Michael Boyle

Inflammatory subtypes in asthma: assessment and identification using induced sputum.

Objective:  The authors sought to investigate the detection of non‐eosinophilic asthma using induced sputum. Although this is an important subtype of clinical asthma, its recognition is not standardized.

Innate immune activation in neutrophilic asthma and bronchiectasis

Background: The role of the innate immune system in the pathogenesis of asthma is unclear. Activation of innate immune receptors in response to bacterial lipopolysaccharide, viral infection and particulate matter triggers a pre-programmed inflammatory response, which involves interleukin (IL)8 and neutrophil influx. The inflammatory response in asthma is heterogeneous. Aim: To test the hypothesis that innate immune activation may be a relevant inflammatory mechanism in neutrophilic asthma where IL8 levels are increased. Methods: Induced sputum was obtained from non-smoking adults with asthma (n = 49), healthy controls (n = 13) and a positive reference group with bronchiectasis (n = 9). Subjects with asthma were classified into inflammatory subtypes using induced sputum cell counts. Sputum was examined for mRNA expression of the innate immune receptors toll-like receptor (TLR)2, TLR4 and CD14, and inflammatory cytokines. A separate sputum portion was dispersed and the supernatant assayed for surfactant protein A, IL8, soluble CD14 and endotoxin. Results: Expression of innate immune receptors was increased in subjects with bronchiectasis and neutrophilic asthma compared with other asthma subtypes and controls. Increased expression of the receptors TLR2, TLR4 and CD14, as well as the pro-inflammatory cytokines IL8 and IL1β, was observed. Subjects with neutrophilic asthma had higher airway levels of endotoxin than the other groups studied. Conclusion: There is evidence of activation of the innate immune system in asthma which results in the production of pro-inflammatory cytokines and may contribute to the pathogenesis of neutrophilic asthma.

Methylation differences at the HLA-DRB1 locus in CD4+ T-Cells are associated with multiple sclerosis

Background: Multiple sclerosis (MS) is thought to be caused by T-cell mediated autoimmune dysfunction. Risk of developing MS is influenced by environmental and genetic factors. Modifiable differences in DNA methylation are recognized as epigenetic contributors to MS risk and may provide a valuable link between environmental exposure and inherited genetic systems. Objectives and methods: To identify methylation changes associated with MS, we performed a genome-wide DNA methylation analysis of CD4+ T cells from 30 patients with relapsing–remitting MS and 28 healthy controls using Illumina 450K methylation arrays. Results: A striking differential methylation signal was observed at chr. 6p21, with a peak signal at HLA-DRB1. After prioritisation, we identified a panel of 74 CpGs associated with MS in this cohort. Most notably we found evidence of a major effect CpG island in DRB1 in MS cases (pFDR < 3 × 10−3). In addition, we found 55 non-HLA CpGs that exhibited differential methylation, many of which localise to genes previously linked to MS. Conclusions: Our findings provide the first evidence for association of DNA methylation at HLA-DRB1 in relation to MS risk. Further studies are now warranted to validate and understand how these findings are involved in MS pathology.

Induced sputum IL-8 gene expression, neutrophil influx and MMP-9 in allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity reaction to the fungus Aspergillus fumigatus, causing severe asthma that may progress to bronchiectasis. Sputum neutrophilia can occur in association with sputum eosinophilia and correlates with the degree of bronchiectasis. The mechanisms of sputum neutrophilia in ABPA are not known. The aim of this study was to investigate the role of the chemokine interleukin (IL)-8 in sputum neutrophilia in ABPA. Induced sputum was obtained from subjects with ABPA (n=29), and compared to nonsensitised asthma (n=9) and healthy controls (n=21). Semiquantitative polymerase chain reaction was used to assess IL-8 gene expression in induced sputum and IL-8 protein was measured by enzyme-linked immunosorbent assay. Sputum IL-8 protein was significantly higher in ABPA compared to asthma and controls. IL-8 messenger ribonucleic acid/glyceraldehyde-3-phosphate dehydrogenase ratio was elevated in ABPA compared to asthma and controls. Sputum IL-8 correlated with sputum neutrophils, matrix metalloproteinase-9 levels and forced expiratory volume in one second. Interleukin-8 gene expression and protein release were increased in allergic bronchopulmonary aspergillosis and correlated with airway neutrophilia and airway obstruction. The interleukin-8-mediated neutrophil influx in allergic bronchopulmonary aspergillosis may induce lung damage via release of matrix metalloproteinase-9, potentially leading to bronchiectasis.

ONCOSTATIN M (OSM) IS INCREASED IN ASTHMA WITH INCOMPLETELY REVERSIBLE AIRFLOW OBSTRUCTION

Oncostatin M, a unique member of the interleukin (IL)-6 cytokine family, is thought to be involved in airway remodeling. The expression of oncostatin M in the lower airways is unknown. The aim of this study was to measure the sputum expression of oncostatin M in patients with asthma with and without irreversible airflow obstruction. Induced sputum was collected from nonsmoking adults with stable asthma (n = 53), 31 with incomplete reversibility of airflow obstruction. Peripheral blood cells were isolated and stimulated with lipopolysaccharide in 10 participants with asthma and irreversible airflow obstruction. Oncostatin M protein levels were determined in supernatant, whereas RNA was extracted to determine Oncostatin M mRNA expression using real-time polymerase chain reaction (PCR). Oncostatin M mRNA expression and protein levels were significantly higher in the sputum of asthmatics with irreversible airflow obstruction. Sputum oncostatin M levels were highest in people with severe airflow obstruction and were localized to airway neutrophils and macrophages. Peripheral blood neutrophils released more oncostatin M when stimulated with lipopolysaccharide compared with unstimulated neutrophils. Sputum oncostatin M is increased in asthma with irreversible airflow obstruction and is present in airway neutrophils and macrophages. Oncostatin M may link airway inflammation to remodeling in asthma.

Sulphadiazine desensitization in patients with AIDS and cerebral toxoplasmosis

The objectives of this study were to evaluate the efficacy of a sulphadiazine desensitization protocol to treat patients with AIDS and cerebral toxoplasmosis (CT) and known sulphonamide allergy, to ensure that an adequate dose of sulphadiazine (2-4 g/day) was achieved rapidly (within 4-5 days), and to assess the effect of concurrent corticosteroid (CS) administration on the success rate of the regimen. Sixteen patients with CT and a past history or current manifestations of sulphonamide allergy were desensitized to sulphadiazine from October 1988 to December 1989. The protocol employed the oral administration of gradually increasing increments of sulphadiazine 3-hourly over 5 days. Success was defined as tolerance of 2-4 g oral sulphadiazine per day for at least 7 days until death or the present time without any allergic reactions. Our success rated overall was 10 out of 16 patients (62%). Seven patients achieved a final dose of 4 g/day and three a dose of 2 g/day. Concurrent CS administration did not appear to affect the outcome in the small number of patients studied. Our sulphadiazine regimen rapidly, successfully and safely desensitized patients with CT and sulphonamide allergy, allowing the optimal first-line treatment to continue. The aetiology of allergy in HIV-infected patients and the mechanisms by which desensitization works are unknown.

Definition of two distinct types of AIDS-associated non-Hodgkin lymphoma

Summary Non‐Hodgkin lymphoma (NHL) in a human immunodeficiency virus (HIV)‐infected person is an AIDS‐defining condition. There is both an increased incidence of NHL and a poorer prognosis for the disease in these HIV‐infected persons, compared with patients who spontaneously develop NHL.

Human immunodeficiency virus-related primary cutaneous aspergillosis

A 31‐year‐old Caucasian man with AIDS developed a crusted violaceous plaque under adhesive tape near a central venous catheter insertion site. Histological examination demonstrated a ruptured hair follicle containing collections of fungal hyphae typical of Aspergillus spp. A culture of the biopsy material grew Aspergillus fumigatus. The patient responded to removal of the catheter and the occlusive dressing, in addition to itraconazole therapy. Aspergillosis must be considered in the differential diagnosis of cutaneous lesions in human immunodeficiency virus‐infected patients, in particular when the lesion occurs under adhesive tape or an occlusive dressing.

The effects of circuit and humidifier type on contamination potential during mechanical ventilation: A laboratory study

BACKGROUND This study was undertaken because of concerns that ventilator humidifiers could be exacerbating the problem of nosocomial pneumonia in patients receiving mechanical ventilation. METHODS Four different brands of humidifiers were used in conjunction with a siemens Servo 900B mechanical ventilator (Siemens Life Support Services, Solna, Sweden). In the first part, the ventilator was operated with humidifiers filled with contaminated water at room temperature. The viability of airborne particles and the effect of flow rates on the number of particles produced were assessed. In the second part, we measured the effect of time and temperature on bacterial survival in humidifier chambers. Because only bubble-through humidifiers were determined to produce infectious particles, the speed with which a contaminated bubble-through humidifier could infect circuit condensate was also determined. Aliquots of chamber water and circuit condensate, as well as air samples and distal circuit swabs, were cultured. RESULTS Humidifiers other than bubble-through humidifiers did not produce aerosols. Particle production by bubble-through humidifiers varied directly with flow rate (R2 = 0.91). Chamber temperatures did not affect chamber colony counts except in bubble-through humidifiers. Although chamber colony counts in bubble-through humidifiers decreased with time, organisms remained viable throughout the study. When bubble-through humidifiers were heated, both condensate and effluent gas became heavily contaminated within minutes of flow initiation. CONCLUSIONS Bubble-through humidifiers produce aerosols that readily contaminate both circuit condensate and effluent gas. Avoiding bubble-through humidifiers should improve patient safety while allowing changes in practice that can result in significant cost savings.

A role for autoantibodies in atherogenesis

An increased risk of cardiovascular disease (CVD) has long been recognized amongst people with autoimmune disease. It has been unclear whether this is due mainly to the ensuing treatment, particularly steroids, or whether some of this risk is due to the autoimmune process itself with subsequent inflammation. Indeed, a large body of evidence supports a role for chronic inflammation in atherogenesis, and autoantibodies have been identified as mediators in this complex inflammatory environment. Our aim is to carry out a systematic review of existing literature in order to formally establish the strength of the association between autoantibodies and atherosclerosis, amongst individuals without clinical autoimmune disease. An electronic search of five databases to June 2016 was performed by two independent reviewers. Inclusion criteria were analytical studies of adults, with at least two studies per autoantibody. Quality analysis was carried out using the Newcastle-Ottawa scale and the Cochrane Risk of Bias Quality Assessment Tool where appropriate. Where possible, studies were pooled using random effects models. Raised levels of anti-cardiolipin (odds ratio [OR] = 1.30; 95% CI: 1.15-1.49) and anti-oxidized low-density lipoprotein Immunoglobulin (Ig) G (OR = 1.25; 95% CI: 1.11-1.41), unspecified anti-cyclic citrullinated protein (OR = 3.09; 95% CI: 1.49-6.41) and anti-human heat shock protein 60 IgA (OR = 1.57; 95% CI: 1.15-2.16) were observed to increase the risk of cardiovascular outcomes. Alternatively, Anti-phosphorylcholine IgM (OR = 1.31; 95% CI: 1.14-1.50) conferred protection against CVD. Our results support an important role for autoantibodies in mediating cardiovascular events, independent of therapeutic treatments. Future research may focus on the presence of autoantibodies as markers of immune dysregulation and CVD risk.