Alpha-Tryptase as a Risk-Modifying Factor for Mast Cell-Mediated Reactions.

PURPOSE OF REVIEW: To provide an overview on the current understanding of genetic variability in human tryptases and summarize the literature demonstrating the differential impact of mature tryptases on mast cell-mediated reactions and associated clinical phenotypes. RECENT FINDINGS: It is becoming increasingly recognized that tryptase gene composition, and in particular the common genetic trait hereditary alpha-tryptasemia (HαT), impacts clinical allergy. HαT has consistently been associated with clonal mast cell disorders (MCD) and has also been associated with more frequent anaphylaxis among these patients, and patients in whom no allergic trigger can be found, specifically idiopathic anaphylaxis. Additionally, more severe anaphylaxis among Hymenoptera venom allergy patients has been linked to HαT in both retrospective and prospective studies. An increased relative number of α-tryptase-encoding gene copies, even in the absence of HαT, has also been associated with systemic mastocytosis and has been shown to positively correlate with the severity of mast cell-mediated reactions to vibration and food. These findings may be due to increased generation of α/ß-tryptase heterotetramers and differences in their enzymatic activity relative to ß-tryptase homotetramers. HαT is a naturally occurring overexpression model of α-tryptase in humans. Increased relative α-tryptase expression modifies immediate hypersensitivity symptoms and is associated with more frequent and severe mast cell-mediated reactions, ostensibly due to increased α/ß-tryptase heterotetramer production.

Tracheostomy dislodgement: Are obese patients at increased risk?

BACKGROUND: Obesity is a risk factor for tracheostomy-related complications. We aimed to investigate whether obesity was associated with a risk of unplanned tracheostomy dislodgement or decannulation (DD). METHODS: Retrospective review of patients undergoing tracheostomy at a single institution from 2013 to 2019 was performed. The primary outcome was unplanned DD within 42 days. Obesity was assessed by body mass index (BMI) and skin-to-trachea distance (STT) measured on computed tomographic images. RESULTS: 25 (12%) episodes of unplanned DD occurred in 213 patients within 42 days. BMI ≥35 kg/m2 was associated with STT ≥80 mm (p < 0.0001). On multivariate analysis, STT ≥80 mm but not BMI was an independent predictor of unplanned DD (hazard ratio = 8.34 [95% confidence interval 2.85-24.4]). CONCLUSIONS: STT ≥80 mm was a better predictor of unplanned DD than BMI. Assessment of STT in addition to BMI may be useful to identify patients that would benefit from extended length tracheostomy tubes.

Validation of the Khorana score in acute myeloid leukemia patients: a single-institution experience.

BACKGROUND: Although patients with acute myeloid leukemia (AML) were shown to have an increased risk of thrombosis, no thrombosis risk assessment scoring system has been developed for AML patients. The Khorana Risk Score (KRS), which has been widely used for thrombosis risk assessment in the clinical setting, was developed on the basis of solid tumor data and has not been validated among AML patients. This study aims to validate the use of the KRS as a thrombosis risk-scoring system among patients with AML. METHODS: Using data from H. Lee Moffitt Cancer Center and Research Institution's Total Cancer Care Research Study, we retrospectively identified patients who were histologically confirmed with AML from 2000 to 2018. Clinical and laboratory variables at the time of AML diagnosis were characterized and analyzed. The thrombotic event rate was estimated with the Kaplan-Meier method and compared using the log-rank test. RESULTS: A total of 867 AML patients were included in the analysis. The median age at AML diagnosis was 75 years (range, 51-96), and the majority were male (65%, n = 565). A total of 22% (n = 191), 51% (n = 445), 24% (n = 207), and 3% (n = 24) of patients had a KRS of 0, 1, 2, and 3, respectively. A total of 42 thrombotic events (3% [n = 6/191] with a KRS of 1; 5% [n = 23/445] with a KRS of 2; 6.3% [n = 13/207] with a KRS of 3) were observed, with a median follow-up of 3 months (range, 0.1-307). There was no statistical difference in the risk of thrombosis between these groups (P = .1949). CONCLUSIONS: Although there was an increased risk of thrombosis associated with a higher KRS among AML patients with a KRS of 1 to 3, the difference was not statistically significant. Furthermore, only a few patients were found to have a KRS > 3, and this was largely due to pancytopenia, which is commonly associated with AML. These results indicate the need for a better thrombotic risk-scoring system for AML patients.