In landen waar veel parasitaire infecties voorkomen (afrika bv.) schijnen significant minder allergieen te heersen.
Dat is tenminste een van de theorieen waar het aan kan liggen:
Suppression of TH2-type allergic reactions by helminth infection.Fallon PG, Mangan NE.
Institute of Molecular Medicine, Department of Clinical Medicine, Trinity College Dublin Centre for Health Sciences, St James's Hospital, Dublin, Ireland. pfallon@tcd.ie
There is no immunological mechanism to adequately explain the sudden epidemic in allergies noted in the last 30 years in developed countries. The reduction in the development of allergic disorders observed in individuals infected with parasitic helminths, however, supports a possible role for worms in suppressing allergies. Helminths regulate the immunity of the host to ensure a mutually beneficial environment for the survival of both the parasite and the host. This interplay between helminths and allergic responses raises fundamental questions in immunobiology. Harnessing current mechanistic studies for translational research into helminth infections and atopy might have potential for the identification of novel biomarkers, and even therapeutics, in allergic diseases.
PMID: 17318233 [PubMed - indexed for MEDLINE]
Ook mensen op het platteland hebben minder vaak hooikoorts:
Increased sensitization in urban vs. rural environment - Rural protection or an urban living effect?Priftis KN, Anthracopoulos MB, Nikolaou-Papanagiotou A, Mantziou V, Paliatsos AG, Tzavelas G, Nicolaidou P, Mantzouranis E.
Department of Allergy-Pneumonology, Penteli Children's Hospital, Athens, Greece.
In a population-based longitudinal cohort study, we tested the hypothesis that children growing up in a high-traffic polluted urban area (UA) in the Athens' basin have higher prevalence of allergies and sensitization when compared with those growing up in a Greek provincial rural area (RA). We recruited 478 and 342 children aged 8-10 living in the UA and the RA, respectively. Respiratory health was assessed by a parent-completed questionnaire in three phases: 1995-96 (phase 1), 1999-2000 (phase 2), 2003-04 (phase 3) and skin-prick testing to common indoor and outdoor aeroallergens was performed at phases 1 and 2. Reported asthma and eczema did not differ between the two areas, whereas reported hay fever was persistently more prevalent in the UA than in the RA (16.5%, 17.0%, 18.2% vs. 7.0%, 8.3%, 9.6%, respectively). Sensitization was more prevalent in the UA at both phases (19.0% vs. 12.1% in phase 1, 20.0% vs. 14.1% in phase 2). Residential area contributed independently to sensitization to >/=1 aeroallergens (OR: 0.29; 95% CI: 0.13-0.66; p = 0.003) and to polysensitization (OR: 0.28; 95% CI: 0.10-0.82; p = 0.020) in phase 1. These associations were independent of farming practices. No significant contributions were found in phase 2. Our results suggest that long-term exposure to urban environment is associated with a higher prevalence of hay fever but not of asthma or eczema. The negative association between rural living and the risk of atopy during childhood, which is independent of farming practices, implies that it is mainly driven by an urban living effect.
PMID: 17432999 [PubMed - in process]
Er is echter nog niet echt duidelijkheid over.
Het mooi kotsende meisje.