The importance of specific IgE antibodies in epidemiology of allergic rhinitis and asthma – the Epidemiology of Allergic Diseases in Poland (ECAP) survey: part one. Influence of allergy risk factors on concentration of specific IgE antibodies in serum

Introduction
Specific immunoglobulins E (sIgE) are important parameters to estimate severity of allergic diseases.

Aim
To determine the influence of allergy risk factors on the concentration of specific IgE antibodies in serum.

Material and methods
The concentration of sIgE antibodies against allergens Dermatophagoides pteronyssinus, cat dander, timothy grass, Alternaria alternata were determined in serum of 4077 respondents randomly selected from 9 regions (ECAP study). The positive results of sIgE (≥ 0.35 IU/ml) were correlated to answers in questionnaires ECRHSII and ISAAC.

Results
sIgE are more frequently detected in respondents declaring an allergic disease of a father than of a mother (D. pteronyssinus p < 0.05, A. alternata p < 0.01). An early beginning to attend school, kindergarten or nursery increases the frequency of sIgE detection (p < 0.05). If the number of children who slept in the same room as a respondent before the respondent was five years old, was lower, sIgE antibodies are more frequently detected (p < 0.05). Relating to: 1) all 4 allergens, sIgE are the most frequently detected in respondents declaring absence of a carpet/rug at home (p < 0.05), 2) cat dander – less frequently detected in respondents who have a cat at home at the age of 1–4 years (p < 0.005).

Conclusions
Carpets/rugs capture a portion of mite, epidermal, mould allergens located at home, wherefore absence of a carpet or rug causes greater stimulation of an immune system by these allergens; as a consequence, IgE antibodies are the most frequently detected in respondents. Household contacts of the respondents, at the age of 1–4 years, with cats induced partial immune tolerance to cat dander.