Systematic diagnostic evaluation for immune-related colitis: a single institutional review of advanced melanoma patients treated with ipilimumab

Colitis can be a life-threatening immune-related adverse event (irAE) for patients with metastatic melanoma treated with immune checkpoint blockade, a new anti-cancer immunotherapy. With the increasing use of PD-1/PD-L1 and CTLA-4 inhibitors, particularly in combination in melanoma and other cancers, timely and accurate diagnosis of colitis will become increasingly important for oncologists. The main goal of this study is to understand the clinical presentation of ipilimumab-induced colitis and to validate the use of CT scans as a safe and effective diagnostic tool. We analyzed a cohort of 303 patients who received ipilimumab at Dana Farber Cancer Institute on an expanded access protocol or standard of care between the years of 2008 and 2015. Age, number of doses and frequency of ipilimumab doses were found to be clinical characteristics which could help differentiate patients who develop ipilimumab induced colitis from those who only present with diarrhea and other gastrointestinal symptoms. Of the 303 patients, 100 (33%) developed diarrhea and 43 (14%) received treatment with corticosteroids for ipilimumab-induced colitis. For all patients with suspected immune-related colitis, an effort was made to firmly establish the diagnosis prior to or immediately after initiation of treatment. Forty-one of 43 patients (95%) who received steroids for presumed immune-related colitis had a colonoscopy and 27 of 43 (63%) patients had both computed tomography (CT) of the abdomen/pelvis and a colonoscopy including biopsy. In the 31 patients with a CT and biopsy, CT was highly predictive of the presence of colitis on biopsy (sensitivity 85%, specificity 75%, PPV 96%) and the absence of CT findings was predictive of a negative biopsy (negative LR 0.2). In the 44 patients who had symptoms and CT evaluation, CT was highly predictive of the need for steroids to reach resolution of symptoms (sensitivity 85%, specificity 88%, PPV 92%, positive LR 7.3). Fifteen of the 17 patients with negative CT findings did not require steroids to reach resolution of symptoms. In conclusion, CT of the abdomen/pelvis is a fast, reliable, and non-invasive mode of diagnosing ipilimumab-induced immune-related colitis, whereas colonoscopy may not be needed to firmly establish that diagnosi

Anaphylaxis in the 21st century: phenotypes, endotypes, and biomarkers

Anaphylaxis is the most serious of all allergic reactions and can be fatal. The diagnosis is frequently delayed, and misdiagnosis often occurs with asthma or urticaria. Biomarkers such as tryptase are not routinely checked, and appropriate treatment with epinephrine is not administered in a majority of cases, increasing the risk of poor outcomes. The objective of this review is to provide a better understanding of the pathophysiology of anaphylaxis with a description of phenotypes, endotypes, and biomarkers available in both the clinical and research settings. Expanding knowledge with regard to the presentation, causes, and triggers for anaphylaxis among health care providers will improve its diagnosis and management, increase patient safety, and decrease morbidity and mortality

Drug Hypersensitivity and Desensitizations: Mechanisms and New Approaches

Drug hypersensitivity reactions (HSRs) are increasing in the 21st Century with the ever expanding availability of new therapeutic agents. Patients with cancer, chronic inflammatory diseases, cystic fibrosis, or diabetes can become allergic to their first line therapy after repeated exposures or through cross reactivity with environmental allergens. Avoidance of the offending allergenic drug may impact disease management, quality of life, and life expectancy. Precision medicine provides new tools for the understanding and management of hypersensitivity reactions (HSRs), as well as a personalized treatment approach for IgE (Immunoglobuline E) and non-IgE mediated HSRs with drug desensitization (DS). DS induces a temporary hyporesponsive state by incremental escalation of sub-optimal doses of the offending drug. In vitro models have shown evidence that IgE desensitization is an antigen-specific process which blocks calcium flux, impacts antigen/IgE/FcεRI complex internalization and prevents the acute and late phase reactions as well as mast cell mediator release. Through a “bench to bedside” approach, in vitro desensitization models help elucidate the molecular pathways involved in DS, providing new insights to improved desensitization protocols for all patients. The aim of this review is to summarize up to date information on the drug HSRs, the IgE mediated mechanisms of desensitization, and their clinical applications

A dumbbell rescue stent graft facilitates clamp-free repair of aortic injury in a porcine model

Objective: Noncompressible torso hemorrhage is a high-mortality injury. We previously reported improved outcomes with a retrievable rescue stent graft to temporize aortic hemorrhage in a porcine model while maintaining distal perfusion. A limitation was that the original cylindrical stent graft design prohibited simultaneous vascular repair, given the concern for suture ensnarement of the temporary stent. We hypothesized that a modified, dumbbell-shaped design would preserve distal perfusion and also offer a bloodless plane in the midsection, facilitating repair with the stent graft in place and improve the postrepair hemodynamics. Methods: In an Institutional Animal Care and Use Committee-approved terminal porcine model, a custom retrievable dumbbell-shaped rescue stent graft (dRS) was fashioned from laser-cut nitinol and polytetrafluoroethylene covering and compared with aortic cross-clamping. Under anesthesia, the descending thoracic aorta was injured and then repaired with cross-clamping (n = 6) or dRS (n = 6). Angiography was performed in both groups. Operations were divided into phases: (1) baseline, (2) thoracic injury with either cross-clamp or dRS deployed, and (3) recovery, after which the clamp or dRS were removed. Target blood loss was 22% to simulate class II or III hemorrhagic shock. Shed blood was recovered with a Cell Saver and reinfused for resuscitation. Renal artery flow rates were recorded at baseline and during the repair phase and reported as a percentage of cardiac output. Phenylephrine pressor requirements were recorded. Results: In contrast with cross-clamped animals, dRS animals demonstrated both operative hemostasis and preserved flow beyond the dRS angiographically. Recovery phase mean arterial pressure, cardiac output, and right ventricular end-diastolic volume were significantly higher in dRS animals (P = .033, P = .015, and P = .012, respectively). Whereas distal femoral blood pressures were absent during cross-clamping, among the dRS animals, the carotid and femoral MAPs were not significantly different during the injury phase (P = .504). Cross-clamped animals demonstrated nearly absent renal artery flow, in contrast with dRS animals, which exhibited preserved perfusion (P<.0001). Femoral oxygen levels (partial pressure of oxygen) among a subset of animals further confirmed greater distal oxygenation during dRS deployment compared with cross-clamping (P = .006). After aortic repair and clamp or stent removal, cross-clamped animals demonstrated more significant hypotension, as demonstrated by increased pressor requirements over stented animals (P = .035). Conclusions: Compared with aortic cross-clamping, the dRS model demonstrated superior distal perfusion, while also facilitating simultaneous hemorrhage control and aortic repair. This study demonstrates a promising alternative to aortic cross-clamping to decrease distal ischemia and avoid the unfavorable hemodynamics that accompany clamp reperfusion. Future studies will assess differences in ischemic injury and physiological outcomes. Clinical Relevance: Noncompressible aortic hemorrhage remains a high-mortality injury, and current damage control options are limited by ischemic complications. We have previously reported a retrievable stent graft to allow rapid hemorrhage control, preserved distal perfusion, and removal at the primary repair. The prior cylindrical stent graft was limited by the inability to suture the aorta over the stent graft owing to risk of ensnarement. This large animal study explored a dumbbell retrievable stent with a bloodless plane to allow suture placement with the stent in place. This approach improved distal perfusion and hemodynamics over clamp repair and heralds the potential for aortic repair while avoiding complications