Bronchial Hyperreactivity Is Related To Airflow Limitation And Independent Of Allergen Exposure In Hay Fever Patients
G Ciprandi, I Cirillo, A Vizzaccaro, C Klersy, G Marseglia, E Pallestrini
allergen exposure, bronchial hyperreactivity, fef 25-75, hay fever, nasal airflow
G Ciprandi, I Cirillo, A Vizzaccaro, C Klersy, G Marseglia, E Pallestrini. Bronchial Hyperreactivity Is Related To Airflow Limitation And Independent Of Allergen Exposure In Hay Fever Patients. The Internet Journal of Asthma, Allergy and Immunology. 2004 Volume 4 Number 1.
in allergic rhinitis are caused by the IgE-dependent inflammatory cascade consequent to allergen exposure (1). There is close association between allergen exposure and inflammatory events in allergic rhinitis as evidenced by the concept of minimal persistent inflammation (2). In addition, allergen avoidance is typically characterized by the absence of both symptoms and nflammation as clearly demonstrated in hay fever patients outside the pollen season (3).
Moreover, the ARIA document provided clear evidence concerning the link between upper and lower airways (4). Allergic rhinitis and asthma frequently coexist as well; we reported that 77% of conscripts with respiratory allergy suffered from asthma associated with allergic rhinitis (5). Allergic rhinitis has been demonstrated to be a strong risk factor for the onset of asthma, mainly when BHR is present (6).
Very recently, we reported that hay fever patients frequently show early bronchial airflow impairment, as evidenced by low values of FEF 25-75, and BHR during the pollen season (7).
Thus, this study aimed at evaluating a group of hay fever subjects perceiving nasal symptoms alone to investigate the relationships among nasal TSS, nasal and bronchial airflow, and BHR both during and outside the pollen season.
Materials And Methods
The study was approved by the Institutional Review Board and an informed consent was obtained from each patient.
Forty-eight hay fever patients were prospectively and consecutively evaluated (all males, age 22.8 ± 5.4 years). All of them were Navy soldiers who were referred to the Navy Hospital for periodic fitness visit. Subjects were visited during the spring 2003.All of them were evaluated with rhinomanometry, spirometry and methacholine bronchial challenge during the pollen(which pollen season, is there only one?) (in our region the most important allergenic pollens are grasses, Parietaria and Betulaceae that have the peak during the spring) season, i.e. in the spring. Successively, all of them were re-evaluated outside the pollen season, i.e. in the winter, a season without pollens in our geographic area (3,7).
A detailed clinical history and a complete physical examination, including allergy evaluation, were performed. The patients were included in the study on the basis of a clinical history of seasonal(?Spring yes) allergic rhinitis and positive skin prick test only for pollens (including:
Nasal airflow was reported as the sum of recorded airflow through right and left nostrils in milliliter per second at a pressure difference of 150 Pa across the nasal passage. Four or more airflow measurements were performed for each patient and the mean was recorded when reproducible values were achieved.
Spirometry: spirometry was
Methacholine challenge: methacholine was administered using a dosimetric computerized apparatus (MEFAR MB3, Marcos, Italy), activated by the inhalator effort. Subjects inhaled progressively increasing doses of methacholine, starting from 30 µg until 1,200/ml µg in 11 steps. The procedure was stopped if and when the FEV1 fell by more than 20% from baseline. A computerized algorithm provided the provocation dose (PD20) value. If no response was obtained with the maximal cumulative dose of 1,200 µg/ml, the test was considered negative.
Statistical analysis: This was performed with Stata 8, using Mann Whithey U test to compare the absolute value? Or percent predicted? If percent predicted used, please provide reference values/equation(see ref 9) used percent predicted values of FEF 25th-75th between positive and negative BHR patients and a general linear model to assess the association of log-transformed MCH and FEF 25-75, TSS or nasal air flow. Pearson R was computed.
All rhinitics were consecutive subjects meeting the inclusion and exclusion criteria and agreeing to join the study. No adverse event was reported during the study.
With multivariate analysis, the association between MCH (log-transformed) and FEF 25-75 in patients with BHR proved both independent from season (p<0.001) and of a similar magnitude in both periods (p for interaction=0.603) (figure 2).
The present findings suggest some considerations concerning the link between upper and lower airways and the variations of respiratory parameters consequent on allergen exposure in patients with hay fever.
Firstly, BHR is detectable in more than 50% of patients and its prevalence is substantially independent of allergen exposure. BHR positive subjects showed lower FEF 25-75 values than BHR negative patients and this finding persists also outside the pollen season. There is moreover a significant relationship between FEF 25-75 values and BHR. FEF 25-75 has been proposed as a marker of small airways impairment (10) and we very recently demonstrated that reduced FEF 25-75 values and BHR were common findings in hay fever patients (7). It is noteworthy to underline that the relationship between FEF 25-75 and BHR is present also outside the pollen season. These results support the concept that BHR in hay fever constitutes a pathophysiologic event appearing to be independent of allergen exposure. Thus, whereas allergen exposure is the necessary event capable of inducing the occurrence of inflammation and symptoms, BHR appears to be a constant and independent variable.
Secondly, nasal symptom intensity and nasal airflow limitation are closely associated with BHR. This issue highlights the importance of upper airways in inducing and worsening BHR. It is of note that these relationships persist also outside the pollen season, probably as consequence of hypertrophic turbinates.
In conclusion, this study provides evidence that nasal symptoms and nasal airflow impairment as well as early bronchial airflow limitation are closely associated with BHR, whereas BHR is independent of allergen exposure in hay fever patients.
Giorgio Ciprandi, M.D. Allergologia - U.O. ORL Dipartimento Regionale Testa-Collo Padiglione Specialità (piano terzo) Ospedale San Martino Largo R. Benzi 10, 16132 Genoa, Italy Phone 00 39 10 5552124 FAX 00 39 10 5556682 E-mail email@example.com