Experimental Human Pneumococcal Challenge: Effect of Asthma on Human Responses to Pneumoccous

Rationale Pneumococcal pneumonia is a leading cause of death globally, and susceptibility to invasive and pulmonary infection is increased in chronic respiratory conditions. Pneumococcal colonisation of the nasopharynx necessarily precedes disease, but the relationship of colonisation with Streptococcus pneumoniae and chronic respiratory disease (such as asthma) is unknown. Asthma is a heterogenous condition representing several phenotypes which have corresponding clinical characteristics and responses to therapy. Immune responses mediated by cytokines from cells such T helper cells 2 (Th2) and Th17 lead to airway inflammation. Both this inflammatory pathology, and the treatment of it (with inhaled corticosteroids) potentially affect nasopharyngeal colonisation with S.pneumoniae. Hypothetically, airway inflammation might increase the potential for bacterial attachment, or increase bacterial clearance, or both. As nasopharyngeal colonisation is immunogenic in healthy adults, the balance of these opposing mechanisms may impact the resulting immune response. We have safely used the experimental human pneumococcal challenge (EHPC) model in healthy individuals to study nasopharyngeal colonisation and its associated mucosal and systemic immune responses. Objectives Using experimental pneumococcal challenge in people with asthma, I examined the acquisition of nasopharyngeal colonisation of Streptococcus pneumoniae, its association with clinical characteristics, and systemic immune responses. I compared the results with historic data from earlier EHPC studies of healthy controls. Methods I enrolled people with physician-diagnosed, well-controlled asthma on maintenance inhaled corticosteroids. Participants were challenged with pneumococcus serotype 6B, as this is not isolated from nasal samples within the local community. Blood and mucosal samples were collected at baseline and on days 2,7, 9, 14, 22 and 29 after challenge. The results were compared to healthy controls from 4 experimental human challenge studies, with 2 performed concurrently and 2 in previous years. Main Results Experimental colonisation rates were not significantly increased in people with asthma compared to healthy controls. The number of colonised participants (nasal wash positive for bacterial culture at any time point) was 28 (56%) in asthma vs 68 (45%) in healthy controls (Pearson’s chi square p=0.178). The density calculated using the area under time cure (AUC) was similar in people with asthma compared to healthy controls (median [IQR] asthma 63.49 [14.04-116.3] vs healthy controls 81.18 [48.15-104.5] Mann Whitney U test p=0.060). Acquisition of colonisation was independent of baseline characteristics such as blood eosinophils and fractional exhaled nitric oxide levels. The duration of experimental colonisation was significantly shorter in asthma compared to healthy controls (median [IQR] 14 [7-29] vs 29[14-29]) p=0.034 Mann Whitney U test. Colonisation led to an increase in IgG titres to capsular polysaccharide and pneumococcal proteins in people with asthma as previously described in healthy controls. Body mass index correlated positively with likelihood of colonisation in people with asthma. Median BMI for the whole cohort was 24.6 (IQR) (21.6-27.5), with colonised participants (nasal wash positive for bacterial culture at any time point) having a higher BMI median 24.7 (24.1-29.0) vs 23.5 (20.1-26.4) in non-colonised (p=0.019 independent samples t test). Conclusions: Experimental colonisation is not affected by clinical characteristics of asthma, and it is positively correlated with a high BMI. The rate and density of experimental nasopharyngeal colonisation in people with asthma are similar as seen in healthy controls. The duration of colonisation is significantly reduced in people with asthma compared to healthy controls, with a similar immunogenic effect as seen in healthy controls. Interventions to reduce the likelihood of severe and invasive pneumococcal disease, to which people with asthma are more prone, could be targeted at specific sub-groups. Further investigation could suggest if those with higher BMI should have a lower threshold for vaccination

Quantifying and reducing inhaler prescription errors in secondary care

BACKGROUND Junior doctors commonly prescribe inhaled medication for patients admitted to hospitals, and this may be a potential source of prescription error. Objective To determine the potential type, frequency and cost of prescription errors for inhaled medication, and ascertain if a simple educational intervention can improve junior doctors' knowledge and reduce these. METHODS We carried out a prospective study looking at the types and cost of inhaled prescription errors. Simultaneously we tested knowledge of junior doctors' using a quiz. Both the studies were carried out before and after the introduction of inhaler flash cards (pictures of devices with, instructions on use and the medication they contain) on specific wards. This was followed by an electronic feedback survey. RESULTS Error rates varied greatly (p = 6.8 × 10(-8)) by device, with 23 % of Evohaler and Accuhaler prescriptions being incorrect. The average cost of an erroneously prescribed medication was £45.50. There were 14 % incorrect prescriptions before the intervention. There was no significant improvement in junior doctors' knowledge of inhalers or the rate of prescription error after the intervention. CONCLUSION Prescription errors of inhaled medication are common and costly to rectify. There is a need for improved teaching and training of junior doctors and medical students

Single use and conventional bronchoscopes for Broncho alveolar lavage (BAL) in research: a comparative study (NCT 02515591)

Background Broncho alveolar lavage (BAL) is widely used for investigative research to study innate, cellular and humoral immune responses, and in early phase drug trials. Conventional (multiple use) flexible bronchoscopes have time and monetary costs associated with cleaning, and carries a small risk of cross infection. Single use bronchoscopes may provide an alternative, but have not been evaluated in this context. Methods Healthy volunteers underwent bronchoscopy at a day-case clinical research unit using the Ambu® aScopeTM single-use flexible intubation bronchoscope. Broncho alveolar lavage was performed from a sub segmental bronchus within the right middle lobe; a total of 200 ml of warmed normal saline was instilled then aspirated using handheld suction. BAL volume yield, cell yield and viability were recorded. Results Ten volunteers, (mean age 23 years, six male) participated. Bronchoscopies were carried out by one of two senior bronchoscopists, experienced in the technique of obtaining BAL for research purposes. The results were compared to 50 (mean age 23, 14 male) procedures performed using the conventional scope by the same two bronchoscopists. The total volume yield was significantly higher in the disposable group median 152 ml (IQR 141–166 ml) as compared to conventional 124 ml (110–135 ml), p = <0.01. The total cell yield and viability were similar in both groups, with no significant differences. Conclusions With single use bronchoscopes, we achieved a larger BAL volume yield than conventional bronchoscopes, with comparable cell yield and viability. Better volume yields can potentially reduce post procedure side effects such as pleuritic chest pain and cough. The risk of cross infection can be eliminated, providing reassurance to researchers and participants. Reduced maintenance requirements can be cost effective. These could potentially be used for early phase drug development studies. Trial registration This trial was registered prospectively in July 2015 with the National Clinical Trials register, with the following registration number assigned: NCT 02515591

FSH Beyond Fertility

The traditional view of follicle-stimulating hormone (FSH) as a reproductive hormone is changing. It has been shown that FSH receptors (FSHRs) are expressed in various extra-gonadal tissues and mediate the biological effects of FSH at those sites. Molecular, animal, epidemiologic, and clinical data suggest that elevated serum FSH may play a significant role in the evolution of bone loss and obesity, as well as contributing to cardiovascular and cancer risk. This review summarizes recent data on FSH action beyond reproduction

Symptoms associated with influenza vaccination and experimental human pneumococcal colonisation of the nasopharynx

Background Nasopharyngeal colonisation by S. pneumoniae is a prerequisite for invasive pneumococcal infections. Influenza co-infection leads to increased susceptibility to secondary pneumonia and mortality during influenza epidemics. Increased bacterial load and impaired immune responses to pneumococcus caused by influenza play a role in this increased susceptibility. Using an Experimental Human Challenge Model and influenza vaccines, we examined symptoms experienced by healthy adults during nasal co-infection with S. pneumoniae and live attenuated influenza virus. Methods Randomised, blinded administration of Live Attenuated Influenza Vaccine (LAIV) or Tetravalent Inactivated Influenza Vaccine (TIV) either preceded bacterial inoculation or followed it, separated by a 3-day interval. The presence and density of S. pneumoniae was determined from nasal washes. Participants completed a symptom questionnaire from the first intervention until 6 days post second intervention. Results The timing and type of influenza vaccination and presence of S. pneumoniae in the nasopharynx significantly affected symptom reporting. In the study where influenza vaccination preceded bacterial inoculation: nasal symptoms were less common in the LAIV group than the TIV group (OR 0.57, p < 0.01); with colonisation status only affecting the TIV group where more symptoms were reported by colonised participants compared to non-colonised participants following inoculation (n = 12/23 [52.17%] vs n = 13/38 [34.21%], respectively; p < 0.05). In the study where influenza vaccination followed bacterial inoculation: no difference was seen in the symptoms reported between the LAIV and TIV groups following inoculation and subsequent vaccination; and symptoms were unaffected by colonisation status. Conclusion Symptoms experienced during live viral vaccination and bacterial co-infection in the nasopharynx are directly affected by the precedence of the pathogen acquisition. Symptoms were directly affected by nasal pneumococcal colonisation but only when TIV was given prior to bacterial exposure

Inflammation induced by influenza virus impairs human innate immune control of pneumococcus

Secondary bacterial pneumonia following influenza infection is a significant cause of mortality worldwide. Upper respiratory tract pneumococcal carriage is important as both determinants of disease and population transmission. The immunological mechanisms that contain pneumococcal carriage are well-studied in mice but remain unclear in humans. Loss of this control of carriage following influenza infection is associated with secondary bacterial pneumonia during seasonal and pandemic outbreaks. We used a human type 6B pneumococcal challenge model to show that carriage acquisition induces early degranulation of resident neutrophils and recruitment of monocytes to the nose. Monocyte function associated with clearance of pneumococcal carriage. Prior nasal infection with live attenuated influenza virus induced inflammation, impaired innate function and altered genome-wide nasal gene responses to pneumococcal carriage. Levels of the cytokine IP-10 promoted by viral infection at the time of pneumococcal encounter was positively associated with bacterial density. These findings provide novel insights in nasal immunity to pneumococcus and viral-bacterial interactions during co-infection

Pneumococcal colonization impairs mucosal immune responses to live attenuated influenza vaccine.

Influenza virus infections affect millions of people annually, and current available vaccines provide varying rates of protection. However, the way in which the nasal microbiota, particularly established pneumococcal colonization, shape the response to influenza vaccination is not yet fully understood. In this study, we inoculated healthy adults with live Streptococcus pneumoniae and vaccinated them 3 days later with either tetravalent-inactivated influenza vaccine (TIV) or live attenuated influenza vaccine (LAIV). Vaccine-induced immune responses were assessed in nose, blood, and lung. Nasal pneumococcal colonization had no impact upon TIV-induced antibody responses to influenza, which manifested in all compartments. However, experimentally induced pneumococcal colonization dampened LAIV-mediated mucosal antibody responses, primarily IgA in the nose and IgG in the lung. Pulmonary influenza-specific cellular responses were more apparent in the LAIV group compared with either the TIV or an unvaccinated group. These results indicate that TIV and LAIV elicit differential immunity to adults and that LAIV immunogenicity is diminished by the nasal presence of S. pneumoniae. Therefore, nasopharyngeal pneumococcal colonization may affect LAIV efficacy

Nasal Pneumococcal Density is Associated with Microaspiration and Heightened Human Alveolar Macrophage Responsiveness to Bacterial Pathogens.

RATIONALE Pneumococcal pneumonia remains a global health problem. Colonization of the nasopharynx with S.pneumoniae (Spn), although, a prerequisite of infection, is the main source of exposure and immunological boosting in children and adults. However, our knowledge of how nasal colonization impacts on the lung cells, especially on the predominant alveolar macrophage (AM) population, is limited. OBJECTIVES Using a Controlled Human Infection Model to achieve nasal colonization with 6B serotype, we investigated the effect of Spn colonization on lung cells. METHODS We collected bronchoalveolar lavages from healthy pneumococcal challenged participants aged 18-49 years. Confocal microscopy, molecular and classical microbiology were used to investigate microaspiration and pneumococcal presence in the lower airways. AM opsonophagocytic capacity was assessed by functional assays in vitro, whereas flow cytometry and transcriptomic analysis were used to assess further changes on the lung cellular populations. MEASUREMENTS AND MAIN RESULTS AM from Spn-colonized exhibited increased opsonophagocytosis to pneumococcus (11.4% median increase) for four months after clearance of experimental pneumococcal colonization. AM had also increased responses against other bacterial pathogens. Pneumococcal DNA detected in the BAL samples of Spn-colonized were positively correlated with nasal pneumococcal density (r=0.71, p=0.029). Similarly, AM heightened opsonophagocytic capacity was correlated with nasopharyngeal pneumococcal density (r=0.61, p=0.025). CONCLUSIONS Our findings demonstrate that nasal colonization with pneumococcus and microaspiration prime AM, leading to brisker responsiveness to both pneumococcus and unrelated bacterial pathogens. The relative abundance of AM in the alveolar spaces, alongside with their potential for non-specific protection, render them an attractive target for novel vaccines. Clinical trial registration available at http://www.isrctn.com, ID: ISRCTN16993271

Two randomized trials of effect of live attenuated influenza vaccine on pneumococcal colonization

The human nasopharynx is frequently colonized by Streptococcus pneumoniae (the pneumococcus), serving as the reservoir for transmission, a state which necessarily precedes invasive pneumococcal infection. Influenza infection increases pneumococcal colonization density and dysregulates host immune responses, increasing the risk of secondary bacterial pneumonia and death

Novel Analysis of Immune Cells from Nasal Microbiopsy Demonstrates Reliable, Reproducible Data for Immune Populations, and Superior Cytokine Detection Compared to Nasal Wash

The morbidity and mortality related to respiratory tract diseases is enormous, with hundreds of millions of individuals afflicted and four million people dying each year. Understanding the immunological processes in the mucosa that govern outcome following pathogenic encounter could lead to novel therapies. There is a need to study responses at mucosal surfaces in humans for two reasons: (i) Immunological findings in mice, or other animals, often fail to translate to humans. (ii) Compartmentalization of the immune system dictates a need to study sites where pathogens reside. In this manuscript, we describe two novel non-invasive nasal mucosal microsampling techniques and their use for measuring immunological parameters: 1) using nasal curettes to collect cells from the inferior turbinate and; 2) absorptive matrices to collect nasal lining fluid. Both techniques were well tolerated and yielded reproducible and robust data. We demonstrated differences in immune populations and activation state in nasal mucosa compared to blood as well as compared to nasopharyngeal lumen in healthy adults. We also found superior cytokine detection with absorptive matrices compared to nasal wash. These techniques are promising new tools that will facilitate studies of the immunological signatures underlying susceptibility and resistance to respiratory infections