[The immunological parameters and risk factors for pollen-induced allergic rhinitis and asthma]

Naturally occurring exposure to pollen allergens causes symptoms of allergic rhinitis, conjunctivitis and asthma in susceptible individuals. It is, however, unknown why some subjects develop only an allergic rhinitis while others develop asthma as well. The aim of this study was to investigate the difference of immunological parameters in patients with pollen-induced seasonal allergic rhinitis (SAR) and asthma and to determine the risk factors for pollinosis with asthma. We evaluated the demographic and clinical characteristics of the patients, sensitisation pattern to tree-, grass- and weed-pollen and perennial inhalant allergens according to skin prick tests, allergic inflammation parameters (blood and nasal eosinophil count, serum IgE, eosinophil cationic protein levels) in and out of the pollinosis season. Logistic regression analysis was used to rate the effect of covariates on risk for pollinosis and asthma. One hundred and one patients (52 men and 49 women) aged 16-63 years (median 24 yrs.) with pollinosis symptoms were investigated. All patients suffered from moderate-severe seasonal allergic rhinitis, 96% from concomitant allergic conjunctivitis, 23.8% had seasonal asthma. The significant clinical and demographic risk factors for pollinosis with asthma were smoking (OR=15.4, p=0.003) and pollinosis season lasting more than 14 weeks (OR=5.6, p=0.02). The patients with seasonal allergic rhinitis alone were significantly more frequently sensitized to orchard grass (p=0.005), ragweed (p=0.02), lamb's quarter (p=0.05) allergens. During the season the blood eosinophil count raised in all patients (p<0.01). It was shown statistically that there were no differences between groups in blood and nasal eosinophil count, serum eosinophil cationic protein level. The patients with seasonal allergic rhinitis and asthma had higher levels of serum IgE during the season (p=0.05) and out of it (p=0.01). More than two times elevated serum IgE in acute and symptom-free period of pollinosis was considered as a significant risk factor for pollinosis with asthma (OR=3.5, p=0.04 and OR=3.4, p=0.03).

Pollinosis presented with seasonal asthma in 23.8% of cases. Our data indicate that patients with seasonal allergic rhinitis and asthma differ from the patients with seasonal allergic rhinitis alone according to higher serum IgE levels. Prolonged pollinosis season, smoking and high IgE levels increase the risk for seasonal asthma in pollen-induced allergic rhinitis subjects.