Total and Specific Immunoglobulin E for Detection of Most Prevalent Aeroallergens in a Jordanian Cohort

Allergies are defined as an immune response to non-microbial environmental antigens (allergens) that involve T_H2 cells, mast cells, eosinophils and immunoglobulin E (IgE). Atopic disorders such as urticaria, asthma, hay fever, and eczema exhibit a strong familial predisposition and specific IgE-mediated reaction after exposure to the allergens. Aeroallergens involved in the hypersensitivity reactions include pollens, animal dander, fungal spores and house dust mite. Frequency and type of aeroallergens vary in different countries based on climate, vegetation and geographic areas.

Due to increased prevalence of allergic diseases, in vitro diagnostic tests are commonly utilized in our area. The aim of our study is to evaluate the association between total and specific IgE and to study frequency of different aeroallergens in the population.

The study was conducted in a time period between 1/12/2017 and 15/11/2018 at King Hussein Medical Center, Amman, Jordan. A total of 80 patients with symptoms of allergic disorders were included, ages of individual's ranged between 1 year and 77 years, 58.8 % (n=47) of which male and 41.2 % (n=33) female. Blood samples from all patients were collected into a 10 ml gel separator (with clot activator) tubes and tested for total IgE and specific IgE.

A total of 80 patients aged 1-77 years were divided into 4 groups depending on the normal value of total IgE as follow: 1-5 years, 6-9 years, 10-15 years, and adult. A total of 43(53.75%) patients exhibited elevated total IgE level, and 37(46.25%) had normal level. 41(51.2%) patients had elevated total IgE and positive specific IgE. The sensitivity and specificity of total IgE when using specific IgE as standard test was 77.4% and 92.5% respectively. The accuracy rate of the total IgE test was 82.5%. The most common aeroallergens were dermatophagoides pteronyssinus (13.6%), followed by grass mix (12.8).

Testing of specific IgE is an essential procedure that helps to detect the cause of allergy. Although negative specific IgE could not exclude allergen sensitization due to limitations of detection method and allergen selection, and positive total and specific IgE indicate probability of sensitization.