Biology Reference
In-Depth Information
INTRODUCTION
The relationships between parasitic and allergic diseases were
perceived before the discovery of IgE. The subject has been of interest to
several disciplines and progressively has been focused on particular
parasites and specific allergies such as asthma. The search for explana-
tions to the worldwide increase in the prevalence of immune-mediated
diseases has led to increased attention that research groups in experi-
mental allergy are giving to this problem. Currently there are several
strategies for studying the interactions between
Ascaris
and allergy,
focusing mainly on clinical cohorts for analyzing the impact of ascariasis
on asthma pathogenesis, diagnosis and severity; genetic epidemiology
surveys to explore the genetic and evolutionary basis of the Th2
responses; and animal models to study asthma pathogenesis at experi-
mental level (
Figure 2.1
).
Ascariasis is a geohelminth disease where adult parasites live in the
intestine while larvae migrate through tissues including the lungs.
Although similar to the allergic reaction, the immune response to this
nematode is modulated to variable degrees by parasite-induced immu-
nosuppression. Atopy is the genetic predisposition to produce high levels
of serum total IgE or specific IgE, while allergy (or allergic disease) is
atopy plus the clinical symptoms. Ascariasis has been controlled in
Evolutionary and
genetic aspects of
allergy and the
immune responses to
Ascaris
Family studies on susceptibility to ascariasis,
molecular genetic analysis in populations, region
resequencing, whole genome sequencing,
comparative and functional genomics. Epigenetic
modifications
Epidemiology: helminthiasis as a
risk factor for asthma. Atopy as a
protective factor for
helminthiasis
Phenotypes: skin test,
bronchoprovocation, severity,
effects of anthelmintic therapy
Diagnostic problems in the
tropics: cross-reactivity and
component resolved diagnosis
Epidemiology analysis, discovering
and characterizing new allergens,
testing the diagnostic value of
specific components in populations
Clinical influences of
ascariasis on asthma
Investigating the
impact of
Ascaris
/allergy links
The effect of immunomodulator
Ascaris
molecules on asthma
Child cohorts: parasites and gut microbial
colonization. Early sensitization and cross-
reactivity. Biological markers and clinical
evolution
Effects of ascariasis on
the pathogenesis of
allergy: humans
Modulation of allergic responses by
Ascaris
infection. Effects of cross-reactive allergen
sensitization in the strength of IgE responses.
Gene expression in susceptible mouse strains
Effects of ascariasis on
the pathogenesis of
allergy:animal models
FIGURE 2.1
Several aspects of the
Ascaris
-allergy association are currently under
investigation. Results from most of these studies are discussed in this chapter. Component
resolved diagnosis employs purified allergens instead of the whole extracts for determining
the immune reactivity (mainly specific IgE) of patients.
