Specific immunoglobulin E analysis in adults presenting with birch pollen allergy symptoms
Orrela, Salla (2022-04-27)
Specific immunoglobulin E analysis in adults presenting with birch pollen allergy symptoms
(27.04.2022)
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
avoin
Julkaisun pysyvä osoite on:
https://urn.fi/URN:NBN:fi-fe2022052037915
https://urn.fi/URN:NBN:fi-fe2022052037915
Tiivistelmä
The increase of IgE-mediated allergies and asthma is a socioeconomic challenge in developed countries. Although there are millions of people suffering from different types of allergies, they are often underdiagnosed, and almost half of the allergic people have not received a proper diagnosis for their symptoms.
Pollens are a major cause of allergic symptoms. Birch pollen is the most common cause of rhinitis and rhinoconjunctivitis in Finland. The major birch pollen allergen Bet v 1 is a protein that is associated with a majority of immunoglobulin E (IgE)-mediated allergies in the spring. It is very cross-reactive, so people who are sensitized to Bet v 1 may often react to many fruits and vegetables, too. Bet v 1 is the most commonly used allergen in immunotherapies of birch pollen allergy, but since also many other allergens are causing allergic symptoms, a specific diagnosis is important in order to treat the patient correctly.
This Master’s thesis aimed to determine the current prevalence and specific allergens of birch pollen
allergy in adults living in South-West Finland and suffering from significant symptoms of seasonal rhinitis or rhinoconjunctivitis, suspected on clinical grounds to be caused by allergy to birch pollen. The study included 148 volunteers (44 males and 104 females). A component analysis was performed to explore the presence of specific IgE antibodies against Bet v 1, other major birch pollen allergens (Bet v2 and Bet v 4) and several other known main airborne and food allergens in the Finnish adult population. Most (84 %) of the subjects were positive (positivity threshold, serum IgE concentration ≥ 0.35 kUA/L) for at least one specific IgE species against plant- or animal-derived allergens, and 80 % of the study participants were found to be sensitized to birch pollen, according to the serum IgE analysis. Specific IgE antibodies against Bet v 1 were observed in almost all participants who were IgE-positive for birch pollen antigens as a group (116 of 118 subjects). In 24 subjects (16 %), no IgE- based allergy diagnosis could be established. 30 subjects (20 %) were negative for IgE against birch pollen.
The average IgE concentration tended to be lower in older subjects. The mean IgE concentration of airborne allergens in the youngest age group (18-29 years) was significantly higher (p<0.0001) than in the oldest age group (50-65 years). No difference was observed between male and female subjects.
Many subjects who were found to be sensitized to food allergens had IgE antibodies against allergens that are known to cause cross-reactivity with birch pollen, for example, soy component Gly m 4 and peanut component Ara h 8. It has been previously shown that IgE antibodies to Gly m 4 and Ara h 8 allergens are generally due to sensitization to birch pollen since these allergens are Bet v 1 homologs, all belonging to the PR-10 protein family.
Based on the current results, it remains relevant to include specific serum IgE analysis in the diagnostic work-up of persons presenting with interfering symptoms of rhinitis or rhinoconjunctivitis during the birch pollen season and being considered for initiation of allergen immunotherapy with Bet v 1 –targeted products.
Pollens are a major cause of allergic symptoms. Birch pollen is the most common cause of rhinitis and rhinoconjunctivitis in Finland. The major birch pollen allergen Bet v 1 is a protein that is associated with a majority of immunoglobulin E (IgE)-mediated allergies in the spring. It is very cross-reactive, so people who are sensitized to Bet v 1 may often react to many fruits and vegetables, too. Bet v 1 is the most commonly used allergen in immunotherapies of birch pollen allergy, but since also many other allergens are causing allergic symptoms, a specific diagnosis is important in order to treat the patient correctly.
This Master’s thesis aimed to determine the current prevalence and specific allergens of birch pollen
allergy in adults living in South-West Finland and suffering from significant symptoms of seasonal rhinitis or rhinoconjunctivitis, suspected on clinical grounds to be caused by allergy to birch pollen. The study included 148 volunteers (44 males and 104 females). A component analysis was performed to explore the presence of specific IgE antibodies against Bet v 1, other major birch pollen allergens (Bet v2 and Bet v 4) and several other known main airborne and food allergens in the Finnish adult population. Most (84 %) of the subjects were positive (positivity threshold, serum IgE concentration ≥ 0.35 kUA/L) for at least one specific IgE species against plant- or animal-derived allergens, and 80 % of the study participants were found to be sensitized to birch pollen, according to the serum IgE analysis. Specific IgE antibodies against Bet v 1 were observed in almost all participants who were IgE-positive for birch pollen antigens as a group (116 of 118 subjects). In 24 subjects (16 %), no IgE- based allergy diagnosis could be established. 30 subjects (20 %) were negative for IgE against birch pollen.
The average IgE concentration tended to be lower in older subjects. The mean IgE concentration of airborne allergens in the youngest age group (18-29 years) was significantly higher (p<0.0001) than in the oldest age group (50-65 years). No difference was observed between male and female subjects.
Many subjects who were found to be sensitized to food allergens had IgE antibodies against allergens that are known to cause cross-reactivity with birch pollen, for example, soy component Gly m 4 and peanut component Ara h 8. It has been previously shown that IgE antibodies to Gly m 4 and Ara h 8 allergens are generally due to sensitization to birch pollen since these allergens are Bet v 1 homologs, all belonging to the PR-10 protein family.
Based on the current results, it remains relevant to include specific serum IgE analysis in the diagnostic work-up of persons presenting with interfering symptoms of rhinitis or rhinoconjunctivitis during the birch pollen season and being considered for initiation of allergen immunotherapy with Bet v 1 –targeted products.