The IgE response to Ascaris molecular components is associated with clinical indicators of asthma severity

Abstract

BackgroundAsthma is a common chronic disease worldwide and Ascaris lumbricoides infection (ascariasis) is frequent in tropical regions. However, the effect of ascariasis on asthma severity has not been sufficiently explored. We sought to evaluate the influence of the IgE immune response to Ascaris extract and purified house dust mites (HDM) and Ascaris allergens on indicators of asthma severity in patients living in the tropics.MethodsAsthmatic patients from Cartagena, Colombia were recruited. Clinical assessment included questionnaires, physical examination, allergy skin tests, spirometry, parasite stool examination and IgE antibody measurements. Asthma was diagnosed by a physician according to validated criteria. Indicators of severity were occurrence of severe dyspnea episodes, night awakenings events, > 4 emergency room (ER) visits and hospitalizations during the last year. Specific IgE to Der p 2, Ascaris spp., Blomia tropicalis and Dermatophagoides pteronyssinus extracts was determined by ImmunoCap. IgE to tropomyosins (Asc l 3, Blo t 10 and Der p 10), Blo t 5 and Asc s 1 was detected by ELISA. Logistic regression analyses were used to explore the relationships between sensitization and indicators of asthma severity.ResultsAfter adjustment for HDM sensitization, Ascaris sensitization remained associated with severe dyspnea (aOR: 1.90, 95% CI: 1.08 - 3.34, p = 0.03) and > 4 ER visits (aOR: 2.23, 95% CI: 1.15 - 4.30, p = 0.02). We also found that sensitization to the species specific markers Blo t 5 and Asc s 1, as well as the cross-reactive tropomyosins of D. pteronyssinus and Ascaris were associated with > 4 ER visits. Der p 2 sensitization was associated with bronchodilator responsiveness (aOR: 2.24: 1.25-4.02, p = 0.01). Remarkably, significantly higher IgE levels to HDM species specific allergens were found in Ascaris sensitized patients.ConclusionsIn this tropical population, IgE sensitization to Ascaris and the cross-reactive tropomyosins was frequent and associated with clinical indicators of asthma severity. The significant relationship between sensitization to the nematode-specific marker Asc s 1 and ER attendance supports these findings. Moreover, ascariasis increases the human IgE responses to HDM specific allergens.

Influencia del estilo de vida, la dieta y la vitamina D en la atopia en niños colombianos afrodescendientes

“…Lo anterior podría explicarse por la elevada prevalencia de infestación por geohelmintos, la cual de acuerdo con reportes epidemiológicos recientes es de 50 a 60 % en la población infantil colombiana. 28 Los geohelmintos, entre ellos los del género Ascaris spp., poseen componentes moleculares que inducen la producción de anticuerpos IgE que ocasionan reactividad cruzada con alérgenos de Blomia tropicalis y Dermatophagoides pteronyssinus, tal como señalan Buendía et al, 29 lo que indica una capacidad inmunomodulatoria que debe ser analizada en investigaciones posteriores.…”

Inmunorregulación inducida por helmintos: una actualización

“…Aunque solo en 8 % a 15 % de los casos se demuestra morbilidad (65), el espectro de efectos sobre la respuesta inmune es más amplio, dada la influencia de la inmunomodulación que genera en la expresión de otros fenotipos y procesos biológicos en el hospedero (66). Se entiende menos la inmunomodulación ejercida por Ascaris que la de otros nemáto-dos, pues no en todos los casos la inmunosupresión es el efecto predominante (67). La alta prevalencia de la infección sugiere que este parásito tiene mecanismos exitosos para controlar la respuesta inmune del hospedero a favor de su supervivencia (6).…”

“…Se sabe que la respuesta inmune contra Ascaris se caracteriza por una fuerte polarización hacia el perfil Th2/IgE (68). Su ciclo pulmonar se asocia a manifestaciones clínicas parecidas al asma y en algunas poblaciones la infección se ha asociado con mayor riesgo de alergias (67,69) y, viceversa, la predisposición atópica protege del desarrollo de infecciones intensas por parásitos (70), pero no por otros patógenos (71). De igual manera, en algunos modelos de exposición al extracto proteico funciona como un adyuvante Th2.…”

The tropics, helminth infections and hygiene hypotheses

“…In the tropics, a gradient can be detected from rural communities, heavily parasited and exhibiting less allergic symptoms [18], to urban settings less exposed and light parasited where the effect of the helminthiases is predominantly IgE/ Th2 enhancer [19] and allergic diseases are as frequent as in industrialized societies and have even increased during the last decade [1]. An additional relationship between helminth and allergy is found in developed wealthy countries where there is no parasite-derived immunoregulation [12].…”