Seasonal variation in bronchial hyperreactivity (BHR) in allergic patients

Performance Characteristics of Spirometry With Negative Bronchodilator Response and Methacholine Challenge Testing and Implications for Asthma Diagnosis

BACKGROUND

In patients with a history suggestive of asthma, diagnosis is usually confirmed by spirometry with bronchodilator response (BDR) or confirmatory methacholine challenge testing (MCT).

RESEARCH QUESTION

We examined the proportion of participants with negative BDR testing who had a positive MCT (and its predictors) result and characteristics of MCT, including effects of controller medication tapering and temporal variability (and predictors of MCT result change), and concordance between MCT and pulmonologist asthma diagnosis.

STUDY DESIGN AND METHODS

Adults with self-reported physician-diagnosed asthma were recruited by random-digit dialing across Canada. Subjects performed spirometry with BDR testing and returned for MCT if testing was nondiagnostic for asthma. Subjects on controllers underwent medication tapering with serial MCTs over 3 to 6 weeks. Subjects with a negative MCT (the provocative concentration of methacholine that results in a 20% drop in FEV₁ [PC₂₀] > 8 mg/mL) off medications were examined by a pulmonologist and had serial MCTs after 6 and 12 months.

RESULTS

Of 500 subjects (50.5 ± 16.6 years old, 68.0% female) with a negative BDR test for asthma, 215 (43.0%) had a positive MCT. Subjects with prebronchodilator airflow limitation were more likely to have a positive MCT (OR, 1.90; 95% CI, 1.17-3.04). MCT converted from negative to positive, with medication tapering in 18 of 94 (19.1%) participants, and spontaneously over time in 25 of 165 (15.2%) participants. Of 231 subjects with negative MCT, 28 (12.1%) subsequently received an asthma diagnosis from a pulmonologist.

INTERPRETATION

In subjects with a self-reported physician diagnosis of asthma, absence of bronchodilator reversibility had a negative predictive value of only 57% to exclude asthma. A finding of spirometric airflow limitation significantly increased chances of asthma. MCT results varied with medication taper and over time, and pulmonologists were sometimes prepared to give a clinical diagnosis of asthma despite negative MCT. Correspondingly, in patients for whom a high clinical suspicion of asthma exists, repeat testing appears to be warranted.

Respiratory Allergic Disorders

Allergic asthma refers to a chronic reversible bronchoconstriction influenced by an allergic trigger, leading to symptoms of cough, wheezing, shortness of breath, and chest tightness. Allergic bronchopulmonary aspergillosis is a complex hypersensitivity reaction, often in patients with asthma or cystic fibrosis, occurring when bronchi become colonized by Aspergillus species. The clinical picture is dominated by asthma complicated by recurrent episodes of bronchial obstruction, fever, malaise, mucus production, and peripheral blood eosinophilia. Hypersensitivity pneumonitis is a syndrome associated with lung inflammation from the inhalation of airborne antigens, such as molds and dust.

Co-existence and seasonal variation in rhinitis and asthma symptoms in patients with asthma

BACKGROUND

Asthma and rhinitis are common diseases that often occur concomitantly. However, in patients with asthma, the concurrent assessment of seasonal variation in rhinitis and asthma symptoms has not been comprehensively addressed. We prospectively evaluated seasonal changes in rhinitis and asthma symptoms over one year.

METHODS

Fifty-six patients with asthma were enrolled. Asthma and rhinitis symptoms were assessed by using the State of the Impact of Allergic Rhinitis on Asthma Control (SACRA) questionnaire, developed and validated in Japan by the committee　of Global Initiative for Asthma and the committee of Allergic Rhinitis for asthma and its impact on Asthma.

RESULTS

Fifty-three patients completed the study. Forty-five patients (85%) had nasal symptoms during at least one or more seasons and 15 patients (28%) had perennial rhinitis. The association between asthma symptoms and rhinitis symptoms, assessed by a visual analogue scale (VAS), was significant during each season; seasonal variations of symptoms were synchronous. Uncontrolled asthma was more prevalent in patients with moderate-to-severe rhinitis compared to those with mild rhinitis. The VAS score of asthma symptoms in patients with asthma and perennial rhinitis was significantly higher than that in patients with non-perennial rhinitis or without rhinitis, across every season, except for spring. Correlations were more significantn patients less than 65 years of age than in older patients.

CONCLUSION

Rhinitis is common in patients with asthma. Symptoms of rhinitis and asthma often co-exist, and the association between these symptoms may be stronger n younger patients with asthma than older.

Exhaled particles as markers of small airway inflammation in subjects with asthma

Exhaled breath contains suspended particles of respiratory tract lining fluid from the small airways. The particles are formed when closed airways open during inhalation. We have developed a method called Particles in Exhaled air (PExA^® ) to measure and sample these particles in the exhaled aerosol. Here, we use the PExA^® method to study the effects of birch pollen exposure on the small airways of individuals with asthma and birch pollen allergy. We hypothesized that birch pollen-induced inflammation could change the concentrations of surfactant protein A and albumin in the respiratory tract lining fluid of the small airways and influence the amount of exhaled particles. The amount of exhaled particles was reduced after birch pollen exposure in subjects with asthma and birch pollen allergy, but no significant effect on the concentrations of surfactant protein A and albumin in exhaled particles was found. The reduction in the number of exhaled particles may be due to inflammation in the small airways, which would reduce their diameter and potentially reduce the number of small airways that open and close during inhalation and exhalation.

Long-term intense exposure to grass pollen can mask positive effects of allergenic immunotherapy on non-specific bronchial hyperresponsiveness

INTRODUCTION

There are many potential factors that can modulate bronchial reactivity, including exposure to allergens, viral infections, and medications. The aim of this study was to analyze the effect of grass pollination intensity on the bronchial reactivity in seasonal allergic rhinitis (SAR) patients subjected to subcutaneous allergenic immunotherapy (SCIT).

MATERIAL AND METHODS

This study, performed between 2005 and 2008, included 41 patients with confirmed sensitivity to grass pollens and predominating symptoms of SAR, randomly assigned to desensitization by pre-seasonal or maintenance SCIT. Bronchial provocation challenge with histamine was performed before the onset of immunotherapy, and repeated three times after each pollen season covered by this study. Bronchial reactivity was analyzed with regard to grass pollination intensity in 2005-2008 (air concentration of grass pollen grains, seasonal number of days when air concentration of grass pollen reached at least 20 or 50 grains per 1 m(3)).

RESULTS

After 3 years of SCIT, a significant decrease in bronchial responsiveness was observed in the analyzed group as confirmed by an increase in PC20 FEV1 histamine values (p = 0.001). An inverse tendency was observed after 2 years of SCIT, however. This second year of SCIT corresponded to the 2007 season, when a significantly higher number of days with at least 50 grains of pollen per 1 m(3) of air was recorded.

CONCLUSIONS

FLUCTUATIONS IN POLLINATION INTENSITY OBSERVED DURING CONSECUTIVE YEARS OF IMMUNOTHERAPY CAN INFLUENCE BRONCHIAL REACTIVITY IN PATIENTS SUBJECTED TO SCIT (ISRCTN REGISTER: ISRCTN 86562422).

Effects of pollen season on central and peripheral nitric oxide production in subjects with pollen asthma

BACKGROUND

Pollen exposure of allergic subjects with asthma causes increased nitric oxide (NO) in exhaled air (FENO) suggestive of increased airway inflammation. It is, however, unclear to what extent NO production in peripheral airways and alveoli are involved.

OBJECTIVES

The aim of the present investigation was to analyze the relationship between central and peripheral components of FENO to clarify the distribution of pollen induced inflammation in asthma.

SUBJECTS AND METHODS

13 pollen allergic non-smoking subjects with mild-intermittent asthma and 12 healthy non-smoking control subjects were examined with spirometry and FENO at flows between 50 and 270 mL/s during and out of pollen season.

RESULTS

Spirometry was normal and unaffected by season in subjects with asthma as well as controls. Out of season subjects with asthma had significantly higher FENO, elevated airway production (JáwNO) and preacinar/acinar production (CANO) than controls. Pollen exposure resulted in significantly increased FENO and JáwNO but not CANO. FENO among controls were not affected by season. Individual results showed, however, that CANO increased substantially in a few subjects with asthma. The increased CANO in subjects with asthma may be explained by increased NO production in preacinar/acinar airways and back diffusion towards the alveoli.

CONCLUSIONS

The findings may indicate that subjects with allergic asthma have airway inflammation without alveolar involvement outside the pollen season and pollen exposure causes a further increase of airway inflammation and in a few subjects obstruction of intra acinar airways causing impeded back diffusion. Increased NO production in central airways, unassociated with airway obstruction could be an alternative explanation. These effects were not disclosed by spirometry.

The influence of sensitisation to pollens and moulds on seasonal variations in asthma attacks

No large study has described the seasonal variation in asthma attacks in population-based asthmatics in whom sensitisation to allergen has been measured.

2637 young adults with asthma living in 15 countries reported the months in which they usually had attacks of asthma and had skin-prick tests performed. Differences in seasonal patterns by sensitisation status were assessed using generalised estimating equations.

Most young adults with asthma reported periods of the year when their asthma attacks were more common (range: 47% in Sweden to 86% in Spain). Seasonal variation in asthma was not modified by sensitisation to house dust mite or cat allergens. Asthmatics sensitised to grass, birch and Alternaria allergens had different seasonal patterns to those not sensitised to each allergen, with some geographical variation. In southern Europe, those sensitised to grass allergens were more likely to report attacks occurred in spring or summer than in winter (OR March/April 2.60, 95% CI 1.70–3.97; OR May/June 4.43, 95% CI 2.34–8.39) and smaller later peaks were observed in northern Europe (OR May/June 1.25, 95% CI 0.60–2.64; OR July/August 1.66, 95% CI 0.89–3.10). Asthmatics reporting hay fever but who were not sensitised to grass showed no seasonal variations.

Seasonal variations in asthma attacks in young adults are common and are different depending on sensitisation to outdoor, but not indoor, allergens.

Seasonal variation in asthma attacks is associated with sensitisation to pollens and moulds, but not indoor allergenshttp://ow.ly/nsuRS

Photoperiod-driven variation in an allergic response is independent of allergen exposure

Allergy prevalence and severity varies seasonally in humans, presumably due to intra-annual changes in allergen exposure. However, it is possible that seasonality of allergic responses is also influenced by seasonal changes in the immune system. Here, we asked whether extended exposure to different day lengths would alter allergic responses to pentadecylcatechol (PDC), an allergenic component of poison ivy ( Toxicodendron radicans (L.) Kuntze), in Siberian hamsters ( Phodopus sungorus (Pallas, 1773)), a species exhibiting extensive seasonal variation in immune functions. We found that contact dermatitis responses were larger in short day-length (SD) housed animals than in long day-length (LD) housed animals even though sensitization and challenge dosages of allergen were identical. Furthermore, SD animals were smaller and had regressed reproductive tissues compared with LD animals, results typically observed in this species in response to photoperiod. These data suggest that endogenous changes in immune functions, perhaps via melatonin, may underlie some seasonal variation in allergic responses.

Seasons can influence the results of the methacholine challenge test

OBJECTIVE

This study tried to evaluate whether a methacholine test may be influenced by the seasons.

METHODS

We considered 4826 consecutive subjects with normal spirometry (50.53% males; age: 35.1±16.2; forced expiratory volume in one second: 99.5±13.0%) who underwent a methacholine test for suspected asthma symptoms between 2000 and 2010. They were subdivided into four groups, like the seasons, according to the test dates.

RESULTS

A total of 1981 (41%) resulted normal (no PD(20) was obtained with 2400 μg of methacholine); the others showed a mean LogPD(20) of 2.52±0.5 μg. The number of subjects with bronchial hyper-responsiveness (BHR) found in autumn (789, 62.3%) was higher than in summer (583, 56.7%; P=0.03). A higher number of females and overweight/obese subjects showed a BHR in autumn compared with the other seasons. The spring mean LogPD(20) value (2.48±0.48 μg) was lower if compared with the one measured in summer (2.59±0.49 μg; P=0.05). LogPD(20) value was lower in females and non-smokers in spring compared with summer (P<0.05). Overweight/obese non-smokers showed a lower LogPD(20) in spring and autumn compared with that in summer (P<0.05). Autumn was a risk factor (OR: 1.378; P=0.001) for BHR (using a PD(20) <2 400 μg as BHR limit), while spring (OR: 1.330; P=0.021) and autumn (OR: 1.331; P=0.020) were risk factors for a more severe BHR (using a PD(20) <400 μg as BHR limit).

CONCLUSION

There was a higher probability of finding BHR in outpatients with suspected asthma in autumn and spring compared with summer. Spring is the season where BHR may be more severe. Females and overweight/obese subjects were those mainly involved in this seasonal variability of BHR.

Allergic rhinitis

Allergic rhinitis is a very common disorder that affects people of all ages, peaking in the teenage years. It is frequently ignored, underdiagnosed, misdiagnosed, and mistreated, which not only is detrimental to health but also has societal costs. Although allergic rhinitis is not a serious illness, it is clinically relevant because it underlies many complications, is a major risk factor for poor asthma control, and affects quality of life and productivity at work or school. Management of allergic rhinitis is best when directed by guidelines. A diagnostic trial of a pharmacotherapeutic agent could be started in people with clinically identified allergic rhinitis; however, to confirm the diagnosis, specific IgE reactivity needs to be recorded. Documented IgE reactivity has the added benefit of guiding implementation of environmental controls, which could substantially ameliorate symptoms of allergic rhinitis and might prevent development of asthma, especially in an occupational setting. Many classes of drug are available, effective, and safe. In meta-analyses, intranasal corticosteroids are superior to other treatments, have a good safety profile, and treat all symptoms of allergic rhinitis effectively. First-generation antihistamines are associated with sedation, psychomotor retardation, and reduced academic performance. Only immunotherapy with individually targeted allergens has the potential to alter the natural history of allergic rhinitis. Patients' education is a vital component of treatment. Even with the best pharmacotherapy, one in five affected individuals remains highly symptomatic, and further research is needed in this area.

Seasonal variability of the methacholine challenge test

BACKGROUND

Since the intensity of some variables that influence bronchial hyper-responsiveness (BHR) varies across different seasons of the year, the percentage of positive metacholine challenge test (MCT) is theoretically subjected to seasonal variation. This study has looked at the seasonal variability of MCT among young adults with suspected asthma.

METHODS

The number of MCT performed and its corresponding proportion of positive results were retrospectively evaluated and compared for different seasons over a 5-year period.

RESULTS

Overall 645 subjects (mean age 21.4 +/- 2.3 yr) underwent MCT during the study period. Two-hundred nine MCTs (34.2%) were performed in the winter, significantly higher when compared to any other season of the year. Positive MCT (defined as PC(20) < 16 mg/mL) was noted in 163 patients (25.2%). The proportion of positive MCTs has shown significant seasonal trend, (p < 0.0001, chi-square test for trend), it was significantly higher in the winter and in the spring (32.2% and 32.4%, respectively) when compared with the summer (13.4%).

CONCLUSIONS

This study showed a significant seasonal variability for both pattern of referral to MCT and the seasonal prevalence of BHR young adults. These findings probably reflect seasonal variation in the intensity of external stimuli that involve in the pathogenesis of BHR, such as allergens burden and respiratory tract infections across the year. We suggest that interpretation of a positive MCT as predictive of BHR and of asthma should take into account the observed seasonal variability of the test.

Bronchodilator response after negative methacholine challenge test predicts future diagnosis of asthma

BACKGROUND

Currently there are no reliable means to predict the likelihood of a subject with negative results from a methacholine challenge test (MCT) to be diagnosed with asthma in the future. We sought to determine whether the magnitude of the response to bronchodilator (BD) administered after a negative MCT has a predictive value for future asthma.

METHODS

Over a 5 -year period, starting from January 2004, the change in the forced expiratory volume in 1 second (FEV(1)) after inhaling BD (salbutamol) was recorded among subjects with negative MCT despite symptoms suggestive of asthma such as wheezing and dyspnea. Subjects with a significant response to BD (defined as improvement in FEV(1) of more than 200 ml and 12%) were questioned for the presence of asthma on January 2009.

RESULTS

Overall 645 subjects (mean age 21.4 +/- 2.3 years) underwent MCT. Negative MCT (defined as PC(20) > 16 mg/mL) was noted in 482 (74.7%) patients of whom significant response to BD was identified in 35. Over a median observation time of 2.1 years, 11 of them (31.4% of the study population and 1.7% of the entire cohort) were subsequently diagnosed with asthma. Improvement of FEV(1) by 20% predicted asthma with sensitivity, specificity, and positive predictive values of 86.9%, 66.6%, 83.3%, respectively, p = 0.0022.

CONCLUSIONS

Our findings suggest that administration of BD after a negative MCT enhances the diagnostic accuracy of the challenge test as it identifies subjects who are likely to develop clinical asthma in the future.

Airway hyperresponsiveness: a comparative study of methacholine and exercise challenges in seasonal allergic rhinitis with or without asthma

BACKGROUND

Asymptomatic airway hyperreactivity in allergic rhinitis is a risk factor for later development of asthma. Although non-specific bronchial hyperresponsiveness (BHR) has been measured by several stimuli, the most appropriate measurement technique still remains unclear.

OBJECTIVE

To investigate whether an exercise challenge can be used to predict BHR in seasonal allergic rhinitis patients with or without asthma and to compare this bronchial reactivity with a methacholine challenge technique.

METHODS

Forty-six consecutive patients with seasonal allergic rhinitis only (n = 31) and with both seasonal allergic rhinitis and asthma (n = 15) were included in the study during the pollination period. Subjects underwent first methacholine (mch) and then exercise challenge testing (ECT). There was a 1-week interval between the tests. ECT was performed on a bicycle ergometer. Positive result was defined as a 15% decrease in forced expiratory volume in 1 second (FEV(1)) post-exercise. A patient's bronchial reactivity to methacholine was considered as hyperresponsive if PC(20) was less than 8 mg/mL.

RESULTS

Mch PC(20) values were significantly lower in patients with both rhinitis and asthma (p < 0.062). Among the 46 patients, mch PC(20) values were significantly different between patients who had positive and negative exercise challenge tests (p = 0.007). All patients with rhinitis alone had a negative ECT and 10 had a positive mch challenge. Change in FEV(1) values after ECT was significantly higher in patients with both rhinitis and asthma compared to those with rhinitis alone (p = 0.009). There was a significant relation between positivity of mch and exercise challenges (p = 0.025). ECT positivity was found to be a significant confounding factor in the diagnosis of asthma (p = 0.001). Specificity and sensitivity values were 100% and 24% for ECT and 68% and 100% for mch, respectively.

CONCLUSION

Exercise challenge presents poor diagnostic value for detecting bronchial responsiveness in individuals with allergic rhinitis alone during the pollen season.

Seasonal patterns of controller and rescue medication dispensed in underserved children with asthma

OBJECTIVE

To determine whether temporal trends exist for short-acting beta agonist (SABA), oral corticosteroid (OCS), and anti-inflammatory prescription fills in children with persistent asthma.

METHOD

This was a longitudinal analysis of pharmacy record data and health information data obtained by parent report over 12 months for children with persistent asthma 2 to 9 years of age. Eligible children had to report current nebulizer use and one or more emergency department visits or hospitalizations within the past 12 months.

RESULTS

Children were primarily African-American (89%), male (64%), received Medicaid health insurance (82%), and were a mean age of 4.5 years (SD 2.1). Few families (11%) reported any problems paying for their child's asthma medications at baseline or at the 12-month follow-up. There was a high degree of association between filling a rescue (SABA or OCS) and controller (leukotriene modifier, inhaled corticosteroid, cromolyn) medication during the same month for all months with Pearson's correlation coefficients ranging from a low of 0.28 for October to a high of 0.53 in September. Short-acting beta agonist fills were significantly more likely to be filled concurrently with inhaled corticosteroid fills. However, significantly fewer prescription fills were obtained in the summer months with an acceleration of medication fills in September through December and an increase in early spring.

CONCLUSIONS

There was a summer decline in both inhaled corticosteroid and SABA fills. Timing of asthma monitoring visits to occur before peak prescription fill months, i.e., August and December for an asthma "tune-up," theoretically could improve asthma control. During these primary care visits children could benefit from more intensive monitoring of medication use including monitoring lung function, frequency of prescription refills, and assessment of medication device technique to ensure that an effective dose of medication is adequately delivered to the respiratory tract. Additionally, scheduling non-urgent asthma care visits at pre-peak prescription fill months can take advantage of "step down" during decreased symptom periods and when appropriate restart daily controller medications to "step up" prior to peak asthma periods.

Assessing individual employee risk factors for occupational asthma in primary aluminium smelting

AIMS

To assess the significance of individual risk factors in the development of occupational asthma of aluminium smelting (OAAS).

METHODS

A matched case-control study nested in a cohort of 545 workers employed in areas with moderate to high levels of smelting dust and fume. The cohort comprised those who had their first pre-employment medical examination between 1 July 1982 and 1 July 1995; follow up was until 31 December 2000. Forty five cases diagnosed with OAAS and four controls per case were matched for the same year of pre-employment and age within +/-5 years. The pre-employment medical questionnaires were examined, blinded as to case-control status, and information obtained on demographics and details of allergic symptoms, respiratory risk factors, respiratory symptoms, and spirometry. Data from the subsequent medical notes yielded subsequent history of hay fever, family history of asthma, full work history, date of termination or diagnosis, and tobacco smoking history at the end-point.

RESULTS

There was a significant positive association between hay fever diagnosed either at or during employment and OAAS (adjusted OR 3.58, 95% CI 1.57 to 8.21). A higher forced expiratory ratio (FEV1/FVC%) at employment reduced the risk of developing OAAS (adjusted OR 0.93, 95% CI 0.88 to 0.99). The risk of OAAS was more than three times higher in individuals with an FER of 70.0-74.9% than in individuals with an FER > or =80.0% (adjusted OR 3.46, 95% CI 1.01 to 11.89).

CONCLUSIONS

Individuals with hay fever may be more susceptible to occupational asthma when exposed to airborne irritants in aluminium smelting. The pathological basis may be reduced nasal filtration and increased bronchial hyperresponsiveness.

8. Occupational asthma and allergies

A diversity of airborne dusts, gases, fumes, and vapors can cause dose-related symptoms in individuals exposed in the workplace. More than 250 chemicals have been incriminated as a cause of occupational asthma (OA). The prevalence of OA ranges from 2% to 6% of the asthmatic population. Predisposing factors facilitating the development of OA include the work environment, climatic conditions, genetic proclivities, tobacco and recreational drug use, respiratory infection, and bronchial hyperresponsiveness. Pathogenetically, new-onset OA may be immunologic or nonimmunologic in origin. The immunologic variants are usually caused by high molecular-weight allergens such as grain dust and animal or fish protein. Symptoms ensue after a latent period of months to years. Nonimmunologic OA can be precipitated by a brief, high-level exposure to a potent irritant. Symptoms occur immediately or within a few hours of the exposure. In either instance, once the diagnosis is established, the worker should be removed from the workplace. If the diagnosis is made in a timely fashion, most workers experience improvement. Prevention is the best therapeutic intervention.

Mouldy houses influence symptoms of asthma among atopic individuals

BACKGROUND

The influence of current levels of indoor fungi on asthma is a controversial issue that needs to be resolved in order to advise patients appropriately.

OBJECTIVE

To assess the seasonal variation in indoor fungal levels and the impact of these levels on asthma among mould-sensitized individuals.

METHODS

Thirty-five young adults with current asthma and sensitization to fungi were visited four times over 1 year. At each home visit a questionnaire was administered and samples of dust and air were collected. Participants also recorded information on symptoms, peak expiratory flows (PEF) and medication use. Dust samples were analysed for house dust mite allergen (Der p 1) and total fungal biomass (ergosterol). Total and genus-specific fungal propagules were identified in air samples. Seasonal variation in allergen levels and significant independent effects of fungal levels on peak flow variability (PFV) were identified by repeated measures analysis of variance.

RESULTS

Significant seasonal variations were observed in viable airborne fungi, ergosterol levels in the floor dust and PFV. PFV correlated significantly with symptom scores and the dose of reliever medication. PFV was also significantly associated with smoking and visible mould. The association between visible mould and PFV was independent of season, smoking and the dose of reliever medication. However, there was no association between total fungi, specific fungi or ergosterol and PFV. Der p 1 levels had no significant influence on asthma, even in HDM-sensitized individuals.

CONCLUSIONS

Mouldy homes adversely influence asthma in asthmatics sensitized to fungi.

Seasonal pattern of early mortality and infectious complications in liver transplant recipients

Seasonal variation has been documented in the frequency and attributable mortality of a number of medical illnesses and infections in the nontransplantation setting. Whether similar trends exist in transplant recipients is not known. Seasonal rates of overall and early mortality and contributory variables stratified by season were assessed in 190 consecutive liver transplant recipients who underwent transplantation over a 10-year period. The frequency of infectious complications and rejection was also assessed and stratified by season of transplantation. Early (deaths occurring in the first year posttransplantation), but not overall, mortality correlated significantly with seasonality. Of patients with early mortality, 43% (13 of 30 patients) died in winter; 23% (7 of 30 patients), in spring; 13% (4 of 30 patients), in summer; and 20% (6 of 30 patients), in fall. The frequency of deaths in winter was significantly greater than for all other seasons (P = .022). The high wintertime mortality could not be explained by previously recognized risk factors portending a poor outcome, e.g., United Network for Organ Sharing status, Child-Pugh score, surgical time, blood loss, pretransplantation and posttransplantation dialysis, infections, rejection, or increased immunosuppression. Strong trends toward a higher rate of cytomegalovirus disease in patients who underwent transplantation in fall (P = .09) and bacterial infections in those who underwent transplantation in winter were documented (P = .09). There was no correlation between seasonality and rejection. Early mortality in winter in liver transplant recipients was significantly greater than if the deaths were totally random. Whether the seasonal clustering of deaths and infections is triggered by respiratory viruses, yet unrecognized viruses, or unknown exogenous factors remains to be determined.

History and future perspectives of treating asthma as a systemic and small airways disease

Asthma is an inflammatory disorder in which the small airways of the lung play an important role. There is also evidence for the systemic nature of asthma. No current method adequately measures small airways function alone. Therefore, a combination of functional and clinical parameters should be used to ensure that patients with asthma are adequately treated with due consideration of the small airways. Previously therapeutic strategies have focused on bronchodilation and attenuation of airway inflammation. While early oral therapies had the advantage of reaching the small airways and treating the systemic aspect of asthma, they were associated with serious side-effects. Inhaled therapies were therefore developed to limit these effects. However, inhaled therapies have the disadvantage of limited penetration into the peripheral airways and an inability to treat the systemic component of asthma. They are also associated with local and systemic side-effects. The future for asthma treatment is likely to be a systemically administered medication with few side-effects targeting disease-specific mediators. The leukotriene receptor antagonists and anti-IgE monoclonal antibodies are examples of such therapies and the emergence of other new strategies is awaited.

Is it important to perform pollen skin prick tests in the season?

BACKGROUND

Seasonal exposure to pollens causes the characteristic symptoms of respiratory allergy as well as an increase in specific IgE levels and inflammatory mediator release. However, little is known about the effect of natural allergen exposure on the skin test reactivity of patients with seasonal allergy.

OBJECTIVE

The aim of this study was to investigate the monthly variation in skin test reactions with pollen allergens during pollen season and its relation to pollen counts.

METHODS

Fifteen subjects with seasonal allergic rhinitis and/or asthma (4 male, 11 female) between the ages of 13 and 52 (mean 33.9 +/- 2.9) who lived in Ankara, Turkey were selected for this study. Patients were monitored from the beginning of March to the end of September 1997, and skin prick tests were performed using 5 grass, 12 tree, and 5 weed pollen allergen extracts every month. Atmospheric pollen grains were counted in the Ankara area between January and December, 1997.

RESULTS

There were small but statistically significant increases in tree pollen-induced wheal sizes in May when compared with other months (P < 0.05). Skin test reactivity was correlated with tree pollen counts (r = 0.978, P < 0.05). There was not a significant difference in skin test reactivity to grass and weed pollens between months.

CONCLUSIONS

Although skin test reactivity may be slightly greater to tree pollen during the tree pollen season, the timing of skin testing is not a critical determinant in patients with pollen allergy.

Cytokine expression in the lower airways of nonasthmatic subjects with allergic rhinitis: influence of natural allergen exposure

BACKGROUND

Natural exposure to pollen provokes an increase in airway responsiveness in nonasthmatic subjects with seasonal allergic rhinitis. This natural exposure may induce inflammatory cell recruitment and cytokine release, leading to lower airway inflammation.

OBJECTIVE

The aim of this study was to characterize lower airway inflammation in nonasthmatic pollen-sensitive subjects.

METHODS

We performed immunohistochemical tests on bronchial biopsy specimens from subjects with rhinitis who had no past or current history of asthma to evaluate cytokine expression and inflammatory cell numbers and activation both in and out of the pollen season.

RESULTS

The number of CD4(+), CD8(+), and CD45RO(+) lymphocyte subpopulations were significantly higher during the pollen season compared with the out-of-season period (P <.04). Furthermore, EG1(+) cells tended to increase after natural pollen exposure (P =.06). The number of IL-5(+) cells increased significantly after natural exposure to pollen compared with out-of-season numbers (P <.01). This increase in IL-5 expression was correlated with the numbers of CD3(+), CD4(+), CD45RO(+), and EG1(+) cells. The numbers of tryptase-positive, IFN-gamma(+), and IL-4(+) cells did not change after natural exposure.

CONCLUSION

This study showed that natural pollen exposure was associated with an increase in lymphocyte numbers, eosinophil recruitment, and IL-5 expression in the bronchial mucosa of nonasthmatic subjects with allergic rhinitis.