Recommendations for surveillance of pulmonary dysfunction among childhood, adolescent, and young adult cancer survivors: a report from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Childhood, adolescent, and young adult (CAYA) cancer survivors are at risk of pulmonary dysfunction. Current follow-up care guidelines are discordant. Therefore, the International Late Effects of Childhood Cancer Guideline Harmonization Group established and convened a panel of 33 experts to develop evidence-based surveillance guidelines. We critically reviewed available evidence regarding risk factors for pulmonary dysfunction, types of pulmonary function testing, and timings of surveillance, then we formulated our recommendations. We recommend that CAYA cancer survivors and healthcare providers are aware of reduced pulmonary function risks and pay vigilant attention to potential symptoms of pulmonary dysfunction, especially among survivors treated with allogeneic haematopoietic stem cell transplantation, thoracic radiotherapy, and thoracic surgery. Based on existing limited evidence and current lack of interventions, our panel recommends pulmonary function testing only for symptomatic survivors. Since scarce existing evidence informs our recommendation, we highlight the need for prospective collaborative studies to address pulmonary function knowledge gaps among CAYA cancer survivors.

Elexacaftor-Tezacaftor-Ivacaftor improve Gastro-Oesophageal reflux and Sinonasal symptoms in advanced cystic fibrosis

Upper gastrointestinal and upper airway disease are common in cystic fibrosis (CF) and may contribute to lower airway infection and inflammation. In a longitudinal cohort study of 32 patients (23 men; median age 32.5 years) with advanced CF lung disease (median FEV₁ 24.8% predicted) starting elexacaftor-tezacaftor-ivacaftor, the reflux symptom index score fell from a pre-treatment median (IQR) of 15 (11-23) to 5 (2.8-7.3) (p<0.001), the Hull airway reflux score fell from a median of 26.5 (16.3-39) to 7.5 (4-12) (p<0.001), and the sinonasal outcome score from a median of 36.5 (22-24) to 20 (10-32) (p<0.001) at 6 months on treatment. Mean FEV₁% predicted rose by 9.2 points, the median respiratory domain score of the CF Questionnaire-Revised rose by 27.8 points and mean body mass index rose by 2.6 kg/m². In addition to improving lung function and weight, CFTR modulators improve upper airway and gastro-oesophageal reflux symptoms in advanced CF.

Decontamination Strategies Used for AFB Culture Significantly Reduce the Viability of Mycobacterium abscessus Complex in Sputum Samples from Patients with Cystic Fibrosis

Nontuberculous mycobacteria are important respiratory pathogens in patients with cystic fibrosis (CF). For diagnosis, international guidelines recommend culture of sputum that has been decontaminated via chemical treatment. Fifty-six sputum samples from 32 patients known to be previously colonized or infected with NTM were subdivided, and the aliquots were subjected to six different decontamination strategies, followed by quantitative culture for NTM. Thirty sputum samples contained Mycobacterium abscessus complex (MABSC) and 11 contained Mycobacterium avium complex (MAC). Decontamination strategies included treatment with N-acetyl L-cysteine with 2% sodium hydroxide (NALC-NaOH), 4% NaOH, 1% chlorhexidine, 0.5 N sulfuric acid, 5% oxalic acid, double decontamination with NALC-NaOH, followed by 5% oxalic acid, and saline (0.85%) as a control. The samples were also cultured directly with no treatment. Treatment with NALC-NaOH resulted in an average reduction in colony count of 87% for MABSC when compared with direct culture. NaOH at 4% caused a 98.3% average reduction in colony count. All treatments that included NaOH resulted in colony counts that were statistically lower than those obtained from direct culture or the saline-treated control (p < 0.05). Standard treatments using sulfuric or oxalic acids were less deleterious, but still resulted in an average reduction in colony count of at least 30%. The viability of MAC was much less affected by most decontamination treatments. In conclusion, the viability of MABSC was severely compromised by standard decontamination regimens. This supports recent evidence showing that optimal recovery of MABSC is achieved by culture on an appropriate selective agar without decontamination of sputum samples.

The impact of COVID-19 shielding on the wellbeing, mental health and treatment adherence of adults with cystic fibrosis

People with cystic fibrosis (CF) were advised to undertake 'shielding' at home during the COVID-19 pandemic to reduce their risk of infection. We studied the impact shielding had on their wellbeing, mental health (GAD-7 and PHQ-9 scores) and adherence to treatment. 63 (46%) of 137 people surveyed responded (19 anonymously; 44 gave their identity). Most (94%) adhered to shielding advice 'all the time/often' but many (76%) found this difficult with disruption of their routines, relationships and exercise habits. Treatment adherence rates were high and continued during COVID-19. Depression scores were low and remained stable. Clinically significant anxiety rates rose from 27% pre-COVID-19 to 54% during COVID-19 and seven patients requested a psychology consultation from this study. There is a need to monitor the wellbeing of people with CF during the ongoing COVID-19 pandemic.

Oral cysteamine as an adjunct treatment in cystic fibrosis pulmonary exacerbations: An exploratory randomized clinical trial

BACKGROUND

Emerging data suggests a possible role for cysteamine as an adjunct treatment for pulmonary exacerbations of cystic fibrosis (CF) that continue to be a major clinical challenge. There are no studies investigating the use of cysteamine in pulmonary exacerbations of CF. This exploratory randomized clinical trial was conducted to answer the question: In future pivotal trials of cysteamine as an adjunct treatment in pulmonary exacerbations of CF, which candidate cysteamine dosing regimens should be tested and which are the most appropriate, clinically meaningful outcome measures to employ as endpoints?

METHODS AND FINDINGS

Multicentre double-blind randomized clinical trial. Adults experiencing a pulmonary exacerbation of CF being treated with standard care that included aminoglycoside therapy were randomized equally to a concomitant 14-day course of placebo, or one of 5 dosing regimens of cysteamine. Outcomes were recorded on days 0, 7, 14 and 21 and included sputum bacterial load and the patient reported outcome measures (PROMs): Chronic Respiratory Infection Symptom Score (CRISS), the Cystic Fibrosis Questionnaire-Revised (CFQ-R); FEV1, blood leukocyte count, and inflammatory markers. Eighty nine participants in fifteen US and EU centres were randomized, 78 completed the 14-day treatment period. Cysteamine had no significant effect on sputum bacterial load, however technical difficulties limited interpretation. The most consistent findings were for cysteamine 450mg twice daily that had effects additional to that observed with placebo, with improved symptoms, CRISS additional 9.85 points (95% CI 0.02, 19.7) p = 0.05, reduced blood leukocyte count by 2.46x109 /l (95% CI 0.11, 4.80), p = 0.041 and reduced CRP by geometric mean 2.57 nmol/l (95% CI 0.15, 0.99), p = 0.049.

CONCLUSION

In this exploratory study cysteamine appeared to be safe and well-tolerated. Future pivotal trials investigating the utility of cysteamine in pulmonary exacerbations of CF need to include the cysteamine 450mg doses and CRISS and blood leukocyte count as outcome measures.

CLINICAL TRIAL REGISTRATION

NCT03000348; www.clinicaltrials.gov.

Krebs von den Lungen-6 (KL-6) is a pathophysiological biomarker of early-stage acute hypersensitivity pneumonitis among pigeon fanciers

BACKGROUND

Identifying early stages of hypersensitivity pneumonitis (HP) is hampered by variable presentation, heterogeneous or undetected causal antigens and lack of gold-standard biomarkers. Krebs von den Lungen (KL)-6 is pathophysiological biomarker of alveolar epithelial damage. Pigeon fanciers, susceptible to HP, provide a model to investigate early HP.

OBJECTIVE

To test the hypothesis that plasma concentrations of KL-6 are increased in early-stage acute HP.

METHODS

Clinical history, spirometry and blood samples were obtained from pigeon fanciers, 20 with intermittent acute symptoms indicative of developing HP, 27 with no symptoms and 10 healthy subjects with no avian exposure. Plasma KL-6 (units/mL) and pigeon antigen-specific IgG antibody were quantified by enzyme immunoassay. Blood lymphocytes were quantified by flow cytometry and antigen specificity by in vitro cytokine production.

RESULTS

KL-6 was higher in fanciers than controls, median (IQR) 452 (244, 632) vs 274 (151, 377), P = .01. Although fanciers with symptoms had similar antigen exposure and lung function, they had higher KL-6 than those without, 632 (468, 1314) vs 320 (200, 480), P < .001. KL-6 correlated with IgG antibody titre in those with symptoms, r = .591, P = .006. High KL-6, irrespective of symptom category, was associated with higher antibody (P = .006) and lymphocyte proliferation (P = .041), and lower CD4+ T lymphocyte proportion (P = .032).

CONCLUSION AND CLINICAL RELEVANCE

Raised KL-6 is associated with acute symptoms of early-stage HP, and its correlation with antibody may support therapeutic strategies when HP is suspected. KL-6 may act as a mechanistic biomarker of early pathogenesis by linking lung pathophysiological changes with an endotype of immune hypersensitivity.

Haemoptysis with subtle computed tomography signs

A 70-year-old woman was referred to the respiratory department with a 6-month history of dry cough and intermittent minor haemoptyis. This was associated with a sensation of chest discomfort and some shortness of breath on moderate exertion with no orthopnoea or paroxysmal nocturnal dyspnoea. She had a background of coronary artery disease treated by stenting two years previously. She also had a hiatus hernia, type 2 diabetes and cervical spondylosis.

Can you diagnose this 70-year-old woman with a 6-month history of dry cough and intermittent minor haemoptyis?http://ow.ly/klfE30nAlhH

An evaluation of methods for the isolation of nontuberculous mycobacteria from patients with cystic fibrosis, bronchiectasis and patients assessed for lung transplantation

BACKGROUND

RGM medium is an agar-based, selective culture medium designed for the isolation of nontuberculous mycobacteria (NTM) from the sputum of patients with cystic fibrosis (CF). We evaluated RGM medium for the detection of NTM in patients with CF (405 samples), bronchiectasis (323 samples) and other lung diseases necessitating lung transplantation (274 samples).

METHODS

In total, 1002 respiratory samples from 676 patients were included in the study. Direct culture on RGM medium, with incubation at two temperatures (30 °C and 37 °C), was compared with conventional culture of decontaminated samples for acid-fast bacilli (AFB) using both a solid medium (Löwenstein-Jensen medium) and a liquid medium (the Mycobacterial Growth Indicator Tube; MGIT).

RESULTS

For all three patient groups, significantly more isolates of NTM were recovered using RGM medium incubated at 30 °C than by any other method (sensitivity: 94.6% vs. 22.4% for conventional AFB culture; P < 0.0001). Significantly more isolates of Mycobacterium abscessus complex were isolated on RGM at 30 °C than by AFB culture (sensitivity: 96.1% vs. 58.8%; P < 0.0001). The recovery of Mycobacterium avium complex was also greater using RGM medium at 30 °C compared to AFB culture (sensitivity: 83% vs. 70.2%), although this difference was not statistically significant and a combination of methods was necessary for optimal recovery (P = 0.21).

CONCLUSIONS

In the largest study of RGM medium to date, we reaffirm its utility for isolation of NTM from patients with CF. Furthermore; we show that it also provides an effective tool for culture of respiratory samples from patients with bronchiectasis and other lung diseases.

Current characteristics, challenges and coping strategies of young people with cystic fibrosis as they transition to adulthood

This study provides detailed data on the current characteristics, perceptions and outcomes of 45 young people with cystic fibrosis (CF) as they transition into adulthood. Although many had severe disease, they generally coped well, found attendance at a transition clinic helpful and welcomed the increased independence of an adult healthcare environment. Levels of psychological distress were low with only 15.6% having anxiety and 6.7% depression. The main psychological coping strategy used was optimistic acceptance. Overall, most remained stable after transfer but 33% had some decline in lung function and 9% in nutritional status, requiring intensification of treatment. They had high levels of satisfaction with their relationships and life situations and 76% were in employment or education. These results are encouraging and as life expectancy improves, young adults with CF are coping well with transition into adulthood.

Ivacaftor and symptoms of extra-oesophageal reflux in patients with cystic fibrosis and G551D mutation

BACKGROUND

Extra-oesophageal reflux (EOR) may lead to microaspiration in patients with cystic fibrosis (CF), a probable cause of deteriorating lung function. Successful clinical trials of ivacaftor highlight opportunities to understand EOR in a real world study.

METHODS

Data from 12 patients with CF and the G551D mutation prescribed ivacaftor (150mg bd) was collected at baseline, 6, 26 and 52weeks. The changes in symptoms of EOR were assessed by questionnaire (reflux symptom index (RSI) and Hull airway reflux questionnaire (HARQ)).

RESULTS

Six patients presented EOR at baseline (RSI >13; median 13; range 2-29) and 5 presented airway reflux (HARQ >13; median 12; range 3 to 33). Treatment with ivacaftor was associated with a significant reduction of EOR symptoms (P<0∙04 versus baseline) denoted by the reflux symptom index and Hull airway reflux questionnaire.

CONCLUSION

Ivacaftor treatment was beneficial for patients with symptoms of EOR, thought to be a precursor to microaspiration.

A service evaluation of an integrated model of palliative care of cystic fibrosis

BACKGROUND

Patients with advanced cystic fibrosis have severe symptoms with a complex trajectory of exacerbations and recovery. They are often awaiting lung transplantation, and many die without receiving specialist palliative care.

AIM

We introduced an integrated model whereby palliative specialists joined the cystic fibrosis team to provide palliative care in parallel with standard care.

DESIGN

A service evaluation of this model of care was undertaken in a prospective case series documenting symptoms and outcomes, the views of the cystic fibrosis team and the experience of the palliative specialists.

SETTING/PARTICIPANTS

Over 3 years, 28 (10%) of 282 patients attending the cystic fibrosis centre had specialist palliative care.

RESULTS

They had advanced lung disease (mean forced expiratory volume in 1 s (FEV1) = 0.86 L (25% predicted)), and 17 died: 6 were on a transplant waiting list at death; 10 were unsuitable and 1 died post transplantation. All who died over these 3 years had specialist palliative care. Four patients had successful transplants. Assessment showed a high prevalence of breathlessness, cough, pain, vomiting and fatigue, with a significant impact on daily life. The cystic fibrosis team rated this model of care highly, felt that palliative care should be members of the team, and thought that patients had found it helpful. The palliative specialists gained knowledge of cystic fibrosis, found it beneficial to meet patients earlier in the disease, and identified unmet needs in managing bereavement and the effects of deaths on other patients with cystic fibrosis.

CONCLUSION

This model has been successful in overcoming the difficulties in access to specialist palliative care for patients with cystic fibrosis.

A novel culture medium for isolation of rapidly-growing mycobacteria from the sputum of patients with cystic fibrosis

BACKGROUND

Isolation of mycobacteria from the sputum of patients with cystic fibrosis (CF) is challenging due to the overgrowth of cultures by other bacteria and fungi. In this setting, Burkholderia cepacia selective agar (BCSA) has been recommended as a convenient and effective culture medium for the isolation of rapidly-growing, non-tuberculous mycobacteria (NTM). A novel selective culture medium (RGM medium) was evaluated for the isolation of rapidly-growing NTM from the sputum of children and adults with CF.

METHODS

A total of 118 isolates of rapidly-growing mycobacteria and 98 other bacteria and fungi were inoculated onto RGM medium. These were assessed for growth at 30°C over a seven day period. A total of 502 consecutive sputum samples were collected from 210 patients with CF. Each sample was homogenized and cultured onto RGM medium and also onto BCSA. Cultures were incubated for 10days at 30°C.

RESULTS

Of 118 isolates of mycobacteria all but one grew well on RGM medium, whereas 94% of other bacteria and fungi were inhibited. A total of 55 sputum samples (from 33 distinct patients) yielded NTM using a combination of both RGM and BCSA (prevalence: 15.7%). NTM were recovered from 54 sputum samples using RGM medium compared with only 17 samples using BCSA (sensitivity 98% vs. 31%; P≤0.0001). A total of 419 isolates of non-mycobacteria were recovered from sputum samples on BCSA compared with 46 on RGM medium.

CONCLUSIONS

RGM medium offers a simple and effective culture method for the isolation of rapidly-growing mycobacteria from sputum samples from patients with CF without decontamination of samples. RGM medium allows for the systematic screening of all sputum samples routinely referred for culture from patients with CF.

A metagenomic approach to characterize temperate bacteriophage populations from Cystic Fibrosis and non-Cystic Fibrosis bronchiectasis patients

Pseudomonas aeruginosa (Pa), normally a soil commensal, is an important opportunistic pathogen in Cystic Fibrosis (CF) and non-Cystic Fibrosis Bronchiectasis (nCFBR). Persistent infection correlates with accelerated decline in lung function and early mortality. The horizontal transfer of DNA by temperate bacteriophages can add gene function and selective advantages to their bacterial host within the constrained environment of the lower lung. In this study, we chemically induce temperate bacteriophages from clonal cultures of Pa and identify their mixed viral communities employing metagenomic approaches. We compared 92 temperate phage metagenomes stratified from these clinical backgrounds (47 CF and 45 nCFBR Pa isolates) using MG-RAST and GeneWise2. KEGG analysis shows the complexity of temperate phage accessory gene carriage increases with duration and severity of the disease. Furthermore, we identify the presence of Ig-like motifs within phage structural genes linked to bacterial adhesion and carbohydrate binding including Big_2, He_Pig, and Fn3. This study provides the first clinical support to the proposed bacteriophage adherence to mucus (BAM) model and the evolution of phages interacting at these mucosal surfaces over time.

Assessment of sample handling practices on microbial activity in sputum samples from patients with cystic fibrosis

AIM

The aim of this study was to quantitatively and qualitatively assess the effect of sample storage on the metabolically active microbial community found in sputum samples from patients with cystic fibrosis (CF).

METHODS

Sputum samples were collected and split in two equal aliquots one of which was immersed in RNAlater and refrigerated immediately, the second stored at room temperature for 24 h and RNAlater was subsequently added. mRNA was extracted, and RT-PCR-DGGE and qPCR analysis of the bacterial and fungal communities was carried out.

RESULTS

Significant differences in the bacterial communities between the two protocols were observed but there were no significant difference seen in the fungal community analyses. Analysis by qPCR demonstrated that room temperature storage gave statistically significant increases in eubacteria and Pseudomonas spp. and a statistically significant decrease in those of Haemophilus influenzae.

CONCLUSIONS

The analysis of metabolically active microbial communities from CF sputum using molecular techniques indicated that samples should be stored at 4 degrees C upon addition of RNAlater to obtain an accurate depiction of the CF lung microbiota. Also, storing respiratory samples at room temperature may cause an over representation of Pseudomonas aeruginosa and mask the presence of other clinically significant organisms.

An integrated model of provision of palliative care to patients with cystic fibrosis

Palliative care of patients with cystic fibrosis (CF) is often undertaken by CF teams rather than palliative care teams because of the specialist nature of the disease and the potential role of lung transplantation. We developed an integrated model of provision of palliative care whereby most care is delivered by the CF team using palliative guidelines and pathways, with additional support available from the specialist palliative care team when needed. We report our experience of the terminal care of 40 patients with CF with regard to the circumstances of death, lung transplantation status, specific symptoms and provision of palliative treatments. The transition from disease modifying treatments to palliative care was particularly complex. Patients had a high level of symptoms requiring palliation and most died in hospital. Palliative care is a crucial component of a CF service and requires the specialist skills of both the CF and palliative care teams.

Nerve growth factor in serum and lymphocyte culture in pigeon fanciers' acute hypersensitivity pneumonitis

BACKGROUND

Nerve growth factor (NGF) is a neurotrophic cytokine with immunomodulatory activity. NGF contributes to neurogenic inflammation and has been described in asthma and idiopathic pulmonary fibrosis.

OBJECTIVES

To identify and quantify NGF in serum and peripheral blood lymphocyte cultures from pigeon fanciers, and to investigate an association with the immune response to inhaled avian antigens, and with symptoms of acute hypersensitivity pneumonitis (HP).

METHODS

NGF was quantified and compared with serum IgG antibody against inhaled avian antigens, with serum C-reactive protein (CRP), and with KL-6, a marker of lung interstitial inflammation. These were measured using enzyme-linked immunoassay. Levels were compared with symptom history in 55 pigeon fanciers (26 subjects with acute HP but symptom-free at the time of testing) and 15 subjects with no avian exposure.

RESULTS

Pigeon fanciers had higher-than-normal serum IgG antibody, CRP, and KL-6 levels (p < 0.01 each). These measures were unrelated to HP symptom category; instead, in all pigeon fanciers, the concentrations of CRP and KL-6 correlated with each other and with the antibody titers (p < 0.01 each). Serum NGF levels were normal; however, NGF production by mitogen-activated lymphocytes was higher than normal, and correlated with IgG antibody titer (p < 0.05) and with serum CRP (p < 0.05).

CONCLUSIONS

Serum NGF was normal in pigeon fanciers; however, their blood lymphocytes ex vivo synthesized increased NGF in concentrations that correlated with the titer of serum IgG antibody to inhaled avian antigens. These also correlated with CRP and KL-6 levels, suggesting that antigen exposure in seropositive subjects is associated with subclinical inflammation involving coordinated synthesis of neurotrophin and immune mediators.

Interstitial lung disease: progress and problems

Interstitial lung disease involves all areas of medicine as it often occurs in patients with comorbidities or as a consequence of systemic diseases and their treatment. Typically the physician is faced with a breathless patient, a diffusely abnormal chest radiograph, and a wide differential diagnosis. Progress has been made in using high resolution computed tomography as the key investigation in characterising the pattern and extent of the disease. Bronchoalveolar lavage is particularly important in excluding infection as a cause of diffuse lung infiltrates. Surgical lung biopsies have led to a new classification system for the range of histopathological patterns of disease that were previously known by the collective term cryptogenic fibrosing alveolitis. Problems persist in deciding when a surgical lung biopsy is clinically justified, in understanding the pathogenesis of these diseases, and in finding more effective treatments.

Lung Transplantation Outcome in Cystic Fibrosis Patients With Previous Pneumothorax

BACKGROUND

High perioperative mortality that results from hemorrhage from pleural adhesions was reported in the early experience of heart-lung transplantation. This led to previous pleural procedures becoming a relative/absolute contraindication to transplantation in some centers, despite the advent of bilateral lung transplantation. Has this lead to a more conservative approach to pneumothorax management in patients with cystic fibrosis (CF)? And what is the effect of previous pleural procedures on surgical outcome of lung transplantation?

METHODS

We reviewed 3 groups of patients transplanted at this center from 1989 to 2002, matched for year of lung transplantation. Group A comprised 16 patients with CF with a history of previous pneumothorax with or without pleural procedure. Group B comprised 16 patients with CF with no history of pneumothorax. Group C comprised 16 noninflammatory/nonbronchiectatic patients with no history of pneumothorax. Measured outcomes included blood products provided intraoperatively; operation and cardiopulmonary bypass times; postoperative hemorrhage; times to extubation, discharge from the intensive care unit and hospital discharge; forced expiratory volume at 1 second at 6 months; 30-day mortality; pleural adhesions graded descriptively; and previous pneumothorax management (Group A only). There were 35 pneumothorax episodes in the 16 patients in Group A. Nine episodes were managed with observation alone. Nine patients required invasive management, 25 chest drains were placed, 3 patients received medical pleurodesis, and 2 underwent thoracic surgical intervention.

RESULTS

No significant difference was observed between the 3 groups regarding blood products intraoperatively or duration of procedure. Pleural adhesions found at operation were significantly more in Group A, with dense adhesions found only in Group A (p<0.05). Group C was significantly more likely to be free from adhesions, with 13 patients clear (p<0.01 Group C vs Group A, Group C vs Group B). No statistically significant difference was found in the other measured parameters.

CONCLUSIONS

Pneumothorax is treated conservatively in a potential lung transplant population. Patients with CF and previous pneumothorax with or without pleural procedures undergoing lung transplantation have dense pleural adhesions; however, this does not affect surgical outcome significantly. Patients with emphysema, fibrosing alveolitis, or obliterative bronchiolitis were significantly more likely to be free of pleural adhesions, suggesting that the inflammatory/chronic infective component of CF independently contributes to the increased pleural adhesions. Previous pleural procedures for pneumothorax should not be considered a contraindication in the assessment of suitability for lung transplantation.

Takes your breath away--the immunology of allergic alveolitis

Extrinsic allergic alveolitis (synonym: hypersensitivity pneumonitis) is caused by inhaling antigenic aerosols which induce hypersensitivity responses in susceptible individuals. It is an interstitial inflammatory disease affecting the distal, gas-exchanging parts of the lung, in contrast to allergic asthma where the inflammation is more proximal, affecting the conducting airways. The aims of this review are to describe current concepts of the immunology of this model of lung inflammation, to describe some of the constitutional and environmental characteristics which affect disease susceptibility and development, and to describe topics for prospective study.

Hypersensitivity pneumonitis: current concepts

Hypersensitivity pneumonitis (HP), or extrinsic allergic alveolitis, is due to a hypersensitivity reaction after repeated inhalation of finely dispersed antigens, mainly organic particles or low molecular weight chemicals. The essence of this disease is an interaction between the host's immune system and external antigen, influenced by both genetic and environmental factors. In susceptible subjects, it leads to a combined type III allergic reaction of Gell and Coombs (with formation of precipitines) and a type IV lymphocytic reaction (with a granulomatous inflammation in the distal bronchioles and alveoli). This review gives an update on epidemiology, antigens, pathogenesis, host susceptibility, environmental factors, clinical features, diagnosis and treatment in HP. The list of aetiological agents is long and new sources of antigens are constantly being identified. Host risk factors are poorly characterized, with the exception of those linked to exposure factors. Environmental factors and cofactors may be critical for the pathogenesis of the disease. HP is not a uniform disease entity, but a complex dynamic clinical syndrome such that different patterns of disease emerge over time. The diagnosis is made from a combination of clinical features, radiographic abnormalities, lung function tests and immunological tests. The use of inhalation challenge tests for the diagnosis has been hampered by the lack of standardization. Antigen avoidance is the key element in the treatment. There is often an apparent beneficial response to corticosteroids, but it may be difficult to distinguish between the effects of treatment, the natural course of the disease and the effect of antigen avoidance.

Interstitial lung disease induced by exogenous agents: factors governing susceptibility

The purpose of this review is to describe the present state of knowledge regarding host susceptibility factors that may determine the occurrence, development and severity of interstitial lung disease (ILD) caused by exogenous agents. First, host susceptibility may pertain to differences in the delivery and/or persistence of the noxious agent in the lung. The deposition and clearance of inhaled particles or fibres may vary depending on innate anatomical or physiological characteristics, and on acquired changes, such as nasal disease or smoking-induced alterations. Genetically- or environmentally-induced interindividual differences in the expression of pulmonary biotransformation enzymes may form the basis for, or contribute to the risk of, drug-induced interstitial lung disease. Secondly, there are genetic and acquired variations in various enzymatic and nonenzymatic defence systems that protect cells and tissues against oxidative stress, which is often involved in the pathogenesis of interstitial lung disease caused by particles, fibres, metals, organic agents and drugs. Thirdly, the occurrence of immunological sensitization is dependent on both genetic and environmental factors. This has been demonstrated in chronic beryllium lung disease and in hypersensitivity pneumonitis. Fourthly, the propensity of individuals to develop particular types of inflammation, such as granulomas, is probably under genetic control. The regulation and resolution of inflammation and fibrogenesis caused by dust particles are also partly determined by genetic factors, involving cytokine networks and growth factors. In conclusion, although the issue of genetics pervades the entire discussion of host susceptibility, genes are not the only determinants of health and disease. Environmental factors may be equally important in shaping host susceptibility. Therefore, research must be focused on both the genetic bases and the environmental determinants of interstitial lung disease, in order to provide mechanism-based prevention strategies, early detection of, and improved therapy for these conditions.

Asthmagenicity of coal mine roof-bolting resins: an assessment using inhalation provocation tests

Inhalation provocation tests were used to assess whether the volatile products of an activated resin had caused occupational asthma in a non-random sample of six asthmatic coal miners. The resin system uses the polymerization of polyester and styrene under the influence of the cross-linking agent dibenzoyl peroxide to secure roof, wall and floor bolts in mine tunnels. The tests were conducted sequentially in a double-blind fashion over a 'dose' range which extended just beyond the maximum likely to have been experienced occupationally during a single day's work. The tests were monitored by symptoms, changes in the forced expiratory volume in 1 s (FEV1) and changes in airway responsiveness. All subjects completed the series of tests without any significant decrements in FEV1 or significant increases in airway responsiveness. We conclude that the use of this resin system is not likely to have been the cause of the asthma in the test subjects, nor in the larger group of miners of which they were a sample, but neither possibility is fully excluded and the participants may not have been adequately representative of other asthmatic coal miners.

Epidemiology and molecular typing of an outbreak of tuberculosis in a hostel for homeless men

AIM

To investigate a possible outbreak of tuberculosis in a hostel for homeless men using IS6110 profiling, a polymerase chain reaction (PCR) based fingerprinting technique.

METHODS

Eight cases of tuberculosis were diagnosed in residents of the hostel over a period of 28 months. To provide epidemiological data, a heminested inverse PCR (HIP) assay targeting the insertion sequence IS6110 together with its upstream flanking region was used to fingerprint the eight isolates of M tuberculosis under investigation.

RESULTS

The HIP technique gave IS6110 profiles which showed that while three isolates were clearly distinct, the remaining five strains were indistinguishable, suggesting the latter were representatives of a single outbreak strain.

CONCLUSIONS

The HIP assay proved discriminatory and facilitated repeated testing for the direct comparison of strains as more patients presented over the protracted course of this outbreak.

Asthma precipitated by cessation of lithium treatment

We report symptomatic asthma, associated with objective and highly significant increases in both airway responsiveness and airflow limitation, presenting de novo in a male patient 6 weeks after suddenly discontinuing lithium carbonate therapy.

Pigeon fanciers' lung: identification of disease-associated carbohydrate epitopes on pigeon intestinal mucin

Pigeon intestinal mucin, a complex high molecular weight glycoprotein, is a key antigen in the development of pigeon fanciers' lung (PFL). We have studied the specificity of antibodies to mucin in patients with PFL and asymptomatic antibody-positive individuals. Extensive papain digestion, which removes the non-glycosylated regions of the mucin leaving the heavily glycosylated 'bottle brush' regions, resulted in a 600-fold decrease in IgG3 antibody titres with little effect on IgG1 and IgG2 titres. This suggests that IgG1 and IgG2 are directed against the region rich in O-linked sugar chains whilst the majority of the IgG3 is directed against epitopes which are proteinase-sensitive. Lectin mapping of the carbohydrates present on pigeon intestinal mucin demonstrated high levels of exposed N-acetyl neuraminic acid, N-acetyl galactosamine and N-acetyl glucosamine, with lower levels of fucose and some galactose. Sera from pigeon fanciers inhibited binding of lectins specific for N-acetyl neuraminic acid, N-acetyl galactosamine, internal N-acetyl glucosamine and fucose. Sera from people with PFL, compared with sera from asymptomatic antibody-positive fanciers, had significantly higher titres of antibody that inhibited binding of four lectins specific for N-acetyl galactosamine and one fucose-specific lectin, suggesting that these sugars may play a dominant role in disease-associated epitopes. The results suggest that different IgG subclasses recognize different epitopes on mucin and that the epitopes recognized by the major subclasses are present on the O-linked oligosaccharides. Further, the carbohydrate-specific anti-mucin antibodies produced by PFL patients may differ in their specificity from those found in asymptomatic individuals.

Pigeon fanciers' lung: the mucin antigen is present in pigeon droppings and pigeon bloom

BACKGROUND

Pigeon intestinal mucin has been implicated as an important antigen pigeon fanciers' lung. This study investigated whether mucin is detectable in pigeon droppings and bloom, the likely antigenic sources in disease.

METHODS

Soluble extracts of a number of materials found in a pigeon loft were prepared and specific IgG subclass antibodies to these antigens were measured in 14 antibody-positive pigeon fanciers. Cross-reactivity between these materials and purified pigeon intestinal mucin was investigated by inhibition of anti-mucin ELISA. Mucin was purified from the soluble extracts of these crude antigen mixtures by CsCl density gradient centrifugation.

RESULTS

The patterns of IgG subclass responses to purified pigeon intestinal mucin and to the four materials collected from the pigeon loft were similar. Subclass differences between symptomatic and asymptomatic individuals, demonstrable against purified mucin, were similarly seen against pigeon droppings and pigeon bloom. Both pigeon droppings and pigeon bloom were capable of inhibiting IgG binding to purified pigeon mucin, and mucin inhibited substantially the binding of IgG to these materials. Glycoprotein with a density similar to that described for pigeon intestinal mucin was purified from each source.

CONCLUSION

Pigeon intestinal mucin is present in a variety of materials found in the environment of the pigeon loft in a form capable of reacting with anti-mucin antibodies in the sera of exposed individuals. Reduction in exposure to these materials may decrease the likelihood of developing pigeon fanciers' lung and minimise reactions in sensitised individuals.

Adverse effects of a single dose of (+)-sotalol in patients with mild stable asthma

AIMS

To investigate the effect of (+)-sotalol, which is not thought to possess clinically significant beta-adrenoceptor blocking activity, on airway responsiveness in subjects with mild asthma.

METHODS

A placebo controlled, double-blind, single dose, cross over study, evaluating the effects of oral (+)-sotalol 300 mg and oral (+/-)-sotalol 240 mg, on airway responsiveness, FEV1, and heart rate in 18 asthmatic volunteers with quantifiable levels of airway responsiveness.

RESULTS

Compared with placebo, (+)-sotalol induced a significant increase in airway responsiveness, and a significant decrease in FEV1, but there was no significant change in heart rate. Following (+/-)-sotalol there was no significant effect on airway responsiveness, but there were significant decreases in FEV1 and heart rate. In one subject both (+)-sotalol and (+/-)-sotalol provoked a 49% decrement in FEV1, and in another there were decrements of 20% and 18%, respectively.

CONCLUSIONS

Despite theoretical considerations, it cannot be assumed that (+)-sotalol is safe in patients with asthma.

Lung abscess complicating chondromas in Carney's syndrome

Carney's syndrome consists of a combination of three rare tumours: gastric leiomyosarcoma, pulmonary chondroma and catecholamine-secreting paraganglioma. We describe a young woman with Carney's syndrome, who developed a lung abscess, due to obstruction of a bronchus by a chondroma, 11 yrs after having had a partial gastrectomy for a leiomyosarcoma.

IgG subclass responses to pigeon intestinal mucin are related to development of pigeon fanciers' lung

BACKGROUND

Pigeon fanciers' lung (PFL) is a form of extrinsic allergic alveolitis. Affected individuals produce antibodies to various pigeon antigens, and the resulting immune complexes are thought to initiate the disease. However, high antibody titres also occur in some asymptomatic individuals. Previously attention has focused on protein antigens, but we have recently identified pigeon intestinal mucin as a novel antigen in PFL.

OBJECTIVE

To determine the relationship between IgG subclass antibodies to pigeon intestinal mucin and the development of pigeon fanciers' lung.

METHODS

Sera were collected from 250 pigeon fanciers, who also completed a clinical questionnaire. Sera were screened for precipitating antibodies to pigeon serum and droppings. Individuals with symptoms and precipitating antibodies were considered to have classical PFL. Serum IgG and IgG subclass antibodies to pigeon intestinal mucin and pigeon serum proteins were investigated by quantitative enzyme-linked immunosorbent assay (ELISA).

RESULTS

Very high titres of IgG antibodies against pigeon mucin were found in all precipitin-positive individuals. A strong positive correlation was seen between titres of antibodies to mucin and to serum proteins, but this was not due to crossreactivity. No significant differences in IgG titres to either mucin or pigeon serum proteins were found between individuals with PFL and asymptomatic precipitin positive fanciers. IgG1 and IgG2 were the major subclasses of anti-mucin, with lower titres of IgG3. Patients with PFL had significantly higher titres of IgG1 to mucin than asymptomatic, precipitin-positive individuals. In contrast, no significant differences were seen between PFL and asymptomatic precipitin-positive sera with respect to the subclass titres against pigeon serum proteins.

CONCLUSION

The high titres of anti-mucin IgG in sera of all individuals with PFL, together with the finding that high IgG1 titres to mucin are associated with the development of disease confirm pigeon intestinal mucin as an important antigen in PFL.

Occupational asthma in an isothiazolinone manufacturing plant

A chemical plant operator developed asthma five months after starting work in an isothiazolinone manufacturing plant. He described symptoms of late asthmatic reactions after work with isothiazolinone. Airway responsiveness to methacholine improved tenfold when he was removed from the plant for 18 days. A workplace challenge study then resulted in a deterioration in airway responsiveness to its earlier level and in progressive falls in forced expiratory volume in one second (FEV1) over three days at work compared with control days, indicating statistically significant late asthmatic reactions of increasing severity.

Cyclophosphamide in severe steroid-resistant bronchiolitis obliterans organizing pneumonia

A patient receiving carbamazepine and imipramine presented with severe bronchiolitis obliterans organizing pneumonia (BOOP). He developed progressive respiratory failure in spite of high-dose steroid treatment. Cyclophosphamide was given as adjunctive therapy, and a rapid improvement was seen. The authors suggest that an early therapeutic trial of cyclophosphamide should be considered in patients with BOOP who fail to respond to steroids.

Asthma, airways responsiveness and air pollution in two contrasting districts of northern England

BACKGROUND

To assess the possible magnitude of differences between normal populations an epidemiological investigation of asthma was conducted in two strongly contrasting districts of northern England--rural West Cumbria on the west coast and urban Newcastle upon Tyne on the east coast.

METHODS

A cross sectional survey of randomly identified men aged 20-44 years was conducted in two phases: phase 1, a postal survey of respiratory symptoms and asthma medication in 3000 men from each district; and phase 2, a clinical assessment of 300 men from each district comprising investigator administered questionnaires, skin prick tests, spirometry, and methacholine challenge tests.

RESULTS

The phase 1 (but not phase 2) study showed a small excess of "ever wheezed" in Newcastle (44% versus 40%), but neither phase showed differences between the two districts for recent wheeze or for other symptoms characteristic of asthma. There were also no differences with regard to diagnosed asthma, current asthma medication, spirometric parameters, or airways responsiveness. The prevalence of quantifiable airways responsiveness (PD20 < or = 6400 micrograms) was 27.7% in West Cumbria and 28.2% in Newcastle. Regression analyses showed that PD20 was negatively associated with atopy and positively with forced expiratory volume in one second (FEV1); that an association between PD20 and current smoking could be explained by diminished FEV1; and that PD20 was not related to geographical site of residence.

CONCLUSIONS

Neither airways responsiveness nor the other parameters of diagnostic relevance to asthma varied much between the two study populations, despite the apparent environmental differences. The most obvious of these were the levels of outdoor air pollution attributable to vehicle exhaust emissions, the ambient levels of which were 2-10 fold greater in Newcastle. Our findings consequently shed some doubt over the role of such pollution in perceived recent increases in asthma prevalence. It is possible, however, that an air pollution effect in Newcastle has been balanced by asthmagenic effects of other agents in West Cumbria.

Effect of dietary sodium on airways responsiveness and its importance in the epidemiology of asthma: an evaluation in three areas of northern England

BACKGROUND

Although several investigations have shown a relationship between asthma (or its surrogate, airways responsiveness) and dietary or urinary sodium, others have not, and the matter remains controversial. This "salt effect" has been investigated during two recent epidemiological surveys of men in northern England. The first assessed the possible effect on airways responsiveness of occupational exposure to welding fumes, and the second characterised airways responsiveness in two geographically distinct residential areas. Thus, three separate study areas/populations were involved.

METHODS

Investigation 1 involved 1059 shipyard workers aged 16-27 years who were exposed variously to welding fumes, and Investigation 2 involved 587 men aged 20-44 years who lived in rural West Cumbria or in urban Newcastle upon Tyne. In Investigation 1, a 24 hour urine specimen was requested from each subject with quantifiable airways responsiveness (PD20 < or = 6400 micrograms methacholine) and from an equal number of subjects without measurable airways responsiveness from the same occupational subgroup. In Investigation 2, every subject was asked to provide a 24 hour urine specimen.

RESULTS

Of the men undergoing methacholine tests, satisfactory 24 hour urine specimens were obtained from 234 (22.1%) in Investigation 1 and 232 (39.5%) in Investigation 2. Analysis using multiple linear regression, multiple linear logistic regression, and multiple regression for censored data produced consistent results within each study population but conflicting results between them, such that there was no hint of a relationship between airways responsiveness and 24 hour urinary sodium excretion in the shipyard workers of Investigation 1 nor in the rural West Cumbrian population of Investigation 2, but an association was found in the urban Newcastle population of Investigation 2. All study populations were sufficiently large to demonstrate anticipated relationships between airways responsiveness and atopy, baseline FEV1, and (Newcastle only) age.

CONCLUSIONS

If airways responsiveness is related to dietary sodium the relationship is not likely to be strong.