Elevated serum total IgE alter the diagnostic performance of radio-immune assays for ß-lactam specific antibody dosing.

BACKGROUND: In vivo allergy tests and the detection of drug-specific antibodies are widely used in the diagnosis of ß-lactam induced immediate-type hypersensitivity reactions. The diagnostic performance of immunoenzymatic tests for the demonstration of serum-specific IgE (IgEs) antibodies is influenced by total IgE values (IgEt). The aim of this study was to investigate whether the result obtained by radioimmunoassays (RIA) for ß-lactams IgEs antibodies is correlated to IgEt. METHODS: 68 paired in vivo and in vitro tests were performed for the culprit drugs in 49 patients with suspected previous hypersensitivity reactions to ß-lactams. 14 controls who tolerated the tested antibiotics were similarly investigated. The dosing of IgEt was performed using the Immulite Immunoassay (Siemens). We detected IgEs using a sandwich-type RIA with sepharose as solid phase (Pathologie Cellulaire et Moléculaire en Nutrition, France) and anti-IgEs I(125)-labelled antibodies (Immunotech, Czech Republic). RESULTS: RIA-IgEs sensitivity was 56.52% in patients with IgEt < 120 IU/mL and 90.90% in patients with IgEt > 120 IU/mL (p = 0.0052). All patients with IgEt > 500 IU/mL had positive RIA results. RIA-IgEs specificity was 90.90% for IgEt < 120 IU/mL and 66.66% for IgEt > 120 IU/mL. The linear equation that fits the relation between IgEt and IgEs is: IgEs = (IgEt + 81.644)/137.94, with a correlation coefficient of 0.4. CONCLUSIONS: Serum total IgE alter the diagnostic performance of radioimmunoassays for ß-lactam specific antibody dosing. Assays for the detection of both IgEt and IgEs need to be performed for each individual investigated, retrospectively, to confirm clinical immediate-type hypersensitivity reactions.

Is a positive history of non-anaesthetic drug allergy a predictive factor for positive allergy tests to anaesthetics?

AIMS: International recommendations stipulate not performing screening skin tests to a drug in the absence of a clinical history consistent with that specific drug allergy. Nevertheless, two publications showed that a positive history of non-anaesthetic drug allergy was the only predictive factor for a positive skin test when screening for allergy to anaesthetic drugs was done. We selected from a surgical population 40 volunteers with a prior history of allergy to non-anaesthetic drugs in order to analyse the prevalence of positive allergy tests to anaesthetics. METHODS: The selected adult patients were tested for 11 anaesthetic drugs using in vivo tests: skin prick (SPT) and intradermal (IDT) tests and in vitro tests: the basophil activation test (BAT) and detection of drug-specific immunoglobulin E (IgE). RESULTS: The prevalence for the positive SPT and IDT was 1.6% and 5.8% respectively. The result of flow cytometry agreed with the SPT in five out of seven positive SPT (71%). IgEs confirmed two positive SPT with corresponding positive BAT. Ten per cent of the patients had a positive prick test to neuromuscular blocking agents (NMBA). For midazolam none of the SPT was positive, but 11 patients had positive IDT nonconfirmed by BAT. CONCLUSION: The prevalence of positive in vivo and in vitro allergy tests to NMBAs is higher in our study population. This could be an argument for pre-operative SPT to NMBAs for the surgical population with reported non-anaesthetic drug allergies. A larger prospective study is needed to validate changes in clinical practice.

Multiple Anesthetic Drug Sensitization in a Hairdresser With Previous Immediate-Type Hypersensitivity to Penicillin: A Case Report.

Risk factors for intraoperative immediate-type hypersensitivity reactions may require allergological evaluation. We report the case of a hairdresser with a positive history of penicillin hypersensitivity and anaphylactic shock during previous general anesthesia, whose in vivo and in vitro allergy tests were positive for neuromuscular blocking agents, opioids, and midazolam. Immediate-type hypersensitivity reactions to antibiotics and professional exposure to hairdressing products might induce simultaneous cross-sensitization to multiple drugs that are commonly used during general anesthesia.

Threshold for basophil activation test positivity in neuromuscular blocking agents hypersensitivity reactions.

BACKGROUND: Several different criteria for the positivity of the flow-assisted Basophil Activation Test (BAT) for the diagnosis of Neuromuscular Blocking Agents (NMBA) hypersensitivity reactions have been used in past studies. Our aims were to determine the threshold for BAT positivity expressed as the stimulation index (SI, calculated as the percentage of activated basophils after stimulation with NMBA divided by the number of basophils with no NMBA stimulation) and as the percentage of activated basophils, and to determine the sensitivity and specificity of BAT for NMBAs. METHODS: 22 consenting adult patients with previous intraanaesthetic NMBAs-related hypersensitivity reactions were tested for the culprit drug. 34 controls who tolerated NMBAs were similarly tested. BAT was performed using Flow2Cast technique and the up-regulation of the CD63 marker on the basophils was measured using Cell Quest programme (FACSCalibur Becton Dickinson, USA). Receiver operating characteristics curve (ROC) analysis was performed. RESULTS: ROC curve analysis for BAT results versus history yields a stimulation index of 1.76 as the optimal threshold, with an AUC of 0.81 (CI 95% 0.69-0.93, p < 0.01) and a percentage of activated basophils > 5.01%, with an AUC of 0.84 (CI 95% 0.72-0.95, p < 0.01). Considering both thresholds (the SI ≥ 1.76 together with the percentage of activated basophils > 5%) as diagnostic criteria, 15 patients had positive BAT, the overall BAT sensitivity being 68.18% (CI 95% 45.11-82.26%). None of the controls fulfilled both criteria and the specificity of the test was 100% (CI 95% 87.35-100%). CONCLUSIONS: With a stimulation index ≥ 1.76 and a percentage of activated basophils > 5.01% as threshold, the performance of BAT for NMBAs yields 68.18% sensitivity and 100% specificity.

Epidemiology of self-reported drug-induced immediate-type hypersensitivity reactions in the surgical population: a 5-year single-center survey in a romanian allergo-anaesthesia center.

AIM: Immediate-type hypersensitivity drug reactions are frequently under-reported, epidemiological data being imprecise. The aim of our study was to identify the drugs involved and to describe the clinical characteristics of previous immediate-type hypersensitivity reactions in a large series of Romanian surgical patients, and to establish the concordance between in vivo and in vitro tests. METHODS: Of the 807 surgical patients referred to our outpatient department of allergo-anaesthesia, we retrospectively enrolled 632 patients with previous drug-induced hypersensitivity reactions. The allergological work-up included a complete allergological history, allergological skin tests and in vitro tests. RESULTS: The drugs involved were: antibiotics in 68% of our patients (with 83.02% being ß-lactams), followed by NSAIDs in 43.28% (50.24% of them being metamizol), general anaesthetics in 9.33%, and local anaesthetics or other drugs, each in 6.32% of the 632 patients. The clinical features reported were urticaria in 63.13%, angioedema in 41.77%, bronchospasm in 15.82%, hypotension in 16.61% and cardiovascular collapse in 21.51% of our patients; 31.80% of the referred patients were confirmed as being positive by at least one diagnostic test. The agreement between in vivo tests and BAT was fair (k=0.35), while between in vivo tests and IgE, the concordance was poor (k=0.12). CONCLUSIONS: The data obtained from the patients referred to our clinic without any filters and restrictions indicates the pattern of drug-induced immediate-type hypersensitivity reactions and the most frequently involved drugs in Romania. At the end of the allergological work-up we confirmed 31.80% of our patients as having drug-induced hypesensitivity.