Delineating residential macrophage heterogeneity in lung disease (P3282)

In healthy lungs, alveolar macrophages comprise >95% of the immune cells in the alveolar airspaces where they regulate local lung surfactant production and act as the primary sentinels of respiratory pathogens. Interestingly, increased AMΦ numbers are observed in many animal models of chronic lung diseases and also clinically in patients with COPD. Combining flow cytometry and chimeric mice studies, we observed that residential AMΦs form two distinct subpopulations (by either remaining Mac-1neg/low or turning Mac-1pos) during acute inflammation and in chronic inflammatory lung disease subsequent to SHIP-1 deletion. SHIP-1-/- mice which spontaneously develop COPD-like lung disease maintain both Mac-1neg/low and Mac-1pos AMΦ subpopulations. This additional Mac-1pos subpopulation highly expresses MMP-12 and tracks with the induction of lung disease using SHIP-1-/- chimeric mice. Altogether, our results suggest that residential AMΦ heterogeneity is a component of acute lung inflammation and chronic inflammatory lung disease. Consequently, whether residential AMΦ heterogeneity may be a novel hallmark of inflammation-driven human lung diseases has been our final area of study. Overall, our studies of both animal models and patient samples may allow us to better understand the role of AMΦ heterogeneity in lung homeostasis and disease.

Clinical and epidemiological profile of patients with severe H1N1/09 pandemic influenza in Australia and New Zealand: an observational cohort study

Background Pandemic influenza H1N1/09 emerged in April 2009 and spread widely in Australia and New Zealand. Although an unprecedented number of cases required intensive care, comparative community-based studies with seasonal influenza strains have not shown any significant differences in clinical symptoms or severity. Methods The authors performed active surveillance on confirmed influenza-related admissions and compared the clinical profile of patients with pandemic H1N1/09 influenza and patients with seasonal influenza at eight hospitals in Australia and one hospital in New Zealand. Results During the 1 July and 30 November 2009, 560 patients with confirmed influenza were admitted, of which 478 had H1N1/09, and 82 had other seasonal strains. Patients with H1N1/09 influenza were younger, were more likely to have fever and were more likely to be pregnant but less likely to have chronic obstructive pulmonary disease and ischaemic heart disease than patients with seasonal strains. Other clinical features and comorbidities were reported in similar proportions. Admission to intensive care was required in 22% of patients with H1N1/09 influenza and 12% in patients with other strains. Hospital mortality was 5% in patients with H1N1 influenza. Conclusions The clinical features of H1N1/09 influenza and seasonal strains were similar in hospitalised patients. A higher proportion of patients had comorbidities than had been reported in community-based studies. Although the overall mortality was similar, the authors found evidence that H1N1/09 caused severe disease in a higher proportion of hospitalised patients.

A hypothesis to phenotype COPD exacerbations by aetiology

COPD exacerbations have traditionally been defined on the basis of symptoms or health-care utilization without specific reference to the suspected aetiology. Consequently, the term 'exacerbation' has been used to include all patients experiencing an acute deterioration of symptoms associated with COPD. However, exacerbations are known to result from a variety of causes and do not necessarily constitute an equivalent event in the same patient, between different patients or between individual research studies. We therefore hypothesize that phenotyping exacerbations by aetiology may identify exacerbation subgroups, clarify benefits of therapeutic intervention in the subgroups and overall improve clinical care. An acronym is proposed to facilitate phenotyping COPD exacerbations.

Influenza A/H1N1_09: Australia and New Zealand's winter of discontent

Influenza A/H1N1_09 emerged in Mexico at the end of the Northern Hemisphere winter. Within weeks, the focus shifted to the Southern Hemisphere as the introduction of the novel virus coincided with the beginning of the influenza season. Intensive public health and health services planning had occurred in Australia and New Zealand as preparation for an influenza pandemic before 2009. However, this first pandemic wave was quite different to what had been expected. Key elements of the pandemic and response are outlined from the perspective of clinicians working at the frontline of patient care. In particular, they examine why past influenza pandemics and recent history are poor predictors of the current pandemic, the discordance between potential for transmission and disease severity, the broad clinical spectrum of H1N1_09 infection, clinical and health service management issues, and the relationship between health care and government policy. Finally, they address the need for the respiratory community to show leadership in times of crisis. Lessons learned in Australia and New Zealand during 2009 have important messages for similarly resourced countries in the Northern Hemisphere in the coming months as they face their own influenza season.

Influenza A (H1N1 09): public health lessons and questions

Influenza A (H1N1 09) has been in Australia for 2 months and, in a world that had been preparing for a potentially dramatic outbreak due to H5 avian influenza, it has challenged global and national planning assumptions, definitions of pandemic influenza and our public health interventions. It has also highlighted how much we have yet to learn about both pandemic and seasonal influenza.

The role of the bronchial provocation challenge tests in the diagnosis of exercise-induced bronchoconstriction in elite swimmers

BACKGROUND

The International Olympic Committee-Medical Commission (IOC-MC) accepts a number of bronchial provocation tests for the diagnosis of exercise-induced bronchoconstriction (EIB) in elite athletes, none of which have been studied in elite swimmers. With the suggestion of a different pathogenesis involved in the development of EIB in swimmers, there is a possibility that the recommended test for EIB in elite athletes, the eucapnic voluntary hyperpnoea (EVH) challenge, may be missing the diagnosis in elite swimmers.

OBJECTIVE

The aim of this study was to assess the effectiveness of the EVH challenge, the field swim challenge and the laboratory cycle challenge in the diagnosis of EIB in elite swimmers.

DESIGN

33 elite swimmers were evaluated on separate days for the presence of EIB using 3 different bronchial provocation challenge tests: an 8 minute field swim challenge, a 6 minute laboratory EVH challenge, and an 8 minute laboratory cycle challenge.

MAIN OUTCOME MEASUREMENTS

Change in forced expiratory volume in 1 second (FEV(1)) pre and post test protocol. A fall in FEV(1) from baseline of > or =10% post challenge was diagnostic of EIB.

RESULTS

Only 1 of the 33 subjects (3%) had a positive field swim challenge with a fall in FEV(1) of 16% from baseline. 18 of the 33 subjects (55%) had a positive EVH challenge, with a mean fall in FEV(1) of 20.4 (SD 11.7)% from baseline. 4 of the subjects (12%) had a positive laboratory cycle challenge, with a mean fall in FEV(1) of 14.8 (4.7)% from baseline. Only 1 of the 33 subjects was positive to all 3 challenges.

CONCLUSIONS

These results suggest that the EVH challenge is a highly sensitive challenge for identifying EIB in elite swimmers, in contrast to the laboratory and field-based exercise challenge tests, which significantly underdiagnose the condition. The EVH challenge, a well-established and standardised test for EIB in elite winter and summer land-based athletes, should thus be used for the diagnosis of EIB in elite swimmers, as recommended by the IOC-MC.

Telephone based asthma management - financial and individual benefits

METHODS

The authors calculated the cost of delivering telephone based asthma management compared to usual care. Self efficacy and quality of life were measured at recruitment, 6 months and 12 months. Participants were invited to comment on their experience of the telephone based intervention.

RESULTS

The intervention was well accepted. At 12 months there was a clinically important improvement in mean quality of life in the intervention group not seen in the control group. Telephone based management costs were offset by reductions in the number of readmissions in the intervention group.

DISCUSSION

Telephone based asthma management offers a well accepted, low cost yet potentially effective means of delivering asthma care.

A pilot study of telephone based asthma management

BACKGROUND

Self management programs have been advocated for adults who have recently been admitted to hospital or have recently attended an emergency department because of asthma. A new telephone based approach has already been trialled for the management of a number of other chronic conditions. This study sought to determine the effect of a telephone based asthma management program for adults with asthma.

METHODS

Adults with one or more previous admissions for asthma to either or both of two tertiary hospitals between 1 May 2001 and 30 November 2003 were invited to participate. All participants received one face-to-face session with an asthma educator. Participants were randomised to intervention (six telephone calls over 6 months) or control (usual care) groups. Measures of health care utilisation and morbidity were collected weekly for 12 months.

RESULTS

Seventy-one adults (54 females) with a mean age of 36.2 years were recruited to the study. Twenty hospital re-admissions were recorded for the control group and one for the intervention group at 12 months. Re-admission was significantly associated with allocation to control group (p=0.05). The control group was significantly more likely to report being woken by asthma on more than half the nights of the week (p=0.03).

DISCUSSION

Telephone based self management intervention results in clinically important reductions in hospital re-admission in adults previously hospitalised with asthma.