Mastocytosis and COVID19 infection and vaccination: A pediatric series

Introduction: Mastocytosis encompasses a heterogeneous group of diseases characterized by an accumulation of clonal mast cells (MC) in the skin and/or internal organs, and symptoms of MC activation. This MC activation can be elucidated by several factors, including infections or vaccination. Objective(s): We present our experience with COVID infection and vaccination in a series of 133 patients with pediatric mastocytosis. Method(s): Between January 1998 and December 2022, 133 pediatric patients have been referred to our hospital owing to clinically suspected MC disorder, mainly with mastocytosis in the skin. The final diagnoses of mastocytosis were established by the presence of typical skin lesions together with an increase of MC numbers in a biopsy from lesional skin or activating KIT mutations in lesional skin tissue. Serum baseline tryptase and total immunoglobulin E levels were measured, and patients underwent a comprehensive allergy workup to confirm atopic status and history of anaphylaxis. Regarding vaccination, REMA's (Spanish Network on Mastocytosis) protocol was followed. Result(s): 13 patients with COVID infection were identified, of which 25 (56,8%) were female and 0% had symptoms of MC activation. All of them had an asymptomatic or mild course of COVID infection. None of the patients experimented MC activation symptoms during viral illness. Regarding COVID vaccination, all patients received premedication with antihistamine 60 minutes prior vaccination. No one experimented immediate reactions and only one patient (0,75%) referred worsening of MC activation symptoms (baseline pruritus, urtication and brain fog) only after the first doses, recovering without changes in his treatment (oral cromoglycate and antihistamine) in two months. Discussion(s): Although MC have been implicated in the pathogenesis of cytokine storm in COVID19, there is no clinical evidence of SARSCoV- 2-induced MC activation, perhaps related to the fact that bone marrow MC lack angiotensin-converting enzyme 2 receptors.

Leukocyte Cpd by in the Detection of Sarscov- 2 Pneumonia

Introduction: Leukocyte differential, present certain features in SARS-CoV2 infected patients neutrophilia, lymphopenia and morphology alterations, which could be useful for screening. Cell population data (CPD) are reported as part of leukocyte differentials by Sysmex XN analyze;they are morphometric parameters that characterize neutrophils, lymphocytes and monocytes and classify them according to their volume, granularity and their content in nucleic acids. CPD reflects in numbers the changes in morphology and activation status triggered by infections. We aimed to evaluate the predictive power of CPDs for the differential diagnosis of COVID19 versus non-COVID19 pneumonia. Method(s): The prospective, observational, multicenter study was conducted in 3 hospitals, including patients > 18 years admitted with the diagnosis community-acquired pneumonia in the period November 2019 - October 2020. Complete blood count were analyzed using Sysmex XN counters. Diagnosis of SARS-CoV-2 infection was done using real-time reverse transcriptionpolymerase chain reaction. Patients were divided into two groups: (1) referral cohort in a hospital for the development of the model (2) the sample of two other hospitals for its validation. Multivariate logistic regression model has been developed for the detection of COVID patients. Robustness of the model has been evaluated by means of the area under the ROC curve and the calibration of the model. Statisticalsignificance p < 0.05. Result(s): 598 patients were recruited, 322 in the referral cohort and 276 in the validation group. The average age was 67.0 years (Standard Deviation 14.59 years ) and 61.49 % male. Neutrophil lymphocyte ratio, NE-WZ, LYY, LY-Z, LY-WX, LY- WY, MO- WY, MO-Z were included in the multivariate analysis, and presented a significant association for the differential diagnosis of SARS-CoV-2 infection with AUC of 0.84 (95% CI 0.82-0.92) in the referral cohort and 0.77 (0.69-0.85) in the validation cohort Conclusion(s): Leukocyte differential and CPDs could be very useful in the differential diagnosis of SARS-CoV-2 pneumonia and lead to a cheap and early diagnosis of the disease.

All Roads Lead to Rome: Results of Non-Invasive Respiratory Therapies Applied in a Tertiary-Care Hospital Without an Intermediate Care Unit During the COVID-19 Pandemic

Introduction: Non-invasive respiratory therapies (NRT) were widely used in the first wave of the COVID-19 pandemic in different settings, depending on availability. The objective of our study was to present 90-day survival and associated factors in patients treated with NRT in a tertiary hospital without an Intermediate Respiratory Care Unit. The secondary objective was to compare the outcomes of the different therapies. Methods: Observational study of patients treated with NRT outside of an intensive care or intermediate respiratory care unit setting, diagnosed with COVID-19 and acute respiratory distress syndrome by radiological criteria and SpO2/FiO2 ratio. A multivariate logistic regression model was developed to determine independently associated variables, and the outcomes of high flow nasal cannula and continuous positive airway pressure were compared. Results: In total, 107 patients were treated and 85 (79.4%) survived at 90 days. Before starting NRT, the mean SpO2/FiO2 ratio was 119.8 ± 59.4. A higher SOFA score was significantly associated with mortality (OR 2,09;95% CI 1.34-3.27), while self-pronation was a protective factor (OR 0.23;95% CI 0.06-0.91). High flow nasal cannula was used in 63 subjects (58.9%), and continuous positive airway pressure in 41 (38.3%), with no differences between them. Conclusion: Approximately 4 out of 5 patients treated with NRT survived to 90 days, and no significant differences were found between high flow nasal cannula and continuous positive airway pressure.