Pathophysiology and laboratory diagnosis of pernicious anemia

Autoimmune Atrophic Gastritis: A Clinical Review

Autoimmune atrophic gastritis (AAG) is a chronic condition characterized by the presence of atrophy in the oxyntic mucosa due to anti-parietal cell antibodies. This review provides a comprehensive and up-to-date overview of autoimmune atrophic gastritis, reporting recent evidence on epidemiology, pathogenesis, diagnosis, clinical presentation, risk of malignancies, and management. The prevalence of AAG has been estimated at between 0.3% and 2.7% in the general population. The diagnosis of AAG is based on a combination of the serologic profile and the histological examination of gastric biopsies. Patients with AAG are often asymptomatic but can also have dyspeptic or reflux symptoms. The atrophy of the oxyntic mucosa leads to iron and vitamin B12 malabsorption, which may result in anemia and neurological affections. Autoimmune atrophic gastritis is associated with an increased risk of type I neuroendocrine tumors (NETs) and gastric cancer, with an incidence rate of 2.8% and 0.5% per person/year, respectively. Management is directed to reinstate vitamins and iron and to prevent malignancies with endoscopic surveillance. In conclusion, atrophic autoimmune gastritis is an infrequent condition, often asymptomatic and misdiagnosed, that requires an early diagnosis for appropriate vitamin supplementation and endoscopic follow-up for the early diagnosis of NETs and gastric cancer.

Oral Lesions Associated with Systemic Disease

Oral manifestations may be the first sign of a systemic disease, or represent lesions associated with an established or recurrent disease. Oral health care providers are often the first to recognize these signs. Some lesions have characteristic features that allow for early detection and intervention. On the contrary, clinical manifestations may be diverse and require a comprehensive evaluation to establish a definitive diagnosis. This article reviews the oral manifestations of select systemic diseases to help clinicians develop a differential diagnosis that leads to early diagnosis and timely intervention.

Rapid Progression of Autoimmune Gastritis after Helicobacter pylori Eradication Therapy: A Case Report

We herein report a case of autoimmune gastritis (AIG) with rapid progression after Helicobacter pylori eradication therapy. The patient's previous gastritis had followed the course of type B gastritis before eradication therapy for many years. Immediately after eradication, we diagnosed her with AIG and carefully followed changes in the endoscopic and histopathological findings and serum markers. All of these clinical findings showed significant atrophic progression in the corporal area for approximately three years. We concluded that H. pylori eradication therapy exacerbated AIG in this case.

Increase of Deep Intraepithelial Lymphocytes in the Oxyntic Mucosa of Patients With Potential and Overt Autoimmune Gastritis

Pathological correlates of potential autoimmune gastritis (AIG), defined by anti-parietal cell antibody (PCA) positivity in the absence of gastric atrophy, have never been described. We herein aimed to assess intraepithelial lymphocyte (IEL) infiltration in gastric corpus of AIG patients. From 2000 to 2021, among 53 potential AIG patients, we focused on nine (median age 61 years, IQR 53-82; four females) who subsequently developed overt AIG. IEL infiltration of the oxyntic mucosa was assessed before and after developing overt AIG by measuring deep and superficial CD3+ IEL. AIG patients with different degrees of corpus atrophy, healthy controls (HC), active H. pylori gastritis, celiac disease (CD), and Hashimoto’s thyroiditis patients were included as controls. Of note, deep, but not superficial, CD3+ IEL count was higher (p<0.001) in potential AIG compared to HC and H. pylori gastritis. Deep CD3+ IEL infiltration did not change before or after the evolution into atrophy (median 9.6, IQR 8.8-12.4, vs 11.3, IQR 9.4-12.9). No difference was found in deep CD3+ IEL infiltration among potential, mild, and severe AIG, and compared to Hashimoto’s thyroiditis or CD. A deep CD3+ IEL cut-off of >7/100 epithelial cells allowed discrimination of any AIG stage and severity (AUC=0.842). We conclude that an increased deep CD3+ IEL infiltration of the oxyntic mucosa could represent a marker of potential AIG. Prospective studies including a larger number of potential AIG patients are needed.

Elevated IL-19 Serum Levels in Patients With Pernicious Anemia and Autoimmune Gastritis

Pernicious anemia (PA) is a megaloblastic anemia consisting of hematological, gastric and immunological alterations. The immunopathogenesis of PA is sustained by both autoantibodies (e.g. intrinsic factor (IFA) antibodies and anti parietal cell (PCA) antibodies and autoreactive T cells specific for IFA and the parietal cell proton pump ATPase. Iron deficient anemia (IDA) is a microcytic anemia and represents the most common cause of anemia worldwide. Our work aimed to investigate serum levels of several interleukins (IL) of the IL-20 cytokine subfamily in patients with PA, with IDA and in healthy subjects (HC). We compared serum levels of IL-19, IL-20, IL-26, IL-28A and IL-29 in 43 patients with PA and autoimmune gastritis, in 20 patients with IDA and no autoimmune gastritis, and in 47 HC. Furthermore, we analyzed the IL-19 cytokine production by gastric lamina propria mononuclear cells (LPMC) in eight patients with PA and four HC. We found that patients with PA have significantly higher serum levels of IL-19 (163.68 ± 75.96 pg/ml) than patients with IDA (35.49 ± 40.97 pg/ml; p<0.001) and healthy subjects (55.68 ± 36.75 pg/ml; p<0.001). Gastric LPMC from all PA patients were able to produce significantly higher levels of IL-19 (420.67 ± 68.14 pg/ml) than HC (53.69 ± 10.92 pg/ml) (p<0.01). Altogether, our results indicate that IL-19 serum levels are significantly increased in patients with PA but not with IDA and that IL-19 is produced in vivo in the stomach of PA patients. These data open a new perspective on PA pathogenesis and suggest that IL-19 may represent a novel important tool for the management of patients with PA.

Paget's disease of bone and megaloblastic anemia in a 72‑year‑old patient: A case report and systematic literature review

Paget's disease of bone (PDB) is characterized by abnormal osteoclastic bone resorption with disorganized bone neo-formation, primarily affecting elderly (>55 years) patients. Although the majority of patients are asymptomatic, some patients may experience bone pain due to local periosteal involvement or osteoarthritic lesions in the spine; in addition, limb deformities may lead to secondary gait problems or degenerative joint changes. Anemia has an overall prevalence of 12-17% in elderly adults (>65 years old), with macrocytic anemia being the less common type. Megaloblastic anemia is a macrocytic anemia characterized by the presence of large, immature, nucleated cells (megaloblasts) in the blood, with the most common cause being a deficiency of folate and/or vitamin B12. We herein report the rare case of a 72-year-old male patient exhibiting both these conditions, with the aim of discussing the possible association between the two and, most importantly, the clinical management of the patient in a real-life setting over a period of 10 years. The patient was diagnosed based on clinical symptoms (bone pain), radiological imaging and specific laboratory tests, and received discontinuous courses of bisphosphonates and cyanocobalamin supplementation therapy, based mainly on aggravated symptomatology. A systematic literature review was also performed and revealed not only the scarcity of reports on similar cases, but also the mechanisms that may underlie the possible association of PDB with macrocytic anemia due to vitamin B12 deficiency in elderly patients.

Validation of diagnostic strategies of autoimmune atrophic gastritis: A case report

BACKGROUND

Autoimmune atrophic gastritis (AAG) is a type of chronic gastritis that mainly affects the gastric corpus. Due to the lack of standard diagnostic criteria and overlaps with the courses of Helicobacter pylori-related atrophic gastritis, reports on the diagnostic strategy of AAG at an early stage are limited.

CASE SUMMARY

A 71-year-old woman with severe anemia was diagnosed with AAG. Endoscopic views and pathological findings showed the coexistence of normal mucosa in the gastric antrum and atrophic mucosa in the gastric fundus. Serological tests showed that anti-parietal cell antibodies and anti-intrinsic factor antibodies were both positive. Immunohistochemical results, which showed negative H⁺-K⁺ ATPase antibody staining and positive chromogranin A (CgA) staining, confirmed the mechanism of this disease. After vitamin B12 and folic acid supplementation, the patient recovered well.

CONCLUSION

Successful diagnosis of AAG includes serological tests, endoscopic characteristics, and immunohistochemistry for H⁺-K⁺ ATPase and CgA antibodies.

Impaired Quality of Life in Patients with Autoimmune Atrophic Gastritis

BACKGROUND

Autoimmune atrophic gastritis (AAG) leads to vitamin B12 deficiency that may manifest with neuropsychiatric disorders, such as emotional instability, cognitive deficits, depression, and personality changes.

AIMS

To evaluate the quality of life (QoL) in patients with AAG and the interplay between QoL, psychopathological symptoms, and demographic factors.

METHODS

This is an observational, cross-sectional study including 102 patients with AAG (mean age 62 ± 13 years), 100 with functional gastrointestinal disorders (mean age 38.3 ± 17 years), 100 with other chronic organic gastrointestinal diseases (mean age 50.9 ± 21.4 years), and 100 healthy controls (mean age 37.5 ± 18.9 years). The 36-Item Short Form Health Survey questionnaire (SF-36) and the General Health Questionnaire-12 were administered. The results of the scales were compared among the study groups. Linear regression analyses were fitted to identify independent predictors of QoL in AAG patients.

RESULTS

QoL was significantly different among the four groups in all subdomains. In particular, the AAG group was significantly (P < 0.01) more impaired than the functional gastrointestinal disorder group in the physical functioning and it was significantly more impaired than the control group in all the quality of life subdomains with exception of vitality. Vitamin B12 serum level was a significant (P < 0.04) independent predictor of physical functioning.

CONCLUSIONS

Patients with AAG have a decreased QoL compared to healthy controls, but in line with that of patients with organic gastrointestinal disorders. Physical component is responsible for worsening QoL. Vitamin B12 supplementation may positively affect patient's perception of body functioning.

Genetic feature engineering enables characterisation of shared risk factors in immune-mediated diseases

BACKGROUND

Genome-wide association studies (GWAS) have identified pervasive sharing of genetic architectures across multiple immune-mediated diseases (IMD). By learning the genetic basis of IMD risk from common diseases, this sharing can be exploited to enable analysis of less frequent IMD where, due to limited sample size, traditional GWAS techniques are challenging.

METHODS

Exploiting ideas from Bayesian genetic fine-mapping, we developed a disease-focused shrinkage approach to allow us to distill genetic risk components from GWAS summary statistics for a set of related diseases. We applied this technique to 13 larger GWAS of common IMD, deriving a reduced dimension "basis" that summarised the multidimensional components of genetic risk. We used independent datasets including the UK Biobank to assess the performance of the basis and characterise individual axes. Finally, we projected summary GWAS data for smaller IMD studies, with less than 1000 cases, to assess whether the approach was able to provide additional insights into genetic architecture of less common IMD or IMD subtypes, where cohort collection is challenging.

RESULTS

We identified 13 IMD genetic risk components. The projection of independent UK Biobank data demonstrated the IMD specificity and accuracy of the basis even for traits with very limited case-size (e.g. vitiligo, 150 cases). Projection of additional IMD-relevant studies allowed us to add biological interpretation to specific components, e.g. related to raised eosinophil counts in blood and serum concentration of the chemokine CXCL10 (IP-10). On application to 22 rare IMD and IMD subtypes, we were able to not only highlight subtype-discriminating axes (e.g. for juvenile idiopathic arthritis) but also suggest eight novel genetic associations.

CONCLUSIONS

Requiring only summary-level data, our unsupervised approach allows the genetic architectures across any range of clinically related traits to be characterised in fewer dimensions. This facilitates the analysis of studies with modest sample size by matching shared axes of both genetic and biological risk across a wider disease domain, and provides an evidence base for possible therapeutic repurposing opportunities.

Autoimmune Hemolytic Anemia After Cyanocobalamin Replacement in a Patient With a Previous Diagnosis of Pernicious Anemia: A Case Report

Pernicious anemia (PA) is associated with other autoimmune diseases, such as hypothyroidism, type 1 diabetes mellitus (DM1), Addison's disease, and vitiligo. The association between PA and autoimmune hemolytic anemia (AIHA) is rare, with less than 30 cases reported in the literature. In this paper, we report a case of a patient with a confirmed diagnosis of PA, who, six months after starting treatment with cyanocobalamin, presented with severe hemolysis with a positive direct antiglobulin test (DAT) for warm antibodies; the patient responded well to glucocorticoid treatment. AIHA in PA patients can be triggered by cyanocobalamin replacement due to the expression of membrane antigens by mature red blood cells entering into the peripheral circulation. This association should be considered because these patients, in addition to cyanocobalamin replacement, will require immunosuppressive treatment, usually with glucocorticoids.

Receiving a Diagnosis of Pernicious Anemia: Exploring Experiences of Relationships With Health Professionals

OBJECTIVES

Pernicious anemia (PA) is a chronic condition caused by vitamin B12 deficiency. This is a qualitative study using interpretative phenomenological analysis (IPA), which aimed to explore the patients lived experience of diagnosis and treatment.

METHODS

Eleven semistructured interviews were conducted in PA patients; these covered participants' diagnostic and treatment journeys, the responses of others to their diagnosis, and the role health professionals have played in their medical care. Interviews were analyzed for recurrent themes using IPA.

RESULTS

Three superordinate themes were identified: "The struggle to achieve a diagnosis," "The significance of a diagnosis," and "Battling for sufficient treatment." Participants were dissatisfied with their medical care due to diagnostic delay, insufficient treatment, and poor relationships with their health professionals. Many experienced, anticipated, and internalized stigma, which led to a reduced quality of life and withdrawal from the medical profession.

DISCUSSION

Participants' interactions with their health professionals hindered their adaptation to their condition; this affected their psychological and physical well-being. Increased clinician awareness of stigma in the PA population symptoms and effective patient-centered communication is required.

Autoimmune atrophic gastritis: The role of Helicobacter pylori infection in children

BACKGROUND

Autoimmune atrophic gastritis (AIG) is very rare in children. Despite a better understanding of histopathologic changes and serological markers in this disease, underlying etiopathogenic mechanisms and the effect of Helicobacter pylori (H pylori) infection are not well known. We aimed to investigate the relation between AIG and H pylori infection in children.

MATERIALS AND METHODS

We evaluated the presence of AIG and H pylori infection in fifty-three patients with positive antiparietal cell antibody (APCA). Demographic data, clinical symptoms, laboratory and endoscopic findings, histopathology, and presence of H pylori were recorded.

RESULTS

The children were aged between 5 and 18 years, and 28 (52.8%) of them were male. Mean age was 14.7 ± 2.6 years (median: 15.3; min-max: 5.2-18), and 10 (18.8%) of them had AIG confirmed by histopathology. In the AIG group, the duration of vitamin B12 deficiency was longer (P = .022), hemoglobin levels were lower (P = .018), and APCA (P = .039) and gastrin (P = .002) levels were higher than those in the non-AIG group. Endoscopic findings were similar between the two groups. Intestinal metaplasia was higher (P = .018) in the AIG group. None of the patients in the AIG group had H pylori infection (P = .004). One patient in the AIG group had enterochromaffin-like cell hyperplasia.

CONCLUSIONS

Our results show that, in children, H pylori infection may not play a role in AIG. AIG could be associated with vitamin B12 deficiency, iron deficiency, and APCA positivity in children. APCA and gastrin levels should be investigated for the early diagnosis of AIG and intestinal metaplasia.

Natural history of autoimmune atrophic gastritis: a prospective, single centre, long-term experience

BACKGROUND

Autoimmune atrophic gastritis (AAG) is an immune-mediated disorder characterised by destruction of gastric oxyntic mucosa AIM: To explore gastric histopathological evolution in a cohort of AAG patients over a prolonged follow-up METHODS: Single centre prospective study enrolling consecutive patients with histologically confirmed AAG between 2000 and 2018. All AAG patients undergoing endoscopic follow-up every 1-3 years were classified as having stages 1, 2 or 3 according to atrophy severity (mild, moderate and severe). AAG patients with either glandular or neuroendocrine dysplasia/neoplasia were classified as having stage 4. Disease stage progression, and changes in serum anti-parietal cell antibody (PCA), chromogranin A and gastrin-17 were assessed.

RESULTS

In total, 282 AAG patients (mean age 60.3 years; F:M ratio 2.4:1; median follow-up 3 years, interquartile range 1-7) were enrolled. All patients with stages 1 or 2 progressed to stage 2 or 3 over time with a steady trend (P = .243) and regression from a severe to a milder stage was never noticed. Disease progression of patients with stages 1 or 2 occurred within the first 3 years. PCA positivity rate did not change over time. Stage 3 patients had higher gastrin-17 levels compared to patients with stages 1 and 2 (median 606 vs 295 pg/mL; P < .001). In stage 3, the hazard ratio for the risk of developing stage 4 was 6.6 (95% CI 1.5-29; P = .001).

CONCLUSIONS

AAG is a steadily progressive disease, in which stages 1 and 2 always progress to stage 3. The risk of developing a complicated disease stage is greater in patients with more severe gastric lesions.

Cell Blood Count Alterations and Patterns of Anaemia in Autoimmune Atrophic Gastritis at Diagnosis: A Multicentre Study

BACKGROUND

Autoimmune atrophic gastritis (AAG) leads to iron and/or vitamin B12 malabsorption, with subsequent haematological alterations which could represent the sole clinical manifestation. We aimed to assess patterns of anaemia and micronutrient deficiencies in patients with AAG at the time of diagnosis.

METHODS

Observational, multicentre, cross-sectional study including consecutive adult patients diagnosed with AAG within the last ten years. Cell blood count, red cell distribution width, serum vitamin B12, and ferritin were collected. Multivariate analysis for predictive factors of anaemia was computed.

RESULTS

654 AAG patients (mean age 59.2 ± 13.8 years, female (F): male (M) ratio = 2.3:1) were included. Anaemia was present in 316 patients (48.3%; mean age 60.1 ± 15.8 years, F:M ratio = 2.3:1). Pernicious anaemia (132/316 cases, 41.7%) was more common in males (27.1% versus 12.4%; p = 0.001) and in older patients (63.0 ± 14.6 versus 58.9 ± 14.9 years; p = 0.014), while iron deficiency anaemia (112/316 cases, 35.4%) was more common in females (16.9% versus 10.0%; p = 0.039) and in younger patients (56.8 ± 16.6 versus 60.2 ± 14.6 years; p = 0.043). The prevalence of iron deficiency was equally distributed between anaemic and non-anaemic patients (p = 0.9). Anisocytosis (odds ratio: 10.65, 95% confidence interval: 6.13-18.50, p < 0.0001) was independently associated with anaemia.

CONCLUSIONS

Anaemia is a common manifestation in AAG patients, mostly due to micronutrient deficiencies. Scant haematologic alterations and micronutrient deficiencies may precede overt anaemia.

Determinants of diagnostic delay in autoimmune atrophic gastritis

BACKGROUND

Autoimmune atrophic gastritis (AAG) is characterised by a wide clinical spectrum that could delay its diagnosis.

AIMS

To quantify the diagnostic delay in patients suffering from AAG and to explore possible risk factors for longer diagnostic delay.

METHODS

Consecutive patients with AAG evaluated at our gastroenterological outpatient clinic between 2009 and 2018 were included. Diagnostic delay was estimated as the time lapse occurring between the appearance of the first likely symptoms, laboratory alterations, and other clues indicative of AAG and the final diagnosis. Patient-dependent and physician-dependent diagnostic delays were also assessed. Multivariable regression models were fitted.

RESULTS

291 patients with AAG (mean age at diagnosis 61 ± 15 years; F:M ratio = 2.3:1) were included. The median overall diagnostic delay was 14 months (interquartile range [IQR] 4-41). Factors associated with longer median overall diagnostic delay were female sex (17 months, IQR 5-48), having a previous misdiagnosis (36 months, IQR 17-125) and a history of infertility/miscarriages (33 months, IQR 8-120), whereas a higher level of education was associated with longer patient-dependent diagnostic delay (4 months, IQR 1-12). First evaluation by a gastroenterologist was associated with a median longer diagnostic delay (6 months, IQR 2-15) compared to an internist (3 months, IQR 3-31) and a haematologist (1 month, IQR 0-2). Age, socioeconomic or marital status did not affect the diagnostic delay.

CONCLUSIONS

AAG is burdened by substantial diagnostic delay, especially in female patients, and due to lack of awareness, particularly among gastroenterologists. Uncommon vitamin B12 deficiency-related manifestations are overlooked and may prolong the diagnostic delay.

Management and the pregnancy outcomes of patients positive for anti-parietal cell antibody

BACKGROUND

Autoimmunity is related to poor obstetric outcomes in previous studies.

OBJECTIVE

To evaluate the management and the pregnancy outcomes of patients positive for anti-parietal cell antibody (APCA).

METHODS

We retrospectively evaluated obstetric, neonatal outcomes and Beksac Obstetrics Index (BOI) of pregnancies with APCA positivity. Coexisting Methylentetrahydrofolate reductase (MTHFR) polymorphisms, other autoimmune antibody positivities, or thrombophilias were also evaluated in terms of obstetric outcomes.

RESULTS

Of 39 pregnancies, three resulted in abortions (7.6%). The median gestational week and birthweight was 37 weeks and 2795 g. The median APGAR scores were 8, 9, and 9 for first, fifth, and tenth minute, respectively. Analysis involving additional risk factors showed no significant difference between the groups, evaluating APCA titers, MTHFR polymorphisms, or thrombophilia status. Significant difference was only observed for the fifth minute APGAR scores between the groups with other autoantibody positivities (p= 0.036). Despite lack of significant differences, patients with positivity for more than one autoimmune antibody had lower APGAR scores for the first and tenth minute, respectively (p= 0.727; p= 0.083). BOI analysis showed a statistically significant difference between the groups, demonstrating that more than one "antibody positivity" indicated a worse obstetric history.

CONCLUSIONS

Patients with more than one autoantibody positivity, including APCA, must be considered as high-risk patients.

Systematic Review and Pragmatic Clinical Approach to Oral and Nasal Vitamin B12 (Cobalamin) Treatment in Patients with Vitamin B12 Deficiency Related to Gastrointestinal Disorders

The objective of this review is to provide an update on the effectiveness of oral and nasal vitamin B12 (cobalamin) treatment in gastrointestinal (GI) disorders. Relevant articles were identified by PubMed and Google Scholar systematic search, from January 2010 and June 2018, and through hand search of relevant reference articles. Additional studies were obtained from references of identified studies, the Cochrane Library and the ISI Web of Knowledge. Data gleaned from reference textbooks and international meetings were also used, as was information gleaned from commercial sites on the web and data from CARE B12 research group. For oral vitamin B12 treatment, 4 randomized controlled trials (vs. intramuscular), 4 narrative and 4 systematic reviews, and 13 prospective studies fulfilled our inclusion criteria. These studies concerned patients with vitamin B12 deficiency related to: food-cobalamin malabsorption (n = 6), Biermer’s disease (n = 3), veganism or vegetarianism (n = 1), total gastrectomy after Roux-en-Y gastric bypass (n = 2) and Crohn’s disease (n = 1). Four prospective studies include patients with vitamin B12 deficiency related to the aforementioned etiologies, except veganism or vegetarianism. The systematic present review documents that oral vitamin B12 replacement, at a daily dose of 1000 μg (1 mg), was adequate to normalize serum vitamin B12 levels and cure main clinical manifestations related to vitamin B12 deficiency, in GI disorders, and thus, with safety profile. For nasal vitamin B12 treatment, only one preliminary study was available. We conclude that oral vitamin B12 is an effective alternative to intramuscular vitamin B12 (except in patients presenting with severe neurological manifestations). Oral vitamin B12 treatment avoids the discomfort, contraindication (in patients with anticoagulation), and cost of monthly injections.

Physiologic, pathophysiologic, and pharmacologic regulation of gastric acid secretion

PURPOSE OF REVIEW

The present review summarizes the past year's literature, both clinical and basic science, regarding physiologic and pharmacologic regulation of gastric acid secretion in health and disease.

RECENT FINDINGS

Gastric acid kills microorganisms, assists digestion, and facilitates absorption of iron, calcium, and vitamin B12. The main stimulants of acid secretion are the hormone gastrin, released from antral G cells; paracrine agent histamine, released from oxyntic enterochromaffin-like cells; and neuropeptide acetylcholine, released from antral and oxyntic intramural neurons. Gastrin is also a trophic hormone that participates in carcinogenesis. Helicobacter pylori may increase or decrease acid secretion depending upon the acuity and predominant anatomic focus of infection; most patients manifest hypochlorhydria. Despite the fact that proton pump inhibitors (PPIs) are amongst the most widely prescribed drugs, they are underutilized in patients at high risk for UGI bleeding. Although generally considered well tolerated, concerns have been raised regarding associations between PPI use and dementia, kidney disease, myocardial infarction, pneumonia, osteoporosis, dysbiosis, small bowel injury, micronutrient deficiency, and fundic gland polyps.

SUMMARY

Our understanding of the physiologic, pathophysiologic, and pharmacologic regulation of gastric secretion continues to advance. Such knowledge is crucial for improved and safe management of acid-peptic disorders.

Increased risk of pernicious anemia following scabies: a nationwide population-based matched-cohort study

Objectives

Scabies is a common and annoying disorder. Pernicious anemia (PA) is a serious disease which, when untreated, leads to death. Mounting evidence suggests that immune-mediated inflammatory processes play a role in the pathophysiology of both diseases. The relationship between these two diseases has not been investigated. We conducted this study to explore the potential relationship between scabies and PA.

Materials and methods

This nationwide, population-based study was conducted using the National Health Insurance Research Database of Taiwan. In total, 5,407 patients with scabies were identified as a study group and 20,089 matched patients were randomly selected as a control group. We tracked patients in both groups for a 7-year period to identify the incidence of PA. The demographic characteristics and comorbidities of the patients were analyzed, and Cox proportional hazards regression was used to calculate the hazard ratios for PA.

Results

Of the 25,496 patients in this study, 183 (0.7%) patients with newly diagnosed PA were identified during the 7-year follow-up period; 71 of 5,407 (1.3%) from the scabies group and 112 of 20,089 (0.6%) from the control group. Patients with scabies had a higher risk of subsequent PA, with a crude hazard ratio of 2.368. After adjusting for covariates, the adjusted hazard ratio was 1.51 (95% confidence interval: 1.09–2.08).

Conclusion

This study demonstrated an increased risk of PA (adjusted hazard ratio 1.51) among patients with scabies. Immune-mediated inflammatory processes may contribute to this association. Further studies are warranted to investigate the entire pathological mechanisms between these two diseases. Physicians should pay attention to patients with history of scabies presented with anemia. Further confirmative tests of PA may contribute to correct diagnosis and initiation of vitamin B12 supplement.

Clinical usefulness of serum antibodies as biomarkers of gastrointestinal and liver diseases

The progressively growing knowledge of the pathophysiology of a number of immune-mediated gastrointestinal and liver disorders, including autoimmune atrophic gastritis, coeliac disease, autoimmune enteropathy, inflammatory bowel disease, autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cholangitis and autoimmune pancreatitis, together with the improvement of their detection methods have increased the diagnostic power of serum antibodies. In some cases - coeliac disease and autoimmune atrophic gastritis - they have radically changed gastroenterologists' diagnostic ability, while in others - autoimmune hepatitis, inflammatory bowel disease and autoimmune pancreatitis - their diagnostic performance is still inadequate. Of note, serum antibody misuse in clinical practice has raised a number of controversies, which may generate confusion in the diagnostic management of the aforementioned disorders. In this review, we critically re-evaluate the usefulness of serum antibodies as biomarkers of immune-mediated gastrointestinal and liver disorders, and discuss their pitfalls and merits.

Autoantibody Repertoire in APECED Patients Targets Two Distinct Subgroups of Proteins

High titer autoantibodies produced by B lymphocytes are clinically important features of many common autoimmune diseases. APECED patients with deficient autoimmune regulator (AIRE) gene collectively display a broad repertoire of high titer autoantibodies, including some which are pathognomonic for major autoimmune diseases. AIRE deficiency severely reduces thymic expression of gene-products ordinarily restricted to discrete peripheral tissues, and developing T cells reactive to those gene-products are not inactivated during their development. However, the extent of the autoantibody repertoire in APECED and its relation to thymic expression of self-antigens are unclear. We here undertook a broad protein array approach to assess autoantibody repertoire in APECED patients. Our results show that in addition to shared autoantigen reactivities, APECED patients display high inter-individual variation in their autoantigen profiles, which collectively are enriched in evolutionarily conserved, cytosolic and nuclear phosphoproteins. The APECED autoantigens have two major origins; proteins expressed in thymic medullary epithelial cells and proteins expressed in lymphoid cells. These findings support the hypothesis that specific protein properties strongly contribute to the etiology of B cell autoimmunity.