Discrete tissue microenvironments instruct diversity in resident memory T cell function and plasticity.

Tissue-resident memory T (TRM) cells are non-recirculating cells that exist throughout the body. Although TRM cells in various organs rely on common transcriptional networks to establish tissue residency, location-specific factors adapt these cells to their tissue of lodgment. Here we analyze TRM cell heterogeneity between organs and find that the different environments in which these cells differentiate dictate TRM cell function, durability and malleability. We find that unequal responsiveness to TGFß is a major driver of this diversity. Notably, dampened TGFß signaling results in CD103- TRM cells with increased proliferative potential, enhanced function and reduced longevity compared with their TGFß-responsive CD103+ TRM counterparts. Furthermore, whereas CD103- TRM cells readily modified their phenotype upon relocation, CD103+ TRM cells were comparatively resistant to transdifferentiation. Thus, despite common requirements for TRM cell development, tissue adaptation of these cells confers discrete functional properties such that TRM cells exist along a spectrum of differentiation potential that is governed by their local tissue microenvironment.

Randomized Trial of BCG Vaccine to Protect against Covid-19 in Health Care Workers.

BACKGROUND: The bacille Calmette-Guérin (BCG) vaccine has immunomodulatory "off-target" effects that have been hypothesized to protect against coronavirus disease 2019 (Covid-19). METHODS: In this international, double-blind, placebo-controlled trial, we randomly assigned health care workers to receive the BCG-Denmark vaccine or saline placebo and followed them for 12 months. Symptomatic Covid-19 and severe Covid-19, the primary outcomes, were assessed at 6 months; the primary analyses involved the modified intention-to-treat population, which was restricted to participants with a negative test for severe acute respiratory syndrome coronavirus 2 at baseline. RESULTS: A total of 3988 participants underwent randomization; recruitment ceased before the planned sample size was reached owing to the availability of Covid-19 vaccines. The modified intention-to-treat population included 84.9% of the participants who underwent randomization: 1703 in the BCG group and 1683 in the placebo group. The estimated risk of symptomatic Covid-19 by 6 months was 14.7% in the BCG group and 12.3% in the placebo group (risk difference, 2.4 percentage points; 95% confidence interval [CI], -0.7 to 5.5; P = 0.13). The risk of severe Covid-19 by 6 months was 7.6% in the BCG group and 6.5% in the placebo group (risk difference, 1.1 percentage points; 95% CI, -1.2 to 3.5; P = 0.34); the majority of participants who met the trial definition of severe Covid-19 were not hospitalized but were unable to work for at least 3 consecutive days. In supplementary and sensitivity analyses that used less conservative censoring rules, the risk differences were similar but the confidence intervals were narrower. There were five hospitalizations due to Covid-19 in each group (including one death in the placebo group). The hazard ratio for any Covid-19 episode in the BCG group as compared with the placebo group was 1.23 (95% CI, 0.96 to 1.59). No safety concerns were identified. CONCLUSIONS: Vaccination with BCG-Denmark did not result in a lower risk of Covid-19 among health care workers than placebo. (Funded by the Bill and Melinda Gates Foundation and others; BRACE ClinicalTrials.gov number, NCT04327206.).

Impact of a drug allergy education course for non-specialists: Findings from ADAPT-A randomized crossover trial.

BACKGROUND: The consequences of drug allergy remain a global health concern. Drug allergy is often a neglected topic and many non-specialists lack sufficient knowledge or confidence in evaluating or managing this common condition. Evidence-based interventions to better equip non-specialists to tackle drug allergy are needed. The aim of the study is to evaluate the effectiveness of an intensive educational course on drug allergy knowledge and practice of non-specialists. METHODS: A randomized crossover trial (NCT06399601) was conducted among practicing physicians and nurses participating in an intensive drug allergy course-Advances in Drug Allergy & Penicillin Testing (ADAPT). Participants' baseline knowledge and self-reported practices were assessed with standardized questionnaires (scored from 0 to 100, with "satisfactory" defined as ≥60/100). Participants were randomized into two cohorts and attended ADAPT at different time points. Serial responses before and after the course were compared within and between cohorts. RESULTS: Seventy participants (25 physicians, 45 nurses) randomized into two groups completed the course. Baseline drug allergy knowledge (58.0 ± 19.9) and self-reported practice (36.9 ± 24.3) were unsatisfactory among non-specialists, with significantly lower scores from nurses than physicians in both domains (knowledge: 49.0 ± 17.4 vs. 74.0 ± 12.7; practice: 32.1 ± 21.3 vs. 53.3 ± 23.1; all p < 0.001). Following completion of ADAPT, participants demonstrated significant improvements in knowledge (58.0 ± 19.9 vs. 77.7 ± 15.9, p < 0.001) and self-reported practice (36.9 ± 24.3 vs. 71.0 ± 20.2, p < 0.001). All participants (100%) and 99% of participants agreed that the course improved their clinical knowledge and practice, respectively. CONCLUSIONS: ADAPT, an intensive drug allergy educational course was effective in improving drug allergy knowledge and practice for non-specialists. Further longitudinal studies are required to evaluate long-term impact.

Omalizumab for management of hypersensitivity reactions to anticancer drugs.

Hypersensitivity reactions to anticancer drugs include treatment-limiting toxicity. Standard drug desensitisation offers temporary tolerance and hence requires repetition. We used omalizumab, an anti-immunoglobulin E antibody, to overcome immediate and delayed hypersensitivity reactions to various anticancer drugs. Seven of the eight patients in the current study successfully resumed the desired anticancer drug regimen without standard desensitisation. No safety issues from omalizumab were observed.

Antibiotic allergy labels and optimal antimicrobial stewardship.

BACKGROUND: Although common, antimicrobial allergy labels (AAL) rarely reflect immunologically-mediated hypersensitivity and can lead to poorer outcomes from alternative antimicrobial agents. Antimicrobial stewardship programs are ideally placed to assess AAL early as a means of improving antimicrobial use. AIMS: To quantify the prevalence of AAL in patients referred for antimicrobial stewardship review and assess their impact on antibiotic prescribing, patient mortality, hospital length of stay, readmission and rates of multidrug-resistant infections. METHODS: We conducted a retrospective analysis of adult patients referred for inpatient antimicrobial prospective audit and feedback rounds (PAFR) through an electronic referral system (eReferrals) over a 12-month period in 2015. Outcome data were collected for a period of 36 months following the initial review. RESULTS: Of the 639 patient records reviewed, 630 met inclusion criteria; 103 (16%) had an AAL, of which 82 (13%) had reported allergies to ß-lactam antibiotics. Those with AAL were significantly less likely to be receiving guideline-recommended antimicrobial therapy (50% vs 64%, P = 0.0311); however, there were no significant difference in mortality, hospital length of stay, readmission or increased incidence of multidrug-resistant infections. CONCLUSIONS: Our cohort demonstrated that AAL was associated with reduced adherence to antibiotic guidelines. The lack of association with adverse outcomes may reflect limitations within the study including retrospective cohort study numbers and observational nature, further skewed by high rates of poor documentation. A clear opportunity exists for antimicrobial stewardship programs to incorporate allergy assessment, de-labelling, challenge and referral into these rounds.

Penicillin allergy SHACK: Survey of hospital and community knowledge.

AIM: Penicillin allergy accounts for the majority of all reported adverse drug reactions in adults and children. Foregoing first-line antibiotic therapy due to penicillin allergy label is associated with an increased prevalence of infections by resistant organisms and longer hospitalisation. Clinician awareness of allergy assessment, referral indications, management of allergy and anaphylaxis is therefore vital but globally lacking. We aim to assess the knowledge of penicillin allergy, assessment and management in Western Australian health professionals. METHODS: An anonymous survey was distributed to pharmacists, nurses and physicians within Western Australian paediatric and adult Hospitals, Community and General Practice. RESULTS: In total, 487/611 were completed and included in the statistical analysis. Only 62% (301/487) of respondents routinely assessed for patient medication allergies. Of those who assessed allergy, 9% (28/301) of respondents met the Australian standards for allergy assessment. Only 22% (106/487) of participants correctly cited all indications for management with adrenaline in anaphylaxis to antibiotics and 67% (197/292) of physicians rarely or never referred to an allergy service. Paediatric clinicians had an increased understanding of allergy assessment and anaphylaxis management. Recent penicillin allergy education within a 5-year period led to significant improvements in allergy knowledge. CONCLUSION: Overall, knowledge, assessment and management of penicillin allergies among practitioners in Western Australia are currently inadequate in adults and paediatric clinicians to provide safe and effective clinical care. The implementation of a targeted education program for WA health professionals is urgently required and is expected to improve clinician knowledge and aid standardised penicillin assessment (de-labelling) practices.

Asia-Pacific survey of physicians' perceptions and managements of chronic rhinosinusitis.

BACKGROUND: The diagnosis and management of patients with chronic rhinosinusitis (CRS) may vary between otolaryngologists and allergists. Moreover, the adherence of different practitioners to European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS) 2020 guideline recommendations has not been previously ascertained in Asia-Pacific regions. OBJECTIVE: Different specialists' perceptions and managements of CRS in Asia-Pacific regions were assessed in an attempt to gauge these practices against EPOS 2020 guidelines. METHODS: A transregional, cross-sectional survey was conducted to assess otolaryngologists' and allergists' perceptions and managements of CRS with regard to diagnosis, management and adherence to EPOS 2020 guidelines. RESULTS: Sixteen physicians in Asia-Pacific regions responded to the questionnaire. A total of 71.4% of otolaryngologists preferred to diagnose CRS with a combination of positive nasal symptoms and nasal endoscopy plus sinus CT, whereas 22.2% of allergists took such criterion to diagnose CRS. Compared to allergists, otolaryngologists more often considered the endotype classification (85.8% versus 55.5%). For the preferred first-line treatment, in addition to intranasal corticosteroids recommended by all respondents, 66.7% of allergists preferred antihistamines, whereas 71.4% of otolaryngologists preferred nasal saline irrigation. Regarding the proper timing of surgery, 71.5% of otolaryngologists reported 8-12 weeks of treatment after the initiation of medication, while more than half of the allergists recommended 4-6 weeks of medical treatment. CONCLUSIONS: This survey shows that variable perceptions and practices for CRS may exist between physicians with different specialties and highlights the need for increased communication and awareness between otolaryngologists and allergists to improve the diagnosis and treatment of CRS.

Deep sequence analysis of HIV adaptation following vertical transmission reveals the impact of immune pressure on the evolution of HIV.

Human immunodeficiency virus (HIV) can adapt to an individual's T cell immune response via genomic mutations that affect antigen recognition and impact disease outcome. These viral adaptations are specific to the host's human leucocyte antigen (HLA) alleles, as these molecules determine which peptides are presented to T cells. As HLA molecules are highly polymorphic at the population level, horizontal transmission events are most commonly between HLA-mismatched donor/recipient pairs, representing new immune selection environments for the transmitted virus. In this study, we utilised a deep sequencing approach to determine the HIV quasispecies in 26 mother-to-child transmission pairs where the potential for founder viruses to be pre-adapted is high due to the pairs being haplo-identical at HLA loci. This scenario allowed the assessment of specific HIV adaptations following transmission in either a non-selective immune environment, due to recipient HLA mismatched to original selecting HLA, or a selective immune environment, mediated by matched donor/recipient HLA. We show that the pattern of reversion or fixation of HIV adaptations following transmission provides insight into the replicative cost, and likely compensatory networks, associated with specific adaptations in vivo. Furthermore, although transmitted viruses were commonly heavily pre-adapted to the child's HLA genotype, we found evidence of de novo post-transmission adaptation, representing new epitopes targeted by the child's T cell response. High-resolution analysis of HIV adaptation is relevant when considering vaccine and cure strategies for individuals exposed to adapted viruses via transmission or reactivated from reservoirs.

Drug Reaction with Eosinophilia and Systemic Symptoms: A Complex Interplay between Drug, T Cells, and Herpesviridae.

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, also known as drug induced hypersensitivity (DiHS) syndrome is a severe delayed hypersensitivity reaction with potentially fatal consequences. Whilst recognised as T cell-mediated, our understanding of the immunopathogenesis of this syndrome remains incomplete. Here, we discuss models of DRESS, including the role of human leukocyte antigen (HLA) and how observations derived from new molecular techniques adopted in key studies have informed our mechanism-based understanding of the central role of Herpesviridae reactivation and heterologous immunity in these disorders.

Antimicrobial anaphylaxis: the changing face of severe antimicrobial allergy.

OBJECTIVES: The epidemiology, clinical characteristics and outcomes of antimicrobial-associated anaphylaxis remain ill-defined. We sought to examine antimicrobial anaphylaxis with regard to: (i) the frequency of implicated antimicrobials; (ii) attributable mortality; and (iii) referral for definitive allergy assessment. METHODS: This was conducted through a national retrospective multicentre cohort study at five Australian tertiary hospitals (January 2010 to December 2015). Cases of antimicrobial anaphylaxis were identified from ICD-10 coding and adverse drug reaction committee databases. RESULTS: There were 293 participants meeting the case definition of antimicrobial anaphylaxis and 310 antimicrobial anaphylaxis episodes. Of 336 implicated antimicrobials, aminopenicillins (62/336, 18.5%) and aminocephalosporins (57/336, 17%) were implicated most frequently. ICU admission occurred in 43/310 (13.9%) episodes; however, attributable mortality was low (3/310, 1%). The rate of anaphylaxis to IV antibiotics was 3.5 (95% CI=2.9-4.3) per 100 000 DDDs and the rate of hospital-acquired anaphylaxis was 1.9 (95% CI=2.1-3.3) per 100 000 occupied bed-days. We observed overall low rates of hospital discharge documentation (222/310, 71.6%) and follow-up by specialist allergy services (73/310, 23.5%), which may compromise medication safety and antimicrobial prescribing in future. CONCLUSIONS: This study demonstrated that a high proportion of severe immediate hypersensitivity reactions presenting or acquired in Australian hospitals are secondary to aminopenicillins and aminocephalosporins. Overall rates of hospital-acquired anaphylaxis, predominantly secondary to cephalosporins, are low, and also associated with low inpatient mortality.

The role of skin testing and extended antibiotic courses in assessment of children with penicillin allergy: An Australian experience.

AIM: To determine if skin testing (ST) in addition to extended oral provocation challenge (OPC) is necessary for beta-lactam allergy verification in an Australian paediatric population. METHODS: This was a retrospective study (176 children) that undertook assessments for beta-lactam allergy from 2006 to 2015 at a tertiary paediatric hospital. Patients either underwent direct OPC without ST or ST plus challenge if ST was negative. RESULTS: The analysis included children with a history of varying rash types/severity as well as angioedema and reported anaphylaxis. A direct OPC was undertaken in 73 children. Three children reacted with one anaphylaxis. A total of 103 children underwent ST, with 13 children (12.6%) reacting. Of the 90 who subsequently proceeded to OPC, 4 reacted. A total of 132 children were given an extended oral course of the culprit antibiotic, to which 6 children reacted. CONCLUSIONS: A direct OPC with the culprit drug in Australian children can be safely performed, avoiding resource-intensive and painful ST. Our data demonstrate that a prior history of anaphylaxis does not necessarily predict IgE-mediated allergy, as detected by positive immediate ST or reactions to oral challenge. Such history should not detract from efforts to assess these children for antibiotic allergy. We suggest that extended courses of at least 5 days are important in paediatric antibiotic de-labelling as six children (4.5% of those who were prescribed the extended course) reacted in our study and even developed symptoms late in the extended course, from days 2 to 6.

An update on allergy and anaphylaxis in pediatric anesthesia.

Childhood allergy is common, and increasing. Many children are incorrectly labeled as having allergy or adverse drug reactions. This can pose a dilemma for anesthetists and lead to a change in practice or drug selection. We review the pathophysiology of hypersensitivity reactions and the implications for anesthesia of food allergy, atopy, and family history of allergy in children. The epidemiology of anaphylaxis is discussed. We discuss the common triggers of perioperative anaphylaxis in children and explore emerging triggers including chlorhexidine and sugammadex. Accurate data on pediatric perioperative anaphylaxis is limited worldwide, with marked geographic variation. This highlights the need for accurate local, district and/or nationwide incident reporting. The clinical features, diagnosis, and management of anaphylaxis under anesthesia are discussed. We review the process of expert allergy testing following a suspected case of anaphylaxis to guide future safe anesthesia administration. The preoperative consultation is an opportunity for referral for allergy testing to allow de-labeling. This has the potential for improved antibiotic stewardship and more effective treatment with first-line therapeutic agents.

Allergy alerts - The incidence of parentally reported allergies in children presenting for general anesthesia.

BACKGROUND AND AIM: Pediatric patients increasingly report allergies, including allergies to food and medications. We sought to determine the incidence and, nature of parent-reported allergies in children presenting for surgery and its significance for anesthetists. METHODS: We prospectively collected data on admissions through our surgical admission unit over a 2-month period at a pediatric tertiary care teaching hospital. Data collected included patient demographics, history of atopy, with more comprehensive information collected if an allergy was reported. A clinical immunologist and an anesthetist reviewed the documentation of all patients reporting an allergy. RESULTS: We reviewed 1001 pediatric patients, 158 (15.8%) patients with parent-reported allergies; to medications/drugs (n = 73), food (n = 66), environmental allergens (dust/grasses, n = 35), tapes/dressings (n = 27), latex (n = 4), and venom (eg, bee, wasp, n = 9). Forty-one patients reported antibiotic allergies, with Beta-lactam antibiotics being the most common, with the majority presenting with rash alone (57%). Ten patients reported allergies to nonsteroidal anti-inflammatory drugs and eight to opioids. Twenty-four patients reported egg and/or peanut allergy. Only 3/1001 (0.3%) patients were deemed to have evidence of likely IgE-mediated drug allergy. Of the reported allergies, only 60 (38.2%) had been investigated prior, most likely to be followed up were food (53%) and environmental allergies (44.4%). Only 4/73 (5.5%) reported medication allergies had further follow-up. Just four patients (0.4% of the entire cohort) had drug sensitivities/allergies that were likely to majorly alter anesthesia practice. CONCLUSION: Only the minority of parent-reported allergies in pediatric surgical patients were specialist confirmed and likely to be clinically relevant. Self-reported food allergy is commonly specialist verified whereas reactions to medications were generally not. Over-reporting of allergies is increasingly common and limits clinician choice of medications. Better education of patients and their families and more timely verification or dismissal of parent-reported reactions is urgently needed.

Non-immediate heparin and heparinoid cutaneous allergic reactions: a role for fondaparinux.

Non-immediate allergic cutaneous reactions to heparins have been increasingly reported, typically manifesting as large, eczematous plaques at sites of subcutaneous injection. Patients may demonstrate cross-reactivity between unfractionated heparin, low molecular weight heparin and semi-synthetic heparinoids, making finding an alternative difficult. Fondaparinux has been identified as a useful alternative in such patients; here we present the first two documented cases in Australia and a literature review.

The broad assessment of HCV genotypes 1 and 3 antigenic targets reveals limited cross-reactivity with implications for vaccine design.

OBJECTIVE: Developing a vaccine that is cross-reactive between HCV genotypes requires data on T cell antigenic targets that extends beyond genotype-1. We characterised T cell immune responses against HCV genotype-3, the most common infecting genotype in the UK and Asia, and assessed within genotype and between genotype cross-reactivity. DESIGN: T cell targets were identified in 140 subjects with either acute, chronic or spontaneously resolved HCV genotype-3 infection using (1) overlapping peptides and (2) putative human leucocyte antigens (HLA)-class-I wild type and variant epitopes through the prior assessment of polymorphic HCV genomic sites associated with host HLA, in IFNγ-ELISpot assays. CD4+/CD8+ T cell subsets were defined and viral variability at T cell targets was determined through population analysis and viral sequencing. T cell cross-reactivity between genotype-1 and genotype-3 variants was assessed. RESULTS: In resolved genotype-3 infection, T cells preferentially targeted non-structural proteins at a high magnitude, whereas in chronic disease T cells were absent or skewed to target structural proteins. Additional responses to wild type but not variant HLA predicted peptides were defined. Major sequence viral variability was observed within genotype-3 and between genotypes 1 and 3 HCV at T cell targets in resolved infection and at dominant epitopes, with limited T cell cross-reactivity between viral variants. Overall 41 CD4/CD8+ genotype-3 T cell targets were identified with minimal overlap with those described for HCV genotype-1. CONCLUSIONS: HCV T cell specificity is distinct between genotypes with limited T cell cross-reactivity in resolved and chronic disease. Therefore, viral regions targeted in natural HCV infection may not serve as attractive targets for a vaccine that aims to protect against multiple HCV genotypes.

Assessing the contribution of plastic-associated obesogenic compounds to cardiometabolic diseases.

PURPOSE OF REVIEW: To present recent evidence that strengthens the concept that exogenous pollutants contribute to adipose dysfunction and increased rates of disease and to highlight the ineffective regulation of this risk as industry switches to related but similarly toxic variants. RECENT FINDINGS: Substitutes for common phthalates and the highly regulated bisphenol A (BPA) show similar deleterious effects on adipocytes. The well tolerated limit for BPA exposure has been reduced in Europe to below the level detected in recent population studies. Additionally, the role for BPA-induced inflammation mediated by interleukin 17a has been described in animal and human studies. SUMMARY: Despite experimental and associative evidence that supports plastics and plastic associated chemicals deleteriously influencing adipose homeostatasis and contributing to metabolic diseases, structurally related alternate chemicals are being substituted by manufacturers to circumvent trailing regulatory actions.