The association between seropositivity to human toxocariasis and childhood asthma in northern Iran: a case-control study.

BACKGROUND: Besides the well-known risk factors, Toxocara infection is thought to play a significant etiological role in the development of childhood asthma. To further explore this association, the prevalence of Toxocara infection in sera of asthmatic children and healthy controls in northern Iran was investigated. METHODS: In this case-control study, cases were 145 physician-confirmed asthmatic children diagnosed according to the Global Initiative for Asthma (GINA) guidelines. Controls were 115 age-sex-residence-matched children who did not have physician-diagnosed asthma. The presence of anti-Toxocara immunoglobulin G (IgG) was tested using enzyme-linked immunosorbent assay. Univariate and multivariate logistic regression methods were used for case-control comparisons. RESULTS: Seropositivity rate was 4.1% (95% CI, 3.4-4.7%) in asthmatic children and 0.86% (95% CI, 0.71-1.0%) in controls, suggesting a strong association (P-value < 0.02). Moreover, Toxocara infection was not significantly more prevalent (P-value = 0.12) in children with moderate sustainable asthma (9.3%, 3/32) than in children with mild sustainable asthma (2.3%, 3/113). Mean total immunoglobulin E (IgE) level was significantly higher in Toxocara-infected children (222.3 ± 367.1) than in non-infected children (143.19 ± 218.05) in the case group (P-value < 0.05). CONCLUSIONS: Our findings indicated that Toxocara infection can play an important role in childhood asthma. Further experimental and epidemiological studies are needed to clarify this hypothesis.

The association between seropositivity to human toxocariasis and childhood asthma in northern Iran: a case-control study

BACKGROUND: Besides the well-known risk factors, Toxocara infection is thought to play a signif­icant etiological role in the development of childhood asthma. To further explore this associa­tion, the prevalence of Toxocara infection in sera of asthmatic children and healthy controls in northern Iran was investigated. METHODS: In this case-control study, cases were 145 physician-confirmed asthmatic children diag­nosed according to the Global Initiative for Asthma (GINA) guidelines. Controls were 115 age- sex-residence-matched children who did not have physician-diagnosed asthma. The presence of anti-Toxocara immunoglobulin G (IgG) was tested using enzyme-linked immunosorbent assay. Univariate and multivariate logistic regression methods were used for case-control comparisons. RESULTS: Seropositivity rate was 4.1% (95% CI, 3.4-4.7%) in asthmatic children and 0.86% (95% CI, 0.71-1.0%) in controls, suggesting a strong association (P-value < 0.02). Moreover, Toxocara infection was not significantly more prevalent (P-value = 0.12) in children with moderate sus­tainable asthma (9.3%, 3/32) than in children with mild sustainable asthma (2.3%, 3/113). Mean total immunoglobulin E (IgE) level was significantly higher in Toxocara-infected children (222.3 ± 367.1) than in non-infected children (143.19 ± 218.05) in the case group (P-value < 0.05). CONCLUSIONS: Our findings indicated that Toxocara infection can play an important role in child­hood asthma. Further experimental and epidemiological studies are needed to clarify this hypothesis

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Exposure to Toxocara spp. and Ascaris lumbricoides infections and risk of allergic rhinitis in children.

BACKGROUND: Substantial experimental studies suggest a role for helminthes infections in the pathogenesis of allergies, but epidemiologic data have been inconsistent. Unlike to asthma, the association between helminthes infection and allergic rhinitis (AR) has been poorly studied. Therefore, we sought to evaluate the association between exposure to Ascaris and Toxocara infections and AR. METHODS: We did an age- and gender-matched case-control study of 81 children with physician-confirmed AR and 101 control subjects in a referral hospital for pediatric diseases in northern Iran. Exposure to Ascaris and Toxocara infections was evaluated by anti-A. lumbricoides- and anti-Toxocara- IgG antibodies using a commercial enzyme-linked immunosorbent assay. Associations were determined using multivariate logistic regression. RESULTS: Ascaris seropositivity was higher in children with rhinitis than in controls (12.34 vs. 3.96%). Ascaris seropositivity was positively associated with AR in univariate analysis (OR, 3.42; 95% CI 1.03-11.3; P value = 0.035), but this association was not significant after adjustment for potential confounders (OR, 1.85; 95% CI 0.42-8.18). Also Toxocara seropositivity was higher in children with AR than in healthy subjects (3.7% vs. 0.99), indicating non-significant association with AR in both univariate (OR, 3.84; 95% CI 0.39-37.7) and multivariate analyses (OR, 0.8; 95% CI 0.04-15.44). CONCLUSION: Our results revealed that AR is not associated with seropositivity to Ascaris and Toxocara infections in general; however, a higher seropositivity rate was found for both parasites in children with AR. More studies with longitudinal design and larger sample size are needed to elucidate this association.

Association of serum 25-OH vitamin D3 with serum IgE and the Pediatric Asthma Severity Score in patients with pediatric asthma.

Background: Pediatric asthma is a prevalent disease and has a significant immunologic and inflammatory nature. In recent years, the role of vitamin D3 in immunologic processes has been studied, and many aspects of this role have been clarified in some human diseases. Objective: The aim of this study was to evaluate the relationship among the vitamin D3 status, Pediatric Asthma Severity Score (PASS), and inflammatory indicators of pediatric asthma. Methods: Among all of the pediatric patients with asthma and with asthma exacerbation, 100 patients were randomly enrolled in the study and subdivided into three groups according to serum levels of 25-OH vitamin D3. The control group consisted of 100 sex- and age-matched healthy subjects. Asthma exacerbation severity was evaluated based on the PASS before starting the medical care. The count of the white blood cells, eosinophil count, and serum levels of total immunoglobulin E (IgE) plus 25-OH vitamin D3 were measured in all the subjects. The obtained data were then compared via proper statistical tests. A p value of <0.05 was considered as statistically significant. Results: The median level of serum IgE was increased in patients with vitamin D3 deficiency compared with other groups. There was a significant inverse correlation between serum levels of 25-OH vitamin D3 and IgE in pediatric patients with asthma (r = -0.483, p = 0.001). Furthermore, the serum levels of 25-OH vitamin D3 also significantly inversely correlated with the PASS (r = -0.285, p = 0.004). Conclusion: Vitamin D3 deficiency is associated with exacerbation severity and serum IgE levels in patients with pediatric asthma; hence, it can have an important role in pediatric asthma pathogenesis, possibly through IgE.

Exposure to Ascaris lumbricoides infection and risk of childhood asthma in north of Iran.

BACKGROUND: Asthma and Ascaris lumbricoides infection are common health issues affecting 250 and 700 million people worldwide, respectively. The relationship between ascariasis and asthma is a matter of substantial interest and research. METHODS: We performed a case-control study to evaluate whether the exposure to Ascaris infection is associated with asthma in children. We also assessed potential risk factors for Ascaris infection and asthma in study area. We enrolled 145 asthmatic children and 115 healthy controls. The Global Initiative for Asthma guideline was used to evaluate asthma symptoms and severity in study participants. Ascaris infection was assessed by the presence of anti-Ascaris IgG ≥ 11 IU/mL measured by enzyme-linked immunosorbent assay. RESULTS: We have found a significant relationship between exposure to Ascaris and asthma (odds ratio, 2.92; 95% CI 1.04-8.18; P value = 0.034), and this relationship remained significant after adjustment for covariates (adjusted OR, 3.36; 95% CI 1.04-13%; P value = 0.047). Ascaris infection was more frequent in children with mild sustainable asthma (13.2%; 15/113) than in children with moderate sustainable asthma (6.2%, 2/32), although there was a non-significant difference between these groups (OR, 2.3; 95% CI 0.5-10.1; P value = 0.35). Based on results of a multi-regression analysis, contact with soil (OR, 6.7; 95% CI 1.9-23.5), and drinking unsafe water (OR, 4.2; 95% CI 1.2-14.2) were significant risk factors for Ascaris infection in the study area. CONCLUSION: Results of this study suggest that A. lumbricoides infection might affect susceptibility to asthma in children. These results could be useful in prevention, early diagnosis and management of childhood asthma.

Helicobacter pylori evasion strategies of the host innate and adaptive immune responses to survive and develop gastrointestinal diseases.

Helicobacter pylori (H. pylori) is a bacterial pathogen that resides in more than half of the human population and has co-evolved with humans for more than 58,000 years. This bacterium is orally transmitted during childhood and is a key cause of chronic gastritis, peptic ulcers and two malignant cancers including MALT (mucosa-associated lymphoid tissue) lymphoma and adenocarcinoma. Despite the strong innate and adaptive immune responses, H. pylori has a long-term survival in the gastric mucosa. In addition to the virulence factors, survival of H. pylori is strongly influenced by the ability of bacteria to escape, disrupt and manipulate the host immune system. This bacterium can escape from recognition by innate immune receptors via altering its surface molecules. Moreover, H. pylori subverts adaptive immune response by modulation of effector T cell. In this review, we discuss the immune-pathogenicity of H. pylori by focusing on its ability to manipulate the innate and acquired immune responses to increase its survival in the gastric mucosa, leading up to gastrointestinal disorders. We also highlight the mechanisms that resulted to the persistence of H. pylori in gastric mucosa.

The relationship between Toxocara species seropositivity and allergic skin disorders: a systematic review and meta-analysis.

We performed a systematic review and meta-analysis on observational studies to evaluate the possible associations between Toxocara species seropositivity and allergic skin disorders (ASDs). We searched the MEDLINE, ScienceDirect, Scopus, Web of Science and Google Scholar databases to 15 May 2018 to identify the relevant studies. We used a random effects meta-analysis model to generate the pooled odds ratio (OR) and 95% confidence intervals (CIs). Fifteen studies, including eight studies with a case-control design (735 patients and 1342 controls) and seven studies with a cross-sectional design (a total of 4804 participants, 1302 individuals with ASDs and 3502 without ASDs), were included in the meta-analysis. We found an increased risk for ASDs in individuals with Toxocara seropositivity (OR 1.75 [95% CI 1.16 to 2.64]). Subanalysis showed that Toxocara seropositivity was significantly associated with urticaria (OR 2.97 [95% CI 1.53 to 5.76]), however, it was not significantly associated with atopy (OR 1.08 [95% CI 0.55 to 2.15]) and eczema (OR 1.62 [95% CI 0.95 to 2.78]). Moreover, the pooled ORs were 2.34 (95% CI 1.32 to 4.15) and 1.27 (95% CI 0.69 to 2.35) for case-control and cross-sectional studies, respectively. The results of our study support hypotheses regarding the existence of a positive relationship between Toxocara infection and allergic disorders, although this association should be further investigated by longitudinal and mechanism studies.