Evaluation of chlorhexidine sensitization amongst healthcare workers.

BACKGROUND: Chlorhexidine is an antiseptic widely used in healthcare settings. There are increasing reports of significant hypersensitivity reactions associated with its use. Development of chlorhexidine allergy has been identified as an important occupational risk to healthcare workers (HCWs). AIMS: To evaluate the prevalence of sensitization to chlorhexidine amongst HCWs at a large tertiary hospital to assess the potential allergic safety risks associated with chlorhexidine exposure to staff. METHODS: Sensitization to chlorhexidine was evaluated by measurement of serum-specific immunoglobulin E (IgE) in samples collected from staff assessed after a sharps-injury incident and laboratory staff collected for quality assurance procedures. This test method has been shown to have high sensitivity and specificity in the diagnosis of chlorhexidine allergy. Prevalence of sensitization was additionally evaluated with reference to changes in exposure to chlorhexidine-based hand hygiene products because of infection control procedures and the coronavirus disease 2019 pandemic. RESULTS: A total of 320 samples were examined. The prevalence of positive chlorhexidine-specific IgE was 2%. Prevalence of sensitization in samples collected before and after increased chlorhexidine exposure was 1% and 3%. This did not represent a statistically significant difference. CONCLUSIONS: The prevalence figures for chlorhexidine sensitization in this study are higher than have been estimated previously for similar HCW cohorts. Increased exposure to chlorhexidine-based hand hygiene products was not demonstrated to increase sensitization in this group. Given the risk of severe reactions in sensitized individuals, this study indicates that evaluation of chlorhexidine allergy is important when investigating occupational allergy in HCWs.

Distinct bronchial microbiome precedes clinical diagnosis of lung cancer.

Resident microbial populations have been detected across solid tumors of diverse origins. Sequencing of the airway microbiota represents an opportunity for establishing a novel omics approach to early detection of lung cancer, as well as risk prediction of cancer development. We hypothesize that bacterial shifts in the pre-malignant lung may be detected in non-cancerous airway liquid biopsies collected during bronchoscopy. We analyzed the airway microbiome profile of near 400 patients: epithelial brushing samples from those with lung cancer, those who developed an incident cancer, and those who do not develop cancer after 10-year follow-up. Using linear discriminate analysis, we define and validate a microbial-based classifier that is able to predict incident cancer in patients before diagnosis with no clinical signs of cancer. Our results demonstrate the potential of using lung microbiome profiling as a method for early detection of lung cancer.

Morphine and pholcodine-specific IgE have limited utility in the diagnosis of anaphylaxis to benzylisoquinolines.

BACKGROUND: Investigation of immediate hypersensitivity reactions in the perioperative setting involves skin testing and measurement of specific IgE (sIgE) as standard practice. In the case of the neuromuscular blocking agents (NMBAs), the main allergenic epitopes have been shown to be substituted ammonium groups. Commercial assays are available for detection of sIgE to these epitopes using morphine and pholcodine substrates but questions have been raised about the effectiveness of these assays in the diagnosis of benzylisoquinoline anaphylaxis. This study was therefore undertaken to assess the effectiveness of these assays in the diagnosis of hypersensitivity reactions to this group of NMBAs. METHODS: Analysis was carried out on all available results for patients assessed at the Royal North Shore Hospital Anaesthetic Allergy Clinic during the period June 2009 to June 2016. Standardised intradermal skin tests were performed with a panel of NMBAs. Measurement of sIgE to morphine and pholcodine was performed via the Phadia ImmunoCAP® system. RESULTS: For all patients with positive skin test results to NMBAs which included a benzylisoquinoline NMBA (n = 24), 75% exhibited negative sIgE to both morphine and pholcodine. Where patients were reactive to benzylisoquinoline NMBAs alone (n = 12), 100% exhibited negative sIgE results, indicating 0% sensitivity of the assays relative to skin testing, in this subgroup. CONCLUSION: Use of sIgE testing to morphine and pholcodine in the assessment of NMBA immediate hypersensitivity is a valuable tool particularly in the case of reactions to the aminosteroid NMBAs. However, these assays are unreliable in detecting sensitisation to benzylisoquinoline NMBAs.

A novel multiplex polymerase chain reaction assay for detection of both HLA-A*31:01/HLA-B*15:02 alleles, which confer susceptibility to carbamazepine-induced severe cutaneous adverse reactions.

HLA-A*31:01 and HLA-B*15:02 have been widely reported to confer genetic susceptibility to carbamazepine (CBZ)-induced severe cutaneous adverse reactions (SCARs). Accordingly, the screening for these alleles has been highly recommended to prevent SCAR prior to introducing CBZ therapy. Although a number of methods are available for screening of HLA-A*31:01 or HLA-B*15:02 alleles separately, developing an assay that can detect both these alleles would be more clinically practical, cost-effective and less time-consuming. Therefore, in this study, a multiplex polymerase chain reaction (PCR) using TaqMan Probe was designed and validated to be able to detect HLA-A*31:01 and HLA-B*15:02. In comparison with Luminex-SSO/SBT/SSB, the multiplex PCR assay for detection of HLA-A*31:01 and HLA-B*15:02 had a perfect agreement in the validation group of 125 samples. The method was able to detect the target genes at the DNA concentration of 0.037 ng/µL. The unit cost of this assay is less than $5 USD with total time of 110 minutes.

Immune mediated neuropathy following checkpoint immunotherapy.

Checkpoint immunotherapy has revolutionised cancer therapy and is now standard treatment for many malignancies including metastatic melanoma. Acute inflammatory neuropathies, often labelled as Guillain-Barre syndrome, are an uncommon but potentially severe complication of checkpoint immunotherapy with individual cases described but never characterised as a group. We describe a case of acute sensorimotor and autonomic neuropathy following a single dose of combination ipilimumab and nivolumab for metastatic melanoma. A literature search was performed, identifying 14 other cases of acute neuropathy following checkpoint immunotherapy, with the clinical, electrophysiological and laboratory features summarised. Most cases described an acute sensorimotor neuropathy (92%) with hyporeflexia (92%) that could occur from induction up till many weeks after the final dose of therapy. In contrast to Guillain-Barre syndrome, the cerebrospinal fluid (CSF) analysis often shows a lymphocytic picture (50%) and the electrophysiology showed an axonal pattern (55%). Treatment was variable and often in combination. 11 cases received steroid therapy with only 1 death within this group, whereas of the 4 patients who did not receive steroid therapy there were 3 deaths. In conclusion checkpoint immunotherapy - induced acute neuropathies are distinct from and progress differently to Guillain-Barre syndrome. As with other immunotherapy related adverse events corticosteroid therapy should be initiated in addition to usual therapy.

A polymorphism within the psoriasis susceptibility 1 candidate 1 (PSORS1C1) gene is not linked to HLA-B*58:01 in an Australian cohort.

Association exists between HLA-B*58:01 allele and allopurinol Stevens-Johnson syndrome (SJS), especially those of an Asian heritage but associations have been also described in Caucasian populations. This creates the need to develop a rapid, robust and inexpensive assay for pre-screening of HLA-B*58:01. A polymorphism within PSORS1C1 gene was recently found in linkage disequilibrium (LD) with HLA-B*58:01 allele in the Japanese population. The aim of this study is to confirm whether this polymorphism can be used as a surrogate biomarker to identify carriers for HLA-B*58:01. No linkage was found between the two in the Australian cohort.

Rapid and sequential desensitization to both aspirin and clopidogrel.

Hypersensitivity reactions to aspirin and clopidogrel are 2.5% and 1%, respectively. Dual anti-platelet therapy with these drugs is effective in preventing thrombosis following deployment of stents for cerebrovascular and cardiovascular syndromes. Desensitization therapy with both aspirin and clopidogrel may be required for patients undergoing stent implantation that have experienced hypersensitivity to these agents. We report the case of a 58-year-old woman who developed urticaria and angioedema following aspirin therapy for ischaemic cerebrovascular disease. She developed an identical reaction after clopidogrel was subsequently administered. Investigations revealed the presence of an internal carotid artery aneurysm that required deployment of a stent. Rapid desensitization to aspirin over 5.5 h followed 3 days later by rapid desensitization to clopidogrel over 2.5 h was successfully performed prior to stenting. After 4 months she has tolerated this dual anti-platelet therapy without any adverse reaction. Rapid and sequential desensitization to both aspirin and clopidogrel can be successfully performed for patients who require stent deployment but have hypersensitivity to both these anti-platelet agents.

Treatment options for pemphigus foliaceus.

Pemphigus foliaceus belongs to a group of rare autoimmune blistering mucocutaneous conditions. Systemic corticosteroids have markedly reduced the mortality from the disease but its utility is restricted by adverse events. This is further complicated by the fact that steroid-sparing agents are also associated with serious adverse events and there are only few randomized controlled trials demonstrating a beneficial response from the use of these agents. Azathioprine and mycophenolate mofetil appear to be the most feasible first line adjunctive agents in terms of inducing and maintaining remission and harboring a comparatively favourable side effect profile. An enhanced understanding of the pathogenesis of pemphigus has resulted in the implementation of a number of novel therapies including biological agents, intravenous immunoglobulin, and extracorporeal treatment modalities. These therapies have also been mainly studied through case series reports, are expensive and/or difficult to access in some centres, and are associated with a number of deleterious side effects. Rituximab, the anti-CD20 chimeric monoclonal antibody, is currently emerging as the therapy of choice in severe refractory disease. Further studies on the effects and safety profiles of more specific agents, such as peptide immunotherapy and the targeting of intracellular signalling molecules involved in the pathogenesis of pemphigus are needed.

Two Case Reports of Life-Threatening Ethanol-Induced Anaphylaxis.

Adverse reactions to alcoholic beverages are common and diverse in aetiology. Ethanol-induced anaphylaxis, however, is a rare but often life-threatening condition that warrants careful evaluation in suspected individuals. We present the cases of two patients who developed urticaria, angioedema and throat constriction within minutes of consuming white wine. Both individuals demonstrated no adverse reaction to double-blind placebo-controlled challenges to metabisulphite or sodium salicylate. However, an open challenge to white wine elicited urticaria in both subjects. This reaction was reproduced with a double-blind placebo-controlled challenge to ethanol and was accompanied by a rise in serum total tryptase levels. Positive skin test responses to 2% acetic acid, a breakdown product of ethanol, were elicited from both patients but not from three normal controls. These two cases demonstrate the need for a systematic approach for the evaluation of allergic reactions to alcohol.

The genetic control of susceptibility to Mycobacterium tuberculosis.

Mycobacterium tuberculosis is one of the most successful human pathogens, surviv ing in latent foci of infection in one third of humanity, yet causing lung necrosis in sufficient individuals to ensure its transmission. Each stage of the host response to M. tuberculosis is under genetic control, including the initial encounter with mycobacteria by macrophages, epithelial cells and dendritic cells in the lung, induction of the inductive T cell response, and killing by activated macrophages within granulomas. Although environmental factors are important determinants of progression to disease, there is a genetic component underlying susceptibility to tuberculosis (TB), the basis of which may vary in different populations. Recent studies using a variety of methods have defined a number of susceptibility alleles for the development of active TB. Many of these influence macrophage responses to mycobacteria. We have studied the influence of loss of function polymorphisms in the human P2X7 gene on the capacity of macrophages to kill M. tuberculosis. Activation of the P2X7 receptor, an ATP-gated Ca2+ channel, leads to the formation of pores, the activation of phospholipase D, and the induction of apoptosis with death of the infecting mycobacteria. Macrophages from subjects who are heterozygote, homozygote or compound heterozygote for these polymorphisms fail to undergo apoptosis and show partial or complete inhibition of mycobacterial killing. One of these non-functioning polymorphisms was significantly associated with increased susceptibility to TB disease, particularly extrapulmonary disease, in two unrelated cohorts of TB patients. Insights into the genetic regulation of susceptibility to human TB may identify novel methods for controlling latent M. tuberculosis and reducing the burden of tuberculosis.