Longitudinal assessment of the exposure to Ascaris lumbricoides through copromicroscopy and serology in school children from Jimma Town, Ethiopia.

BACKGROUND: We previously demonstrated that serology holds promise as an alternative diagnostic tool to copromicroscopy to monitor and evaluate deworming programs targeting soil-transmitted helminths (STHs). Here we explored the dynamics of anti-Ascaris antibodies (Ab) and evaluated the Ab-isotype of choice to assess the longitudinal exposure to Ascaris in Ethiopian school children. METHODOLOGY: Between October 2018 and February 2020, stool and blood samples were collected every four months from school children (4 to 6 years of age). Stool samples were analyzed by duplicate Kato-Katz to assess the presence and intensity of any STH infection. Plasma Ab-responses against the total extract of Ascaris suum lung third stage larvae were measured through in-house Ab-ELISA's for seven different Ab-isotypes. PRINCIPAL FINDINGS: At baseline, 42.4% of the 66 children were excreting eggs of any STH, Trichuris (37.9%) being the most prevalent. The cumulative prevalence (proportion of children tested that positive at least once over the entire study period) was 56.1% for Trichuris and 31.8% for Ascaris. For Ascaris, re-infections were frequently observed, whereas for Trichuris, children often remained excreting eggs following drug administration. When measuring anti-Ascaris Ab-levels, the cumulative seroprevalence was generally higher (IgG4: 60.6%; IgG1: 50.0%; IgE: 36.4%). The individual anti-Ascaris IgG4 levels at baseline were positively associated with the fecal egg counts averaged over the study period, the rate of egg-appearance and the number of positive test results. There was no apparent cross-reactivity between the anti-Ascaris IgG4 Ab-ELISA and Trichuris. CONCLUSIONS/SIGNIFICANCE: We demonstrate that the children are exposed to STH before the age of four and that the exposure to Ascaris is underestimated when measured with copromicroscopy. Compared to other Ab-isotypes, IgG4 is the Ab-isotype of choice to measure Ascaris exposure in STH endemic settings. Finally, the results also highlight that measuring anti-Ascaris IgG4 levels holds promise as a tool to identify individuals at higher risk for continued exposure to this STH.

Ascaris lumbricoides and ticks associated with sensitization to galactose α1,3-galactose and elicitation of the alpha-gal syndrome.

BACKGROUND: IgE to galactose alpha-1,3 galactose (alpha-gal) causes alpha-gal syndrome (delayed anaphylaxis after ingestion of mammalian meat). Development of sensitization has been attributed to tick bites; however, the possible role of other parasites has not been well studied. OBJECTIVE: Our aims were to assess the presence, relative abundances, and site of localization of alpha-gal-containing proteins in common ectoparasites and endoparasites endemic in an area of high prevalence of alpha-gal syndrome, as well as to investigate the ability of ascaris antigens to elicit a reaction in a humanized rat basophil in vitro sensitization model. METHODS: Levels of total IgE, Ascaris-specific IgE, and alpha-gal IgE were measured in sera from patients with challenge-proven alpha-gal syndrome and from controls without allergy. The presence, concentration, and localization of alpha-gal in parasites were assessed by ELISA, Western blotting, and immunohistochemistry. The ability of Ascaris lumbricoides antigen to elicit IgE-dependent reactivity was demonstrated by using the RS-ATL8 basophil reporter system. RESULTS: Alpha-gal IgE level correlated with A lumbricoides-specific IgE level. Alpha-gal protein at 70 to 130 kDa was detected in A lumbricoides at concentrations higher than those found in Rhipicephalus evertsi and Amblyomma hebraeum ticks. Immunohistochemistry was used to localize alpha-gal in tick salivary acini and the helminth gut. Non-alpha-gal-containing A lumbricoides antigens activated RS-ATL8 basophils primed with serum from subjects with alpha-gal syndrome. CONCLUSION: We demonstrated the presence, relative abundances, and site of localization of alpha-gal-containing proteins in parasites. The activation of RS-ATL8 IgE reporter cells primed with serum from subjects with alpha-gal syndrome on exposure to non-alpha-gal-containing A lumbricoides proteins indicates a possible role of exposure to A lumbricoides in alpha-gal sensitization and clinical reactivity.

WSB1 and IL21R Genetic Variants Are Involved in Th2 Immune Responses to Ascaris lumbricoides.

Genetic and epigenetic factors are considered to be critical for host-parasite interactions. There are limited data on the role of such factors during human infections with Ascaris lumbricoides. Here, we describe the potential role of genetic factors as determinants of the Th2 immune response to A. lumbricoides in Brazilian children. Stool samples were collected from the children to detect A. lumbricoides by microscopy and peripheral blood leukocytes (PBLs) were cultured in whole blood cultures for detection of cytokines (IL-5, IL-10, and IL-13) in vitro. Levels of anti-A. lumbricoides IgE and IgG4 were measured in plasma. DNA was extracted from PBLs and genotyped using Illumina 2.5 Human Omni Beadchip. Candidate genes associated with A. lumbricoides responses were identified and SNVs in these selected genes associated with the Th2 immune response to A. lumbricoides. Haplotype, gene expression, and epigenetic analyses were done to identify potential associations with Th2 immune responses. GWAS on samples from 1,189 children identified WSB1 as a candidate gene, and IL-21R was selected as a biologically relevant linked gene for further analysis. Variants in WSB1 and IL21R were associated with markers of Th2 immune responses: increased A. lumbricoides-specific IgE and IL-5/IL-13 by PBLs from infected compared to uninfected individuals. In infected children, WSB1 but not IL21R gene expression was suppressed and increased methylation was observed in the WSB1 promoter region. This is the first study to show an association between genetic variants in WSB1 and IL21R and Th2 immune responses during A. lumbricoides infections in children. WSB1/IL21R pathways could provide a potential target for the treatment of Th2-mediated diseases.

Expression of Ascaris lumbricoides putative virulence-associated genes when infecting a human host.

BACKGROUND: Ascaris lumbricoides is the most common causative agent of soil-transmitted helminth infections worldwide, with an estimated 450 million people infected with this nematode globally. It is suggested that helminths are capable of evading and manipulating the host immune system through the release of a spectrum of worm proteins which underpins their long-term survival in the host. We hypothesise that the worm overexpresses these proteins when infecting adults compared to children to cirvumvent the more robust defence mechanisms of adults. However, little is known about the parasite's genes and encoded proteins involved during A. lumbricoides infection. Hence, this study was conducted to assess the expression profile of putative virulence-associated genes during an active infection of adults and children. METHODS: In this study, quantitative PCR was performed to evaluate the expression profile of putative virulence-associated genes in A. lumbricoides isolated from infected children and adults. The study was initiated by collecting adult worms expelled from adults and children following anthelminthic treatment. High-quality RNA was successfully extracted from each of six adult worms expelled by three adults and three children, respectively. Eleven putative homologues of helminth virulence-associated genes reported in previous studies were selected, primers were designed and specific amplicons of A. lumbricoides genes were noted. The expression profiles of these putative virulence-associated genes in A. lumbricoides from infected adults were compared to those in A. lumbricoides from infected children. RESULTS: The putative virulence-associated genes VENOM, CADHERIN and PEBP were significantly upregulated at 166-fold, 13-fold and fivefold, respectively, in adults compared to children. Conversely, the transcription of ABA-1 (fourfold), CATH-L (threefold) and INTEGRIN (twofold) was significantly suppressed in A. lumbricoides from infected adults. CONCLUSIONS: On the basis of the expression profile of the putative virulence-associated genes, we propose that the encoded proteins have potential roles in evasion mechanisms, which could guide the development of therapeutic interventions.

Helminth Antigen Exposure Enhances Early Immune Control of Mycobacterium tuberculosis in Monocytes and Macrophages.

Helminth and Mycobacterium tuberculosis (Mtb) coinfection is common and suggested to influence the risk of developing active tuberculosis (TB). It is known that helminths in contrast to TB induce a strong Th2 response in the host. However, the direct impact of helminth antigen exposure on host immunity against TB is largely unknown. Our aim was to explore the effects of helminth antigen exposure on the early immune control of Mtb in monocytes and macrophages. Ascaris lumbricoides (ASC) and Schistosoma mansoni (SM) protein antigens were used to study the immediate effect of helminth antigen exposure in monocytes, on monocyte-to-macrophage differentiation, or mature macrophages, in the control of virulent Mtb H37Rv. Pre-exposure of peripheral blood mononuclear cells reduced Mtb growth in monocytes, especially with SM, but no Th1/Th2 cytokines or activation markers indicated involvement of T cells. Monocytes exposed before maturing into macrophages reduced Mtb growth in macrophages (ASC), and pre-exposure of mature macrophages reduced (ASC) or kept Mtb growth at control levels (SM). This in vitro model shows how helminth infection directly affects the monocyte-macrophage axis at an early stage before cell-mediated immunity develops. During acute helminth coinfection or when helminth antigen concentration is elevated at the site of Mtb infection, these helminths provide an enhanced control and killing of Mtb owing to the direct stimulatory effect of helminth antigens on phagocytic cells.

Identification and Physicochemical Characterization of a New Allergen from Ascaris lumbricoides.

To analyze the impact of Ascaris lumbricoides infection on the pathogenesis and diagnosis of allergic diseases, new allergens should be identified. We report the identification of a new Ascaris lumbricoides allergen, Asc l 5. The aim of this study was to evaluate the physicochemical and immunological features of the Asc l 5 allergen. We constructed an A. lumbricoides cDNA library and Asc l 5 was identified by immunoscreening. After purification, rAsc l 5 was physicochemically characterized. Evaluation of its allergenic activity included determination of Immunoglobulin E (IgE) binding frequency (in two populations: 254 children and 298 all-age subjects), CD203c based-basophil activation tests (BAT) and a passive cutaneous anaphylaxis (PCA) mouse model. We found by amino acid sequence analysis that Asc l 5 belongs to the SXP/RAL-2 protein family of nematodes. rAsc l 5 is a monomeric protein with an alpha-helical folding. IgE sensitization to rAsc l 5 was around 52% in general population; positive BAT rate was 60%. rAsc l 5 induced specific IgE production in mice and a positive PCA reaction. These results show that Asc l 5 has structural and immunological characteristics to be considered as a new allergen from A. lumbricoides.

Immune serum-activated human macrophages coordinate with eosinophils to immobilize Ascaris suum larvae.

Helminth infection represents a major health problem causing approximately 5 million disability-adjusted life years worldwide. Concerns that repeated anti-helminthic treatment may lead to drug resistance render it important that vaccines are developed but will require increased understanding of the immune-mediated cellular and antibody responses to helminth infection. IL-4 or antibody-activated murine macrophages are known to immobilize parasitic nematode larvae, but few studies have addressed whether this is translatable to human macrophages. In the current study, we investigated the capacity of human macrophages to recognize and attack larval stages of Ascaris suum, a natural porcine parasite that is genetically similar to the human helminth Ascaris lumbricoides. Human macrophages were able to adhere to and trap A suum larvae in the presence of either human or pig serum containing Ascaris-specific antibodies and other factors. Gene expression analysis of serum-activated macrophages revealed that CCL24, a potent eosinophil attractant, was the most upregulated gene following culture with A suum larvae in vitro, and human eosinophils displayed even greater ability to adhere to, and trap, A suum larvae. These data suggest that immune serum-activated macrophages can recruit eosinophils to the site of infection, where they act in concert to immobilize tissue-migrating Ascaris larvae.

Ascaris lumbricoides Cystatin Prevents Development of Allergic Airway Inflammation in a Mouse Model.

Severe helminth infections are negatively associated to allergic diseases like asthma; therefore, the immunomodulatory properties of parasite-derived components have been analyzed, raising the possibility of their use as anti-inflammatory molecules. We evaluated the immunomodulatory properties of Ascaris lumbricoides recombinant cysteine protease inhibitor (rAl-CPI) in a mouse model of allergic airway inflammation induced by the house dust mite (HDM) Blomia tropicalis and its effects on human monocyte-derived dendritic cells (HmoDCs). The B. tropicalis sensitized/challenged mice developed extensive cellular airway inflammatory response, which was significantly reduced upon treatment with rAl-CPI prior to B. tropicalis sensitization, affecting particularly the perivascular/peribronchial infiltrate cells, eosinophils/neutrophils, and goblet cells. A significant decrease of Th2 cytokines, total, and specific IgE antibodies was observed in rAl-CPI treated mice. The antibody response was biased to IgG, mainly IgG2a. Administration of rAl-CPI-alone and rAl-CPI before mite sensitization were associated with a significant increase of regulatory T cells (Tregs) in spleen and elevated IL-10 levels in BAL and splenocytes culture supernatants, which was partially affected by anti-IL10 receptor use. In vitro, rAl-CPI showed a modulatory effect on HmoDCs, lowering the expression of HLA-DR, CD83, and CD86, while inducing IL-10 and IL-6 production. This suggests an inhibition of HmoDC maturation and a possible link with the inhibition of the allergic response observed in the murine model.

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

BACKGROUND: In many rural areas of tropical countries such as Indonesia, the prevalence of soil-transmitted helminths (STH) infections remains high. At the same time, the burden of allergic disorders in such rural areas is reported to be low and inversely associated with helminth infections. To reduce the morbidity and transmission of helminth infections, the world health organization recommends preventive treatment of school children by providing mass drug administration (MDA) with albendazole. Here, we had an opportunity to evaluate the prevalence of skin reactivity to allergens before and after albendazole treatment to get an indication of the possible impact of MDA on allergic sensitization. METHODS: A study was conducted among 150 school children living in an area endemic for STH infections. Before and 1 year after anthelminthic treatment with albendazole, stool samples were examined for the presence of STH eggs, skin prick tests (SPT) for cockroach and house dust mites were performed, blood eosinophilia was assessed, and total immunoglobulin E (IgE) and C-reactive protein (CRP) were measured in plasma. RESULTS: Anthelminthic treatment significantly reduced the prevalence of STH from 19.6 before treatment to 6% after treatment (p < 0.001). Levels of total IgE (estimate: 0.30; 95% CI 0.22-0.42, p < 0.0001), CRP (estimate: 0.60; 95% CI 0.42-0.86, p = 0.006), and eosinophil counts (estimate: 0.70; 95% CI 0.61-0.80, p < 0.001) decreased significantly. The prevalence of SPT positivity increased from 18.7 to 32.7%. Multivariate analysis adjusted for confounding factors showed an increased risk of being SPT positive to any allergen (OR 3.04; 95% CI 1.338-6.919, p = 0.008). CONCLUSIONS: This study indicates that 1 year of MDA with albendazole was associated with a reduced prevalence of STH infections. This study shows that the prevalence of allergic sensitization increases after 1 year of albendazole treatment. Placebo-controlled and larger studies are needed to further substantiate a role of deworming treatment in an increased risk of allergic sensitization.

Schistosomiasis Induces Persistent DNA Methylation and Tuberculosis-Specific Immune Changes.

Epigenetic mechanisms, such as DNA methylation, determine immune cell phenotype. To understand the epigenetic alterations induced by helminth coinfections, we evaluated the longitudinal effect of ascariasis and schistosomiasis infection on CD4+ T cell DNA methylation and the downstream tuberculosis (TB)-specific and bacillus Calmette-Guérin-induced immune phenotype. All experiments were performed on human primary immune cells from a longitudinal cohort of recently TB-exposed children. Compared with age-matched uninfected controls, children with active Schistosoma haematobium and Ascaris lumbricoides infection had 751 differentially DNA-methylated genes, with 72% hypermethylated. Gene ontology pathway analysis identified inhibition of IFN-γ signaling, cellular proliferation, and the Th1 pathway. Targeted real-time quantitative PCR after methyl-specific endonuclease digestion confirmed DNA hypermethylation of the transcription factors BATF3, ID2, STAT5A, IRF5, PPARg, RUNX2, IRF4, and NFATC1 and cytokines or cytokine receptors IFNGR1, TNFS11, RELT (TNF receptor), IL12RB2, and IL12B (p < 0.001; Sidak-Bonferroni). Functional blockage of the IFN-γ signaling pathway was confirmed, with helminth-infected individuals having decreased upregulation of IFN-γ-inducible genes (Mann-Whitney p < 0.05). Hypomethylation of the IL-4 pathway and DNA hypermethylation of the Th1 pathway was confirmed by Ag-specific multidimensional flow cytometry demonstrating decreased TB-specific IFN-γ and TNF and increased IL-4 production by CD4+ T cells (Wilcoxon signed-rank p < 0.05). In S. haematobium-infected individuals, these DNA methylation and immune phenotypic changes persisted at least 6 mo after successful deworming. This work demonstrates that helminth infection induces DNA methylation and immune perturbations that inhibit TB-specific immune control and that the duration of these changes are helminth specific.

Host-Parasite Interactions in Individuals with Type 1 and 2 Diabetes Result in Higher Frequency of Ascaris lumbricoides and Giardia lamblia in Type 2 Diabetic Individuals.

Host-parasite interactions in diabetic patients might influence diabetes complications and intestinal parasitosis. The aim was to investigate the occurrence of enteroparasites in individuals with diabetes types 1 and 2. A descriptive study was designed to estimate frequencies of parasites and to compare them in individuals with diabetes types 1 and 2 from two Health Centers and one hospital in the Federal District of Brazil. Patients were allocated to the study by convenience. Three fecal samples of 156 diabetic individuals (120 type 1 and 36 type 2) were analyzed using two parasitological methods. Enteroparasites or commensals frequency in diabetics was 64%. Diabetics infected with up to six species of intestinal parasites or commensals were found. Frequencies of Ascaris lumbricoides and Giardia lamblia were higher in individuals with type 2 diabetes. The lower frequency of A. lumbricoides found in type 1 diabetes may be related to a strong Th2 response to parasites. Autoimmune response developed in type 1 diabetic individuals characterized by the production of Th1 cytokines could explain low frequency of G. lamblia. High frequency of parasites found in type 2 diabetes emphasizes the importance of periodic parasitological examinations in these individuals.

Intestinal parasites: Associations with intestinal and systemic inflammation.

The aim of the present study was to evaluate associations between intestinal parasitic infection with intestinal and systemic inflammatory markers in school-aged children with high rates of obesity. Plasma concentrations of C-Reactive Protein (CRP), leptin, TNF-α, IL-6 and IL-10 were measured as systemic inflammation markers and count of stool leukocytes as marker of intestinal inflammation in 291 children (6-10 years). Intestinal parasitic infection was measured by stool examination. Logistic regression analyses were performed to determine the odds of having high inflammatory markers for each parasite or group of parasites as compared to parasite-free children while adjusting for sex, age, mother's educational level and percentage of body fat. The prevalence of soil-transmitted helminths and intestinal protozoa infections was 12% and 36%, respectively. Parasitic infection was not associated with CRP, IL-6, IL-10 or TNF-α. Children infected with Ascaris lumbricoides (aOR: 5.91, 95% CI: 1.97-17.70) and Entamoeba coli (aOR: 8.46, 95% CI: 2.85-25.14) were more likely to have higher stool leucocytes than parasite-free children. Children with multiple infections (aOR: 10.60, 95% CI: 2.85-25.14) were more likely to have higher leptin concentrations than parasite-free children. Intestinal parasitic infection was not associated with systemic inflammation, but was associated with intestinal inflammation. Having multiple infections were associated with higher leptin concentrations.

Dissociation between skin test reactivity and anti-aeroallergen IgE: Determinants among urban Brazilian children.

BACKGROUND: The dissociation between specific IgE and skin prick test reactivity to aeroallergens, a common finding in populations living in low and middle-income countries, has important implications for the diagnosis and treatment of allergic diseases. Few studies have investigated the determinants of this dissociation. In the present study, we explored potential factors explaining this dissociation in children living in an urban area of Northeast Brazil, focusing in particular on factors associated with poor hygiene. METHODS: Of 1445 children from low income communities, investigated for risk factors of allergies, we studied 481 with specific IgE antibodies to any of Blomia tropicalis, Dermatophagoides pteronyssinus, Periplaneta americana and Blatella germanica allergens. Data on demographic, environmental and social exposures were collected by questionnaire; serum IgG and stool examinations were done to detect current or past infections with viral, bacterial, protozoan and intestinal helminth pathogens. We measured atopy by skin prick testing (SPT) and specific IgE (sIgE) to aerollergens in serum (by ImmunoCAP). SIgE reactivity to B. tropicalis extract depleted of carbohydrates was measured by an in-house ELISA. Total IgE was measured by in house capture ELISA. SNPs were typed using Illumina Omni 2.5. RESULTS: Negative skin prick tests in the presence of specific IgE antibodies were frequent. Factors independently associated with a reduced frequency of positive skin prick tests were large number of siblings, the presence of IgG to herpes simplex virus, Ascaris lumbricoides and Trichuris trichiura infections, living in neighborhoods with infrequent garbage collection, presence of rodents and cats in the household and sIgE reactivity to glycosylated B. tropicalis allergens. Also, SNP on IGHE (rs61737468) was negatively associated with SPT reactivity. CONCLUSIONS: A variety of factors were found to be associated with decreased frequency of SPT such as unhygienic living conditions, infections, total IgE, IgE response to glycosylated allergens and genetic polymorphisms, indicating that multiple mechanisms may be involved. Our data, showing that exposures to an unhygienic environment and childhood infections modulate immediate allergen skin test reactivity, provide support for the "hygiene hypothesis".

[Influence of serum levels of vitamin D on IgE response in schoolchildren with asthma in poor communities]. / Influencia de los niveles séricos de vitamina D sobre la respuesta IgE en niños escolares con asma en comunidades pobres.

BACKGROUND: Asthma is a common disease in the world and vitamin D (Vit-D) has been associated with the presence and severity of this disease. OBJECTIVE: To establish the association between levels of Vit-D and IgE response in schoolchildren with asthma living in four cities in Colombia. METHODS: Case-control study in 1340 schoolchildren (687 asthmatic and 653 controls) from communities in extreme poverty in Barranquilla, Cartagena, Santa Marta, and Montería. Serum concentrations of Vit-D, total IgE, and anti-Dermatophagoides farinae, Periplaneta americana, and Ascaris lumbricoides (AL) specific IgE were measured. RESULTS: Controls reported higher concentrations of Vit-D [61.9 ± 28.4 ng/mL] than cases [53 ± 23.3 ng / mL] (p < 0.05). Total IgE was higher in cases (p < 0.05). Only anti-AL IgE showed a clear difference: in controls, optical density was 0.27 ± 0.25; in cases, 0.22 ± 0.24 (p < 0.05). Vit-D showed differences between cases and controls in each population. CONCLUSIONS: An association could not be demonstrated between Vit-D deficiency and asthma, as total IgE was elevated in patients and controls. The results suggest that Vit-D influences the specif IgE response in poor asthmatic children in areas endemic for helminthiasis.

Antecedentes: El asma es una enfermedad frecuente en el mundo y la vitamina D (Vit-D) se ha asociado con la presencia y severidad de esta enfermedad. Objetivo: Establecer la asociación entre los niveles de Vit-D y la respuesta IgE en escolares con asma residentes de cuatro ciudades colombiananas. Métodos: Estudio de casos y controles en 1340 escolares (687 asmáticos y 653 controles) de comunidades en extrema pobreza de Barranquilla, Cartagena, Santa Marta y Montería. Se midieron las concentraciones séricas de Vit-D, IgE total e IgE específica anti Dermatofagoides farinae, Periplaneta americana y Ascaris lumbricoides (AL). Resultados: Los controles reportaron concentraciones mayores de Vit-D [61.9 ± 28.4 ng/mL] que los casos [53 ± 23.3 ng/mL] (p<0.05). La IgE total fue mayor en los casos (p<0.05). Solo IgE anti-AL mostró una diferencia clara: controles, densidad óptica 0.27 ± 0.25; casos 0.22 ± 0.24 (p<0.05). La Vit-D presentó diferencias entre casos y controles en cada población. Conclusiones: No se pudo demostrar la asociación entre deficiencia de Vit-D y asma, dado que la IgE total estuvo elevada en los pacientes y en los controles. Los resultados sugieren que la Vit-D influye en la respuesta IgE específica en niños asmáticos pobres en zonas endémicas para helmintiasis.

The Effect of Deworming on Tests of Tuberculosis Infection in Children With Recent Tuberculosis Exposure: A Randomized Controlled Trial.

BACKGROUND: Helminth infestations are associated with T-helper cell type 2 (Th2) immune responses, leading to suppression of Th1 responses required to control Mycobacterium tuberculosis infection. We hypothesized that deworming after documented M. tuberculosis exposure might improve Th1 immune responses. METHODS: This was a randomized controlled trial comparing the effect of early versus delayed (after 3 months) deworming on tuberculin skin testing (TST) and Quantiferon-Gold-in-tube responses among children from a setting with a known high burden of M. tuberculosis and helminth co-infection in Cape Town, South Africa. Children aged 6 to 15 years with documented M. tuberculosis exposure were enrolled. Ascaris lumbricoides status was measured by Ascaris-specific IgE and stool microscopy. RESULTS: A total of 250 children (mean age, 9.6 years) were enrolled; 11.9% (27/227) were Ascaris stool microscopy positive and 54.2% (135/249) were Ascaris stool and/or IgE positive (Ascaris status). In univariable analysis, deworming at enrollment was not associated with a negative TST at 3 months (odds ratio, 0.61; 95% confidence interval, 0.35-1.07; P = 0.08). In stratified analysis, children with a positive Ascaris status were more likely to be TST negative at 3 months if dewormed early (odds ratio, 0.49; 95% confidence interval, 0.23-1.04; P = 0.06). In multivariable analysis, deworming was not associated with TST status (adjusted odds ratios, 0.62; 95% confidence interval, 0.34-1.10; P = 0.10). There was no association between deworming and Quantiferon-Gold-in-tube status. CONCLUSIONS: Deworming in children with recent M. tuberculosis exposure is associated with a trend toward a negative TST result. Timing of deworming might influence interpretation of TST in settings with high burdens of tuberculosis and helminths.

Community Rates of IgG4 Antibodies to Ascaris Haemoglobin Reflect Changes in Community Egg Loads Following Mass Drug Administration.

BACKGROUND: Conventional diagnostic methods for human ascariasis are based on the detection of Ascaris lumbricoides eggs in stool samples. However, studies of ascariasis in pigs have shown that the prevalence and the number of eggs detected in the stool do not correlate well with exposure of the herd to the parasite. On the other hand, an ELISA test measuring antibodies to Ascaris suum haemoglobin (AsHb) has been shown to be useful for estimating transmission intensity on pig farms. In this study, we further characterized the AsHb antigen and screened samples from a population-based study conducted in an area that is endemic for Ascaris lumbricoides in Indonesia to assess changes in AsHb antibody rates and levels in humans following mass drug administration (MDA). METHODOLOGY/PRINCIPAL FINDINGS: We developed and evaluated an ELISA to detect human IgG4 antibodies to AsHb. We tested 1066 plasma samples collected at different times from 599 subjects who lived in a village in rural Indonesia that was highly endemic for ascariasis. The community received 6 rounds of MDA for lymphatic filariasis with albendazole plus diethylcarbamazine between 2002 and 2007. While the AsHb antibody assay was not sensitive for detecting all individuals with Ascaris eggs in their stools, the percentage of seropositive individuals decreased rapidly following MDA. Reductions in antibody rates reflected decreased mean egg output per person both at the community level and in different age groups. Two years after the last round of MDA the community egg output and antibody prevalence rate were reduced by 81.6% and 78.9% respectively compared to baseline levels. CONCLUSION/SIGNIFICANCE: IgG4 antibody levels to AsHb appear to reflect recent exposure to Ascaris. The antibody prevalence rate may be a useful indicator for Ascaris transmission intensity in communities that can be used to assess the impact of control measures on the force of transmission.

Helminth infection, fecundity, and age of first pregnancy in women.

Infection with intestinal helminths results in immunological changes that influence co-infections, and might influence fecundity by inducing immunological states affecting conception and pregnancy. We investigated associations between intestinal helminths and fertility in women, using 9 years of longitudinal data from 986 Bolivian forager-horticulturalists, experiencing natural fertility and 70% helminth prevalence. We found that different species of helminth are associated with contrasting effects on fecundity. Infection with roundworm (Ascaris lumbricoides) is associated with earlier first births and shortened interbirth intervals, whereas infection with hookworm is associated with delayed first pregnancy and extended interbirth intervals. Thus, helminths may have important effects on human fertility that reflect physiological and immunological consequences of infection.

Effect of different helminth extracts on the development of asthma in mice: The influence of early-life exposure and the role of IL-10 response.

It is not currently clear whether different parasites have distinct effects on the airway inflammatory response in asthma and whether exposure in early life to helminths have a stronger impact in a potential inhibitory effect on asthma. The aim of this study is to evaluate the effect of exposure to different helminth extracts on the development of allergic pulmonary response in mice, including early-life exposure. Different helminth extracts (Angiostrongylus costaricensis, Angiostrongylus cantonensis and Ascaris lumbricoides) were studied in female adult BALB/c and C57BL/6 IL-10-deficient mice in a protocol of murine asthma, injected intraperitoneally in different periods of exposure (early, pre-sensitization and post-sensitization). Cell counts in bronchoalveolar lavage (BAL), eosinophil peroxidase (EPO) from lung tissue, cytokine levels from BAL/spleen cell cultures, and lung histology were analyzed. Airway cellular influx induced by OVA was significantly inhibited by extracts of A. cantonensis and A. lumbricoides. Extracts of A. lumbricoides and A. costaricensis led to a significant reduction of IL-5 in BAL (p < 0.001). Only the exposure to A. lumbricoides led to an increased production of IL-10 in the lungs (p < 0.001). In IL-10-deficient mice exposed to A. costaricensis pre-sensitization, eosinophil counts and IL-5 levels in BAL and EPO in lung tissue were significantly reduced. In the early exposure to A. cantonensis, lung inflammation was clearly inhibited. In conclusion, different helminth extracts inhibit allergic lung inflammation in mice. IL-10 may not play a central role in some helminth-host interactions. Early exposure to helminth extracts could be a potential strategy to explore primary prevention in asthma.

Proliferative capacity and cytokine production by cells of HIV-infected and uninfected adults with different helminth infection phenotypes in South Africa.

BACKGROUND: It has been suggested that the proliferative capacity of cells from individuals with HIV or both HIV and helminth infections is attenuated and cytokine production is dysregulated. This study describes peripheral blood mononuclear cell proliferation capacity and cytokine profile from individuals with HIV or both HIV and helminth infections in South Africa. METHODS: Forty HIV-infected and 22 HIV-uninfected participants were randomly selected and stratified into different helminth infection phenotypes by egg excretion and Ascaris lumbricoides specific -immunoglobulin-E (IgE) levels. Five day cell cultures of participants, unstimulated or stimulated with Phytohaemaglutinnin, Streptokinase, HIV-1 p24 and Ascaris lumbricoides worm antigens were stained with monoclonal antibody-fluorochrome conjugates (Ki67-FITC and CTLA-APC-4). Percentage expression of Ki67 and CTLA-4 was measured to determine cell proliferation and regulation, respectively. Culture supernatants were analysed for the expression of 13 cytokines using the Bioplex (BioRad) system. Kruskal Wallis was used to test for differences in variables between helminth infected subgroups who were either having eggs in stool and high IgE (egg+IgEhi); or eggs in stool and low IgE (egg+IgElo); or no eggs in stool and high IgE (egg-IgEhi) and those without helminth infection (egg-IgElo). RESULTS: Individuals excreting eggs in stool with high serum IgE (egg+IgEhi phenotype) had potent mitogen responses but consistently produced low, but statistically non-significant antigen-specific (HIV-1 p24 (p = 0.41) and Ascaris (p = 0.19) and recall antigen (Streptokinase; p = 0.31) Ki67 responses. The group also had reduced type 1 cytokines. Individuals excreting eggs in stool with low serum IgE( egg+IgElo phenotype) had a more favourable antiviral profile, characterized by higher IFNγ, IL-2, lower IL-4 and higher IL-10 production. CONCLUSION: The findings suggest that dual HIV/helminth infection with egg excretion and/or high Ascaris IgE phenotye may be linked with poor proliferative capacity and deleterious cytokine profile with regards to HIV control.