Prevalence of filaggrin loss-of-function variants in Chilean population with and without atopic dermatitis.

BACKGROUND: Filaggrin (FLG) loss-of-function variants are major genetic risk factors for atopic dermatitis (AD), but these have not been studied in Latin American populations with and without AD. METHODS: FLG variants R501X and 2282del4 were genotyped in 275 Chilean adults with and without AD from the "Early origins of allergy and asthma" (ARIES) cohort and in 227 patients from an AD cohort based in Santiago, Chile. RESULTS: Among adults in the ARIES cohort, 3.3% were carriers of R501X and 2.9% of 2282del4 variants, all heterozygotes. In this cohort, 6.2% were FLG variant carriers: 11.1% of subjects reporting AD were carriers of FLG variants vs. 5.2% in those without AD (P = 0.13). In this first cohort, FLG variants were not significantly associated with asthma, allergic rhinitis, or food allergy. In the AD cohort, the prevalence of FLG variants was 7% for R501X, 2.2% for the 2282del4 variant, and 9.3% for the combined genotype. In this cohort, FLG variants were present in 15.5% of severe AD vs. 7.1% of mild-to-moderate AD subjects (P = 0.056). Evaluation of Chilean population from both cohorts combined (n = 502) revealed that FLG variants were not significantly associated with AD (OR = 1.92 [95% CI 0.95-3.9], P = 0.067) but were associated with asthma (OR = 2.16 [95% CI 1.02-4.56], P = 0.039). CONCLUSIONS: This is the first study to evaluate FLG loss-of-function variants R501X and 2282del4 in Latin American population, revealing a similar prevalence of these FLG variant carriers to that of European populations. Among Chileans, FLG variants were significantly associated with asthma but not AD.

Naturalization of the microbiota developmental trajectory of Cesarean-born neonates after vaginal seeding.

BACKGROUND: Early microbiota perturbations are associated with disorders that involve immunological underpinnings. Cesarean section (CS)-born babies show altered microbiota development in relation to babies born vaginally. Here we present the first statistically powered longitudinal study to determine the effect of restoring exposure to maternal vaginal fluids after CS birth. METHODS: Using 16S rRNA gene sequencing, we followed the microbial trajectories of multiple body sites in 177 babies over the first year of life; 98 were born vaginally, and 79 were born by CS, of whom 30 were swabbed with a maternal vaginal gauze right after birth. FINDINGS: Compositional tensor factorization analysis confirmed that microbiota trajectories of exposed CS-born babies aligned more closely with that of vaginally born babies. Interestingly, the majority of amplicon sequence variants from maternal vaginal microbiomes on the day of birth were shared with other maternal sites, in contrast to non-pregnant women from the Human Microbiome Project (HMP) study. CONCLUSIONS: The results of this observational study prompt urgent randomized clinical trials to test whether microbial restoration reduces the increased disease risk associated with CS birth and the underlying mechanisms. It also provides evidence of the pluripotential nature of maternal vaginal fluids to provide pioneer bacterial colonizers for the newborn body sites. This is the first study showing long-term naturalization of the microbiota of CS-born infants by restoring microbial exposure at birth. FUNDING: C&D, Emch Fund, CIFAR, Chilean CONICYT and SOCHIPE, Norwegian Institute of Public Health, Emerald Foundation, NIH, National Institute of Justice, Janssen.

Maternal H. pylori is associated with differential fecal microbiota in infants born by vaginal delivery.

Helicobacter pylori colonization may affect the mucosal immune system through modification of microbiota composition and their interactions with the host. We hypothesized that maternal H. pylori status affects the maternal intestinal microbiota of both mother and newborn. In this study, we determine the structure of the fecal microbiota in mothers and neonates according to maternal H. pylori status and delivery mode. We included 22 mothers and H. pylori infection was determined by fecal antigen test. Eleven mothers (50%) were H. pylori-positive (7 delivering vaginally and 4 by C-section), and 11 were negative (6 delivering vaginally and 5 by C-section). Stool samples were obtained from mothers and infants and the fecal DNA was sequenced. The fecal microbiota from mothers and their babies differed by the maternal H. pylori status, only in vaginal birth, not in C-section delivery. All 22 infants tested negative for fecal H. pylori at 15 days of age, but those born vaginally -and not those by C-section- showed differences in the infant microbiota by maternal H. pylori status (PERMANOVA, p = 0.01), with higher abundance of Enterobacteriaceae and Veillonella, in those born to H. pylori-positive mothers. In conclusion, the structure of the infant fecal microbiota is affected by the maternal H. pylori status only in infants born vaginally, suggesting that the effect could be mediated by labor and birth exposures.

Early origins of allergy and asthma (ARIES): study protocol for a prospective prenatal birth cohort in Chile.

BACKGROUND: Growing evidence shows that atopic dermatitis (AD), food allergy (FA), allergic rhinitis, and asthma are largely determined during the first 1000 days (time elapsed from conception to the 2nd birthday). The ARIES birth cohort aims to determine prenatal and perinatal conditions, as well as genetic and epigenetic factors, that participate in the early setting of immune responses, and the role of these in the later determination of the risk of allergic diseases and asthma in the offspring. METHODS: We have designed a birth cohort of 250 families with prenatal recruitment (~ 14 weeks). We will genotype relevant allergy/asthma-associated variants in trios and will perform immunophenotyping and evaluation of allergy biomarkers in cord blood. At 1 and 2 years of age we will assess if infants have developed allergic sensitization, AD, FA, as well as biomarkers of asthma including the asthma predictive index. We will also evaluate how maternal conditions modify immune programming through epigenetic modifications and will then depict newborn epigenetic cues of allergy/asthma risk. Next, we will assess composition/diversity of maternal gut, placenta, breastmilk and infant gut microbiome and their association with immunophenotype and biomarkers at birth, and clinical outcomes at age 1 and 2. Finally, we plan to assess how environmental exposures (perinatal outdoor and indoor pollution, allergens and endotoxin) affect the incidence of allergic sensitization, AD, FA, and risk of asthma. DISCUSSION: The in-depth study of the ARIES birth cohort shall provide crucial information to understand the rising incidence of allergies and asthma in developing countries, and hopefully provide cues on how to prevent and treat these diseases. TRIAL REGISTRATION: clinicaltrials.gov NCT04186949, retrospectively registered on December 5, 2019.

High Helicobacter pylori Bacterial Load and Low Cytokine Expression Levels Are Associated with Nodular Gastropathy.

BACKGROUND AND AIMS: Nodular gastropathy (NG) is an inflammatory condition of the gastric mucosa characterized by the endoscopic detection of multiple millimeter protrusions. A strong association between NG and Helicobacter pylori and a possible role of NG as a risk factor for undifferentiated gastric cancer have been described. The aim of this study was to characterize the pathogenic and inflammatory profile of patients with NG. METHODS: Adult patients referred for upper gastrointestinal endoscopy were prospectively enrolled in this study. H. pylori infection status was determined by rapid urease test. Biopsies were stained with hematoxylin-eosin. Sydney and OLGA scores were used to assess gastritis characteristics and gastric cancer risk. PCR analysis was performed to determine bacterial load and virulence factors CagA (and its EPIYA motifs) and VacA alleles. Finally, gastric mucosa cytokine gene expression (IL-8, IL-1ß, and TNF-α) was determined by real-time RT-PCR. RESULTS: Forty-eight patients, mean age of 36 years, were recruited. All NG patients were infected by H. pylori. OLGA score was similar in both groups (NG patients and non-NG patients). NG patients had higher bacterial load in the gastric corpus (p = 0.01) and significantly less pro-inflammatory cytokine levels than non-NG infected patients (p = 0.01). CONCLUSIONS: In our study, NG is not associated with preneoplastic lesions. An increase in bacterial load without a concomitant increase in mucosal inflammatory cytokine responses in H. pylori-infected subjects with NG may represent a general dampening of immune responses or an additional mechanism of H. pylori active immune evasion.

Helicobacter pylori pediatric infection changes FcεRI expression in dendritic cells and Treg profile in vivo and in vitro.

H. pylori infection shows an inverse relationship with allergies. Dendritic cells regulate mucosal immune responses including the induction of T regulatory cells which are fundamental in Helicobacter pylori-induced dampening of allergies. In this respect expression of high-affinity IgE receptor (FcεRI) has been associated with a regulatory dendritic cell profile. Therefore we aimed to evaluate possible mechanisms by which H. pylori infection might modify atopy in pediatric patients. Here we show that H. pylori-infected children exhibited both increased expression of FcεRI on peripheral myeloid and plasmacytoid dendritic cells and higher levels of Foxp3 and Latency Associated Peptide on T regulatory cells. Moreover, exposure to H. pylori drove increased FcεRI expression and IL-10 secretion by both pediatric H. pylori-exposed monocyte derived dendritic cells and T cells. Finally, we show a positive correlation between expression of FcεRI in circulating myeloid DCs and total Treg cells, suggesting that in children, H. pylori infection may have a modulating role in atopy, mediated by both altered surface expression of FcεRI on children's DC and an increased T regulatory cell profile.

Helicobacter pylori-Clarithromycin Resistance in Symptomatic Pediatric Patients in a High Prevalence Country.

INTRODUCTION: Failure to eradicate Helicobacter pylori despite antibiotic treatment is generally attributed to increasing clarithromycin resistance conferred by point mutations in the 23S-rRNA gene or metronidazole resistance attributed to rdxA gene (HP0954) deletion in patients. Scarce data for pediatric population are available from developing countries. OBJECTIVES: The aim of the present study was to determine the presence of A2142G/C and A2143G mutations in the 23S-rRNA gene and/or rdxA gene (HP0954) deletion in a group of symptomatic H pylori-infected children recruited from an area with high infection rate and risk of gastric cancer. PATIENTS AND METHODS: We recruited 118 patients referred for upper endoscopy for gastrointestinal symptoms. The presence of H pylori was determined by urease test and histological staining. The rdxA gene (HP0954) deletion, and 2142G/C and A2143G mutations were determined by polymerase chain reaction-restriction fragment length polymorphism. A subgroup of infected patients received a 14-day regimen of omeprazole, amoxicillin, and clarithromycin. The effectiveness of this regime was determined by stool antigen determination 8 weeks after treatment. RESULTS: About 21% of the analyzed infected patients showed mutation in the 23S-rRNA gene, with the A2143G transition as the more frequent mutation, and 2% of the patients showed rdxA gene (HP0954) deletion. After treatment, 25% of the patients continued to harbor the bacteria; of these, 67% carried the A2143G mutation. CONCLUSIONS: H pylori-infected pediatric patients from Chile show high prevalence of the mutation responsible for clarithromycin resistance. The failure to eradicate H pylori can be attributed to the presence of the A2143G mutation.

La infección materna por Helicobacter pylori no aumenta el riesgo de contraer la bacteria en el primer trimestre de vida de sus lactantes / Maternal infection due to Helicobacter pylori does not increase the risk of the infection in the first trimester of the life of their infants

Introducción: La infección por H. pylori se adquiere tempranamente en la infancia. Sin embargo, existe escasa información acerca del rol de la lactancia materna y la adquisición de la bacteria en la etapa neonatal/lactante. Objetivo: Evaluar algunos factores que afectan la adquisición de H. pylori en recién nacidos y lactantes hijos de madres infectadas. Pacientes y método: Reclutamiento consecutivo de binomios madre-hijo en maternidad, inmediatamente posparto. Luego de la firma de consentimiento informado, se obtuvo una muestra de deposición de la madre, previo al alta. Posteriormente se obtuvieron 3 muestras de deposición de los recién nacidos/lactantes a los 15, 60 y 90 días de vida, para la detección de antígeno en deposición de H. pylori (HpSAg monoclonal, sensibilidad 94% y especificidad 97%). Además se registraron variables socio-epidemiológicas y biomédicas. Resultados: Se reclutaron 32 binomios madre-hijo, 64 sujetos. Promedio de edad materna de 30,1 ± 5,1 años, 53% parto eutócico, 85% con lactancia materna exclusiva al final del seguimiento. Se encontró 13 madres (40%) infectadas por H. pylori. No hubo infección por H. pylori en los recién nacidos y lactantes a los 3 meses de seguimiento. No hubo diferencia significativa en el nivel socioeconómico entre madres infectadas versus no infectadas (ambos grupos en nivel socioeconómico muy alto: 28% y 32% respectivamente, p = 0,15), ni en el número de habitantes por domicilio entre madres infectadas y no infectadas (3,8 ± 0,8 vs 4,2 ± 1,8 personas, p = 0,18). Conclusión: A pesar de tener un alto porcentaje de madres infectadas por H. pylori, no hubo recién nacidos/lactantes infectados al tercer mes de vida. El rol protector de la lactancia maternal no se puede descartar.

Introduction: H. pylori infection is acquired early in childhood. However, there is little information available regarding the role of breastfeeding and neonatal acquisition of the infection. Objective: To evaluate factors affecting the acquisition of H. pylori in newborns and infants from infected mothers. Patients and method: Consecutive mothers and their newborns were recruited into the study from the maternity unit, immediately after delivery. After signing informed consent, one stool sample from the mother was obtained before hospital discharge. Three stool samples of the newborns were then collected at home at 15, 60, and 90 days of life, for the detection of H. pylori antigen (Monoclonal HpSAg, sensitivity 94% and specificity 97%). The socio-epidemiological and biomedical variables were also analysed using a questionnaire. Results: A total of 32 mother-child pairs (64 subjects) were enrolled. The mean maternal age was 30.1 ± 5.1 years, with 53% vaginal delivery, and 85% exclusively breastfed. There were 13 (40%) infected mothers. No H. pylori infection was detected in newborns and infants up to 3 months of follow-up. No significant differences were found in socioeconomic level between infected versus non-infected mothers (both groups mostly in the very high socioeconomic category: 28% and 32%, respectively, P = .15) and in the number of family members between infected versus non-infected mothers (3.8 ± 0.8 vs 4.2 ± 1.8 persons, P = .18). Conclusion: Despite having a significant percentage of H. pylori-infected mothers, no newborn was infected at the third month of life. The protective role of breastfeeding cannot be ruled out.

[Maternal infection due to Helicobacter pylori does not increase the risk of the infection in the first trimester of the life of their infants]. / La infección materna por Helicobacter pylori no aumenta el riesgo de contraer la bacteria en el primer trimestre de vida de sus lactantes.

INTRODUCTION: H. pylori infection is acquired early in childhood. However, there is little information available regarding the role of breastfeeding and neonatal acquisition of the infection. OBJECTIVE: To evaluate factors affecting the acquisition of H. pylori in newborns and infants from infected mothers. PATIENTS AND METHOD: Consecutive mothers and their newborns were recruited into the study from the maternity unit, immediately after delivery. After signing informed consent, one stool sample from the mother was obtained before hospital discharge. Three stool samples of the newborns were then collected at home at 15, 60, and 90 days of life, for the detection of H. pylori antigen (Monoclonal HpSAg, sensitivity 94% and specificity 97%). The socio-epidemiological and biomedical variables were also analysed using a questionnaire. RESULTS: A total of 32 mother-child pairs (64 subjects) were enrolled. The mean maternal age was 30.1±5.1 years, with 53% vaginal delivery, and 85% exclusively breastfed. There were 13 (40%) infected mothers. No H. pylori infection was detected in newborns and infants up to 3 months of follow-up. No significant differences were found in socioeconomic level between infected versus non-infected mothers (both groups mostly in the very high socioeconomic category: 28% and 32%, respectively, P=.15) and in the number of family members between infected versus non-infected mothers (3.8±0.8 vs 4.2±1.8 persons, P=.18). CONCLUSION: Despite having a significant percentage of H. pylori-infected mothers, no newborn was infected at the third month of life. The protective role of breastfeeding cannot be ruled out.

Peptic ulcer disease in Helicobacter pylori-infected children: clinical findings and mucosal immune response.

OBJECTIVES: Peptic ulcer disease (PUD) is highly prevalent among adults but less common in children. Helicobacter pylori infection, the main cause of PUD, is, however, acquired extremely early in life. The aim of the study was to analyze clinical characteristics of children with PUD in a country with a high prevalence of the disease and to evaluate which host factors could determine this clinical outcome. METHODS: Children referred for upper gastrointestinal (GI) endoscopy with suspicion of peptic diseases were included prospectively during an 8-year period. Antral biopsies were performed to determine H pylori presence and mucosal cytokines profile. RESULTS: A total of 307 children between 3 and 18 years old were enrolled. Of the total, 237 children (46% boys) with complete data were included. H pylori infection was confirmed in 133 (56.1%) participants. Duodenal ulcer (DU) was diagnosed in 32 patients (13.5%); among them 29 were infected with H pylori (90.6%). Infected children had a nodular appearance of the gastric mucosa more often than noninfected children. Noninfected children had fewer lymphoid follicles and less inflammatory infiltrate than infected children. Only mucosal polymorphonuclear cell infiltration was more intense in DU-infected children as compared with non-DU-infected children. DU-infected children had higher levels of mucosal interferon-γ than noninfected and non-DU-infected patients. Non-DU-infected children had also higher levels of mucosal interleukin-10 than noninfected patients (P < 0.05). CONCLUSIONS: PUD in children, especially DU, is strongly associated with H pylori infection in developing countries. There is no distinctive clinical presentation of children with PUD. T-helper cytokine balance may influence clinical outcomes in children.