Reefer AJ, Satinover SM, Wilson BB, Woodfolk JA From the Asthma and Allergic Diseases Center J Allergy Clin Immunol 2007 doi:10.1111/j.1365-2133.2007.07794.x
In both atopic (high IgE) and non-atopic (low IgE) eczema, there seems to be an increased risk of affected areas becoming infected with microbial skin infections. However, the relationship between antimicrobial IgE antibodies and non-atopic disease remains unclear.
This study aimed to examine the relevance of microbial allergens to the allergen-specific IgE antibody repertoire in patients with atopic dermatitis.
Patients with IgE levels <150IU/mL were divided according to sensitivity (n=22) or no sensitivity (n=27) to 11 common food allergens and aero allergens. The prevalence and levels of antimicrobial IgE antibodies were then compared to patients (n=36) with total titres >150IU/mL. Skin-derived serum chemokines were also analysed.
The results showed that patients with low IgE had decreased disease severity, increased age at onset, a striking female predominance and a distinct distribution of skin lesions. High titre IgE antibodies (a sum of eight bacterial and fungal allergens) and multisensitisation-specific microbial allergens were characteristic of patients with high IgE levels with an overall 84 per cent positivity, but antimicrobial IgE antibodies comprised 3 per cent or less of allergen-specific IgE antibodies.
Of those with low IgE, antimicrobial antibodies were detected in only 20 per cent of the patients and titres were negligible. Patients with low IgE and no sensitivity to common allergens had lower levels of serum macrophage inflammatory protein 3 alpha compared with their sensitised counterparts.
From this, it was concluded that antimicrobial IgE antibodies are uncommon in patients with atopic dermatitis and low IgE levels, suggesting that microbial allergens are an unlikely trigger for eczematous eruptions in patients with low IgE levels.
- Dr Nigel Stollery is a GP in Kibworth, Leicestershire, and clinical assistant in dermatology at Leicester Royal Infirmary