Atopy and Asthma in Migrants: The Function of Parasites

Abstract

Migration studies have shown that environmental factors in more developed and industrialized countries facilitate atopy and asthma in a time-dependent manner and are affected by age at immigration. Levels of immunoglobulin E are higher in immigrants than in the local population and gradually decrease to the levels of the general population. Parasitic infestation may function in the prevention and pathogenesis of atopic conditions in immigrants from developing countries. Helminths are associated with a reduced prevalence of clinically important atopic disorders, likely because of induction of a regulatory cell population mechanism. Improved understanding of the immunologic background of helminths and their protective function in humans has led to a growing interest in the possibility of reversal of allergies using parasites and the development of new therapies, such as immunomodulation for allergy using ova from parasites orally or intranasally. Strategies for primary prevention in high-risk atopic individuals and secondary prevention guidelines should be developed for populations in developing countries and for immigrants from developing countries to atopy-prevalent developed countries. Improved understanding of the function of parasitic infection in modulation of the immune response may lead to new therapeutic options for allergic conditions.

Holistic View on Health: Two Protective Layers of Biodiversity

“…In the late 1980s, it was suggested that childhood infections protect against allergies (Strachan 1989). While this has later been shown to be largely incorrect (Bloomfield et al 2016), increased hygiene, improved sanitation, and medical preventive care have led to reduced human infection by helminth parasites, which is considered to be one of the key reasons behind the allergy epidemic (Yazdanbakhsh et al 2002, Rottem et al 2015, Spencer & Zuk 2016. However, recent evidence suggest that the role of parasites is not independent of gut bacteria (Zaiss et al 2015).…”

Susceptibility to allergy in adoptive children: a cross-sectional study at “Bambino Gesù Children’s Hospital”

“…International adoption involves not only exposure to a new macroenvironment, but it also implies significant socioeconomic and cultural changes, such as housing, diet and access to medical services [ 11 ]. A history of admission to unsuitable environments (orphanage, shelter, children’s home or other institution) at a young age, bringing about lack of stimulation, nutritional deficiencies and poor hygiene may influence the physical and mental health of children, making them individuals requiring special care [ 1 ].…”

“…We found that 56.5% of children exceeded normal age-adapted values for IgE and 31.3% of them were diagnosed with a parasitic infection. As numerous outbreaks in institutionalized settings have been reported, it is not surprising that intestinal protozoa are frequently identified on routine screening of international adoptees [ 11 , 28 – 30 ]. In a 2005 study, Murray identified that intestinal parasites are common in international adoptees children, with a prevalence of 14% to 33%.…”

“…If on the one hand, migrants are suddenly exposed to a new composition of environment and allergens and as result may develop higher prevalence of allergies, on the other one they should be more protected from allergic diseases compared to non-migrants because of their richer symbiotic microflora [ 8 – 10 ]. Several studies on allergy in immigrant adults indicate [ 11 , 12 ] that allergy and asthma develop several years after migration to developed countries [ 13 , 14 ]. Few data are presently available in children [ 11 , 12 ].…”

“…Several studies on allergy in immigrant adults indicate [ 11 , 12 ] that allergy and asthma develop several years after migration to developed countries [ 13 , 14 ]. Few data are presently available in children [ 11 , 12 ]. These few data suggest that the development of atopy could present different characteristics in children than in adults both with regard to specific patterns of allergies and to the timing of occurrence [ 7 ].…”