Tanya M. Laidlaw

Hypersensitivity reactions to chemotherapy: Outcomes and safety of rapid desensitization in 413 cases

BACKGROUND Hypersensitivity reactions (HSRs) to chemotherapeutic drugs, including mAbs, often require that the provoking medication be discontinued, thus raising a dilemma for the caregiver: further use could precipitate a severe, even fatal, allergic reaction on re-exposure, but alternative drugs might be poorly tolerated or much less effective compared with the preferred agent. OBJECTIVE We have developed a standardized rapid desensitization protocol for achieving temporary tolerization to drug allergens. In this study we evaluate the safety and efficacy of this protocol. METHODS Ninety-eight patients who had HSRs in response to treatment with carboplatin, cisplatin, oxaliplatin, paclitaxel, liposomal doxorubicin, doxorubicin, or rituximab received rapid desensitization to these agents. A standardized 12-step protocol was used, with treatment given intravenously or intraperitoneally. Initial desensitizations occurred in the medical intensive care unit, whereas most subsequent infusions took place in an outpatient setting. Safety and efficacy of the protocol were assessed by review of treatment records. RESULTS Of the 413 desensitizations performed, 94% induced mild or no reactions. No life-threatening HSRs or deaths occurred during the procedure, and all patients received their full target dose. Most reactions occurred during the first desensitization. Reactions were most commonly reported at the last step of the protocol. Desensitizations through the intravenous and intraperitoneal routes were equally effective. CONCLUSIONS Our standardized 12-step protocol for rapid drug desensitization is safe and effective and has been adopted as the standard of care at our institutions in treating patients with HSRs to chemotherapeutic drugs, including mAbs.

Cysteinyl leukotriene overproduction in aspirin-exacerbated respiratory disease is driven by platelet-adherent leukocytes

Cysteinyl leukotriene (cysLT) overproduction is a hallmark of aspirin-exacerbated respiratory disease (AERD), but its mechanism is poorly understood. Because adherent platelets can convert the leukocyte-derived precursor leukotriene (LT)A(4) to LTC(4), the parent cysLT, through the terminal enzyme LTC(4) synthase, we investigated the contribution of platelet-dependent transcellular cysLT production in AERD. Nasal polyps from subjects with AERD contained many extravascular platelets that colocalized with leukocytes, and the percentages of circulating neutrophils, eosinophils, and monocytes with adherent platelets were markedly higher in the blood of subjects with AERD than in aspirin-tolerant controls. Platelet-adherent subsets of leukocytes had higher expression of several adhesion markers than did platelet nonadherent subsets. Adherent platelets contributed more than half of the total LTC(4) synthase activity of peripheral blood granulocytes, and they accounted for the higher level of LTC(4) generation by activated granulocytes from subjects with AERD compared with aspirin-tolerant controls. Urinary LTE(4) levels, a measure of systemic cysLT production, correlated strongly with percentages of circulating platelet-adherent granulocytes. Because platelet adherence to leukocytes allows for both firm adhesion to endothelial cells and augmented transcellular conversion of leukotrienes, a disturbance in platelet-leukocyte interactions may be partly responsible for the respiratory tissue inflammation and the overproduction of cysLTs that characterize AERD.

Prostaglandin D2: A dominant mediator of aspirin-exacerbated respiratory disease

BACKGROUND Aspirin desensitization followed by high-dose aspirin therapy is routinely performed for patients with aspirin-exacerbated respiratory disease (AERD). Little is known about the contributions of mediators other than cysteinyl leukotrienes to aspirin reactions and to the therapeutic benefit of high-dose aspirin therapy. OBJECTIVE We investigated differences in urinary eicosanoid metabolite levels and blood eosinophil counts in patients with AERD who tolerate and those who fail aspirin desensitization and also in patients with AERD who were successfully treated with high-dose aspirin therapy. METHODS Twenty-nine patients with AERD were stratified into those who tolerated aspirin desensitization (group I) and those who did not (group II). Urine was analyzed for eicosanoid metabolites at baseline, during aspirin reactions, and during high-dose aspirin therapy. Blood was analyzed for cell differentials at baseline and during aspirin therapy. RESULTS Basal prostaglandin D2 metabolite (PGD-M; 13.6 ± 2.7 vs 7.0 ± 0.8 pmol/mg creatinine [Cr], P < .05) and thromboxane metabolite (TX-M; 1.4 ± 0.3 vs 0.9 ± 0.1 pmol/mg Cr, P < .01) levels were higher in group II than in group I. During aspirin reactions, PGD-M levels remained unchanged, whereas TX-M levels (0.7 ± 0.1 pmol/mg Cr, P = .07) tended to decrease in group I. In contrast, PGD-M levels increased dramatically in group II (61.3 ± 19.9 pmol/mg Cr, P < .05), whereas TX-M levels did not change. The decrease in FEV1 inversely correlated with basal urinary levels of both leukotriene E4 and PGD-M. Blood eosinophil and basophil levels increased and urinary PGD-M levels (2.2 ± 0.8 pmol/mg Cr, P < .001) decreased on 2 months of high-dose aspirin therapy in group I. CONCLUSION Failure to tolerate aspirin desensitization in a subset of patients with AERD is associated with prostaglandin D2 overproduction. The increase in blood eosinophil and basophil counts during high-dose aspirin therapy might reflect the functional consequences of decreased prostaglandin D2 release and the therapeutic benefit of aspirin.

Cysteinyl leukotriene receptors, old and new; implications for asthma.

The cysteinyl leukotrienes (cys‐LTs) are three structurally similar, but functionally distinct lipid mediators of inflammation. The parent cys‐LT, LTC4, is synthesized by and released from mast cells, eosinophils, basophils, and macrophages, and is converted to the potent constrictor LTD4 and the stable metabolite, LTE4. While only two cys‐LT‐selective receptors (CysLTRs) have been identified, cloned, and characterized, studies dating back three decades predicted the existence of at least three functional CysLTRs, each with a characteristic physiological function in airways and other tissues. The recent demonstration that mice lacking both known CysLTRs exhibit full (and in some instances, augmented) physiological responses to cys‐LTs verifies the existence of unidentified CysLTRs. Moreover, the ability to manipulate receptor expression in both whole animal and cellular systems reveals that the functions of CysLTRs are controlled at multiple levels, including receptor‐receptor interactions. Finally, studies in transgenic mice have uncovered a potentially major role for cys‐LTs in controlling the induction of Th2 responses to common allergens. This review focuses on these recent findings and their potential clinical implications.

Prostaglandin E2 deficiency causes a phenotype of aspirin sensitivity that depends on platelets and cysteinyl leukotrienes

Significance Aspirin-exacerbated respiratory disease (AERD) is a common, severe variant of asthma, which is associated with overproduction of cysteinyl leukotrienes (cysLTs) and respiratory reactions to drugs that block cyclooxygenase 1. We demonstrate that mice selectively lacking the capacity to up-regulate the generation of prostaglandin E2 with inflammation develop an AERD-like phenotype that depends critically on platelets and thromboxane receptors, which drive transcellular synthesis of cysLTs, which, in turn, activate mast cells with aspirin challenge. The findings suggest a role for antiplatelet or thromboxane-selective antagonists as treatments for AERD. Aspirin-exacerbated respiratory disease (AERD) is characterized by asthma, tissue eosinophilia, overproduction of cysteinyl leukotrienes (cysLTs), and respiratory reactions to nonselective cyclooxygenase (COX) inhibitors. Ex vivo studies suggest that functional abnormalities of the COX-2/microsomal prostaglandin (PG)E2 synthase-1 system may underlie AERD. We demonstrate that microsomal PGE2 synthase-1 null mice develop a remarkably AERD-like phenotype in a model of eosinophilic pulmonary inflammation. Lysine aspirin (Lys-ASA)–challenged PGE2 synthase-1 null mice exhibit sustained increases in airway resistance, along with lung mast cell (MC) activation and cysLT overproduction. A stable PGE2 analog and a selective E prostanoid (EP)2 receptor agonist blocked the responses to Lys-ASA by ∼90%; EP3 and EP4 agonists were also active. The increases in airway resistance and MC products were blocked by antagonists of the type 1 cysLT receptor or 5-lipoxygenase, implying that bronchoconstriction and MC activation were both cysLT dependent. Lys-ASA–induced cysLT generation and MC activation depended on platelet-adherent granulocytes and T-prostanoid (TP) receptors. Thus, lesions that impair the inducible generation of PGE2 remove control of platelet/granulocyte interactions and TP-receptor–dependent cysLT production, permitting MC activation in response to COX-1 inhibition. The findings suggest applications of antiplatelet drugs or TP receptor antagonists for the treatment of AERD.

Pathogenesis of Aspirin-Exacerbated Respiratory Disease and Reactions

Physiologic and pharmacologic studies support the hypothesis that aspirin-exacerbated respiratory disease (AERD) involves fundamental dysregulation in the production of and end-organ responsiveness to both antiinflammatory eicosanoids (prostaglandin E2) and proinflammatory effectors (cysteinyl leukotrienes). The acquired nature of AERD implies a disturbance in a potential epigenetic control mechanism of the relevant mediator systems, which may be a result of incompletely clarified environmental factors (eg, viral or bacterial infections, inhaled pollutants).

Prostaglandin E2 deficiency uncovers a dominant role for thromboxane A2 in house dust mite-induced allergic pulmonary inflammation

Prostaglandin E2 (PGE2) is an abundant lipid inflammatory mediator with potent but incompletely understood anti-inflammatory actions in the lung. Deficient PGE2 generation in the lung predisposes to airway hyperresponsiveness and aspirin intolerance in asthmatic individuals. PGE2-deficient ptges−/− mice develop exaggerated pulmonary eosinophilia and pulmonary arteriolar smooth-muscle hyperplasia compared with PGE2-sufficient controls when challenged intranasally with a house dust mite extract. We now demonstrate that both pulmonary eosinophilia and vascular remodeling in the setting of PGE2 deficiency depend on thromboxane A2 and signaling through the T prostanoid (TP) receptor. Deletion of TP receptors from ptges−/− mice reduces inflammation, vascular remodeling, cytokine generation, and airway reactivity to wild-type levels, with contributions from TP receptors localized to both hematopoietic cells and tissue. TP receptor signaling ex vivo is controlled heterologously by E prostanoid (EP)1 and EP2 receptor-dependent signaling pathways coupling to protein kinases C and A, respectively. TP-dependent up-regulation of intracellular adhesion molecule-1 expression is essential for the effects of PGE2 deficiency. Thus, PGE2 controls the strength of TP receptor signaling as a major bronchoprotective mechanism, carrying implications for the pathobiology and therapy of asthma.

Aspirin-Exacerbated Respiratory Disease Involves a Cysteinyl Leukotriene–Driven IL-33–Mediated Mast Cell Activation Pathway

Aspirin-exacerbated respiratory disease (AERD), a severe eosinophilic inflammatory disorder of the airways, involves overproduction of cysteinyl leukotrienes (cysLTs), activation of airway mast cells (MCs), and bronchoconstriction in response to nonselective cyclooxygenase inhibitors that deplete homeostatic PGE2. The mechanistic basis for MC activation in this disorder is unknown. We now demonstrate that patients with AERD have markedly increased epithelial expression of the alarmin-like cytokine IL-33 in nasal polyps, as compared with polyps from aspirin-tolerant control subjects. The murine model of AERD, generated by dust mite priming of mice lacking microsomal PGE2 synthase (ptges−/− mice), shows a similar upregulation of IL-33 protein in the airway epithelium, along with marked eosinophilic bronchovascular inflammation. Deletion of leukotriene C4 synthase, the terminal enzyme needed to generate cysLTs, eliminates the increased IL-33 content of the ptges−/− lungs and sharply reduces pulmonary eosinophilia and basal secretion of MC products. Challenges of dust mite–primed ptges−/− mice with lysine aspirin induce IL-33–dependent MC activation and bronchoconstriction. Thus, IL-33 is a component of a cysLT-driven innate type 2 immune response that drives pathogenic MC activation and contributes substantially to AERD pathogenesis.

KIT Inhibition by Imatinib in Patients with Severe Refractory Asthma

BACKGROUND Mast cells are present in the airways of patients who have severe asthma despite glucocorticoid treatment; these cells are associated with disease characteristics including poor quality of life and inadequate asthma control. Stem cell factor and its receptor, KIT, are central to mast‐cell homeostasis. We conducted a proof‐of‐principle trial to evaluate the effect of imatinib, a KIT inhibitor, on airway hyperresponsiveness, a physiological marker of severe asthma, as well as on airway mast‐cell numbers and activation in patients with severe asthma. METHODS We conducted a randomized, double‐blind, placebo‐controlled, 24‐week trial of imatinib in patients with poorly controlled severe asthma who had airway hyperresponsiveness despite receiving maximal medical therapy. The primary end point was the change in airway hyperresponsiveness, measured as the concentration of methacholine required to decrease the forced expiratory volume in 1 second by 20% (PC20). Patients also underwent bronchoscopy. RESULTS Among the 62 patients who underwent randomization, imatinib treatment reduced airway hyperresponsiveness to a greater extent than did placebo. At 6 months, the methacholine PC20 increased by a mean (±SD) of 1.73±0.60 doubling doses in the imatinib group, as compared with 1.07±0.60 doubling doses in the placebo group (P=0.048). Imatinib also reduced levels of serum tryptase, a marker of mast‐cell activation, to a greater extent than did placebo (decrease of 2.02±2.32 vs. 0.56±1.39 ng per milliliter, P=0.02). Airway mast‐cell counts declined in both groups. Muscle cramps and hypophosphatemia were more common in the imatinib group than in the placebo group. CONCLUSIONS In patients with severe asthma, imatinib decreased airway hyperresponsiveness, mast‐cell counts, and tryptase release. These results suggest that KIT‐dependent processes and mast cells contribute to the pathobiologic basis of severe asthma. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01097694.)

Alcohol-induced Respiratory Symptoms Are Common in Patients With Aspirin Exacerbated Respiratory Disease

BACKGROUND A large percentage of patients with aspirin exacerbated respiratory disease (AERD) report the development of alcohol-induced respiratory reactions, but the true prevalence of respiratory reactions caused by alcoholic beverages in these patients was not known. OBJECTIVE We sought to evaluate the incidence and characteristics of alcohol-induced respiratory reactions in patients with AERD. METHODS A questionnaire designed to assess alcohol-induced respiratory symptoms was administered to patients at Brigham and Womens Hospital and Scripps Clinic. At least 50 patients were recruited into each of 4 clinical groups: (1) patients with aspirin challenge-confirmed AERD, (2) patients with aspirin-tolerant asthma (ATA), (3) patients with aspirin tolerance and with chronic rhinosinusitis, and (4) healthy controls. Two-tailed Fisher exact tests with Bonferroni corrections were used to compare the prevalence of respiratory symptoms among AERD and other groups, with P ≤ .017 considered significant. RESULTS The prevalence of alcohol-induced upper (rhinorrhea and/or nasal congestion) respiratory reactions in patients with AERD was 75% compared with 33% with aspirin-tolerant asthma, 30% with chronic rhinosinusitis, and 14% with healthy controls (P < .001 for all comparisons). The prevalence of alcohol-induced lower (wheezing and/or dyspnea) respiratory reactions in AERD was 51% compared with 20% in aspirin-tolerant asthma and with 0% in both chronic rhinosinusitis and healthy controls (P < .001 for all comparisons). These reactions were generally not specific to one type of alcohol and often occurred after ingestion of only a few sips of alcohol. CONCLUSION Alcohol ingestion causes respiratory reactions in the majority of patients with AERD, and clinicians should be aware that these alcohol-induced reactions are significantly more common in AERD than in controls who are aspirin tolerant.