Fanny W.S. Ko

Proinflammatory cytokines (IL‐17, IL‐6, IL‐18 and IL‐12) and Th cytokines (IFN‐γ, IL‐4, IL‐10 and IL‐13) in patients with allergic asthma

Allergen‐reactive T helper type‐2 (Th2) cells and proinflammatory cytokines have been suggested to play an important role in the induction and maintenance of the inflammatory cascade in allergic asthma. We compared the plasma concentrations of novel proinflammatory cytokines IL‐17 and IL‐18, other proinflammatory cytokines IL‐6 and IL‐12, Th2 cytokines IL‐10 and IL‐13, and intracellular interferon‐γ (IFN‐γ) and IL‐4 in Th cells of 41 allergic asthmatics and 30 sex‐ and age‐matched health control subjects. Plasma cytokines were measured by enzyme‐linked immunosorbent assay. Intracellular cytokines were quantified by flow cytometry. Plasma IL‐18, IL‐12, IL‐10, IL‐13 concentrations were significantly higher in allergic asthmatic patients than normal control subjects (IL‐18: median 228·35 versus 138·72 pg/ml, P < 0·001; IL‐12: 0·00 versus 0·00 pg/ml, P = 0·001; IL‐10: 2·51 versus 0·05 pg/ml, P < 0·034; IL‐13: 119·38 versus 17·89 pg/ml, P < 0·001). Allergic asthmatic patients showed higher plasma IL‐17 and IL‐6 concentrations than normal controls (22·40 versus 11·86 pg/ml and 3·42 versus 0·61 pg/ml, respectively), although the differences were not statistically significant (P = 0·077 and 0·053, respectively). The percentage of IFN‐γ‐producing Th cells was significantly higher in normal control subjects than asthmatic patients (23·46 versus 5·72%, P < 0·001) but the percentage of IL‐4 producing Th cells did not differ (0·72 versus 0·79%, P > 0·05). Consequently, the Th1/Th2 cell ratio was significantly higher in normal subjects than asthmatic patients (29·6 versus 8·38%, P < 0·001). We propose that allergic asthma is characterized by an elevation of both proinflammatory and Th2 cytokines. The significantly lower ratio of Th1/Th2 cells confirms a predominance of Th2 cells response in allergic asthma.

Temporal relationship between air pollutants and hospital admissions for chronic obstructive pulmonary disease in Hong Kong

Aims: To assess any relationship between the levels of ambient air pollutants and hospital admissions for chronic obstructive pulmonary disease (COPD) in Hong Kong. Methods: A retrospective ecological study was undertaken. Data of daily emergency hospital admissions to 15 major hospitals in Hong Kong for COPD and indices of air pollutants (sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), particulates with an aerodynamic diameter of <10 μm (PM10) and 2.5 μm (PM2.5)) and meteorological variables from January 2000 to December 2004 were obtained from several government departments. Analysis was performed using generalised additive models with Poisson distribution, adjusted for the effects of time trend, season, other cyclical factors, temperature and humidity. Autocorrelation and overdispersion were corrected. Results: Significant associations were found between hospital admissions for COPD with all five air pollutants. Relative risks for admission for every 10 μg/m3 increase in SO2, NO2, O3, PM10 and PM2.5 were 1.007, 1.026, 1.034, 1.024 and 1.031, respectively, at a lag day ranging from lag 0 to cumulative lag 0–5. In a multipollutant model, O3, SO2 and PM2.5 were significantly associated with increased admissions for COPD. SO2, NO2 and O3 had a greater effect on COPD admissions in the cold season (December to March) than during the warm season. Conclusion: Ambient concentrations of air pollutants have an adverse effect on hospital admissions for COPD in Hong Kong, especially during the winter season. This might be due to indoor exposure to outdoor pollution through open windows as central heating is not required in the mild winter. Measures to improve air quality are urgently needed.

Factors associated with difference in prevalence of asthma in children from three cities in China: multicentre epidemiological survey

Abstract Objective To determine the factors associated with difference in prevalence of asthma in children in different regions of China. Design Multicentre epidemiological survey. Setting Three cities in China. Participants 10 902 schoolchildren aged 10 years. Main outcome measures Asthma and atopic symptoms, atopic sensitisation, and early and current exposure to environmental factors. Results Children from Hong Kong had a significantly higher prevalence of wheeze in the past year than those from Guangzhou and Beijing (odds ratio 1.64, 95% confidence interval 1.35 to 1.99). Factors during the first year of life and currently that were significantly associated with wheeze were cooking with gas (odds ratio 2.04, 1.34 to 3.13), foam pillows (2.58, 1.66 to 3.99), and damp housing (1.89, 1.26 to 2.83). Factors protecting against wheeze were cotton quilts and the consumption of fruit and raw vegetables. Conclusion Environmental factors and diet may explain the differences in prevalence of asthma between children living in different regions of China.

Nasal CPAP reduces systemic blood pressure in patients with obstructive sleep apnoea and mild sleepiness

Background: A randomised controlled study was undertaken to examine the effect of nasal continuous positive airway pressure (CPAP) on 24 hour systemic blood pressure (BP) in patients with obstructive sleep apnoea (OSA). Methods: Patients were fitted with an ambulatory BP measuring device as outpatients during normal activities and recorded for 24 hours before starting therapeutic or subtherapeutic (4 cm H2O) CPAP treatment. BP monitoring was repeated before completion of 12 weeks of treatment. The primary end point was the change in 24 hour mean BP. Results: Twenty three of 28 participants in each treatment arm completed the study. There was no significant difference between the two groups in age, body mass index, Epworth Sleepiness Score, apnoea-hypopnoea index, arousal index, and minimum Sao2. Twenty four patients were hypertensive. The pressure in the therapeutic CPAP group was 10.7 (0.4) cm H2O. CPAP usage was 5.1 (0.4) and 2.6 (0.4) hours/night for the therapeutic and subtherapeutic CPAP groups, respectively (p<0.001). After 12 weeks of treatment there were significant differences between the two CPAP groups in mean (SE) changes in 24 hour diastolic BP (−2.4 (1.2) v 1.1 (1.0) mm Hg (95% CI −6.6 to −0.5), p = 0.025); 24 hour mean BP (−2.5 (1.3) v 1.3 (1.1) mm Hg (95% CI −7.2 to −0.2), p = 0.037); sleep time systolic BP (−4.1 (2.1) v 2.2 (1.8) mm Hg (95% CI −11.8 to −0.7), p = 0.028); and sleep time mean BP (−3.6 (1.7) v 1.3 (1.4) mm Hg (95% CI −9.2 to −0.4), p = 0.033). Conclusions: Compared with subtherapeutic CPAP, 12 weeks of treatment with therapeutic CPAP leads to reductions in 24 hour mean and diastolic BP by 3.8 mm Hg and 3.5 mm Hg, respectively, in mildly sleepy patients with OSA.

Air pollution and chronic obstructive pulmonary disease.

Limited data suggest that outdoor air pollution (such as ambient air pollution or traffic‐related air pollution) and indoor air pollution (such as second‐hand smoking and biomass fuel combustion exposure) are associated with the development of chronic obstructive pulmonary disease (COPD), but there is insufficient evidence to prove a causal relationship at this stage. It also appears that outdoor air pollution is a significant environmental trigger for acute exacerbation of COPD, leading to increasing symptoms, emergency department visits, hospital admissions and even mortality. Improving ambient air pollution and decreasing indoor biomass combustion exposure by improving home ventilation are effective measures that may substantially improve the health of the general public.

Temporal relationship between air pollution and hospital admissions for asthmatic children in Hong Kong.

Background Many epidemiological studies have shown positive association between respiratory health and current levels of outdoor air pollution in Europe and America.

Viral Etiology of Acute Exacerbations of COPD in Hong Kong

Introduction Viral respiratory infections may precipitate acute exacerbations of COPD (AECOPD). However, little is known about viral etiology related to AECOPD in Asia. We aimed to study the viral etiology of AECOPD in Hong Kong. Methods Patients admitted to an acute hospital in Hong Kong with AECOPD were recruited prospectively from May 1, 2004, to April 30, 2005. Nasopharyngeal aspirate was collected and assessed by polymerase chain reaction (PCR) and viral culture. Spirometry was performed in the stable phase at 2 to 3 months after hospital discharge. Results There were 262 episodes of AECOPD among 196 patients (mean age, 75.7 ± 7.7 years [± SD]; 160 men). Mean FEV1 was 39.6 ± 18.9% of predicted normal, and FEV1/FVC ratio was 58.0 ± 15.2%. Fifty-eight episodes (22.1%) yielded positive viral PCR results. The viruses identified were influenza A (7.3%), coronavirus OC43 (4.6%), rhinovirus (3.1%), influenza B (2.7%), and respiratory syncytial virus (2.3%). The diagnostic yield of viral identification by PCR was 2.7 times higher than that based on conventional viral culture. The rates of identifying a positive viral etiology by PCR were similar among the subjects with FEV1 ≥ 50%, ≥ 30 to 50%, and < 30% of predicted normal. Viral infection appeared to have no effect on subsequent readmissions or mortality rate over a study period of 1 year Conclusion Influenza A and two less-attended viruses, coronavirus OC43 and rhinovirus, were the common etiologic agents in patients hospitalized with AECOPD in Hong Kong. These should be considered in developing diagnostic and intervening strategies pertaining to AECOPD.

Validation of Embletta portable diagnostic system for identifying patients with suspected obstructive sleep apnoea syndrome (OSAS)

Background and objectives:  This study aimed to evaluate the diagnostic accuracy of Embletta portable diagnostic system (PDS, Medcare, Reykjavik, Iceland) for the screening of sleep apnoea in clinical practice.

Changing Prevalence of Allergic Diseases in the Asia-Pacific Region

Asia-Pacific is one of the most densely populated regions of the world and is experiencing rapid economic changes and urbanization. Environmental pollution is a significant problem associated with the rapid modernization of many cities in South Asia. It is not surprising that the prevalences of asthma and allergies are increasing rapidly, although the underlying reasons remain largely unknown. Many studies from this region have documented the changing prevalence of allergic diseases in various parts of the world. However, the methodologies used were neither standardized nor validated, making the results difficult to evaluate. The International Study of Asthma and Allergies in Childhood (ISAAC) has provided a global epidemiology map of asthma and allergic diseases, as well as the trend of changes in the prevalence of these diseases. Allergic sensitization is extremely common in many Asian communities. However, the prevalence of allergic diseases remains relatively rare. The rapid urbanization in the region, which increases environmental pollution and can affect the rural environment, will likely increase the prevalence of asthma and allergies in Asia.

Clinical and atopic parameters and airway inflammatory markers in childhood asthma: a factor analysis

Background: Recent studies have repeatedly shown weak correlations among lung function parameters, atopy, exhaled nitric oxide level (Feno), and airway inflammatory markers, suggesting that they are non-overlapping characteristics of asthma in adults. A study was undertaken to determine, using factor analysis, whether the above features represent separate dimensions of childhood asthma. Methods: Clinically stable asthmatic patients aged 7–18 years underwent spirometric testing, methacholine bronchial challenge, blood sampling for atopy markers and chemokine levels (macrophage derived chemokine (MDC), thymus and activation regulated chemokine (TARC), and eotaxin), Feno, and chemokines (MDC and eotaxin) and leukotriene B4 measurements in exhaled breath condensate (EBC). Results: The mean (SD) forced expiratory volume in 1 second (FEV1) and Feno of 92 patients were 92.1 (15.9)% predicted and 87.3 (65.7) ppb, respectively. 59% of patients received inhaled corticosteroids. Factor analysis selected four different factors, explaining 55.5% of total variance. The Kaiser-Meyer-Olkin measure of sampling adequacy was 0.587. Plasma total and specific IgE levels, peripheral blood eosinophil percentage, and Feno loaded on factor 1; plasma TARC and MDC concentrations on factor 2; MDC, eotaxin and leukotriene B4 concentrations in EBC on factor 3; and plasma eotaxin concentration together with clinical indices including body mass index and disease severity score loaded on factor 4. Post hoc factor analyses revealed similar results when outliers were excluded. Conclusions: The results suggest that atopy related indices and airway inflammation are separate dimensions in the assessment of childhood asthma, and inflammatory markers in peripheral blood and EBC are non-overlapping factors of asthma.