Immunodeficiency and inborn disorders of vitamin B12 and folate metabolism.

PURPOSE OF REVIEW: Immune dysfunction, including severe combined immunodeficiency, has been described in genetic disorders affecting the metabolism of the vitamins cobalamin (vitamin B12) and folate. We have reviewed reports of clinical findings in patients with a number of inborn errors of cobalamin or folate metabolism, specifically looking for immune problems. RECENT FINDINGS: There is little evidence that immune function is affected in most of the disorders. Exceptions are Imerslund-Gräsbeck syndrome and hereditary folate malabsorption (affecting intestinal absorption of cobalamin and folate, respectively), transcobalamin deficiency (affecting transport of cobalamin in blood and cellular cobalamin uptake), and methylenetetrahydrofolate dehydrogenase 1 deficiency (catalyzing cytoplasmic interconversion of reduced folate coenzyme derivatives). SUMMARY: Although some inborn errors of cobalamin or folate can be associated with immune dysfunction, the degree and type of immune dysfunction vary with no obvious pattern.

Predictivity of Autoimmune Stigmata for Gluten Sensitivity in Subjects with Microscopic Enteritis: A Retrospective Study.

Non-celiac gluten sensitivity (NCGS) is an emerging gluten-related condition. We investigated whether the presence of autoimmune stigmata in a group of patients with clinical suspicion of NCGS and a histological picture of microscopic enteritis (ME) could be a predictive factor of NCGS. Patients with ME were followed up by periodical examinations. At baseline, we collected data about previous clinical history, including autoimmune diseases. NCGS was diagnosed according to Salerno criteria; other causes of ME were diagnosed according to well-established protocols. Patients with celiac disease were excluded. Student's and chi-square tests were used in univariate analysis. Kaplan-Meier curves and Cox regression were used to estimate hazard ratios (HR). Sixty-three patients were included. Twenty-two had a final diagnosis of NCGS; the remaining 41 had non-gluten-related causes of ME. Prevalence of autoimmune thyroiditis was higher among NCGS patients (40.1%) than in other ME (14.6%; p = 0.03). NCGS showed higher positivity rate for anti-gliadin (27.3% versus 2.5%; p = 0.006) and anti-nucleus (45.4% versus 12.2%; p = 0.005). Autoimmune thyroiditis had a non-significant trend (p = 0.06) for NCGS diagnosis, (HR = 2.4). Both anti-gliadin (HR = 2.4; p = 0.04) and anti-nucleus (HR = 2.7; p = 0.04) were directly associated with NCGS diagnosis. In conclusion, NCGS may have a cohort of autoimmune stigmata that can precede its diagnosis.

CVID enteropathy is characterized by exceeding low mucosal IgA levels and interferon-driven inflammation possibly related to the presence of a pathobiont.

Common variable immunodeficiency (CVID), the most common symptomatic primary antibody deficiency, is accompanied in some patients by a duodenal inflammation and malabsorption syndrome known as CVID enteropathy (E-CVID).The goal of this study was to investigate the immunological abnormalities in CVID patients that lead to enteropathy as well as the contribution of intestinal microbiota to this process.We found that, in contrast to noE-CVID patients (without enteropathy), E-CVID patients have exceedingly low levels of IgA in duodenal tissues. In addition, using transkingdom network analysis of the duodenal microbiome, we identified Acinetobacter baumannii as a candidate pathobiont in E-CVID. Finally, we found that E-CVID patients exhibit a pronounced activation of immune genes and down-regulation of epithelial lipid metabolism genes. We conclude that in the virtual absence of mucosal IgA, pathobionts such as A. baumannii, may induce inflammation that re-directs intestinal molecular pathways from lipid metabolism to immune processes responsible for enteropathy.

Non-Celiac Gluten Sensitivity: How Its Gut Immune Activation and Potential Dietary Management Differ from Celiac Disease.

Non-celiac gluten sensitivity (NCGS) is a clinical entity triggered by the ingestion of gluten-containing grains leading to intestinal and/or extraintestinal symptoms that resolve once the gluten-containing foodstuff is eliminated from the diet, and it is diagnosed when celiac disease (CD) and wheat allergy (WA) have been ruled out. The limited knowledge about the pathophysiology of NCGS and the lack of validated biomarkers are still major limitations for clinical studies, making it difficult to differentiate NCGS from other gluten-related disorders (GRD). In the absence of clear-cut diagnostic criteria, NCGS is still mainly a diagnosis of exclusion. Several studies suggest that NCGS is an immune-mediated disease that likely activates an innate immune response. Moreover, it has recently been hypothesized that in addition to gluten, other components of wheat may be responsible for the symptoms observed in individuals without CD. This review aims at discussing available evidence related to the histological and immunological features in the gut mucosa of patients with NCGS and at outlining new dietary opportunities for these patients.

Campylobacter jejuni impairs sodium transport and epithelial barrier function via cytokine release in human colon.

Campylobacter jejuni is the most prevalent cause of foodborne bacterial enteritis worldwide. Patients present with diarrhea and immune responses lead to complications like arthritis and irritable bowel syndrome. Although studies exist in animal and cell models, we aimed at a functional and structural characterization of intestinal dysfunction and the involved regulatory mechanisms in human colon. First, in patients' colonic biopsies, sodium malabsorption was identified as an important diarrheal mechanism resulting from hampered epithelial ion transport via impaired epithelial sodium channel (ENaC) ß- and γ-subunit. In addition, barrier dysfunction from disrupted epithelial tight junction proteins (claudin-1, -3, -4, -5, and -8), epithelial apoptosis, and appearance of lesions was detected, which cause leak-flux diarrhea and can perpetuate immune responses. Importantly, these effects in human biopsies either represent direct action of Campylobacter jejuni (ENaC impairment) or are caused by proinflammatory signaling (barrier dysfunction). This was revealed by regulator analysis from RNA-sequencing (cytometric bead array-checked) and confirmed in cell models, which identified interferon-γ, TNFα, IL-13, and IL-1ß. Finally, bioinformatics' predictions yielded additional information on protective influences like vitamin D, which was confirmed in cell models. Thus, these are candidates for intervention strategies against C. jejuni infection and post-infectious sequelae, which result from the permissive barrier defect along the leaky gut.

The Overlapping Area of Non-Celiac Gluten Sensitivity (NCGS) and Wheat-Sensitive Irritable Bowel Syndrome (IBS): An Update.

Gluten-related disorders have recently been reclassified with an emerging scientific literature supporting the concept of non-celiac gluten sensitivity (NCGS). New research has specifically addressed prevalence, immune mechanisms, the recognition of non-immunoglobulin E (non-IgE) wheat allergy and overlap of NCGS with irritable bowel syndrome (IBS)-type symptoms. This review article will provide clinicians with an update that directly impacts on the management of a subgroup of their IBS patients whose symptoms are triggered by wheat ingestion.

Self-administered hyaluronidase-facilitated subcutaneous immunoglobulin therapy in complicated primary antibody deficiencies.

Hyaluronidase-facilitated subcutaneous immunoglobulin (fSCIg) is a new immunoglobulin product for replacement therapy in patients with primary antibody deficiencies (PAD). The pre-administration of recombinant human hyaluronidase associated with 10% immunoglobulin allowed the infusion of larger (up to 600 ml) amounts of immunoglobulin at a single infusion site, enabling patients to receive the necessary treatment in a single monthly dose. Here, we report the effectiveness and the tolerability of fSCIg in patients with severe PAD-related comorbidities: refractory autoimmune thrombocytopenia; systemic granulomatous disease; severe enteropathy, and Type I diabetes. We conclude that fSCIg could be a feasible option to improve the adherence to replacement therapy also by patients with severe PAD.

[Food Allergy and Intolerance : Distinction, Definitions and Delimitation]. / Nahrungsmittelallergien und andere -unverträglichkeiten : Bedeutung, Begriffe und Begrenzung.

Immunologically mediated hypersensitivity to foods is defined as food allergy, mainly due to immunglobulins of class E (IgE) triggering immediate reactions (type I hypersensitivity) with possible involvement of mucosa, skin, airways, intestinal tract, and the vascular system. Primary food allergy is based on (early) IgE sensitization against animal (e. g., cow's milk, hen's eggs) or plant proteins (e. g. peanut, hazelnut or wheat). In the case of secondary food allergies, IgE against pollen proteins (e. g., birch) reacts to structurally related food proteins (with cross-reactions to stone and pit fruits). Non-immunological food intolerance reactions are mostly based on carbohydrate malassimilation (e. g., lactose intolerance, fructose malabsorption) and are rarely due to pseudo-allergies (e. g., flavors, dyes, preservatives) primarily in patients with chronic urticaria. Common intestinal symptoms are mainly due to functional disorders (e. g., irritable bowel disease), rarely because of inflammatory intestinal diseases (e. g., celiac disease). Histamine intolerance, gluten hypersensitivity, and so-called food type III hypersensitivities are controversial diagnoses. The aforementioned disease entities/models are of variable importance for the affected individuals, the public health system, and society in general.

[Food intolerances caused by enzyme defects and carbohydrate malassimiliations : Lactose intolerance and Co]. / Lebensmittelunverträglichkeiten durch Enzymdefekte und Zuckerverwertungsstörungen : Laktoseintoleranz und Co.

Apart from allergic conditions, carbohydrate malassimiliations (sugar metabolism disorders) are classified within the group of food intolerances. These dose-dependent, yet non-immunological reactions require gastroenterological or internal diagnosis following nutritional therapy. Intolerances to carbohydrates such as lactose (milk sugar) and fructose (fruit sugar) in addition to sugar alcohols (sorbitol, mannitol, lactitol etc.) have been gaining increasing attention in recent decades as they are the cause of a wide range of gastrointestinal symptoms. There are currently various options for both diagnosis and therapy that differ notably in terms of effort, costs, and efficiency. Nutritional change and patient education are the bases of therapy. Non-observance of the trigger will result in increasing complaints and possibly even more infections, e.g., diverticula, rectal disorders, bacterial miscolonization, bile acid malabsorption). For an optimal therapy, the following sugar metabolism disorders have to be differentiated: hypolactasia versus lactose maldigestion, fructose malabsorption versus fructose overload, combined lactose and fructose intolerance, and isolated adverse reactions against sorbitol.For the medical conditions listed above, a three- or four-stage treatment regimen is recommended. Extensive dietary restrictions with regard to the relevant sugar, except for lactose, should not be maintained over a longer period of time.

Multilabel immunofluorescence and antigen reprobing on formalin-fixed paraffin-embedded sections: novel applications for precision pathology diagnosis.

We report new methods for multilabel immunofluorescence (MIF) and reprobing of antigen epitopes on the same formalin-fixed paraffin-embedded (FFPE) sections. The MIF method includes an antigen-retrieval step followed by multilabel immunostaining and examination by confocal microscopy. As examples, we illustrate epitopes localized to the apical and basolateral membranes, and the cytoplasm of enterocytes of normal small intestine and in cases of congenital enteropathies (microvillous inclusion disease and congenital tufting enteropathy). We also demonstrate localization of the bile salt excretion pump protein (BSEP) in bile canalicular membrane of normal hepatocytes and in cases of primary sclerosing cholangitis. To demonstrate colocalization of cytoplasmic and nuclear epitopes we analyzed normal control and hyperplastic pulmonary neuroendocrine cells (PNEC) and neuroepithelial bodies (NEBs), presumed airway sensors in the lungs of infants with bronchopulmonary dysplasia (BPD). As cytoplasmic markers we used anti-bombesin or anti-synaptic vesicle protein 2 (SV2) antibody, respectively, and for nuclear localization, antibodies against neurogenic genes mammalian achaete-scute homolog (Mash1) and prospero homeobox 1 (Prox1), essential for NEB cells differentiation and maturation, hypoxia-inducible factor 1α (HIF1α) a downstream modulator of hypoxia response and a proliferation marker Ki67. The reprobing method consisted of removal of the previously immunolabeled target and immunostaining with different antibodies, facilitating colocalization of enterocyte brush border epitopes as well as HIF1α, Mash1 and Prox1 in PNEC/NEB PNEC and NEBs. As these methods are suitable for routine FFPE pathology samples from various tissues, allowing visualization of multiple epitopes in the same cells/sections with superior contrast and resolution, they are suitable for a wide range of applications in diagnostic pathology and may be particularly well suited for precision medicine diagnostics.

[Autoimmune enteropathy]. / Autoimmuunienteropatia.

Autoimmune enteropathy (AIE) is characterized by protracted diarrhea, malabsorption, immunomediated damage to the intestinal mucosa, and unresponsiveness to changes in diet. The disease is mainly manifested in the small intestine. Lymphocyte deposits are present on the mucous membrane, and anti-enterocyte or anti-goblet cell antibodies have been described in the majority of affected persons. AIE occurs primarily in infants. Immunosuppressive drugs have been used with varying success. The prognosis of AlE is dependent on the degree of severity of the damage to the intestinal mucosa and extraintestinal symptoms and diseases associated therewith.

Gastrointestinal food allergies.

Gastrointestinal food allergies present during early childhood with a diverse range of symptoms. Cow's milk, soy and wheat are the three most common gastrointestinal food allergens. Several clinical syndromes have been described, including food protein-induced enteropathy, proctocolitis and enterocolitis. In contrast with immediate, IgE-mediated food allergies, the onset of gastrointestinal symptoms is delayed for at least 1-2 hours after ingestion in non-IgE-mediated allergic disorders. The pathophysiology of these non-IgE-mediated allergic disorders is poorly understood, and useful in vitro markers are lacking. The results of the skin prick test or measurement of the food-specific serum IgE level is generally negative, although low-positive results may occur. Diagnosis therefore relies on the recognition of a particular clinical phenotype as well as the demonstration of clear clinical improvement after food allergen elimination and the re-emergence of symptoms upon challenge. There is a significant clinical overlap between non-IgE-mediated food allergy and several common paediatric gastroenterological conditions, which may lead to diagnostic confusion. The treatment of gastrointestinal food allergies requires the strict elimination of offending food allergens until tolerance has developed. In breast-fed infants, a maternal elimination diet is often sufficient to control symptoms. In formula-fed infants, treatment usually involves the use an extensively hydrolysed or amino acid-based formula. Apart from the use of hypoallergenic formulae, the solid diets of these children also need to be kept free of specific food allergens, as clinically indicated. The nutritional progress of infants and young children should be carefully monitored, and they should undergo ongoing, regular food protein elimination reassessments by cautious food challenges to monitor for possible tolerance development.

IgG4: not only for allergists.

We describe herein a case of IgG4-related disease with the isolated clinical presentation of malabsorption due to pancreatic failure. Histology of an abdominal lymph node was critical for diagnosis. IgG4-related disease is increasingly recognized as an immunological disorder that can mimic various clinical entities.

[Gastrointestinal manifestations in patients with primary immunodeficiencies causing antibody deficiency]. / Manifestaciones gastrointestinales en pacientes con inmunodeficiencias primarias que cursan con déficit de anticuerpos.

INTRODUCTION: Primary immunodeficiencies can lead to gastrointestinal manifestations that are still not well defined. OBJECTIVE: To analyze gastrointestinal manifestations associated with primary immunodeficiencies. MATERIAL AND METHODS: We performed a retrospective study that included patients diagnosed with primary antibody deficiencies in a third-level hospital. The patients were divided into two groups: isolated IgA deficiency and common variable immunodeficiency syndrome (CVIS). The timing of presentation and type of gastrointestinal symptoms were analyzed. RESULTS: There were 57 patients: 20 with CVIS (35%) and 37 with isolated IgA deficiency (65%). Diagnosis was made in the pediatric age in 17 patients, of whom 13 had isolated IgA deficiency. In 84% of the patients, diagnosis of immunodeficiency was made before the development of gastrointestinal manifestations. Digestive symptoms were found in 74% of the patients, the most frequent being diarrhea. In 46% of the patients, digestive disease was confirmed, mainly through endoscopy. Celiac-like lesions, chronic atrophic gastritis, ulcerative colitis-like disease and Crohn's disease were more common in CVIS. In isolated IgA deficiency, Helicobacter pylori-positive chronic gastritis predominated. Mean age was significantly higher (36 vs. 24 years, p=0.02) and IgA titer significantly lower (17 vs. 34UI/ml; p=0.008) in patients with associated gastrointestinal disease. CONCLUSIONS: Gastrointestinal symptoms are frequent and lead to endoscopic diagnosis in half of patients with primary immunodeficiencies. Ulcerative colitis, and celiac- and Crohn's-like disease are atypical entities that occur in CVIS.

Malabsorption may contribute to malnutrition in the elderly.

Malnutrition, either actually malnourished or at risk, is present in 80% of the elderly population presenting to hospital for admission. Although many factors contribute to this situation, one yet to be explored is malabsorption. We therefore aimed to assess nutritional status as well as the prevalence of altered mucosal permeability and celiac disease among a group of elderly patients presenting for rehabilitation. Forty-eight subjects were recruited (16 females) with a mean age of 83.7 (SD 6.1), body mass index 21.8 kg/m(2) (SD 3.9), mini-nutritional assessment (MNA) 19.5 (SD 3.4). They had no current gastrointestinal symptoms and undertook an assessment of mucosal permeability using the dual sugar absorption test of lactulose (7.5 g) and rhamnose (1 g). Ten of the 48 subjects had increased mucosal permeability with an L:R ration ranging from 0.0860 to 7.706 (N 0.01-0.08). These subjects were all at risk or malnourished according to the MNA score and they had a significantly lower mean MNA score of 17.2 (SD 3.5) compared to normal absorbers with a mean of 19.5 (SD 3.4). Two of the subjects had positive tissue trans-glutaminase antibodies. The higher risk of potential malabsorption in this elderly population has significant implications both for nutritional supplementation and for drug absorption as well as being a possible major contributor to malnutrition.