Multistep IgE Mast Cell Desensitization Is a Dose- and Time-Dependent Process Partially Regulated by SHIP-1.

Multistep mast cell desensitization blocks the release of mediators following IgE crosslinking with increasing doses of Ag. Although its in vivo application has led to the safe reintroduction of drugs and foods in IgE-sensitized patients at risk for anaphylaxis, the mechanisms of the inhibitory process have remained elusive. We sought to investigate the kinetics, membrane, and cytoskeletal changes and to identify molecular targets. IgE-sensitized wild-type murine (WT) and FcεRIα humanized (h) bone marrow mast cells were activated and desensitized with DNP, nitrophenyl, dust mites, and peanut Ags. The movements of membrane receptors, FcεRI/IgE/Ag, actin, and tubulin and the phosphorylation of Syk, Lyn, P38-MAPK, and SHIP-1 were assessed. Silencing SHIP-1 protein was used to dissect the SHIP-1 role. Multistep IgE desensitization of WT and transgenic human bone marrow mast cells blocked the release of ß-hexosaminidase in an Ag-specific fashion and prevented actin and tubulin movements. Desensitization was regulated by the initial Ag dose, number of doses, and time between doses. FcεRI, IgE, Ags, and surface receptors were not internalized during desensitization. Phosphorylation of Syk, Lyn, p38 MAPK, and SHIP-1 increased in a dose-response manner during activation; in contrast, only SHIP-1 phosphorylation increased in early desensitization. SHIP-1 phosphatase function had no impact on desensitization, but silencing SHIP-1 increased ß-hexoxaminidase release, preventing desensitization. Multistep IgE mast cell desensitization is a dose- and time-regulated process that blocks ß-hexosaminidase, impacting membrane and cytoskeletal movements. Signal transduction is uncoupled, favoring early phosphorylation of SHIP-1. Silencing SHIP-1 impairs desensitization without implicating its phosphatase function.

Cytokine profiling, pretreatment with anakinra, and tolerance development in platinum-induced mixed hypersensitivity reactions.

BACKGROUND: Cytokine-release reactions (CRR) induced by platinum-based chemotherapy, manifesting with fever, chills, and rigors, are poorly understood and not easily prevented by usual premedication or desensitization. OBJECTIVE: To gain a better understanding of platinum-induced CRR and to explore the use of anakinra as a tool to prevent its clinical manifestations. METHODS: A cytokine and chemokine panel was obtained before and after platinum infusion in 3 cases with a mixed (immunoglobulin E-mediated and CRR) platinum-induced hypersensitivity reaction and in 5 controls either tolerant or with an immunoglobulin E-mediated platinum-induced hypersensitivity reaction. Anakinra was given as premedication in the 3 CRR cases. RESULTS: Cytokine-release reaction was associated with a marked release of interleukin (IL)-2, IL-5, IL-6, IL-10, and tumor necrosis factor-ɑ in all cases whereas only IL-2 and IL-10 increased in some controls after platinum infusion, and to a lesser extent than in cases. Anakinra seemed to block CRR symptoms in 2 cases. In the third case, who initially had CRR symptoms despite anakinra, tolerance to oxaliplatin appeared to develop after repeated re-exposures, as suggested by the decreasing levels of cytokines after oxaliplatin, except IL-10, and the capacity to progressively shorten the desensitization protocol and taper the premedication, in addition to the negativization of the oxaliplatin skin test result. CONCLUSION: In patients with platinum-induced CRR, anakinra could be a useful premedication to block its clinical manifestations, and monitoring of IL-2, IL-5, IL-6, IL-10, and tumor necrosis factor-ɑ could help predict tolerance development, thereby allowing safe adjustments to the desensitization protocol and premedication.

A randomized double-blind feasibility study comparing cetirizine and diphenhydramine in the prevention of paclitaxel-associated infusion-related reactions: the PREMED-F1 study.

PURPOSE: Cetirizine is a less sedative alternative to diphenhydramine for the prevention of infusion-related reactions (IRR) to paclitaxel. However, its use remains controversial. In this study, we assessed feasibility for a future definitive non-inferiority trial comparing cetirizine to diphenhydramine as premedication to prevent paclitaxel-related IRR. METHODS: This was a single-center randomized prospective feasibility study. Participants were paclitaxel-naive cancer patients scheduled to start paclitaxel chemotherapy. They were randomly assigned to receive either intravenous diphenhydramine 50 mg + oral placebo (control) or intravenous placebo + oral cetirizine 10 mg (intervention) for their first two paclitaxel treatments. The percentage of eligible patients completing a first paclitaxel treatment and the recruitment rate were assessed (feasibility outcomes). Drowsiness was measured at baseline and at selected time points using the Stanford Sleepiness Scale (SSS) (safety outcome). IRR events were also documented (efficacy outcome). RESULTS: Among 37 eligible patients, 27 were recruited and randomized (control 13; intervention 14) and 25 completed the study. The recruitment rate was 4.8 participants/month, meeting the primary feasibility target. Drowsiness was the main adverse effect associated with the premedication. The increase in drowsiness compared to baseline (ΔSSS) was greater in the diphenhydramine group compared to the cetirizine group (median ΔSSS 2 (IQR 3.25) vs median ΔSSS 0 (IQR 1), p < 0.01) when measured one hour after the premedication administration. One participant had an IRR and no unexpected serious adverse event occurred. CONCLUSION: The trial methods were feasible in terms of recruitment, retention, and safety. Cetirizine was significantly less sedating than diphenhydramine. IRR were infrequent and a larger trial is warranted to confirm non-inferiority for IRR prevention. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04237090 (22.01.2020).

Is atopy a risk indicator of chronic obstructive pulmonary disease in dairy farmers?

Allergic mechanisms related to environmental and occupational exposure have been suggested to contribute to the development of chronic obstructive pulmonary disease (COPD). OBJECTIVES: To investigate the relationships between atopy markers, persistent airflow limitation (PAL) and occupational exposure in dairy farmers. METHODS: Clinical and biological (total IgE and 21 allergen specific IgE) markers of atopy were assessed in 101 dairy farmers with PAL (DF-PAL), 85 non-farmers with PAL (NF-PAL) (both groups were prospectively included from a screening program performed between 2011 and 2015), and matched controls, i.e. 98 farmers without PAL (DF-controls) and 89 non-farming subjects without PAL (NF-controls). Occupational exposure in farmers was estimated using a validated questionnaire. RESULTS: Prevalence of allergy history was significantly higher in DF-PAL and in NF-PAL than in controls. Polysensitization, and sensitization to seasonal and food allergens were more frequent in DF-PAL than in DF-controls, respectively: 13.8% vs 1% (adjusted odds ratio (aOR): 17.5 (2.2-134), 11.9% vs 3.1% (aOR: 4.4 (1.2-7.2) and 16.8% vs 4.1% (aOR: 5.2 (1.7-7.2)). The prevalence of atopy markers was similar between NF-PAL patients and NF-controls. CONCLUSIONS: PAL in farmers is associated with a high rate of markers of atopy, supporting atopy as a risk indicator. Clinical trial registered with ClinicalTrials.gov (NCT02540408).

Risk stratification and skin testing to guide re-exposure in taxane-induced hypersensitivity reactions.

BACKGROUND: The optimal approach to patients with hypersensitivity reactions (HSRs) to taxanes has not been established. OBJECTIVE: We sought to assess the safety and efficacy of risk stratification based on the severity of the initial HSR and skin testing for guiding taxane reintroduction in patients with an HSR to these agents. METHODS: Data on 164 patients treated for a taxane-related HSR from April 2011 to August 2014 at the Dana-Farber Cancer Institute and Brigham and Women's Hospital were collected retrospectively. Patients were re-exposed to taxanes either through desensitization, challenge, or regular infusion based on the severity of the initial HSR and skin test response. Depending on the initial risk stratification and tolerance to re-exposure, patients were then treated with shorter desensitization protocols, challenge, or both with the aim of resuming regular infusions, except in patients with a severe immediate initial HSR. RESULTS: Of 138 patients desensitized, 29 (21%) had an immediate and 20 (14%) had a delayed HSR with the procedure. Of 49 patients challenged, 2 (4%) had a mild immediate and 1 (2%) had a delayed HSR with the procedure. No patients had a severe immediate HSR with desensitization or challenge. Thirty-six (22%) patients eventually resumed regular infusions. These patients were more likely to have negative skin test responses and to have experienced a delayed or mild immediate initial HSR. CONCLUSIONS: Risk stratification based on the severity of the initial HSR and skin testing to guide taxane reintroduction is safe and allows a significant number of patients to resume regular infusions.

Asymptomatic subjects with airway obstruction have significant impairment at exercise.

BACKGROUND: The relevance of screening for airway obstruction in subjects not complaining of COPD symptoms may depend on the definition of airway obstruction. Response to exercise in asymptomatic subjects with persistent airway obstruction as defined by a postbronchodilator FEV1/FVC <5th centile lower limit of normal (LLN) remains unknown. METHODS: Dyspnoea (Borg scale), exercise tolerance and ventilatory constraints on tidal volume expansion were assessed in 20 consecutive asymptomatic subjects with persistent mild airway obstruction detected by screening (postbronchodilator FEV1/FVC z-score: -2.14±0.29; FEV1 z-score: -1.02±0.64) undergoing incremental cycle cardiopulmonary exercise testing, compared with 20 healthy controls with normal spirometry matched for age, sex, body mass index and smoking history (FEV1/FVC z-score: -0.13±0.57; FEV1 z-score: 0.32±0.67) and with 20 symptomatic patients with COPD matched for the same characteristics (FEV1/FVC z-score: -2.36±0.51; FEV1 z-score: -1.02±0.48). RESULTS: Asymptomatic subjects with airway obstruction had higher dyspnoea ratings than controls during incremental exercise. Asymptomatic subjects with airway obstruction had also peak oxygen consumption and peak power output that were lower than controls, and similar to those observed in patients with COPD. Although less frequent than in COPD, dynamic hyperinflation was more frequent in asymptomatic subjects with airway obstruction than in controls (85%, 50% and 10%, respectively; p=0.01 in asymptomatic subjects vs controls and p=0.04 vs COPD). CONCLUSIONS: Although they did not present with chronic activity-related dyspnoea, subjects with a postbronchodilator FEV1/FVC

Chemotherapy hypersensitivity reactions in ovarian cancer.

Ovarian cancer is the fifth leading cause of cancer death among women in the United States. Chemotherapy using a taxane and platinum combination is key in improving survival in patients with newly diagnosed advanced ovarian cancer and is also used to treat recurrent platinum-sensitive disease. However, hypersensitivity reactions (HSRs) to chemotherapeutic agents are increasingly common and can greatly limit their use. Moreover, because of the frequent lack of equally effective alternative agents, chances of survival can be compromised. Therefore, physicians caring for these patients must be familiar with the management of HSRs to chemotherapy, and major advancements have recently been made in this field. Most HSRs implicate mast cell and basophil activation either through an IgE-mediated (ie, platinum agents) or nonspecific (ie, taxanes) mechanism. Therefore, these reactions have the potential to lead to anaphylaxis, at which time they should be treated with intramuscular epinephrine. Serum tryptase, which is released alongside histamine after mast cell activation, may be measured after an acute HSR to document mast cell involvement. After an HSR, the decision to re-treat with the same agent or a closely related one will vary depending on the causative drug, the type of HSR, and its severity. Drug desensitization has emerged as a safe and effective way of reintroducing a chemotherapeutic agent or monoclonal antibody responsible for an HSR in a patient who is expected to benefit from its continued use and for whom alternatives are considered less effective and/or more toxic. Currently, candidates for desensitization are preferably evaluated in academic settings with expertise in those procedures, because their use is still limited. Efforts are now needed to increase awareness about desensitization procedures so that more patients may benefit. This challenge will require the close collaboration of patients, nurses, oncologists, and allergists.

Skin testing only with penicillin G in children with a history of penicillin allergy.

BACKGROUND: The absence of commercially available penicilloyl-polylysine (PPL) for most of the last decade severely hampered the practice of penicillin allergy evaluation because skin testing without PPL is reported to have a poor negative predictive value (NPV). OBJECTIVE: To determine the safety and NPV of skin testing without PPL using only penicillin G followed by a 3-dose graded challenge to the incriminated penicillin in children with a history of penicillin allergy. METHODS: Patients evaluated for a history of penicillin allergy at the CHU Sainte-Justine Allergy Clinic between December 2006 and December 2009 were skin tested only with penicillin G and underwent a 3-dose graded challenge to the culprit penicillin if the skin test result was negative. RESULTS: Among 563 patients skin tested to penicillin G, 185 (33%) had a positive skin test result. These patients had a shorter interval between the initial reaction and skin testing compared with patients with a negative skin test result (P = .03). A total of 375 of 378 patients (99%) with a negative skin test result were challenged and 18 (4.8%) reacted, translating into a NPV of 95.2% (95% confidence interval [CI], 92.5%-97.1%). Three of 17 patients with a history of anaphylaxis and a negative skin test result reacted to challenge (NPV, 82.4%; 95% CI, 59.0-93.8%). All challenge reactions were mild and resolved promptly with treatment. CONCLUSION: Among children with a history of penicillin allergy, skin testing only with penicillin G followed by a 3-dose graded challenge to the incriminated penicillin is safe and yields a good NPV. This approach could be useful when PPL is unavailable.

Diagnostic tools for hypersensitivity to platinum drugs and taxanes: skin testing, specific IgE, and mast cell/basophil mediators.

Hypersensitivity reactions (HSRs) to platinum drugs and taxanes are increasing in cancer patients, and rapid drug desensitization has emerged as a safe and effective method to reintroduce these drugs in reactive patients. Optimal management of patients presenting HSRs to chemotherapy depends on the use of various diagnostic tools, which include measurement of mast cell/basophil mediator release following a HSR and skin testing. Serum tryptase should be measured in patients presenting chemotherapy HSRs, and its elevation would support mast cell/basophil activation. Skin testing to platinum drugs has a high sensitivity and specificity and is critical to guide the management of platinum-reactive patients. Taxane skin testing is also emerging as a useful diagnostic and risk stratification tool in the evaluation of patients with HSRs to taxanes. Platinum sIgE assays have been recently developed and can be helpful in combination with skin testing or as an alternative when skin testing is not available.

Outpatient penicillin use after negative skin testing and drug challenge in a pediatric population.

The practice of elective penicillin skin testing could be compromised by the fact that patients, their parents, or their physicians remain reluctant to reuse penicillin-class antibiotics (PCAs) despite a negative evaluation by an allergist. This study addresses reuse of PCAs in a pediatric population after negative penicillin skin testing and drug challenge and factors associated with its reluctance. All children evaluated for a history of penicillin allergy at the CHU Sainte-Justine Allergy Clinic between January 1998 and June 2000 with negative skin testing and drug challenge were included in the study. A telephone survey was conducted between May and October 2002 to assess the perception of the initial reaction by the parents, subsequent use of antibiotics, and antibiotic-related adverse reactions. Among the 200 children selected, parents of 170 (85%) children completed the survey. Since the allergist evaluation, 130 (76%) children had received antibiotics. PCA was used in 59 (45%) children. Parents of 24 (18%) children refused PCAs because they still feared an adverse reaction. They were more likely to have been very frightened by their child's allergic reaction than other parents whose children had used PCAs (p = 0.008). Although elective penicillin skin testing is useful and safe in the pediatric population, a significant proportion of parents still refuse PCAs even though they are needed. Identification of parents that were very frightened by their children's allergic reactions and additional reassurance could improve this situation.

Measurement of Bradykinin Formation and Degradation in Blood Plasma: Relevance for Acquired Angioedema Associated With Angiotensin Converting Enzyme Inhibition and for Hereditary Angioedema Due to Factor XII or Plasminogen Gene Variants.

Bradykinin (BK)-mediated angioedema (AE) states are rare acquired or hereditary conditions involving localized edema of the subcutaneous and submucosal tissues. Citrated plasma from healthy volunteers or patients with hereditary angioedema (HAE) with normal level of C1-inhibitor (C1-INH) was used to investigate pathways of BK formation and breakdown relevant to AE physiopathology. The half-life of BK (100 nM) added to normal plasma was 34 s, a value that was increased ~12-fold when the angiotensin converting enzyme (ACE) inhibitor enalaprilat (130 nM) was added (enzyme immunoassay measurements). The BK half-life was similarly increased ~5-fold following 2 daily oral doses of enalapril maleate in healthy volunteers, finding of possible relevance for the most common form of drug-associated AE. We also addressed the kinetics of immunoreactive BK (iBK) formation and decline, spontaneous or under three standardized stimuli: tissue kallikrein (KLK-1), the particulate material Kontact-APTT™ and tissue plasminogen activator (tPA). Relative to controls, iBK production was rapid (10-20 min) and very intense in response to tPA in plasma of female heterozygotes for variants in gene F12 coding for factor XII (FXII) (p.Thr328Lys, 9 patients; p.Thr328Arg, one). An increased response to Kontact-APTT™ and an early tPA-induced cleavage of anomalous FXII (immunoblots) were also observed. Biotechnological inhibitors showed that the early response to tPA was dependent on plasmin, FXIIa and plasma kallikrein. Results from post-menopausal and pre-menopausal women with HAE-FXII were indistinguishable. The iBK production profiles in seven patients with the plasminogen p.Lys330Glu variant (HAE-PLG) did not significantly differ from those of controls, except for an unexpected, rapid and lanadelumab-resistant potentiation of KLK-1 effect. This enzyme did not cleave plasminogen or factor XII, suggesting a possible idiosyncratic interaction of the plasminogen pathogenic variant with KLK-1 activity. KLK-1 abounds in salivary glands and human saliva, hypothetically correlating with the clinical presentation of HAE-PLG that includes the swelling of the tongue, lips and contiguous throat tissues. Samples from HAE patients with normal C1-INH levels and F12 gene did not produce excessive iBK in response to stimuli. The ex vivo approach provides physiopathological insight into AE states and supports the heterogeneous physiopathology of HAE with normal C1-INH.

Cross-Reactivity to Cephalosporins and Carbapenems in Penicillin-Allergic Patients: Two Systematic Reviews and Meta-Analyses.

BACKGROUND: There is no recent systematic review on the risk of cross-reactivity to cephalosporins and carbapenems in penicillin-allergic patients despite many new studies on the subject. All past reviews have several limitations such as not including any patient with a T-cell-mediated penicillin allergy. OBJECTIVES: To determine the risk of cross-reactivity to cephalosporins and carbapenems in patients with a proven IgE- or T-cell-mediated penicillin allergy. To measure the association between R1 side chain similarity on cephalosporins and penicillins and the risk of cross-reactivity. METHODS: MEDLINE and EMBASE were searched from January 1980 to March 2019. Studies had to include at least 10 penicillin-allergic subjects whose allergy had been confirmed by a positive skin test (ST) or drug provocation test (DPT) result. Cross-reactivity had to be assessed to at least 1 cephalosporin or carbapenem through ST or DPT. Both random-effects and fixed-effect models were used to combine data. A bioinformatic model was used to quantify the similarity between R1 side chains. RESULTS: Twenty-one observational studies on cephalosporin cross-reactivity involving 1269 penicillin-allergic patients showed that the risk of cross-reactivity varied with the degree of similarity between R1 side chains: 16.45% (95% CI, 11.07-23.75) for aminocephalosporins, which share an identical side chain with a penicillin (similarity score = 1), 5.60% (95% CI, 3.46-8.95) for a few cephalosporins with an intermediate similarity score (range, 0.563-0.714), and 2.11% (95% CI, 0.98-4.46) for all those with low similarity scores (below 0.4), irrespective of cephalosporin generation. The higher risk associated with aminocephalosporins was observed whether penicillin allergy was IgE- or T-cell-mediated. Eleven observational studies on carbapenem cross-reactivity involving 1127 penicillin-allergic patients showed that the risk of cross-reactivity to any carbapenem was 0.87% (95% CI, 0.32-2.32). CONCLUSIONS: Although it remains possible that these meta-analyses overestimated the risk of cross-reactivity, clinicians should consider the increased risk of cross-reactivity associated with aminocephalosporins, and to a lesser extent with intermediate-similarity-score cephalosporins, compared with the very low risk associated with low-similarity-score cephalosporins and all carbapenems when using beta-lactams in patients with a suspected or proven penicillin allergy.

Management of Hypersensitivity Reactions to Taxanes.

Taxanes are an important class of antineoplastic agents used in the treatment of a wide variety of cancers. However, paclitaxel and docetaxel, which are the most commonly used taxanes, elicit immediate hypersensitivity reactions (HSRs) in 5% to 10% of patients. Almost all patients that experience these reactions can be safely re-exposed to taxanes either through desensitization or challenge. This article describes the clinical presentation, diagnosis, and management of HSRs to taxanes and discusses the different options for their safe readministration.

Current Knowledge and Management of Hypersensitivity Reactions to Monoclonal Antibodies.

Hypersensitivity reactions (HSRs) to monoclonal antibodies (mAbs) are increasingly frequent as this class of therapeutic agents is rapidly expanding. Immediate and nonimmediate HSRs have been reported with mAbs. Immediate HSRs can be explained by 3 main mechanisms: cytokine release syndrome, IgE-mediated, and IgG-mediated reactions. Importantly, IgE-mediated reactions can occur on first exposure due to preformed specific IgEs, as shown for cetuximab. Almost all patients with an immediate HSR can be safely re-exposed either through desensitization or challenge depending on the severity and mechanism of the initial reaction. An algorithm detailing the general approach to these HSRs and the preferred method of re-exposure is presented in this review. Also, the mAbs that are most frequently implicated in HSRs are discussed individually.

Basophil Activation Test is a Relevant Biomarker of the Outcome of Rapid Desensitization in Platinum Compounds-Allergy.

BACKGROUND: Rapid drug desensitization (RDD) has become a cornerstone in the management of immediate drug hypersensitivity reactions (DHRs) to chemotherapeutic agents. Because of the inherent risk of anaphylaxis during RDD, biomarkers to predict patients at risk of developing such severe reactions are needed. The basophil activation test (BAT) has been used in DHRs as a diagnostic tool. OBJECTIVE: We evaluated basophil CD63 and CD203c expression (BAT) as a biomarker to assess the safety and effectiveness of RDD in platinum compounds-allergic patients. METHODS: Patients allergic to platinum compounds (n = 15) undergoing RDD were assessed through clinical history, skin testing, serum tryptase levels, and BAT. BAT was performed immediately before RDD, assessing CD203c and CD63 expression on basophils. BAT was also performed in 6 patients tolerant to platinum compounds and in 6 healthy volunteers. RESULTS: BAT was positive to CD203c or CD63 in 11 out of 15 patients allergic to platinum compounds (73%), with increased expression of CD203c and CD63 in 11 (73%) and 6 (40%) patients, respectively. Increased CD63 expression tended to be associated with more severe initial reactions. All controls had negative test results. Reactions during RDD were associated with BAT positivity and increased tryptase levels. Only 1 of 4 patients with negative BAT had a mild reaction during RDD. BAT remained positive in multiple sequential RDD. CONCLUSIONS: BAT identified patients allergic to platinum compounds with an increased risk of reactions during desensitization and higher CD63 expression was observed in severe reactions. Multiple RDDs to platinum compounds did not induce persistent hyporesponsiveness on basophils. BAT is a potential biomarker for RDD.

Re-visiting Hypersensitivity Reactions to Taxanes: A Comprehensive Review.

Taxanes (a class of chemotherapeutic agents) are an important cause of hypersensitivity reactions (HSRs) in cancer patients. During the last decade, the development of rapid drug desensitization has been key to allow patients with HSRs to taxanes to be safely re-treated although the mechanisms of these HSRs are not fully understood. Earlier studies suggested that solvents, such as Cremophor EL used to solubilize paclitaxel, were responsible for HSRs through complement activation, but recent findings have raised the possibility that some of these HSRs are IgE-mediated. Taxane skin testing, which identifies patients with an IgE-mediated sensitivity, appears as a promising diagnostic and risk stratification tool in the management of patients with HSRs to taxanes. The management of patients following a HSR involves risk stratification and re-exposure could be performed either through rapid drug desensitization or graded challenge based on the severity of the initial HSR and the skin test result. Rapid drug desensitization has been shown to be an effective and safe method to re-introduce taxanes in hundreds of patients, including those with life-threatening HSRs. Patients with non-severe delayed skin HSRs may benefit from rapid drug desensitization since they may be at increased risk for an immediate HSR upon re-exposure. This review focuses on the clinical presentation, diagnosis, and novel mechanisms of immediate HSRs to taxanes. A new management strategy for HSRs to taxanes based on skin testing and rapid drug desensitization is proposed.