Celiac disease seroprevalence in subjects with dyspeptic symptoms. A study on a Mexican population

INTRODUCTION AND AIMS

Celiac disease (CD) is an autoimmune enteropathy that develops in genetically susceptible individuals. The typical gastrointestinal manifestation is diarrhea but symptoms of dyspepsia, such as epigastric pain, nausea, or satiety, can sometimes appear. Previous studies have reported that the prevalence of CD in patients with dyspepsia can be as high as 7%. The aim of the present study was to evaluate CD seroprevalence in subjects with dyspeptic symptoms and a control group in a Mexican population.

MATERIAL AND METHODS

A case-control study was conducted on blood donors that answered the PAGI-SYM questionnaire for dyspepsia and in whom IgA antibodies to tissue transglutaminase 2 (IgA anti-tTG2) and IgG antibodies to deamidated gliadin peptide (IgG anti-DGP) were determined. CD seroprevalence in subjects with dyspeptic symptoms and in asymptomatic subjects was compared.

RESULTS

A total of 427 subjects (76.3% men), with a mean patient age of 34 years (range of 18-65 years) were included. Of those participants, 87 (20.3%) had symptoms of dyspepsia (group A) and 340 (79.6%) were asymptomatic (group B). Antibodies were positive in one (1.15%) of the group A subjects (1/87, 95% CI 0.2-6 %), whereas they were positive in 4 (1.18%) of the group B subjects (4/340, 95% CI 0.4-2.9%, p = 0.59).

CONCLUSIONS

CD seroprevalence in the study population with dyspeptic symptoms (1%) was not different from that of the control population. Thus, CD screening in Mexican patients with dyspepsia is not justified.

Molecular detection of bovine leukosis virus in naturally infected dairy and dual-purpose cattle in Mexico

The objective of this study was to determine the prevalence of bovine leukosis virus (BLV) in specialized and dual-purpose dairy cows located in the central zone of Veracruz state in Mexico, using endpoint polymerase chain reaction (PCR). The study population consisted of 307 specialized dairy cows and 95 dual-purpose cows from 13 municipalities located in the study area. All cows were apparently healthy and ≥ 3 years old. Cows were stratified by age (3 - 5, 6 - 8 and ≥ 9 years). The overall prevalence of infection was 6.96%; the calculated prevalence in dairy cows was 7.82% and in dual-purpose cows it was 4.21%. The municipality with the highest proportion was Acajete (14.28%), followed by Huatusco and Tomatlán (11.53%). The association analysis confirms the infection's independence to the cows' productive purpose. The results by age strata were 3 - 5 (4.60%), 6 - 8 (8.00%) and ≥ 9 (18.40%) with X2 = 9.96, with an odds ratio of 4.68 for the stratum ≥ 9 years with a significant difference. The present study determined the prevalence of proviral DNA of BLV in dairy and dual-purpose cows in six municipalities in the central zone of Veracruz state, Mexico, using endpoint PCR.

Celiac disease seroprevalence in patients with infertility. A case-control study

BACKGROUND

Although most patients with celiac disease (CD) have digestive manifestations, in some of them they may be of extraintestinal (atypical) nature, such as chronic anemia, ataxia, and fertility disorders.

OBJECTIVE

To determine the prevalence of CD-related antibodies in Mexican women with fertility disorders.

MATERIAL AND METHODS

Case-control study of women who attended evaluation for fertility disorders in a specialized center. h-tTG-IgA, gliadin IgA II and gliadin IgG II were quantified; titers > 30 IU were considered positive.

RESULTS

One-hundred and seventy-one cases and 171 controls were included; 137 patients (80.1%) had infertility, and 34 (19.9%), sterility. Eight patients (4.6%, 95% CI = 2.3-8.9) had at least one positive marker for CD in comparison with one woman in the control group (0.5%, 95% CI = 0.01-3, p = 0.04, odds ratio = 8.3). Six of the eight patients had unexplained infertility.

CONCLUSIONS

Up to 4.6% of women with infertility had at least one positive marker for CD. As in other parts of the world, screening for CD could be recommended in women with infertility, especially in those with unexplained infertility.

Potential of ATR-FTIR-Chemometrics in Covid-19: Disease Recognition

The COVID-19 pandemic has caused major disturbances to human health and economy on a global scale. Although vaccination campaigns and important advances in treatments have been developed, an early diagnosis is still crucial. While PCR is the golden standard for diagnosing SARS-CoV-2 infection, rapid and low-cost techniques such as ATR-FTIR followed by multivariate analyses, where dimensions are reduced for obtaining valuable information from highly complex data sets, have been investigated. Most dimensionality reduction techniques attempt to discriminate and create new combinations of attributes prior to the classification stage; thus, the user needs to optimize a wealth of parameters before reaching reliable and valid outcomes. In this work, we developed a method for evaluating SARS-CoV-2 infection and COVID-19 disease severity on infrared spectra of sera, based on a rather simple feature selection technique (correlation-based feature subset selection). Dengue infection was also evaluated for assessing whether selectivity toward a different virus was possible with the same algorithm, although independent models were built for both viruses. High sensitivity (94.55%) and high specificity (98.44%) were obtained for assessing SARS-CoV-2 infection with our model; for severe COVID-19 disease classification, sensitivity is 70.97% and specificity is 94.95%; for mild disease classification, sensitivity is 33.33% and specificity is 94.64%; and for dengue infection assessment, sensitivity is 84.27% and specificity is 94.64%.

Development of a New Murine Model of Type 2 Autoimmune Hepatitis Using a Human Liver Protein

Autoimmune hepatitis (AIH) is a chronic inflammatory condition of the liver characterized by parenchymal destruction, hypergammaglobulinemia, specific autoantibody production, and hepatic fibrosis and necrosis. Murine models of AIH have been described; however, little is known about the immunologic mechanisms of tissue destruction. In this study, a new murine model of type 2 AIH was developed using recombinant human cytochrome P450 (CYP) 2D6 emulsified with complete Freund's adjuvant (CFA). BALB/c mice were immunized with 2 μg/mL i.p. of CYP2D6 in CFA. The control group received CFA or phosphate-buffered saline alone. Alanine aminotransferase activity, autoantibody production, IgG concentrations, histologic damage, and specific T-cell response were evaluated. Persistent AIH, characterized by cellular infiltration, hepatic fibrosis, elevated alanine aminotransferase, and the production of anti-liver kidney microsomal antibody type 1 developed in CFA/CYP2D6-immunized mice. These mice presented high levels of IgG and its subclasses IgG1, IgG2a, and IgG2b against liver self-proteins. Interestingly, IL-2+ and interferon γ-positive Cyp2d6-specific T cells were present in greater concentrations in mice immunized with CFA/CYP2D6 compared with control. Immunization with CFA, in combination with a natural human autoantigen like CYP2D6, was demonstrated to break tolerance, resulting in a chronic form of autoimmune-related liver damage. This murine model of type 2 AIH is expected to be instrumental in understanding the immunologic mechanisms of the pathogenesis of this autoimmune liver disease.

The Prevalence of Anti-Zein Antibodies: A Comparative Study between Celiac Disease and Irritable Bowel Syndrome

Celiac disease (CD) is a chronic immune-mediated enteropathy triggered by exposure to dietary gluten in genetically predisposed individuals. In contrast, irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder affecting the large intestine, without an autoimmune component. Here, we evaluated the prevalence of IgA and IgG antibodies to maize zeins (AZA) in patients with CD and IBS. Using an in-house ELISA assay, the IgA and IgG anti-zein antibodies in the serum of 37 newly diagnosed CD (16 biopsy proved and 21 serological diagnosis) and 375 IBS patients or 302 healthy control (HC) subjects were measured. Elevated levels of IgA AZA were found in CD patients compared with IBS patients (p < 0.01) and HC (p < 0.05). CD patients had the highest prevalence (35.1%), followed by IBS (4.3%) and HCs (2.3%) (p < 0.0001). IgG AZA antibodies were not found in any CD patients, IBS patients, or HC subjects. A significant positive correlation was found between IgA AZA with IgA anti-gliadin (AGA, r = 0.34, p < 0.01) and IgA anti-deaminated gliadin peptides (DGP, r = 0.42, p < 0.001) in the celiac disease group. Taken together, our results show for the first time a higher prevalence of AZA IgA antibodies in newly diagnosed CD patients than in IBS patients, confirming a biased immune response to other gliadin-related prolamins such as maize zeins in genetically susceptible individuals.

A unique immune signature of serum cytokine and chemokine dynamics in patients with Zika virus infection from a tropical region in Southern Mexico

OBJECTIVES

To describe the kinetics of circulating cytokines and chemokines in humans with ZIKAV infection.

METHODS

Serum levels of different immune mediators in patients with ZIKAV infection were measured at distinct stages of the disease, as well as in culture supernatants from human monocytes infected with a clinical ZIKAV isolate. We also looked for clinical features associated with specific immune signatures among symptomatic patients.

RESULTS

We evaluated 23 ZIKAV-infected patients. Their mean age was 32 ± 8.3 years and 65% were female. ZIKAV patients showed elevated IL-9, IL-17A, and CXCL10 levels at acute stages of the disease. At day 28, levels of CCL4 and CCL5 were increased, whereas IL-1RA, CXCL8 and CCL2 were decreased. At baseline, IL-7 was increased among patients with headache, whereas CCL2, and CCL3 were decreased in patients with bleeding and rash, respectively. Our clinical ZIKAV isolate induced a broad immune response in monocytes that did not resemble the signature observed in ZIKAV patients.

CONCLUSIONS

We showed a unique immune signature in our cohort of ZIKAV-infected patients. Our study may provide valuable evidence helpful to identify immune correlates of protection against ZIKAV.

Optimization of Zika virus envelope protein production for ELISA and correlation of antibody titers with virus neutralization in Mexican patients from an arbovirus endemic region

BACKGROUND

Zika virus (ZIKV) has become a global threat with immediate need for accurate diagnostics, efficacious vaccines and therapeutics. Several ZIKV envelope (Env)-based vaccines have been developed recently. However, many commercially available ZIKV Env are based on the African lineage and produced in insect cells. Here, we sought to produce Asian-lineage ZIKV Env in mammalian cells for research and clinical applications.

METHODS

We designed various gene expression constructs to optimize the production of ZIKV using prM-Env and full or C-terminal truncations of Env; with or without a rat CD4 fusion partner to allow large-scale production of soluble protein in mammalian HEK293 cells. Protein expression was verified by mass spectrometry and western-blot with a pan-flavivirus antibody, a ZIKV Env monoclonal antibody and with immune sera from adenoviral (ChAdOx1) ZIKV Env-vaccinated mice. The resulting Env-CD4 was used as a coating reagent for immunoassay (ELISA) using both mouse and human seropositive sera.

RESULTS

Replacement of the C-terminus transmembrane Env domain by a rat CD4 and addition of prM supported optimal expression and secretion of Env. Binding between the antigens and the antibodies was similar to binding when using commercially available ZIKV Env reagents. Furthermore, antibodies from ZIKV patients bound ZIKV Env-CD4 in ELISA assays, whereas sera from healthy blood donors yielded minimal OD background. The serological outcomes of this assay correlated also with ZIKV neutralisation capacity in vitro.

CONCLUSIONS

Results obtained from this study indicate the potential of the Asian-lineage Zika Env-CD4 and Env proteins in ELISA assays to monitor humoral immune responses in upcoming clinical trials as well as a sero-diagnostic tool in ZIKV infection.

Association of Single-Nucleotide Polymorphisms in Immune-Related Genes with Development of Dengue Hemorrhagic Fever in a Mexican Population

Single-nucleotide polymorphisms (SNPs) occurring in immune-related genes have been associated with risk or protection for development of dengue, depending on ethnicity. Here, we genotyped seven SNPs located in immune response-related genes to identify their association with severe forms of dengue in patients from an endemic region in Mexico. One hundred and thirty-eight patients with dengue fever (DF), thirty-one dengue hemorrhagic fever (DHF) patients, as well as 304 healthy donors were genotyped by using a TaqMan-based approach. SNP analysis, including rs1800629 (TNF), rs4804803 (CD209), rs2780831 (JAK1), rs1801274 (FCGR2A), rs231775 (CTLA4), rs12979860, and rs8099917 (IFNL3), was performed. The rs1800629 A-allele in the TNF gene was associated with an increased risk of DHF (OR = 3.4, CI = 1.235-9.284 p = 0.0212) whereas SNPs rs4804803, rs2780831, rs1801274, rs231775, rs12979860, and rs8099917 showed no association in this cohort. These results show that allelic variations in TNF can play an important role in the development of DHF. However, the lack of association between all remaining SNPs and DHF suggests that the genetic background might directly modify the role of these immune-related molecules, leading to the milder illness often observed in a Mexican population.

Evaluation of the safety and adjuvant effect of a detoxified listeriolysin O mutant on the humoral response to dengue virus antigens

Listeriolysin O (LLO) has been proposed as a potential carrier or adjuvant molecule in the vaccination field. However, the cytotoxic and pro-apoptotic effects of LLO are the major limitations for this purpose. Here, we have performed a preclinical safety evaluation and characterized a new potential adjuvant application for a non-cytolytic LLO mutant (dtLLO) to enhance and modulate the immune response against the envelope (E) protein from dengue virus. In addition, we have studied the adjuvant effects of dtLLO on human immune cells and the role of membrane cholesterol for the binding and proinflammatory property of the toxoid. Our in-vivo results in the murine model confirmed that dtLLO is a safer molecule than wild-type LLO (wtLLO), with a significantly increased survival rate for mice challenged with dtLLO compared with mice challenged with wtLLO (P < 0·001). Histopathological analysis showed non-toxic effects in key target organs such as brain, heart, liver, spleen, kidney and lung after challenge with dtLLO. In vitro, dtLLO retained the capacity of binding to plasma membrane cholesterol on the surface of murine and human immune cells. Immunization of 6-8-week-old female BALB/c mice with a combination of dtLLO mixed with E protein elicited a robust specific humoral response with isotype diversification of immunoglobulin (Ig)G antibodies (IgG1 and IgG2a). Finally, we demonstrated that cholesterol and lipid raft integrity are required to induce a proinflammatory response by human cells. Taken together, these findings support a potential use of the dtLLO mutant as a safe and effective adjuvant molecule in vaccination.

Non-Conjugated Chitosan-Based Nanoparticles to Proteic Antigens Elicit Similar Humoral Immune Responses to Those Obtained with Alum

Biodegradables Chitosan-based Nanoparticles (CS NPs) have been extensively studied as delivery system for therapeutic molecules and as efficient carriers or adjuvants in experimental vaccination. Physicochemical association between CS NPs and antigens is a key step for the biological function as carrier devices. However, for the adjuvant CS NPs property, it is not well known if coupling with vaccine antigens is required or not to potentiate the immune response. To address this issue, in this work, we evaluated the potential adjuvant effect of CS NPs by simply mixing with two different antigens such as Bovine Serum Albumin (BSA) or E protein from Dengue Virus serotype 2 (E protein DENV2). Thus the CS NPs were prepared by ionic gelation with sodium tripolyphosphate, resulting particles among 68 and 188 nm of size. Immunization of 6–8 week old female BALB/c mice, were carried out by intraperitoneal route with a simple combination of CS NPs either with BSA (CS NPs-BSA) at 10 μg or with E protein DENV2 (CS NPs-Protein E) at 5 μg. Combinations with the above antigens with CS NPs elicited robust specific primary and secondary humoral responses comparable to alum, a well-known adjuvant. BSA-specific IgG titers were detectable by day 14 after priming with the CS NPs-BSA formulation, with titers that ranged from 102 to 103 EU ml-. After a second immunization, the anti-BSA titers ranged around 104 EU ml-. In contrast, in the group of mice immunized with the protein alone, BSA-specific serum IgG titers were undetectable at day 14 and 28. For the immunizations with the CS NPs-E protein formulation, we observed also a remarkable specific-antibody production in the primary response, with titers reaching 103 EU ml-. After the booster immunization the anti-E protein DENV2 antibodies titers reached peak values around 104 EU ml-. Interestingly, for both antigens, the combination with CS NPs polarized the immune response to a Th2-like profile, which is characterized mainly by the production of the IgG1 Isotype, confirming that CS NPs can enhance and modulate the humoral immune responses against different antigens independently of physicochemical conjugation. This could represent a simplification in the use of CS NPs as adjuvants in vaccination.

Elevated circulating levels of IL-21 and IL-22 define a cytokine signature profile in type 2 autoimmune hepatitis patients

 Background and aims. Autoimmune hepatitis (AIH) is a chronic inflammatory condition of the liver in which the immunological mechanisms involved in tissue destruction and/or repair are still unclear. Different pro-inflammatory cytokines have been shown to play a determinant role in AIH pathogenesis. Here, we aim to compare the circulating levels of pro- and anti-inflammatory cytokines such as IL-6, TNF-?, IL-17A/F, IL-21, IL-22, IL-23, and IL-10 in patients with type 2 AIH compared to patients with type 1 AIH and healthy controls (HC). Fourty-six Mexican patients with AIH were recruited in our study. Patients were classified as type 1 or 2 AIH based on immune serological markers. Fourty-four serum samples from healthy individuals were included as controls. Serum cytokine levels were determined by ELISA technique.

RESULTS

Compared to healthy controls, serum levels of IL-17F, IL-21, IL-23, IL-10, IL-6, and TNF-?, but not IL-17A and IL-22, were significantly increased in AIH patients. When patients were grouped by aminotransferase activity, a biomarker of active disease, a positive correlation between serum IL-17F and alanine transaminase (rs: 0.4739; P = 0.0009) and aspartate transaminase (rs: 0.4984; P = 0.0004) levels was found. A cytokine signature profile associated with type 2 AIH was characterized by high serum IL-21 (type 1 AIH: 0.66 pg/mL; type 2 AIH: 331.1 pg/mL; P = 0.0042) and IL-22 (type 1 AIH: 0.1 pg/mL; type 2 AIH: 55.26 pg/mL; P = 0.0028) levels.

CONCLUSIONS

We show for the first time, differential regulation of certain pro-inflammatory cytokines associated with disease progression and AIH type in Mexican patients.

Prevalence of celiac disease and related antibodies in patients diagnosed with irritable bowel syndrome according to the Rome III criteria. A case-control study

BACKGROUND

The cost-effectiveness for screening for celiac disease (CD) in patients with irritable bowel syndrome (IBS), specifically in the diarrhea (IBS-D) subtype, is beneficial if the prevalence is >1%. However, recent studies have shown controversial results. In this large case-control study, our aim was to determine the prevalence of CD and a panel of related antibodies in patients diagnosed with IBS.

MATERIALS AND METHODS

Four hundred IBS patients (Rome III) and 400 asymptomatic healthy controls were prospectively evaluated using antihuman tissue transglutaminase (h-tTG IgA) and deamidated gliadin peptide antibodies (DGP II IgA and DGP II IgG). Duodenal biopsy was performed on the patients that were positive for the h-tTG IgA and/or DGP II IgG antibodies.

RESULTS

The mean age of the population was 44.47 ± 18.01 years and 335 (82%) of the subjects were women. Twenty-one patients and six controls had at least one positive test for CD (5.25% VS 1.5%, p = 0.003, OR 3.63 [95% CI 1.4-9.11]). Eighteen patients were positive for h-tTG and/or DGP-II IgG. Histologic confirmation of CD was 2.5% in the IBS patients vs 0.5% in the controls (p = 0.04, OR 5.21). The IBS-D subtype had the highest prevalence for serological positivity (12.7%).

CONCLUSIONS

Up to 5.2% of the patients with IBS according to the Rome III criteria were positive for at least one of the CD-related antibodies and 2.5% had biopsy-confirmed CD. Therefore, in our population, screening for CD in subjects with IBS appears to be a reasonable strategy, especially in the IBS-D subgroup.

Lower IgG somatic hypermutation rates during acute dengue virus infection is compatible with a germinal center-independent B cell response

BACKGROUND

The study of human B cell response to dengue virus (DENV) infection is critical to understand serotype-specific protection and the cross-reactive sub-neutralizing response. Whereas the first is beneficial and thus represents the ultimate goal of vaccination, the latter has been implicated in the development of severe disease, which occurs in a small, albeit significant, fraction of secondary DENV infections. Both primary and secondary infections are associated with the production of poly-reactive and cross-reactive IgG antibodies.

METHODS

To gain insight into the effect of DENV infection on the B cell repertoire, we used VH region high-throughput cDNA sequencing of the peripheral blood IgG B cell compartment of 19 individuals during the acute phase of infection. For 11 individuals, a second sample obtained 6 months later was analyzed for comparison. Probabilities of sequencing antibody secreting cells or memory B cells were estimated using second-order Monte Carlo simulation.

RESULTS

We found that in acute disease there is an increase in IgG B cell diversity and changes in the relative use of segments IGHV1-2, IGHV1-18, and IGHV1-69. Somewhat unexpectedly, an overall low proportion of somatic hypermutated antibody genes was observed during the acute phase plasmablasts, particularly in secondary infections and those cases with more severe disease.

CONCLUSIONS

Our data are consistent with an innate-like antiviral recognition system mediated by B cells using defined germ-line coded B cell receptors, which could provide a rapid germinal center-independent antibody response during the early phase of infection. A model describing concurrent T-dependent and T-independent B cell responses in the context of DENV infection is proposed, which incorporates the selection of B cells using hypomutated IGHV segments and their potential role in poly/cross-reactivity. Its formal demonstration could lead to a definition of its potential implication in antibody-dependent enhancement, and may contribute to rational vaccine development efforts.

Dynamics of interleukin-21 production during the clinical course of primary and secondary dengue virus infections

Previous studies have revealed the clinical relevance of pro-inflammatory cytokine production during dengue virus (DENV) infections. In this study, we evaluated the production of interleukin-21 (IL-21), a key soluble mediator mainly produced by CD4+ T cells. The aim of this study was to investigate the role of IL-21 production during the clinical course of primary and secondary DENV infections and the potential association of IL-21 serum levels with the disease pathogenesis. Blood samples from DENV-infected patients were collected on different days after the onset of symptoms. Patients were classified according to their phase of disease (acute vs. convalescent phases), the type of infection (primary vs. secondary), and the clinical severity of their disease (dengue fever (DF) vs. dengue hemorrhagic fever (DHF)). IL-21 levels were measured using a quantitative capture ELISA assay. The levels of IL-21 were significantly elevated in the disease group compared with the control group. IL-21 was detected in primary and secondary DENV infections, with a significantly higher concentration in the convalescent phase of primary infections. IL-21 levels were significantly higher in patients with secondary acute DHF infections when compared with those with secondary acute DF infection. There was a relationship between the elevated serum levels of IL-21 and the production of DENV-specific IgM and IgG antibodies. Taking together, our results show for the first time the involvement of IL-21 during the clinical course of DENV infections. We speculate that IL-21 may play a protective role in the context of the convalescent phase of primary infections and the acute phase of secondary infections.

Lipopopeptidephosphoglycan from Entamoeba histolytica activates human macrophages and dendritic cells and reaches their late endosomes

Lipopopeptidephosphoglycan (LPPG) is a complex macromolecule from the surface of Entamoeba histolytica trophozoites. We analysed the interaction between LPPG and human macrophages and dendritic cells (DCs) and found that LPPG is internalized by these cells and activates them. The internalization process involves intracellular traffic from the cell membrane to late endosomes, as shown by co-localization of LPPG with late endosomes marked with FITC-dextran and LAMP-1. LPPG-activated DCs have increased expression of co-stimulatory molecules CD80, CD86 and CD40 and produce pro-inflammatory cytokines TNF-alpha, IL-8 and IL-12. Taken together, these results show that LPPG activates antigen-presenting cells and reaches intracellular compartments that are involved in antigen presentation.