Absence of mycobacterium avium subsp. paratuberculosis in Crohn's patients

Advances in understanding the genetic architecture of antibody response to paratuberculosis in sheep by heritability estimate and LDLA mapping analyses and investigation of candidate regions using sequence-based data

BACKGROUND

Paratuberculosis is a contagious and incurable disease that is caused by Mycobacterium avium subsp. paratuberculosis (MAP) with significant negative effects on animal welfare and farm profitability. Based on a large naturally infected flock over 12 years, we analyzed repeated enzyme-linked immunosorbent assay tests (ELISA), OvineSNP50 BeadChip genotypes and whole-genome sequences imputed from 56 influential animals. The main goals were to estimate the genetic parameters of proxy traits for resistance to MAP, identify genomic regions associated with the host's immune response against MAP and search for candidate genes and causative mutations through association and functional annotation analyses of polymorphisms identified by sequencing.

RESULTS

Two variables were derived from ELISA tests. The first, a binary variable, assessed the infection status of each animal over the entire productive life, while the second considered the level of antibody recorded over time. Very similar results were obtained for both variables. Heritability estimates of about 0.20 were found and a significant region capturing 18% and 13% of the genetic variance was detected on ovine chromosome 20 by linkage disequilibrium and linkage analysis on OvineSNP50 positions. Functional annotation and association analyses on the imputed sequence polymorphisms that were identified in this region were carried out. No significant variants showed a functional effect on the genes that mapped to this region, most of which belong to the major histocompatibility complex class II (MHC II). However, the conditional analysis led to the identification of two significant polymorphisms that can explain the genetic variance associated with the investigated genomic region.

CONCLUSIONS

Our results confirm the involvement of the host's genetics in susceptibility to MAP in sheep and suggest that selective breeding may be an option to limit the infection. The estimated heritability is moderate with a relevant portion being due to a highly significant region on ovine chromosome 20. The results of the combined use of sequence-based data and functional analyses suggest several genes belonging to the MHC II as the most likely candidates, although no mutations in their coding regions showed a significant association. Nevertheless, information from genotypes of two highly significant polymorphisms in the region can enhance the efficiency of selective breeding programs.

The role of gastrointestinal pathogens in inflammatory bowel disease: a systematic review

The inflammatory bowel diseases (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), are chronic, progressive, inflammatory conditions of the gastrointestinal tract. Imbalance in the gut microbial community, or dysbiosis, and the subsequent immune response, represent the critical relationship between genetic susceptibility, microbes, and environment factors, that result in IBD. Gastrointestinal pathogens - a common cause of dysbiosis - have been implicated as an environmental trigger in new onset IBD, as well as flare of existing IBD. In this article, we systematically review clinical data regarding the association between specific gastrointestinal pathogens and IBD. Numerous bacteria, viruses, fungi, and parasites have been implicated in the pathogenesis of IBD, and exacerbations of existing disease. In this article, we will also specifically discuss the less recognized microbes that have an inverse association with IBD, including certain bacterial pathogens, such as Helicobacter pylori, and parasites, such as Trichuris species. Future prospective and experimental studies are required to establish causality and clarify potential mechanisms of enteric pathogens in modifying the risk and course of IBD.

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): paratuberculosis

Paratuberculosis has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on the eligibility of paratuberculosis to be listed, Article 9 for the categorisation of paratuberculosis according to disease prevention and control rules as in Annex IV and Article 8 on the list of animal species related to paratuberculosis. The assessment has been performed following a methodology composed of information collection and compilation, expert judgement on each criterion at individual and, if no consensus was reached before, also at collective level. The output is composed of the categorical answer, and for the questions where no consensus was reached, the different supporting views are reported. Details on the methodology used for this assessment are explained in a separate opinion. According to the assessment performed, paratuberculosis can be considered eligible to be listed for Union intervention as laid down in Article 5(3) of the AHL. The disease would comply with the criteria in Sections 3, 4 and 5 of Annex IV of the AHL, for the application of the disease prevention and control rules referred to in points (c), (d) and (e) of Article 9(1). The animal species to be listed for paratuberculosis according to Article 8(3) criteria are several species of mammals and birds as susceptible species and some species of the families Bovidae, Cervidae and Leporidae as reservoirs.

Current status of Mycobacterium avium subspecies paratuberculosis infection in animals & humans in India: What needs to be done?

Mycobacterium avium subspecies paratuberculosis (MAP) has emerged as a major health problem for domestic livestock and human beings. Reduced per animal productivity of domestic livestock seriously impacts the economics of dairy farming globally. High to very high bioload of MAP in domestic livestock and also in the human population has been reported from north India. Presence of live MAP bacilli in commercial supplies of raw and pasteurized milk and milk products indicates its public health significance. MAP is not inactivated during pasteurization, therefore, entering into human food chain daily. Recovery of MAP from patients with inflammatory bowel disease or Crohn's disease and animal healthcare workers suffering with chronic gastrointestinal problems indicate a close association of MAP with a number of chronic and other diseases affecting human health. Higher bioload of MAP in the animals increases the risk of exposure to the human population with MAP. This review summarizes the current status of MAP infection in animals as well as in human beings and also highlights the prospects of effective management and control of disease in animals to reduce the risk of exposure to human population.

Recent insights into the molecular pathogenesis of Crohn's disease: a review of emerging therapeutic targets

Chronic inflammatory bowel diseases (IBDs) are a subject of great interest in gastroenterology, due to a pathological mechanism that is difficult to explain and an optimal therapeutic approach still undiscovered. Crohn's disease (CD) is one of the main entities in IBD, characterized by clinical polymorphism and great variability in the treatment response. Modern theories on the pathogenesis of CD have proven that gut microbiome and environmental factors lead to an abnormal immune response in a genetically predisposed patient. Genome-wide association studies in patients with CD worldwide revealed several genetic mutations that increase the risk of IBD and that predispose to a more severe course of disease. Gut microbiota is considered a compulsory and an essential part in the pathogenesis of CD. Intestinal dysmicrobism with excessive amounts of different bacterial strains can be found in all patients with IBD. The discovery of Escherichia coli entero-invasive on resection pieces in patients with CD now increases the likelihood of antimicrobial or vaccine-type treatments. Recent studies targeting intestinal immunology and its molecular activation pathways provide new possibilities for therapeutics. In addition to antitumor necrosis factor molecules, which were a breakthrough in IBD, improving mucosal healing and resection-free survival rate, other classes of therapeutic agents come to focus. Leukocyte adhesion inhibitors block the leukocyte homing mechanism and prevent cellular immune response. In addition to anti-integrin antibodies, chemokine receptor antagonists and SMAD7 antisense oligonucleotides have shown encouraging results in clinical trials. Micro-RNAs have demonstrated their role as disease biomarkers but it could also become useful for the treatment of IBD. Moreover, cellular therapy is another therapeutic approach under development, aimed for severe refractory CD. Other experimental treatments include intravenous immunoglobulins, exclusive enteral nutrition, and granulocyte colony-stimulating factors.

Mycobacterium avium subspecies hominissuis in Crohn's disease: a case report

We have cultured Mycobacteria avium subspecies hominissuis (MAH) from the blood of a patient with Crohn’s disease. The patient is a 21 year-old-female with a diagnosis of Crohn’s disease for two years. She had been treated with corticosteroids and Humira for six months. A blood specimen was cultured in a specialized medium, and there was visible bacterial growth present in the liquid culture medium after eight weeks. PCR analysis of the bacterial growth and subsequent direct sequencing of the PCR amplicon confirmed the presence of MAH. The significance of this finding is discussed.

Mycobacterium avium subspecies paratuberculosis in the etiology of Crohn’s disease, cause or epiphenomenon?

The origin of inflammatory bowel disease is unknown. Attempts have been made to isolate a microorganism that could explain the onset of inflammation, but no pathological agent has ever been identified. Johne’s disease is a granulomatous chronic enteritis of cattle and sheep caused by Mycobacterium avium subspecies paratuberculosis (MAP) and shows some analogies with Crohn’s disease (CD). Several studies have tried to clarify if MAP has a role in the etiology of CD. The present article provides an overview of the evidence in favor and against the “MAP-hypothesis”, analyzing the methods commonly adopted to detect MAP and the role of antimycobacterial therapy in patients with inflammatory bowel disease. Studies were identified through the electronic database, MEDLINE, and were selected based on their relevance to the objective of the review. The presence of MAP was investigated using multiple diagnostic methods for MAP detection and in different tissue samples from patients affected by CD or ulcerative colitis and in healthy controls. On the basis of their studies, several authors support a close relationship between MAP and CD. Although increasing evidence of MAP detection in CD patients is unquestionable, a clear etiological link still needs to be proven.

Infectious etiopathogenesis of Crohn’s disease

Important advances during the last decade have been made in understanding the complex etiopathogenesis of Crohn’s disease (CD). While many gaps in our knowledge still exist, it has been suggested that the etiology of CD is multifactorial including genetic, environmental and infectious factors. The most widely accepted theory states that CD is caused by an aggressive immune response to infectious agents in genetically predisposed individuals. The rise of genome-wide association studies allowed the identification of loci and genetic variants in several components of host innate and adaptive immune responses to microorganisms in the gut, highlighting an implication of intestinal microbiota in CD etiology. Moreover, numerous independent studies reported a dysbiosis, i.e., a modification of intestinal microbiota composition, with an imbalance between the abundance of beneficial and harmful bacteria. Although microorganisms including viruses, yeasts, fungi and bacteria have been postulated as potential CD pathogens, based on epidemiological, clinicopathological, genetic and experimental evidence, their precise role in this disease is not clearly defined. This review summarizes the current knowledge of the infectious agents associated with an increased risk of developing CD. Therapeutic approaches to modulate the intestinal dysbiosis and to target the putative CD-associated pathogens, as well as their potential mechanisms of action are also discussed.

Mycobacterium avium subspecies paratuberculosis causes Crohn's disease in some inflammatory bowel disease patients

Crohn’s disease (CD) is a chronic inflammatory condition that plagues millions all over the world. This debilitating bowel disease can start in early childhood and continue into late adulthood. Signs and symptoms are usually many and multiple tests are often required for the diagnosis and confirmation of this disease. However, little is still understood about the cause(s) of CD. As a result, several theories have been proposed over the years. One theory in particular is that Mycobacterium avium subspecies paratuberculosis (MAP) is intimately linked to the etiology of CD. This fastidious bacterium also known to cause Johne’s disease in cattle has infected the intestines of animals for years. It is believed that due to the thick, waxy cell wall of MAP it is able to survive the process of pasteurization as well as chemical processes seen in irrigation purification systems. Subsequently meat, dairy products and water serve as key vehicles in the transmission of MAP infection to humans (from farm to fork) who have a genetic predisposition, thus leading to the development of CD. The challenges faced in culturing this bacterium from CD are many. Examples include its extreme slow growth, lack of cell wall, low abundance, and its mycobactin dependency. In this review article, data from 60 studies showing the detection and isolation of MAP by PCR and culture techniques have been reviewed. Although this review may not be 100% comprehensive of all studies, clearly the majority of the studies overwhelmingly and definitively support the role of MAP in at least 30%-50% of CD patients. It is very possible that lack of detection of MAP from some CD patients may be due to the absence of MAP role in these patients. The latter statement is conditional on utilization of methodology appropriate for detection of human MAP strains. Ultimately, stratification of CD and inflammatory bowel disease patients for the presence or absence of MAP is necessary for appropriate and effective treatment which may lead to a cure.

Role of the gut microbiota in inflammatory bowel disease pathogenesis: What have we learnt in the past 10 years?

Our understanding of the microbial involvement in inflammatory bowel disease (IBD) pathogenesis has increased exponentially over the past decade. The development of newer molecular tools for the global assessment of the gut microbiome and the identification of nucleotide-binding oligomerization domain-containing protein 2 in 2001 and other susceptibility genes for Crohn’s disease in particular has led to better understanding of the aetiopathogenesis of IBD. The microbial studies have elaborated the normal composition of the gut microbiome and its perturbations in the setting of IBD. This altered microbiome or “dysbiosis” is a key player in the protracted course of inflammation in IBD. Numerous genome-wide association studies have identified further genes involved in gastrointestinal innate immunity (including polymorphisms in genes involved in autophagy: ATG16L1 and IGRM), which have helped elucidate the relationship of the local innate immunity with the adjacent luminal bacteria. These developments have also spurred the search for specific pathogens which may have a role in the metamorphosis of the gut microbiome from a symbiotic entity to a putative pathogenic one. Here we review advances in our understanding of microbial involvement in IBD pathogenesis over the past 10 years and offer insight into how this will shape our therapeutic management of the disease in the coming years.

Subspecies identification and significance of 257 clinical strains of Mycobacterium avium

Mycobacterium avium is abundant in the environment. It has four subspecies of three types: the human or porcine type, M. avium subsp. hominissuis; the bird type, including M. avium subsp. avium serotype 1 and serotype 2, 3 (also M. avium subsp. silvaticum); and the ruminant type, M. avium subsp. paratuberculosis. We determined the subspecies of 257 M. avium strains isolated from patients at the M.D. Anderson Cancer Center from 2001 to 2010 and assessed their clinical significance. An assay of multiplex PCR was used for the typing. Results showed M. avium subsp. hominissuis to be most common (n = 238, 92.6%), followed by M. avium subsp. avium serotype 1 (n = 12, 4.7%) and serotype 2, 3 (n = 7, 2.7%). No strains of M. avium subsp. paratuberculosis were found. Of the 238 patients with M. avium subsp. hominissuis, 65 (27.3%) showed evidence of definite or probable infections, mostly in the respiratory tract, whereas the rest had weak evidence of infection. The bird-type subspecies, despite being infrequently isolated, caused relatively more definite and probable infections (10 of 19 strains, 52.6%). Overall, women of 50 years of age or older were more prone to M. avium infection than younger women or men of all ages were. We therefore conclude that M. avium subsp. hominissuis is the dominant M. avium subspecies clinically, that the two bird-type subspecies do cause human infections, and that M. avium infects mainly postmenopausal women. The lack of human clinical isolation of the ruminant type subspecies may need further investigation.

Mycobacterium avium subspecies paratuberculosis: an insidious problem for the ruminant industry

Mycobacterium avium subspecies paratuberculosis is considered as one of the most serious problems affecting the world's ruminant industry due to its significant impact on the global economy and the controversial issue that it may be pathogenic for humans. M. avium subspecies paratuberculosis is the causative agent of Johne's disease in animals and might be implicated in cases of human Crohn's disease. We provide an insight into M. avium subspecies paratuberculosis from some bacteriological, clinical, and molecular epidemiological perspectives.

Crohn's disease and the mycobacterioses: a quarter century later. Causation or simple association?

It has been more than 25 years since Mycobacterium paratuberculosis was first proposed as an etiologic agent in Crohn's disease based on the isolation of this organism from several patients. Since that time, a great deal of information has been accumulated that clearly establishes an association between M. paratuberculosis and Crohn's disease. However, data are conflicting and difficult to interpret and the field has become divided into committed advocates and confirmed skeptics. This review is an attempt to provide a thorough and objective summary of current knowledge from both basic and clinical research from the views and interpretations of both the antagonists and proponents. The reader is left to draw his or her own conclusions related to the validity of the issues and claims made by the opposing views and data interpretations. Whether M. paratuberculosis is a causative agent in some cases or simply represents an incidental association remains a controversial topic, but current evidence suggests that the notion should not be so readily dismissed. Remaining questions that need to be addressed in defining the role of M. paratuberculosis in Crohn's disease and future implications are discussed.

Induction of matrix metalloproteinases and TLR2 and 6 in murine colon after oral exposure to Mycobacterium avium subsp. paratuberculosis

Mycobacterium avium subspecies paratuberculosis (MAP) is suspected to be a causative agent in Crohn's disease. Recent evidence suggests that MAP can induce the expression of Matrix Metalloproteinases (MMPs), which are the main proteases in the pathogenesis of mucosal ulcerations in inflammatory bowel disease (IBD). Within the present study, we analysed whether oral MAP exposure can induce colonic MMP expression in vivo. In MAP exposed mice MAP and spheroplasts were visualized in intramucosal leukocyte aggregates. MAP exposed mice exhibited a higher colonic expression of Mmp-2, -9, -13, -14, Timp-1, Tlr2, Tlr6, Il-1β, and Tnf-α. Cell clusters of MMP-9 positive cells adjacent to intramucosal leukocyte aggregates and CD45(+) leukocytes were identified as the major cellular sources of MMP-9. Enhanced TLR2 expression was visualized on the luminal side of colonic enterocytes. Although MAP exposure did not lead to macroscopic intestinal inflammation, the observed MAP spheroplasts in intramucosal leukocyte aggregates together with increased colonic expression of toll-like receptors, pro-inflammatory cytokines, and MMPs upon MAP exposure represents a part of the host immune response towards MAP.

Fecal detection of Mycobacterium avium paratuberculosis using the IS900 DNA sequence in Crohn's disease and ulcerative colitis patients and healthy subjects

BACKGROUND AND AIM

Despite the increasing evidence of MAP/DNA isolation in Crohn's disease (CD), its potential pathogenetic role remains unclear. To further clarify the possible relationship between MAP and CD, we investigated the presence of IS900 DNA fragment in feces from Crohn's disease and ulcerative colitis (UC) patients and from healthy controls (HC).

METHODS

Stool samples were collected from 31 CD, 20 UC, and 23 HC and stored at -20°C in 200-mg aliquots. DNA was extracted. MAP presence was detected with a specific PCR amplifying a 409-bp fragment from IS900. The specificity of PCR for IS900 was confirmed sequencing three positive products. Statistical analysis was performed using the Chi-square test.

RESULTS

Twenty-one of 31 CD (68%), 13 of 20 UC (65%) and 11 of 23 HC (48%) were MAP-positive (CD vs. HC: p = ns; UC vs. HC: p = ns). With the limits of a small sample size, the IS900-positive percentage in CD and UC was higher than HC, although the difference was not statistically significant.

CONCLUSIONS

The possibility to track the MAP presence in human feces represents a new approach to the "MAP hypothesis". Detection of MAP DNA in feces is very common, reaching very high prevalence both in CD and in UC and even in HC. Our findings seem consistent with a high prevalence of MAP asymptomatic infection among the general population and so the possible involvement of MAP in CD pathogenesis could be linked to a specific immune defective response.

Presence of intestinal Mycobacterium avium subspecies paratuberculosis (MAP) DNA is not associated with altered MMP expression in ulcerative colitis

BACKGROUND

Mycobacterium avium subspecies paratuberculosis (MAP) is suspected to be a causative agent in human Crohn's disease (CD). Recent evidence suggests that pathogenic mycobacteria and MAP can induce the expression of Matrix Metalloproteinases (MMP), which are the main proteases in the pathogenesis of mucosal ulcerations in inflammatory bowel disease (IBD). Within this study we assessed the prevalence of intestinal MAP specific DNA in patients with Crohn's disease, ulcerative colitis (UC), and healthy controls. We further analysed regulation patterns of MMPs in mucosal tissues of UC patients with and without intestinal MAP DNA detection.

METHODS

Colonic biopsy samples were obtained from 63 Norwegian and German IBD patients and 21 healthy controls. RNA was quantified by quantitative real-time polymerase chain reaction (PCR) to study MMP gene expression in both pathological and healthy mucosal specimens. The presence of MAP DNA in colonic mucosa was examined using MAP specific PCR.

RESULTS

MAP DNA was detected in 20% of UC patients and 33% of healthy controls but only in 7% of patients with CD. UC patients treated with corticosteroids exhibited a significantly increased frequency of intestinal MAP DNA compared to those not receiving corticosteroids. Expression of MMP-1, -2, -7, -9, -13, -19, -28 and TNF-α did not differ between UC patients with presence of intestinal MAP DNA compared to those without. MMP-2, MMP-9 and MMP-13 were significantly decreased in UC patients receiving corticosteroids.

CONCLUSIONS

The presence of intestinal MAP specific DNA is not associated with altered MMP expression in UC in vivo. Corticosteroids are associated with increased detection of intestinal MAP DNA and decreased expression of certain MMPs. Frequent detection of MAP DNA in healthy controls might be attributable to the wide environmental distribution of MAP and its presence in the food-chain.

Highly specific and quick detection of Mycobacterium avium subsp. paratuberculosis in feces and gut tissue of cattle and humans by multiple real-time PCR assays

Mycobacterium avium subsp. paratuberculosis is the causative agent of Johne's disease (JD) in cattle and may be associated with Crohn's disease (CD) in humans. It is the slowest growing of the cultivable mycobacteria, and culture from clinical, veterinary, food, or environmental specimens can take 4 months or even longer. Currently, the insertion element IS900 is used to detect M. avium subsp. paratuberculosis DNA. However, closely related IS900 elements are also present in other mycobacteria, thus limiting its specificity as a target. Here we describe the use of novel primer sets derived from the sequences of two highly specific single copy genes, MAP2765c and MAP0865, for the quantitative detection of M. avium subsp. paratuberculosis within 6 h by using real-time PCR. Specificity of the target was established using 40 M. avium subsp. paratuberculosis isolates, 67 different bacterial species, and two intestinal parasites. Using the probes and methods described, we detected 27 (2.09%) M. avium subsp. paratuberculosis-positive stool specimens from 1,293 individual stool samples by the use of either IS900 or probes deriving from the MAP2765c and MAP0865 genes described here. In general, bacterial load due to M. avium subsp. paratuberculosis was uniformly low in these samples and we estimated 500 to 5,000 M. avium subsp. paratuberculosis bacteria per gram of stool in assay-positive samples. Thus, the methods described here are useful for rapid and specific detection of M. avium subsp. paratuberculosis in clinical samples.

Mycobacterium avium subsp. paratuberculosis in dairy products, meat, and drinking water

Mycobacterium avium subsp. paratuberculosis (Map) is the cause of Johne's disease, a chronic infection of the gut, in ruminant animals that provide milk and/or meat for human consumption. Map also may be involved in Crohn's disease and type 1 diabetes in humans. Although the role of Map in human diseases has not been established, minimizing the exposure of humans to the organism is considered desirable as a precautionary measure. Infected animals can shed Map in feces and milk, and the organism can become disseminated in tissues remote from the gut and its associated lymph nodes. The presence of at least some Map in raw milk and meat and in natural waters is likely, but the numbers of Map in those foods and waters should be reduced through cooking or purification. The available information relating to Map in milk and dairy products, meats, and drinking water is reviewed here for assessment of the risks of exposure to Map from consumption of such foods and water.

Paucity of mycobacteria in mucosal bowel biopsies from adults and children with early inflammatory bowel disease

BACKGROUND

The presence of Mycobacterium avium subspecies paratuberculosis (MAP) has previously been inferred in the genesis of Crohn's disease (CD), and a higher incidence of MAP PCR positivity has been demonstrated in the gut and peripheral blood of CD patients than in healthy individuals. The objective of this prospective study was to assess the potential etiological role of MAP in the pathogenesis of CD.

METHODS

The presence of mycobacteria was assessed in bowel biopsies from newly diagnosed, treatment naïve Norwegian patients with IBD, including CD and ulcerative colitis (UC), as compared to a hospital-based cohort of CD and UC patients. Biopsies were collected from the small and large bowel in 354 individuals with suspected IBD. Detection of mycobacteria was performed by long-term cultivation in combination with direct detection by MAP IS900-specific PCR.

RESULTS

Among the specimens included from the patients with early IBD, samples from only two of the patients with CD (2.7%) and two of the non-IBD controls (1.5%) exhibited a positive growth signal. None of the CD patients and only one of the non-IBD controls was MAP PCR positive. Only the single PCR positive non-IBD control was also mycobacterial culture positive with Mycobacterium avium subsp. hominissuis. In the referral patients with long-term IBD, the prevalence of growth signal and MAP PCR positivity was higher (52 and 9%, respectively).

CONCLUSIONS

These findings demonstrate the paucity of MAP in the gut of treatment naïve CD patients. This study does not provide evidence for a role of MAP in early IBD.

Detection of Mycobacterium avium ss. Paratuberculosis in Blau Syndrome Tissues

Background and Aim of the Work. Blau syndrome is an inherited granulomatous inflammatory disorder with clinical findings of uveitis, arthritis, and dermatitis. Although rare, Blau syndrome shares features with the more common diseases sarcoidosis and Crohn's disease. The clinical findings of Blau syndrome are indistinguishable from juvenile sarcoidosis; the mutations of Blau syndrome are on the same gene of chromosome 16 (CARD15) that confers susceptibility to Crohn's disease. The product of this gene is part of the innate immune system. Mycobacterium avium ss. paratuberculosis (MAP) is the putative cause of Crohn's disease and has been implicated as a causative agent of sarcoidosis. Methods. Archival tissues of individuals with Blau syndrome were tested for the presence of MAP. Results. DNA evidence of MAP was detected in all of the tissues. Conclusions. This article finds that MAP is present in Blau syndrome tissue and postulates that it has a causal role. The presence of MAP in Blau syndrome—an autosomal dominant, systemic inflammatory disease—connects genetic and environmental aspects of “autoimmune” disease.

Absence of Mycobacterium avium ss paratuberculosis-specific IS900 sequence in intestinal biopsy tissues of Indian patients with Crohn's disease

BACKGROUND AND OBJECTIVE

The role of Mycobacterium avium ss paratuberculosis (MAP) in the etiopathology of Crohn's disease (CD) remains controversial, because of conflicting reports demonstrating the presence of MAP-specific insertion sequence from intestinal biopsy tissues of patients clinically diagnosed for the disease. The present study was carried out to investigate the presence of MAP DNA in the intestinal tissues of CD patients to ascertain the relevance of MAP in Indian patients with CD.

METHODS

Patients diagnosed as CD at our institute were recruited. Healthy individuals without inflammatory bowel disease served as controls. Mucosal biopsy specimens were collected from ileum and colon in duplicates and subjected to histopathological examination and polymerase chain reaction (PCR) amplification. Total DNA (81 CD patients, 85 healthy individuals) and total RNA (12 CD patients, 12 healthy individuals) isolated from tissue specimens was used for amplification of MAP-specific IS900 by nested PCR.

RESULTS

MAP-specific IS900 DNA and RNA could not be detected by nested PCR in the intestinal tissues of any patient with CD.

CONCLUSION

Our results do not support the etiological role of MAP in the pathogenesis of CD in Indian patients.