Effects of maternal geohelminth infections on allergy in early childhood

Abstract

BackgroundMaternal geohelminth infections during pregnancy may protect against allergy development in childhood.ObjectiveWe sought to investigate the effect of maternal geohelminths on the development of eczema, wheeze, and atopy during the first 3 years of life.MethodsA cohort of 2404 neonates was followed to 3 years of age in a rural district in coastal Ecuador. Data on wheeze and eczema were collected by means of questionnaire and physical examination at 13, 24, and 36 months of age. Atopy was measured based on skin prick test (SPT) reactivity to 9 allergens at 36 months. Maternal stool samples were examined for geohelminths by microscopy. Data on potential confounders was collected after birth by questionnaire.ResultsGeohelminths were observed in 45.9% of mothers. Eczema and wheeze were reported for 17.7% and 25.9%, respectively, of 2069 (86.1%) children with complete follow-up to 3 years, and allergen SPT reactivity to any allergen was present in 17.2% and to house dust mite in 8.7%. Maternal geohelminth infections were not significantly associated with eczema (adjusted odds ratio [OR], 1.26; 95% CI, 0.98-1.61), wheeze (adjusted OR, 1.02; 95% CI, 0.82-1.27), and SPT reactivity to any allergen (adjusted OR, 0.79; 95% CI, 0.61-1.01). In subgroup analyses maternal geohelminths were associated with a significantly reduced risk of SPT reactivity to mite and other perennial allergens, and maternal ascariasis was associated with an increased risk of eczema and reduced risk of SPT reactivity to all allergens.ConclusionOur data do not support a protective effect of maternal infections with geohelminth parasites during pregnancy against the development of eczema and wheeze in early childhood, although there was evidence in subgroup analyses for a reduction in SPT reactivity to house dust mites and perennial allergens.

Meta-analysis of antenatal infection and risk of asthma and eczema

“…The cross-sectional [2] and case–control studies [17,18] were considered high quality, while the cohort studies [1,12–16,19] were considered moderate or high quality.…”

Allergens of <b><i>Blomia tropicalis</i></b>: An Overview of Recombinant Molecules

“…Recent studies have also evaluated the cross-reactivity between rBlo t 5 and the group 21 allergens, as well as with crude extracts of B. tropicalis and Ascaris lumbricoides [12,53]. The latter allergen source should be considered in tropical regions due to the high prevalence of helminth infections [54,55,56], which could possibly interfere with the serodiagnosis of mite allergy [57,58]. Interestingly, Carvalho et al [12] showed that rBlo t 5 and rBlo t 21 are less cross-reactive with A. lumbricoides crude extracts than with extracts of B. tropicalis , suggesting that these 2 recombinant allergens might represent markers for the diagnosis of B. tropicalis- sensitized patients.…”

Prevalence of Atopy following Mass Drug Administration with Albendazole: A Study in School Children on Flores Island, Indonesia

“…Epidemiological studies examining the relationships between helminth infections, which are highly prevalent in low-income countries, and allergic disorders have provided evidence for an inverse association between helminth infections and allergic disorders [3, 7, 8]. The strongest evidence for the association between helminth infections and allergy has been provided by small intervention studies that have shown increases in the prevalence or the risk of atopy after anthelmintic treatment of infected children [9, 10].…”

“…As in the case of allergic disorders, chronic helminth infections induce a strong T-helper 2 (Th2) immune response that leads to elevated levels of immunoglobulin E (IgE), eosinophils, basophils, and mast cells [8, 14]. However, unlike immune responses induced by allergens, helminth infections also lead to increased anti-inflammatory cytokines, such as interleukin (IL-10) and transforming growth factor-β [5, 16].…”