Inflammatory bowel disease: susceptibility and disease heterogeneity revealed by human leukocyte antigen genotyping

Differential efficacy of medical therapies for ulcerative colitis according to disease extent: patient-level analysis from multiple randomized controlled trials

Background

Disease extent in Ulcerative Colitis (UC) has prognostic implications for disease course. It is unclear whether the efficacy of medical therapies for moderate to severely active UC vary according to disease extent at enrollment.

Methods

We analyzed patient level data from 11 Phase 2 and 3 clinical trials of advanced therapies in patients with moderate-to-severe UC to assess modifications of advanced therapy effects by disease extent. Primary outcome was clinical response and secondary outcomes were clinical remission, endoscopic response/remission and endoscopic improvement, and Mayo clinic subscore for both induction and maintenance studies. Binary and continuous outcomes were analyzed using the modified Poisson regression model and the mixed-effects model, respectively, adjusting for age, sex, disease duration, concomitant steroid use and prior anti-TNF use. Effect modifications with binary outcomes were quantified by ratios of risk ratio for left-sided to that for extensive colitis while effect modifications with the Mayo subscores were quantified by differences of the differences between mean scores of the left-sided and extensive colitis. Results were presented with point estimates and 95% confidence intervals as well as p-values.

Findings

Eleven clinical trials enrolling 5450 UC patients (infliximab = 2, adalimumab = 2, golimumab = 2, vedolizumab = 2, tofacitinib = 3) were included. In induction trials, there was evidence to suggest effect modification by disease extent for clinical response with tofacitinib (the ratio of RRs 0.67, 95% CI [0.45, 0.99], p = 0.049) and clinical remission with infliximab (ratio of RRs 0.33, 95% CI [0.13, 0.85], p = 0.020) favoring patients with extensive colitis. There was no evidence to suggest effect modification for endoscopic improvement and clinical outcomes. There was evidence to suggest effect modification by disease extent for clinical remission with tofacitinib (ratio of RRs 0.44, 95% CI [0.22, 0.89], p = 0.020) favoring patients with extensive colitis. For symptom subscores from the Mayo Clinic score, tofacitinib was associated with a greater reduction in both stool frequency (difference of differences 0.37, 95% CI [0.08, 0.65], p = 0.012) and rectal bleeding scores (difference of differences 0.25, 95% CI [0.03, 0.47], p = 0.026) in patients with extensive colitis compared to left sided.

Interpretation

These findings underscore the possibility of differential efficacy of medical therapies according to disease distribution. These results warrant further exploration in forthcoming trials to better inform treatment strategies and consideration of disease distribution as a baseline stratification factor in clinical trials.

Funding

This study did not receive any financial support.

Autoimmune Diseases of Digestive Organs-A Multidisciplinary Challenge: A Focus on Hepatopancreatobiliary Manifestation

It is well known that some pathological conditions, especially of autoimmune etiology, are associated with the HLA (human leukocyte antigen) phenotype. Among these diseases, we include celiac disease, inflammatory bowel disease, autoimmune enteropathy, autoimmune hepatitis, primary sclerosing cholangitis and primary biliary cholangitis. Immunoglobulin G4-related diseases (IgG4-related diseases) constitute a second group of autoimmune gastrointestinal, hepatobiliary and pancreatic illnesses. IgG4-related diseases are systemic and rare autoimmune illnesses. They often are connected with chronic inflammation and fibrotic reaction that can occur in any organ of the body. The most typical feature of these diseases is a mononuclear infiltrate with IgG4-positive plasma cells and self-sustaining inflammatory response. In this review, we focus especially upon the hepatopancreatobiliary system, autoimmune pancreatitis and IgG4-related sclerosing cholangitis. The cooperation of the gastroenterologist, radiologist, surgeon and histopathologist is crucial for establishing correct diagnoses and appropriate treatment, especially in IgG4 hepatopancreatobiliary diseases.

In sickness and in health: when myasthenia gravis is a conjugal matter

OBJECTIVE

Genes and environment contribute to the multifactorial etiology of autoimmune diseases. Familial clusters of autoimmune diseases are often observed among first-degree relatives sharing the same genetic background and environmental exposure. Rarer is the occurrence of the same autoimmune diseases in non-consanguineous spouses. We hereinafter report two non-consanguineous spouses who developed one after the other AChR-positive myasthenia gravis.

METHODS

This study has been approved by Catholic University Ethic Committee. The wife, previously affected by Graves-Basedow disease, was the first to be diagnosed with myasthenia gravis, basing on a generalized weakness and an anti-AChR-positive assay. The husband, who suffered from ulcerative colitis, 16 years after his wife diagnosis complained of a mild generalized weakness. Repetitive nerve stimulation test and anti-AChR assay were confirmed myasthenia gravis. In these spouses, myasthenia gravis was not associated with thymoma. Human leukocyte antigen (HLA) class II genotyping showed distinct associations, with the wife carrying the DRB1*03:01 DQB1*02:01 and the husband the DRB1*07 DQB102 alleles.

RESULTS

The wife's haplotype is strongly associated with myasthenia gravis and thyroiditis whereas HLA DRB1*07 allele was found to be related both to late-onset myasthenia gravis and ulcerative colitis.

CONCLUSIONS

Compared with other autoimmune disorders, myasthenia gravis has a lower prevalence. The surveillance environmental exposure may greatly improve our knowledge of non-genetic drivers of autoimmunity.

Review article: the genetics of the human leucocyte antigen region in inflammatory bowel disease

BACKGROUND

The human leucocyte antigen (HLA) complex, located at chromosome 6p21.3 is a highly polymorphic region containing the classical class I and II HLA genes. The region is highly associated with inflammatory bowel disease (IBD), largely through genome-wide association studies (GWAS).

AIMS

To review the role of HLA in immune function, summarise data on risk/protective HLA genotypes for IBD, discuss the role of HLA in IBD pathogenesis, treatment and examine limitations that might be addressed by future research.

METHODS

An organised search strategy was used to collate articles describing HLA genes in IBD, including Crohn's disease and ulcerative colitis.

RESULTS

All classical HLA genes with variation (including HLA-A, B, C, DRB1, DQA1, DQB1, DPA1 and DPB1) harbour IBD-associated genotypes. The most implicated gene is HLA-DRB1, with HLA-DRB1*03:01 the most associated risk allele in both Crohn's disease and ulcerative colitis. Elucidating precise disease associations is challenging due to high linkage disequilibrium between HLA genotypes. The mechanisms by which risk alleles cause disease are multifactorial, with the best evidence indicating structural and electrostatic alteration impacting antigen binding and downstream signalling. Adverse medication events have been associated with HLA genotypes including with thiopurines (pancreatitis) and anti-TNF agents (antibody formation).

CONCLUSIONS

The HLA complex is associated with multiple risk/protective alleles for IBD. Future research utilising long-read technology, ascertainment of zygosity and integration in disease modelling will improve the functional understanding and clinical translation of genetic findings.

Neurotheranostics as personalized medicines

The discipline of neurotheranostics was forged to improve diagnostic and therapeutic clinical outcomes for neurological disorders. Research was facilitated, in largest measure, by the creation of pharmacologically effective multimodal pharmaceutical formulations. Deployment of neurotheranostic agents could revolutionize staging and improve nervous system disease therapeutic outcomes. However, obstacles in formulation design, drug loading and payload delivery still remain. These will certainly be aided by multidisciplinary basic research and clinical teams with pharmacology, nanotechnology, neuroscience and pharmaceutic expertise. When successful the end results will provide "optimal" therapeutic delivery platforms. The current report reviews an extensive body of knowledge of the natural history, epidemiology, pathogenesis and therapeutics of neurologic disease with an eye on how, when and under what circumstances neurotheranostics will soon be used as personalized medicines for a broad range of neurodegenerative, neuroinflammatory and neuroinfectious diseases.

Association Study of Glutathione S-transferases Gene Polymorphisms (GSTM1 and GSTT1) with Ulcerative Colitis and Crohn's Disease in the South of Iran

Background:

Inflammatory bowel diseases (IBDs), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic inflammatory disorders of the gastrointestinal tract. A combination of environmental factors and interactions with a genetic predisposition are suggested to play an important role in the etiology and pathogenesis of the IBD. Glutathione S-transferases (GSTs) are multifunctional enzymes involved in the cellular oxidative stress handling. Possible associations between GSTs gene polymorphisms and susceptibility to UC and CD have been reported in different population. The relationship between GSTM1 and GSTT1 deletion polymorphisms and susceptibility to UC and CD were investigated in the Iranian population.

Materials and Methods:

The study was performed in 106 IBD patients and 243 age- and sex-matched healthy Iranian controls consulting the IBD registry center of the Motahari Clinic, Shiraz University of Medical Sciences, Shiraz, Iran, between 2011 and 2013. GSTM1 and GSTT1 genotyping were performed using multiplex polymerase chain reaction and differences in the distribution of gene polymorphisms were analyzed statistically between the studied groups.

Results:

Statistically significant higher frequency of GSTM1 null genotype was observed in IBD patients (P = 0.01) and in the subgroup of patients with UC (P = 0.04) compared to healthy controls, whereas this was not true for CD patients. No significant association was found between GSTT1 gene polymorphism and UC or CD.

Conclusions:

Absence of GSTT1 functional gene does not play an important role in the pathophysiology and development of IBD, UC, and CD in Iranian population whereas GSTM1 null genotype could be considered as a possible genetic predisposing factor for more susceptibility to IBD and UC.

Comorbidity of Narcolepsy Type 1 With Autoimmune Diseases and Other Immunopathological Disorders: A Case-Control Study

Background

Several evidences suggest that autoimmune diseases (ADs) tend to co-occur in an individual and within the same family. Narcolepsy type 1 (NT1) is a chronic sleep disorder caused by a selective loss of hypocretin-producing neurons due to a mechanism of neural destruction that indicates an autoimmune pathogenesis, although no evidence is available. We report on the comorbidity of ADs and other immunopathological diseases (including allergy diseases) in narcolepsy.

Methods

We studied 158 Caucasian NT1 patients (60.7% male; mean age 49.4 ± 19.7 years), in whom the diagnosis was confirmed by polysomnography followed by a multiple sleep latency test, or by hypocretin-1 levels measurements.

Results

Thirty out of 158 patients (18.99%; 53.3% female; 29 sporadic and one familial cases) had one or more immunopathological diseases associated. A control group of 151 subjects were matched by gender and age with the narcolepsy patients. Results demonstrated that there was a higher frequency of ADs in our series of narcolepsy patients compared to the sample of general population (odds ratio: 3.17; 95% confidence interval: 1.01 - 10.07; P = 0.040). A temporal relationship with the age at onset of the diseases was found.

Conclusions

Cataplexy was significantly more severe in NT1 patients with immunopathological diseases, and immunopathological diseases are a risk factor for severe forms of cataplexy in our series (odds ratio: 23.6; 95% confidence interval: 5.5 - 100.1).

Pathogenesis, diagnosis, and management of ulcerative proctitis, chronic radiation proctopathy, and diversion proctitis

Chronic proctitis refers to persistent or relapsing inflammation of the rectum, which results from a wide range of etiologies with various pathogenic mechanisms. The patients may share similar clinical presentations. Ulcerative proctitis, chronic radiation proctitis or proctopathy, and diversion proctitis are the 3 most common forms of chronic proctitis. Although the diagnosis of these disease entities may be straightforward in the most instances based on the clinical history, endoscopic, and histologic features, differential diagnosis may sometimes become problematic, especially when their etiologies and the disease processes overlap. The treatment for the 3 forms of chronic proctitis is different, which may shed some lights on their pathogenetic pathway. This article provides an overview of the latest data on the clinical features, etiologies, diagnosis, and management of ulcerative proctitis, chronic radiation proctopathy, and diversion proctitis.

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.

Association of HLA-DRB1 alleles and anti-neutrophil cytoplasmic antibodies in Han and Uyghur patients with ulcerative colitis in China

OBJECTIVE

We aimed to study the association between HLA-DRB1 alleles and anti-neutrophil cytoplasmic antibodies (ANCA) among Uyghur and Han patients with ulcerative colitis (UC) in China.

METHODS

Altogether 160 UC patients and 466 healthy controls of Uyghur and Han groups residing in the Xinjiang Uyghur Autonomous Region of China were included. HLA-DRB1 variants were identified from genomic DNA using polymerase chain reaction and gene sequencing. Serum ANCA were determined by indirect immunofluorescence assay.

RESULTS

Among the Uyghur populations, the HLA-DRB1*08 gene frequency was lower in the UC patients than in the control group (P = 0.012, OR 0.12, 95% CI 0.02-0.91); however, that of HLA-DRB1*13 was much higher in the UC patients than in the controls (P = 0.001, OR 4.32, 95% CI 1.92-9.74). In Han patients with UC, there was no significant difference in HLA-DRB1 frequency between UC patients and healthy controls. The positive rate of ANCA in Uyghur patients with UC was significantly higher than in Han UC patients (P = 0.026), and ANCA positivity was associated with an increased frequency of HLA-DRB1*13 in Uyghur UC patients, but no such difference was observed in the Han patients.

CONCLUSIONS

Genetic polymorphisms of the HLA-DRB1*08 and *13 may contribute to the clinical heterogeneity of UC between Uyghur and Han UC patients in China. In Uyghur UC patients, HLA-DRB1*13 may be correlated with ANCA positivity.

Association study of MICA-TM polymorphism with inflammatory bowel disease in the South Tunisian population

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory disorders of the gastro-intestinal tract with unknown etiology. Both environmental and genetic factors are involved in the pathogenesis of these inflammatory bowel diseases (IBD).

AIM

The purpose of the present study was to determine the association between the polymorphism of the transmembrane region of MICA (MICA-TM), and the genetic susceptibility in Tunisian patients with IBD.

PATIENTS AND METHODS

A total of 102 Tunisian patients (66 with UC, 36 with CD) and 123 healthy controls were enrolled in our study. MICA-TM was genotyped by a semiautomatic fluorescent-labelled PCR method, amplicons were analysed on an ABI Prism 310 genotyper. Comparisons of allele frequencies between patients and controls, and between patients' subgroups were performed using SPSS 13.0.

RESULTS

No MICA allele was significantly increased in both groups of IBD compared to controls. The MICA-A5.1 allele was significantly decreased in CD patients (p=0.006, pc=0.03). In UC, MICA-A6 was associated with the presence of extraintestinal manifestations (p=0.04, pc=0.2), whereas MICA-A5 was associated with late age of onset (p=0.04). In CD, MICA-A6 was significantly increased in active disease patients when compared to moderately active or inactive disease (p=0.03, pc=0.15).

CONCLUSION

Some clinical features of CD and UC may be influenced by specific MICA-TM alleles. In our South Tunisian population, MICA plays a disease modifying role, rather than being an important gene in the susceptibility for developing IBD.

An evolutionary perspective on the causes and treatment of inflammatory bowel disease

PURPOSE OF REVIEW

To use insights from evolutionary biology to assess the current evidence for the causes, treatment, and prevention of inflammatory bowel disease (IBD).

RECENT FINDINGS

When analyzed in the context of evolutionary adaptation, recent assessments of genetic, microbial, and environmental associations with IBD implicate infectious causation.

SUMMARY

An evolutionary perspective provides insight into the causes of IBD, interpretation of its manifestations, and assessment of interventions. The evidence implicating infectious causation suggests that future studies of IBD would benefit from increased focus on infectious causes and interventions that prevent or inhibit them.

Difference in DRB1* gene polymorphisms between Han and Uyghur ulcerative colitis patients in China

AIM: To evaluate the association between HLA-DRB1 alleles and Han and Uyghur ulcerative colitis (UC) patients residing in the Xinjiang Uyghur Autonomous Region of China.

METHODS: In this study, 102 UC patients (53 Han including 22 men and 31 women, and 49 Uyghur patients including 25 men and 24 women; aged 48.07 ± 15.83 years) and 310 age- and sex-matched healthy controls were enrolled in the Department of Gastroenterology, Xinjiang People’s Hospital of China from January 2010 to May 2011. UC was diagnosed based on the clinical, endoscopic and histological findings following Lennard-Jones criteria. Blood samples were collected and genomic DNA was extracted by routine laboratory methods, and both polymerase chain reaction and gene sequencing were used to identify HLA-DRB1 allele variants. The potential association between genetic variation and UC in Han and Uyghur patients was examined. There were no statistical differences in HLA-DRB1 allele frequencies in Han UC patients.

RESULTS: There was no significant difference in the sex ratio between the controls and UC patients (P = 0.740). In Han patients with UC (n = 53), HLA-DRB1 *03, *13 allele frequencies were lower than in healthy controls (n = 161), but not statistically significant, and HLA-DRB1*04*11*14 allele frequencies were higher than in healthy controls, but without statistical significance. Differences between Uyghur UC patients and the control group were observed for HLA-DRB1*04 and HLA-DRB1*13, both showed a greater frequency in UC patients (10.21% vs 2.69%, P = 0.043; 14.29% vs 4.03%, P = 0.019). HLA-DRB1*14 also showed a greater frequency in UC patients (14.29% vs 2.69%, P = 0.006). The frequencies of DRB1*04, *13*14 alleles were increased in Uyghur UC patients compared with normal controls. The frequency of DRB1 * 08 was decreased in Uyghur UC patients compared with normal controls. HLA-DRB1 alleles showed no association with UC in Han patients. There were no statistical differences in HLA-DRB1 allele frequencies in Han UC patients. The frequencies of DRB1*04, *13*14 alleles were increased in Uyghur UC patients compared with normal controls. The frequency of DRB1*08 was decreased in Uyghur UC patients compared with normal controls. Polymorphism of the HLA-DRB1 gene may contribute to the clinical heterogeneity of UC between Han and Uyghur UC patients in China.

CONCLUSION: HLA-DRB1*04*13*14 and DRB1*08 may contribute to the clinical heterogeneity of UC between Han and Uyghur UC patients.

Narcolepsy is complicated by high medical and psychiatric comorbidities: a comparison with the general population

BACKGROUND

Individuals affected with narcolepsy represent a vulnerable segment of the population. However, we only have a partial understanding of this vulnerability. Our study aims to examine psychiatric disorders and medical conditions associated with narcolepsy.

METHODS

A total of 320 narcoleptic participants were interviewed regarding sleeping habits, health, medication consumption, medical conditions (International Statistical Classification of Diseases and Related Health Problems, 10th edition), sleep disorders (International Classification of Sleep Disorders, second edition [ICSD-2]) and mental disorders (Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision [DSM-IV-TR]) using Sleep-EVAL. A general population comparison sample (N=1464) matched for age, sex, and body mass index (BMI) and interviewed with the same instrument was used to estimate odds ratios (OR).

RESULTS

Five diseases were more frequently observed among narcoleptic participants, including hypercholesterolemia (OR, 1.51), diseases of the digestive system (OR, 3.27), heart diseases (OR, 2.07), upper respiratory tract diseases (OR, 2.52), and hypertension (OR, 1.32). Most frequent psychiatric disorders among the narcolepsy group were major depressive disorder (MDD) (OR, 2.67) and social anxiety disorder (OR, 2.43), both affecting nearly 20% of narcoleptic individuals. However, most mood and anxiety disorders were more prevalent among the narcoleptic group. Alcohol abuse or alcohol dependence was comparable between groups.

CONCLUSIONS

Narcolepsy is associated with a high comorbidity of both medical conditions and psychiatric disorders that need to be addressed when developing a treatment plan.