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Background Penicillin allergy labels are prevalent, and removal of incorrect labels improves patient outcomes and health economics. Labels may be classified as “low-risk” or “non–low-risk,” of which the symptoms of the latter chiefly suggest immunoglobulin E–mediated etiology. Traditionally, “non–low-risk” allergy labels are evaluated by penicillin skin testing followed by graded multistep penicillin drug provocation testing (DPT). Objective To evaluate the safety of assessing “non–low-risk” labels with single-step direct DPT. Methods We consecutively enrolled inpatients and outpatients of a teaching hospital in Sydney, Australia, with penicillin allergy labels requiring penicillin for first-line treatment. Patients were classified as “low-risk” or “non–low-risk” based on the allergy labels. All patients proceeded directly to amoxicillin DPT, unless there was a history of anaphylaxis within 10 years of assessment to a beta-lactam (except for cefazolin) or Gell and Coombs type 2, type 3, or severe type 4 reaction. This was followed by a course of amoxicillin. Results A total of 149 patients (41 inpatients, 108 outpatients) were enrolled. No patient was excluded from the study. No patient experienced life-threatening reactions to the protocol. There were 85 patients who reported “non–low-risk” allergy labels. One patient developed generalized pruritus and rash that resolved with standard-dose antihistamines, 2 developed delayed benign maculopapular exanthem, and 3 experienced diarrhea during the course of amoxicillin. Conclusion In our cohort, direct single-step DPT was safe, with only 6 patients with “non–low-risk” allergy experiencing benign reactions. We hope that further studies can be performed into single-step direct DPT to evaluate “non–low-risk” penicillin allergy labels. Trial Registration ClinicalTrials.gov Identifier: LNR/16/HAWKE/452.

BackgroundThe lymphocyte transformation test (LTT) is an in vitro assay used to diagnose drug induced hypersensitivity reactions by detecting the activation and expansion of drug-specific memory T cells to the suspected implicated drug. Traditionally radiolabelled thymidine (3H-thymidine) has been used but requires the handling and disposal of radioactive materials.ObjectiveTo examine safe alternatives to 3H-thymidine, test assay modifications for improved assay sensitivity and validate the modified LTT in patients with DRESS and AGEP.MethodsFour proliferation detection assays (BRDU, CyQUANT™, MTT and XTT) were screened for LTT sensitivity. XTT the most sensitive and practical was selected for further validation. Modifications like autologous serum (AS) and regulatory T cell depletion (T-REG) were evaluated for improved assay sensitivity. Finally, an initial validation of the XTT-LTT was performed in 8 patients with DRESS and 2 with AGEP including cytokine testing.ResultsOf the non-radioactive alternatives we tested, XTT a colorimetric assay was the most sensitive and practical to move to validation. The addition of AS increased background signal. Depletion of T-REGs improved sensitivity but cell sorting time and risk of contamination limited benefit.Of eight patients diagnosed with DRESS and 2 with AGEP tested with XTT-LTT assay results showed our assay matched clinical findings of implicated drugs in 8/10 patients when using a stimulation index (SI) ≥2 and 8/10 with analysis by ANOVA. All ten patients were correctly diagnosed by either analysisConclusionXTT appears to be a safe, viable alternative to 3H-thymidine, with high sensitivity and allowing direct cytokine quantification on specific patient cells.

Common variable immunodeficiency (CVID) is established as a heterogeneous collection of disorders of immune dysregulation rather than an infectious complication of antibody deficiency. Approximately 70% of patients have one or more of the non-infectious complications of autoimmunity, enteropathy, polyclonal lymphocytic and malignancy. The CVID-disorders represent a particular challenge as they fall under an umbrella diagnosis governed currently by non-universal diagnostic criteria. The rubric of CVID is shrinking as next generation sequencing is progressively and rapidly identifying the genetic basis for many of its disorders. Although identification of monogenic cause of CVID allows for naming of separate or specific entities, it still provides valuable insight into the immune dysregulation of these disorders along with recognition of a polygenic basis of disease and cellular changes observed in innate and adaptive immune pathways. Cellular abnormalities in the T-cell (reduced regulatory T cells (Tregs) and increased T follicular helper cells), and B-cell compartments (reduced switched memory B-cells and increased peripheral CD21low cells) along with an increase in innate lymphoid cells type 3 promote a milieu for inflammation. Immune dysregulation also results from increased microbial translocation from impaired gastrointestinal barrier function in CVID-patients with loss of Tregs. An understanding of the manifestations and mechanisms of immune dysregulation allows for improved vigilance in screening for the diagnosis, monitoring for complications of disease and the continued development and introduction of targeted therapies for non-infectious phenotypes.

BACKGROUND Screening for HLA-A*31:01/HLA-B*15:02, HLA-B*57:01 and HLA-B*58:01 is recommended in selected populations for prevention of carbamazepine, abacavir, and allopurinol-induced severe cutaneous adverse reactions (SCARs). Compared to conventional methods for detection of HLA alleles, PCR using a tag single nucleotide polymorphism (SNP) can be cost-effective, particularly where the surrogate marker SNP is in absolute linkage disequilibrium with the relevant HLA allele. OBJECTIVE To determine guidelines for prevention of SCARs though predictive screening for the Australian Vietnamese population, the prevalence of four HLA alleles (HLA-A*31:01, HLA-B*15:02, HLA-B*57:01 and HLA-B*58:01) was examined. The utility of surrogate markers, rs2395029 and rs9263726, was investigated to predict for the presence of HLA-B*57:01 and HLA-B*58:01, respectively. METHODS Genotyping for specific HLA alleles was performed in 152 healthy Vietnamese living in Sydney using validated and established PCR-based methods. SNP genotyping was conducted using restriction-fragment-length-polymorphism analysis. RESULTS rs2395029 and rs9263726 strongly correlated with HLA-B*57:01 (? = 1, p < 0.001) and HLA-B*58:01 (Κ = 0.9, p < 0.001) with 100% sensitivity and 100% negative predictive value for predicting the HLA-B*57:01 and HLA-B*58:01 carriers, respectively. A high prevalence of carriers of HLA-A*31:01 (3.29%), HLA-B*15:02 (14.47%), HLA-B*57:01 (6.58%) and HLA-B*58:01 (9.21%) was revealed. CONCLUSIONS Screening is recommended for these alleles in Australian Vietnamese prior to introducing relevant therapies. SNPs, rs2395029 and rs9263726, can be successfully used as surrogate markers for HLA-B*57:01 and HLA-B*58:01 in this population.

Penicillin allergy delabeling confers many benefits, including reduced patient morbidity and mortality and improved health economics. Reports suggest that both patients and clinicians often remain hesitant to take and prescribe penicillins, respectively, after penicillin delabeling. However, follow-up of an individual's penicillin allergy label and incorporation of this into relevant health care records after delabeling have not been well studied in the Australian population.To evaluate the status of penicillin allergy labels in the community 1 year after penicillin delabeling at a tertiary hospital in Australia.A cross-sectional study was performed using follow-up interviews with patients and community primary care providers after 1 year from the date of patients' penicillin delabeling at a tertiary hospital in New South Wales, Australia. The main outcome measures that were evaluated included patient willingness to accept penicillin for future infections, patient self-reported receipt of penicillin-based antibiotics after delabeling, accuracy of penicillin allergy labels in the records of the primary care provider, and prescription of penicillin-based antibiotics by the general practitioner.A total of 86 patients were included in this study. The percentage of patients with a correct penicillin allergy status at 1-year follow-up was 94% in the hospital electronic medical record but only 37% in primary care records. At 1-year follow-up, 14% of delabeled patients continued to reject penicillin prescriptions.Better strategies are required to increase patient confidence in receiving penicillins after penicillin delabeling and to ensure that penicillin allergy labels are translated into the medical records at the primary care level.

Background Following diagnosis of neuromuscular blocking agent (NMBA) anaphylaxis, identifying safe alternatives for subsequent anaesthesia is critical. A patient with anaphylaxis to one NMBA can also have an allergic reaction to other NMBAs (cross-reactivity). Whilst drug provocation testing is standard for identifying or excluding allergy, there is significant risk. In vitro, after an allergen activates basophils, basophils express surface activation markers that can be measured by basophil activation testing (BAT). We compared cross-reactivity between NMBAs assessed by BAT against that by skin testing. Methods All patients attending an anaesthetic allergy clinic in Sydney, Australia between May 2017 and July 2018 diagnosed with NMBA anaphylaxis qualified for this study comparing intradermal skin tests and BAT with a panel of NMBAs (rocuronium, vecuronium, pancuronium, suxamethonium, cisatracurium). Results Of the 61 patients participating, sensitisation on skin testing and on BAT completely matched in only nine patients (15%). Sensitisation was not in agreement for pancuronium, cisatracurium and rocuronium, but was in agreement for vecuronium and suxamethonium. Nine patients with negative skin tests subsequently tolerated cisatracurium, and one false positive on BAT to cisatracurium was detected. Conclusions The utility of BAT in identifying safe NMBAs for subsequent anaesthesia needs further evaluation. BAT detects a different cross-reactivity profile to skin tests. Negative skin testing and BAT might increase confidence in performing drug provocation testing, but this and follow-up of subsequent anaesthesia in our cohort is necessary to determine the clinical significance of BAT sensitisation.

BackgroundEndovascular procedures are standard of care for an increasing range of cerebrovascular diseases. Many endovascular devices contain plastic and are coated with a hydrophilic polymer which has been rarely described to embolize, resulting in distal granulomatous inflammatory lesions within the vascular territory.MethodsWe reviewed three cases of cerebral granulomatous reactions that occurred after endovascular intervention for internal carotid aneurysms. The patient procedure details, presentation, relevant investigations, and treatment course are described. We also provide a literature review on endovascular granulomatous reactions.ResultsThese three cases represent the largest biopsy proven series of cerebral granulomatosis following endovascular intervention. We highlight the variable clinical presentation, with two of the three cases having an unusually delayed onset of up to 4 years following the intervention. We show the characteristic histological findings of granulomatous lesions with foreign body material consistent with a type IV reaction, radiological abnormalities of enhancing lesions within the vascular territory of the intervention, and the requirement of prolonged immunosuppression for maintenance of clinical remission, with two of the three patients requiring a corticosteroid sparing agent. In comparison with the available literature, in addition to hydrophilic gel polymer, we discuss that plastic from the lining of the envoy catheter may be a source of embolic material. We also discuss the recommendations of the Food and Drug Administration and the implementation of novel biomaterials for the prevention of these reactions in the future.ConclusionsThere is a need for increased awareness of this severe complication of cerebral endovascular procedures and further longitudinal studies of its prevalence, optimal management and preventative measures.

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.

Background Nonprescription of penicillin-containing antibiotics in patients diagnosed with penicillin allergy is associated with morbidity and mortality. Adverse reactions to penicillins comprise type A and B reactions. Objective To assess the feasibility of penicillin allergy evaluation without penicillin skin testing (PST) for adult patients with type B reactions and the health and economic benefits of this process. Methods Inpatients at an Australian tertiary hospital between April 1, 2017, and April 30, 2018, with a diagnosis of type B penicillin allergy, requiring a penicillin-containing antibiotic for treatment, were included. All patients underwent clinical history review, PST, and drug provocation testing (DPT). Results Seventy-one patients were enrolled. Sixty-three reported a history of type B or unknown adverse reactions. No patients had a history of anaphylaxis requiring intubation or epinephrine within the last 10 years or a history suggesting Gell and Coombs type 2, 3, or 4 (severe) hypersensitivity reaction. Seven did not complete DPT because the treating team used a β-lactam antibiotic other than amoxicillin. Fifty-four of 56 remaining patients (96%) completed 3-day DPT to amoxicillin with no adverse reaction. Two experienced mild cutaneous reactions. Penicillin allergy evaluation was significantly associated with reduced length of stay, reduced hospital expenditure on bed and second-line antibiotics, and reduced readmission rates. Conclusion Penicillin allergy evaluation with DPT without PST may be feasible for all adult patients with a reported history of type B reactions to penicillins who do not have a history of anaphylaxis within the last 10 years or a type 2, 3, or 4 (severe) hypersensitivity reaction.

Background. Microscopic polyangiitis (MPA) can manifest with atypical features such as pulmonary fibrosis and chronic obstructive pulmonary disease (COPD), which are atypical and unusual features of small vessel vasculitis. Case Presentation. This paper presents two patients with microscopic polyangiitis and respiratory symptoms attributable to atypical pulmonary manifestations. Pulmonary fibrosis was present in both cases, with COPD also present in one patient. Management involved methylprednisone, prednisone, and cyclophosphamide. The second patient also received azathioprine. Both patients responded well to immunosuppressive treatment; however, pulmonary fibrosis and COPD were refractory to immunosuppression. Conclusion. Pulmonary manifestations including pulmonary fibrosis, emphysema, and bronchiectasis are observed in MPA. Evaluation of MPA in unexplained cases should be performed to avoid delays in diagnosis and management. Patients who present with MPA with pulmonary manifestations may respond to treatment, but their pulmonary features demonstrate a refractory nature to such management.

Background Neuromuscular blocking agents (NMBAs) remain the leading cause of perioperative anaphylaxis in Australia. Standard evaluation comprises history, skin tests, and in vitro specific immunoglobulin E tests. Drug provocation tests to suspected NMBA culprits are associated with a significant risk. Basophil activation testing (BAT) is a potentially useful in vitro test that is not commercially available in Australia or as part of standard evaluation. Methods All patients attending the Anaesthetic Allergy Clinic in Sydney, Australia between May 2017 and July 2018 exposed to an NMBA before the onset of anaphylaxis during their anaesthetic qualified for the study. We recruited 120 patients sequentially who received standard evaluation plus BAT using CD63, CD203c, and CD300a as surface activation markers. Results BAT results were expressed as % upregulation above the negative control and stimulation index (mean fluorescence index of stimulated sample divided by the negative control). We calculated cut-offs of 4.45% and 1.44 for CD63, and 8.80% and 1.49 for CD203c, respectively. Sensitivity was 77% with specificity of 76%. A subgroup of 10 patients with NMBA anaphylaxis had no sensitisation on skin tests. BAT using CD63 and CD203c showed sensitisation in six of these 10, and adding CD300a identified sensitisation in nine patients. BAT was positive in seven of nine patients with anaphylaxis of unknown aetiology. Conclusions BAT may be a useful supplement to the standard evaluation in diagnosing NMBA anaphylaxis in patients with suggestive histories, but no sensitisation on skin tests. Ongoing study of this specific group of patients is required to clarify its utility in clinical practice.

We report a 47-year-old woman with highly active neuromyelitis optica (NMO) and persistent high titre anti-aquaporin-4 antibodies (anti-AQP-4) who was resistant to multiple immune therapies until she underwent autologous hematopoietic stem cell transplant (auto-HSCT). NMO is the only demyelinating disease with a clinically useful serum biomarker, aquaporin-4, a water channel protein expressed on astrocytes. Anti-AQP-4 antibodies correlate with NMO disease activity and animal models strongly suggest the antibody is pathogenic. Auto-HSCT was associated with clinical and radiological remission, improved disability and resolution of AQP-4 antibodies which are still undetectable 12 months later. The utility of auto-HSCT for refractory NMO warrants further investigation, particularly with regards to pre-conditioning regimens and the utility of AQP-4 antibodies as a biomarker for immunological and clinical remission.

Objectives Screening for the HLA-B*15:02 allele has been recommended to prevent carbamazepine (CBZ) – induced Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) in individuals with Asian ancestry. We aimed, therefore, to develop and validate a robust and inexpensive method for detection of the HLA-B*15:02 allele. Methods Real-time PCR using TaqMan® probes followed by SYBR® Green was used to detect the HLA-B*15:02 allele prior to treatment with CBZ therapy. Results A total of 121 samples were tested. The assay has a sensitivity of 100% (95% CI: 76.84–100.0%), a specificity of 100% (95% CI: 96.61–100%), a positive predictive value of 100% (95% CI: 76.84–100%) and a negative predictive value of 100.0% (95% CI: 96.61–100.0%), respectively. There was 100% agreement between our results and genotyping using Luminex SSO/SBT/SSP. The lowest limit of detection of the TaqMan® probe is 0.05 ng/μl and the SYBR® Green is 0.5 ng/μl of DNA. The unit cost of using the TaqMan® probe followed by SYBR® Green is only $4.7 USD. Conclusion We developed a novel assay for the detection of the HLA-B*15:02 allele, which is robust, inexpensive and suitable for screening individuals of Asian ancestry in the prevention of CBZ-induced SJS/TEN.

Aim: In prevention of allopurinol and abacavir hypersensitivity, screening HLA-B*58:01/57:01 has been highly recommended prior to commencing these therapies. Therefore, we aimed at developing and validating a rapid and robust screening method for HLA-B*58:01/57:01. Materials & methods: Real-time polymerase chain reaction with TaqMan® probes was employed to detect HLA-B*58:01/57:01. Results: The newly developed assay has the sensitivity of 100% (95% CI: 79.4–100.0%), the specificity of 98.8% (95% CI: 93.6–99.9%), the positive predictive value of 94.1% (95% CI: 71.3–99.9%) and the negative predictive value of 100.0% (95% CI: 95.7–100.0%). The lowest limit of detection is 0.04 ng/µl of DNA. Conclusion: The present method is a rapid and robust assay that is appropriate for screening of HLA-B*58:01/*57:01 alleles.

The HLA B*58:01 allele has been worldwide reported as a pharmacogenetic susceptibility to allopurinol-induced severe cutaneous adverse reactions (SCARs). To prevent these life-threatening conditions, the American College of Rheumatology hingly recommended that the HLA-B*58:01 be screened prior to the initiation of allopurinol therapy. Therefore, we developed a rapid, robust, inexpensive screening method using SYBR® Green real time PCR to detect the HLA-B*58:01 allele. A total of 119 samples were tested. The assay has a sensitivity of 100% (95% CI: 69.15%-100%), a specificity of 100% (95% CI: 96.67%-100%), a positive predictive value of 100% (95% CI: 69.15%-100%) and a negative predictive value of 100% (95% CI: 96.67%-100%). HLA-B*58:01 genotyping results showed 100% agreement with those obtained from Luminex SSO/SBT/SSP. The lowest limit of detection of this method is 0.8 ng/µL of DNA. The unit cost of the test is only $3.8 USD. This novel screening test using SYBR® real time PCR would be appropriate to identify individuals with the HLA-B*58:01 allele for the prevention of allopurinol-induced SCARs.

Lichen planus is a chronic systemic disease of established immune-mediated pathogenesis. [1] It most commonly, protractedly and persistently, involves the mucosa of the oral cavity, but it can involve other sites, namely the skin, the scalp (with inflammation around and affecting the hair follicles) resulting in alopecia), the nails as well as the genital area the vulval and vaginal mucosa, and the glans penis. Other sites of involvement that are far less frequently described include the oesophagus and conjunctiva. There are seven recognized oral presentations of lichen planus: (1) reticular, (2) papular, and (3) plaque-form and the (4) atrophic, (5) ulcerative (erosive) and rare (6) vesiculo-bullous form [2] and (7) desquama‐ tive gingivitis, this latter term is a clinical descriptor, used to describe inflammation, with a mix of erythema, erosion and/or ulceration of the gingival tissues and the immediately adjacent alveolar mucosa, not incited by the presence of dental bacterial plaque. These latter four forms of OLP can be associated with significant discomfort requiring either topical and/or systemic immunosuppressive therapy.

The word “pemphigus” is derived from the Greek term "pemphix” meaning bubble or blister. Pemphigus is a group of autoimmune diseases (see Table 4) characterized by intra-epithelial blistering, resulting in superficial vesicles or bullae that easily rupture, resulting in ulceration of mucosal and/or cutaneous sites. Although rare, pemphigus causes significant morbidity and potential mortality for patients. The two main subtypes are pemphigus vulgaris (PV), and pemphigus foliaceous (PF), of which PV is the most common and clinically, the most aggressive variant, being associated with significant morbidity and mortality, composing 70% of all reported cases of pemphigus: Less common forms and variants include paraneoplastic pemphigus, drug induced pemphigus, and IgA pemphigus. This book chapter focuses on the diagnosis and treatment of PV and PF.