Allergy or Parasites

Immunoglobulin E (IgE) plays a central role in both allergic disease and defence against parasitic infections. It is essential for protection against helminths, yet it also drives allergic inflammation. This dual function creates diagnostic and therapeutic challenges, especially in regions where parasites and allergy coexist.

This review explores
– the structure and function of IgE
– its role in parasitic infections
– molecular mechanisms of allergic disease
– diagnostic strategies
– current and emerging treatments
– key research gaps and future directions

Immunoglobulin E (IgE) in allergic disease and parasitic infections – visual overview of immune mechanisms, diagnostics, cross-reactivity, and treatment pathways.

Key Mediators in IgE-Mediated Responses

Preformed mediators
– Histamine
– Tryptase
– Heparin

Newly synthesised mediators
– Leukotrienes C₄, D₄, E₄
– Prostaglandin D₂
– Thromboxanes

Cytokines and chemokines
– IL-4, IL-5, IL-13
– TNF-α
– CCL3, CCL5, CCL11
– TGF-β

IgE and Parasitic Infections

Soil-transmitted helminths commonly associated with IgE elevation include
– Ascaris lumbricoides
– Strongyloides stercoralis
– Trichuris trichiura
– hookworms (Necator americanus and Ancylostoma duodenale)

These infections stimulate IgE-mediated immune pathways that may
– support parasite expulsion
– enhance epithelial barrier integrity
– increase mucus production
– activate eosinophils

Molecular Cross-Reactivity

Helminth-derived proteins with allergenic potential include
– tropomyosins
– glutathione S-transferases
– paramyosins

Cross-reactivity is particularly relevant for
– house dust mite allergy
– asthma in parasite-endemic regions
– interpretation of IgE test results

Diagnostic Approaches

In vivo testing
– Skin prick testing (SPT) – first-line, rapid, high sensitivity
– Intradermal testing (IDT) – higher sensitivity, lower specificity

In vitro testing
– Total IgE – supportive but non-specific
– Allergen-specific IgE (sIgE) – clinically useful when correlated with history
– Component-resolved diagnostics (CRD) – improves specificity and reduces false positives

Functional assays
– Basophil activation test (BAT) – high specificity but limited availability

Therapeutic Strategies

Management of IgE-mediated disease typically includes
– allergen avoidance
– patient education and written action plans
– pharmacotherapy (antihistamines, corticosteroids, leukotriene antagonists)
– adrenaline auto-injectors for anaphylaxis

Advanced interventions include
– allergen immunotherapy (SCIT, SLIT, OIT)
– biological therapies such as omalizumab
– emerging cytokine-targeted monoclonal antibodies

References

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4. Jogi NO, Kitaba N, Storaas T, et al. Ascaris exposure and its association with lung function, asthma, and DNA methylation in Northern Europe. J Allergy Clin Immunol. 2022;149(6):1960-1969. doi:10.1016/j.jaci.2022.01.008
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7. Immunoglobulin E (IgE): Function, Tests & Disorders. Cleveland Clinic. https://my.clevelandclinic.org/health/body/ige. Updated June 12, 2025. Accessed August 29, 2025.
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