of anti-gliadin and anti-transglutaminase (anti-tTG) antibodies.

RESULTS

The mean age of the FDRs of CD patients and controls was 30 and 35 years, respectively. Also, 51% (n=51) of the FDRs and 51.7% (n=78) of controls were female. CD was diagnosed among 3% (n=3) of the FDRs of CD patients. No significant difference was found in terms of the frequency of HLA-DQ alleles between the FDRs of CD patients and controls. Out of 100 FDRs of CD patients, 40% had HLA-DQ2 allele, 16% carried HLA-DQ8 allele, and 4% had both alleles. Surprisingly, the CD was diagnosed in three subjects among 60 FDRs of CD patients with HLA-DQ2 allele (3% of the whole population). This diagnosis was based on the results of serological tests as well as endoscopy and intestinal biopsy.

CONCLUSION

CD was confirmed among 3% (n=3) of the FDRs of CD patients. We found that HLA typing is not effective in predicting CD among FDRs of CD patients. Other methods such as serological tests have a higher priority compared with HLA-DQ typing.

Non-celiac gluten sensitivity as a rare cause of growth retardation in children: a case series study

AIM

Herein, we present five children and adolescents with a final diagnosis of non-celiac gluten sensitivity (NCGS).

BACKGROUND

Non-celiac gluten sensitivity (NCGS) is a condition characterized by gastrointestinal and extra-intestinal symptoms triggered by ingestion of gluten-containing compounds, e.g., wheat, rye, and barley, in subjects without celiac disease or wheat allergy.

METHODS

Demographic characteristics, clinical manifestations, serum biomarkers and skin prick test were evaluated. Patient data was also recorded after they followed a gluten-free diet (GFD). Height and weight were measured, and all patients were examined 6 months after following the suggested GFD.

RESULTS

All patients had failure to thrive and abdominal pain. Clinical symptoms were reduced, and significant weight and height gains were detected after 1 month of following a gluten-free diet.

CONCLUSION

The relationship between failure to thrive (FTT) and NCGS is still unknown; hence, NCGS may be one of the main causes of FTT which can be prevented by gluten-free diets.

Gluten-Free Diet in IBD: Time for a Recommendation?

Patients and providers alike are highly interested in identifying potentially useful dietary interventions in the management of inflammatory bowel diseases (IBD). This review examines the clinical associations of celiac disease (CeD), non-celiac gluten sensitivity (NCGS), and IBD with a focus on available data of the therapeutic efficacy of gluten-free diet (GFD) or low-gluten-containing diets in the therapy of IBD. There is a strong association between CeD and microscopic colitis, but the prevalence of CeD among IBD patients is similar to that of the general population. Interestingly, in cross-sectional studies nearly one-third of IBD patients report a diagnosis of NCGS, and many follow a GFD. Although animal studies have shown that gluten ingestion may promote intestinal inflammation and increase intestinal permeability, there have been no prospective studies evaluating the role of a GFD in the induction and maintenance of Crohn's disease and ulcerative colitis. Several cross-sectional reports suggest that a GFD may improve symptoms in IBD patients, but due to a lack of high-quality prospective clinical studies, current data do not support the universal use of a GFD in IBD.

The pathogenic role of autoantibodies in recurrent pregnancy loss

In the present manuscript, we review the recent research investigating the pathogenic association between most studied autoantibodies and recurrent pregnancy loss. Pregnancy loss represents a common obstetric complication occurring in about 15%-25% of all clinically recognized pregnancies. The recurrence of pregnancy loss identifies a distinct clinical entity, that is recurrent pregnancy loss (RPL), affecting about 2%-4% of couples. Several factors, including age, chromosomal abnormalities, uterine anomalies, thrombophilic disorders, endocrinopathies, hormonal and metabolic disorders, infections, sperm quality, and lifestyle issues, are involved in RPL. The role of autoantibodies in RPL is only partially determined. In some cases (antiphospholipid antibodies [aPL]), their involvement is well established. In other cases (anti-thyroid autoantibodies, antinuclear, anti-transglutaminase, and anti-endomysial antibodies), it is still debated, despite multiple, although not fully conclusive, evidences strongly suggest a possible involvement in RPL. Further extensive research is needed to definitively confirm or exclude their actual role.

Angiotensin II receptor blockers and gastrointestinal adverse events of resembling sprue-like enteropathy: a systematic review

Background

Olmesartan, an angiotensin II receptor blocker (ARB), is associated with gastrointestinal symptoms resembling sprue-like enteropathy. Some have proposed that enteropathy may be a class effect rather than olmesartan-specific. We performed a systematic review to identify literature of sprue-like enteropathy for all ARBs.

Methods

Case reports, case series and comparative studies of ARBs were searched on PubMed and Embase databases through 21 November 2018 and then assessed.

Results

A total of 82 case reports and case series as well as 5 comparative studies, including 248 cases, were selected and analysed. The ARBs listed in the case reports were olmesartan (233 users; 94.0%), telmisartan (5 users; 2.0%), irbesartan (4 users; 1.6%), valsartan (3 users; 1.2%), losartan (2 users; 0.8%) and eprosartan (1 user; 0.4%). The periods between ARB initiation and onset of symptoms ranged from 2 weeks to 13 years. Histologic results were reported in 218 cases, in which 201 cases (92.2%) were villous atrophy and 131 cases (60.1%) were intraepithelial lymphocytosis. Human leucocyte antigen (HLA) testing was performed in 147 patients, among whom 105 (71.4%) had HLA-DQ2 or HLA-DQ8 haplotypes. Celiac-associated antibodies were tested in 169 patients, among whom 167 (98.8%) showed negative results. Gluten exclusion from the diet failed to relieve symptoms of enteropathy in 127 (97.7%) of 130 patients with information. Complete remission of symptoms after discontinuation of ARB was reported in 233 (97.4%) of the 239 patients with information. Seven cases (2.8%) reported recurrence of symptoms after restarting olmesartan; rechallenge was not reported for the non-olmesartan ARBs. The retrospective studies conducted worldwide had inconsistent study designs (e.g. differences in periods of study and case definition) and findings.

Conclusions

Although enteropathy is rare, clinicians should remain vigilant of this potential adverse event even years after medication initiation.

Olmesartan is not associated with the risk of enteropathy: a Korean nationwide observational cohort study

BACKGROUND/AIMS

Olmesartan, a widely used angiotensin II receptor blocker (ARB), has been linked to sprue-like enteropathy. No cases of olmesartan-associated enteropathy have been reported in Northeast Asia. We investigated the associations between olmesartan and other ARBs and the incidence of enteropathy in Korea.

METHODS

Our retrospective cohort study used data from the Korean National Health Insurance Service to identify 108,559 patients (58,186 females) who were initiated on angiotensin converting enzyme inhibitors (ACEis), olmesartan, or other ARBs between January 2005 and December 2012. The incidences of enteropathy were compared among drug groups. Changes in body weight were compared after propensity score matching of patients in the ACEis and olmesartan groups.

RESULTS

Among 108,559 patients, 31 patients were diagnosed with enteropathy. The incidences were 0.73, 0.24, and 0.37 per 1,000 persons, in the ACEis, olmesartan, and other ARBs groups, respectively. Adjusted rate ratios for enteropathy were: olmesartan, 0.33 (95% confidential interval [CI], 0.10 to 1.09; p = 0.070) and other ARBs, 0.34 (95% CI, 0.14 to 0.83; p = 0.017) compared to the ACEis group after adjustment for age, sex, income level, and various comorbidities. The post hoc analysis with matched cohorts revealed that the proportion of patients with significant weight loss did not differ between the ACEis and olmesartan groups.

CONCLUSION

Olmesartan was not associated with intestinal malabsorption or significant body weight loss in the general Korean population. Additional large-scale prospective studies of the relationship between olmesartan and the incidence of enteropathy in the Asian population are needed.

Treatment of irritable bowel syndrome

Irritable bowel syndrome is a chronic functional gastrointestinal disorder that presents with abdominal pain related to defecation accompanied by a change in stool frequency or form Despite its impact on a patient’s quality of life it has no effect on mortality

A positive clinical diagnosis should be made if the characteristic symptoms are present and red flags are absent Red flags should prompt specialist referral

Consultations should be provided in an empathetic manner addressing the concerns of the patient while providing reassurance

Manipulating diet with the assistance of a dietitian is an appropriate initial treatment for irritable bowel syndrome A low-FODMAP diet is an effective therapy

The distribution of HLA DQ2 and DQ8 haplotypes and their association with health indicators in a general Danish population

Background

Human leukocyte antigen (HLA) DQ2 and DQ8 are important risk factors for some autoimmune diseases such as celiac disease (CD), but their possible role in other diseases and health conditions is not fully explored.

Objectives

The objective of this article is to examine the distribution of HLA DQ2 and HLA DQ8 in an adult general population, and their association with health indicators (diseases, symptoms and biomarkers).

Methods

In this cross-sectional, population-based study, 2293 individuals were screened for HLA DQ2 and DQ8; CD-associated alleles (DQA*0201*03*05/DQB*02*0301/0304*0302/0305) and DQB1*02 homozygosity were determined for screen-positive participants. The National Patient Registry provided diagnosis information.

Results

A total of 47.7% (1093/2293) individuals were positive for DQ2 and/or DQ8: 31.2% (716/2293) only DQ2, 11.9% (273/2293) only DQ8, 4.1% (93/2293) both DQ2 and DQ8. Among nine individuals diagnosed with CD, 89.9% (8/9) had DQ2.5cis, 22.2% (2/9) DQ8 and 22.2% (2/9) DQ2.2 (two both DQ2 and DQ8). HLA DQ2.5 was associated with higher thyroid-stimulating hormone levels, while DQ2/DQ8-positive participants had significantly lower prevalence of irritable bowel syndrome (IBS). DQ2/DQ8 were strongly associated with CD, but no other registry-based diagnoses.

Conclusion

In this general Danish population, 47.7% were HLA DQ2/DQ8 positive and thus potentially at risk for CD. All individuals with CD were DQ2/DQ8 positive; the majority DQ2.5. Surprisingly, DQ2/DQ8-positivity was associated with lower IBS prevalence.

HLA-DQ: Celiac disease vs inflammatory bowel disease

AIM

To determine the genetic predisposition to celiac disease (CeD) in inflammatory bowel disease (IBD) patients by quantifying the frequency of CeD-related human leucocyte antigen (HLA) (HLA-CeD: HLA-DQ2 and -DQ8) in IBD patients globally, by type of IBD and gender, and by calculating the protective/risk contribution of these haplotypes in the development of the IBD disease.

METHODS

We conducted a prospective study with IBD patients from our Unit. Clinical information was gathered and blood was tested for HLA-CeD. The control group was made up of unrelated Valencian organ donors.

RESULTS

1034 subjects were analyzed: 457 IBD [207 ulcerative coliti (UC) and 250 Crohn’s disease (CD)] patients and 577 healthy controls. 39% of the controls and 34% of the patients had HLA-CeD (P = 0.0852). HLA-DQ2 was less frequent in UC patients (P = 0.0287), and HLA-DQ8 in CD (P = 0.0217). In women with UC, the frequency of DQ2.5cis (DQB1*02:01-DQA1*05:01) was reduced ≥ 50% [P = 0.0344; preventive fraction (PF) = 13%]. PFs (7%-14%) were obtained with all HLA-CeD haplotypes. HLA DQB1*02:02-DQA1*02:01 (HLA-DQ2.2) was more frequent in CD patients with respect to controls (P = 0.001) and UC patients (etiological fraction = 15%).

CONCLUSION

HLA-CeD is not more frequent in IBD patients, with an even lower frequency of HLA-DQ2 and -DQ8 in UC and CD respectively. HLA-DQ2.5 confers protection from the development of UC, especially in women, and HLA-DQ8 does so for the appearance of CD. HLA-DQ2.2 is present in 34% of the CD patients and may constitute a genetic risk factor for CD development.

Prevalence of celiac disease in patients with severe food allergy

The association between food allergy and celiac disease (CD) is still to be clarified. We screened for CD 319 patients with severe food allergy (IgE > 85 kU/l against food proteins and a history of severe allergic reactions) who underwent specific food oral immunotherapy (OIT), together with 128 children with mild allergy who recovered without OIT, and compared the prevalence data with our historical data regarding healthy schoolchildren. Sixteen patients (5%) with severe allergy and one (0.8%) with mild allergy tested positive for both genetic and serological CD markers, while the prevalence among the schoolchildren was 1%. Intestinal biopsies were obtained in 13/16 patients with severe allergy and in the one with mild allergy, confirming the diagnosis of CD. Sufferers from severe food allergy seem to be at a fivefold increased risk of CD. Our findings suggest that routine screening for CD should be recommended in patients with severe food allergy.

High Frequency of Haplotype HLA-DQ7 in Celiac Disease Patients from South Italy: Retrospective Evaluation of 5,535 Subjects at Risk of Celiac Disease

Background

Celiac disease (CD) has a strong genetic component mainly due to HLA DQ2/DQ8 encoding genes. However, a minority of CD patients are DQ2/DQ8-negative. To address this issue, we retrospectively characterized HLA haplotypes in 5,535 subjects at risk of CD (either relatives of CD patients or subjects with CD-like symptoms) referred to our center during a 10-year period.

Methods

We identified loci DQA1/DQB1/DRB1 by sequence-specific oligonucleotide-PCR and sequence-specific primer-PCR; anti-transglutaminase IgA/IgG and anti-endomysium IgA by ELISA and indirect immunofluorescence, respectively.

Results

We diagnosed CD in 666/5,535 individuals, 4.2% of whom were DQ2/DQ8-negative. Interestingly, DQ7 was one of the most abundant haplotypes in all CD patients and significantly more frequent in DQ2/DQ8-negative (38%) than in DQ2/DQ8-positive CD patients (24%) (p<0.05).

Conclusion

Our data lend support to the concept that DQ7 represents an additive or independent CD risk haplotype with respect to DQ2/DQ8 haplotypes but this finding should be verified in other large CD populations.

Immunogenetic biomarkers in inflammatory bowel diseases: Role of the IBD3 region

Many studies have demonstrated the linkage between the IBD3 region (6p21.1-23), an area which encompasses the famous human leukocyte antigen (HLA) complex, and Crohn’s disease (CD) or ulcerative colitis (UC). IBD3 is the only region that meets genome-wide significance, and provides stronger evidence of the linkage than 16p13.1-16q12.2 (IBD1), the locus that contains the susceptibility gene CARD15. However, despite these findings, IBD3 susceptibility genes remain elusive and unclear due to the strong linkage disequilibrium, extensive polymorphism, and high gene density that characterize this area and also due to varying allele frequencies in populations around the world. This area presents an extremely high abundance of genes, including the classical and non-classical major histocompatibility complex (MHC) class I and II genes, and other genes, namely MHC class III genes tumor necrosis factor (TNF)-α and -β, and Hsp, whose proteins play key functions in immunological processes. To date, it is not clear which genes within the MHC family contribute to the IBD pathogenesis, although certain HLA alleles have been associated with IBD. Recent insights into the biological function of other genes encoded within the IBD3 region, such as the MHC class I chain-related (MIC) genes, have led investigators to a more comprehensive exploration of this region. MHC class I chain-related molecule A (MICA) is highly polymorphic and interacts with NKG2D, its receptor on the surface of NK, Tγδ and T CD8⁺ cells. Increased expression of MICA in intestinal epithelial cells and increased expression of NKG2D in CD4⁺ T cells (lamina propria) in patients with CD have also been reported. MICA alleles have also been associated with IBD, and a variation at amino acid position 129 of the α2-heavy chain domain seems to categorize MICA alleles into strong and weak binders of NKG2D receptor, thereby influencing the effector cells’ function. In this regard, a relevant role of MICA-129-Val/Met single nucleotide polymorphism has recently been implicated in the pathogenesis of IBD. TNF-α and -β also play an important role in inflammatory response. In fact, IBD is commonly treated with TNF-α inhibitors. Additionally, polymorphisms of TNF-α gene are known to affect the gene expression level and particular TNF-α genotypes may influence the response of IBD patients treated with TNF-α inhibitors.

Systematic review: Sprue-like enteropathy associated with olmesartan

BACKGROUND

The onset of a sprue-like enteropathy in association with olmesartan therapy has been recently reported.

AIMS

To perform a systematic review of the literature and describe three additional cases of olmesartan-associated enteropathy.

METHODS

Electronic and manual bibliographic searches were performed to identify original reports in which subjects who were undertaking olmesartan developed a sprue-like enteropathy. Because of the scarcity of studies with adequate sample size, case series with less than 10 patients and case reports were also considered. Data extraction was performed independently by two reviewers.

RESULTS

A total of 11 publications met our pre-defined inclusion criteria, for an overall number of 54 patients (including our series). Almost all patients presented with diarrhoea and weight loss. Normocytic normochromic anaemia and hypoalbuminaemia were the commonest laboratory defects at presentation. Antibody testing for coeliac disease was always negative. Variable degrees of duodenal villous atrophy were present in 98% of patients, while increased intra-epithelial lymphocytes were documented in only 65% of cases. After discontinuation of olmesartan, all reported patients achieved resolution of signs and symptoms.

CONCLUSIONS

Although the available evidence is limited, the olmesartan-associated sprue-like enteropathy may be considered as a distinct clinical entity, and should be included in the differential diagnosis when serological testing for coeliac disease is negative.