Two subsets of eosinophils have been described: resident eosinophils with homeostatic functions (rEOS) in healthy subjects and in patients with nonallergic eosinophilic asthma, and inflammatory eosinophils (iEOS) in blood and lung samples from patients with allergic asthma. We explored if it would be possible to identify different subsets of eosinophils using flow cytometry and the gating strategy applied to induced sputum. We conducted an observational cross-sectional single-center study of 62 patients with persistent allergic asthma. Inflammatory cells from induced sputum samples were counted by light microscopy and flow cytometry, and cytokine levels in the supernatant were determined. Two subsets of eosinophils were defined that we call E1 (CD66b-high and CD15-high) and E2 (CD66b-low and CD15-low). Of the 62 patients, 24 were eosinophilic, 18 mixed, 10 paucigranulocytic, and 10 neutrophilic. E1 predominated over E2 in the eosinophilic and mixed patients (20.86% vs. 6.27% and 14.42% vs. 4.31%, respectively), while E1 and E2 were similar for neutrophilic and paucigranulocytic patients. E1 correlated with IL-5, fractional exhaled nitric oxide, and blood eosinophils. While eosinophil subsets have been identified for asthma in blood, we have shown that they can also be identified in induced sputum.

Rituximab hypersensitivity reactions are rare but are one of the main causes of rituximab elimination from antilymphoma immunochemotherapy treatments. While the clinical picture may be indistinguishable from other infusion-related reactions, hypersensitivity reactions (HSR) do not disappear and instead become more intense with subsequent administrations. Objective. To describe the use of the 12-step protocol for desensitization to intravenous rituximab in clinical practice and the complementary study of a possible IgE-mediated HSR in the context of B-cell lymphoma treatment. Methods. A 12-step rituximab desensitization protocol was performed prospectively within clinical practice in 10 patients with a history of severe infusion reactions or in patients who had a repeated reaction at subsequent doses despite taking more intense preventive measures. Skin prick tests were performed at the time of reaction and at a later time to eliminate false negatives due to possible drug interference. Results. Overall, with the desensitization protocol, 70% of patients were able to complete the scheduled immunochemotherapy. Two patients had to discontinue the therapy due to clinical persistence and the third due to lymphoma progression. Intradermal tests with 0.1% rituximab were positive in only 20% of cases, demonstrating a mechanism of hypersensitivity. Conclusions. The 12-step desensitization protocol is very effective and assumable within healthcare practice. There is a need to determine the mechanism underlying the infusion reaction in a large proportion of cases due to the risk of future drug exposure.

Objective: Allergen immunotherapy (AIT) is an established treatment for mild to moderate allergic asthma. However, limited data are available regarding its safety and efficacy in patients with severe asthma. This study aimed to gather real-world evidence (RWE) on the safety and effectiveness of AIT in individuals with severe asthma caused by sensitization to at least 1 allergen, who were either currently undergoing AIT or had received it within the past five years. Methods: A retrospective study was conducted in Spain, including patients aged ≥ 6 years with severe asthma (Spanish Guideline for Asthma Management [GEMA] steps 5– 6 and Global Initiative for Asthma [GINA] step 5) sensitized to at least 1 allergen who had received AIT within the previous 5 years, to evaluate safety and effectiveness. Results: The study included 93 patients (54.8% female) with a median age of 40.3 years, including 5 under 14. A total of 16 systemic reactions (SRs) were reported in 8 patients (8.6%), mostly immediate (13/16) and occurring during the initiation phase (12/16), all in patients receiving subcutaneous immunotherapy. Most SRs were mild to moderate, except for 2 severe reactions in 1 patient. Only 3 patients discontinued treatment. Significant improvements in both FeNO and FEV₁ (%) were observed after 6 and 12 months of AIT, respectively. Quality of Life (through mini-AQLQ) scores improved at 1, 2 and 3 years after initiation of AIT compared to baseline. The number of patients who did not require rescue medication for asthma was significantly higher after starting AIT than before treatment. AIT was also associated with a 75.8% reduction in the number of emergency visits. Conclusion: This study confirms the safety and effectiveness of AIT in patients with well-controlled severe asthma in routine clinical practice. Additional prospective real-world studies are needed to better understand the efficacy of AIT in severe asthma.

Background and Aims: Asthma is a heterogeneous respiratory disease that encompasses different inflammatory and functional endophenotypes. Many non‐invasive biomarkers has been investigated to its pathobiology. Heany et al proposed a clinical algorithm that classifies severe asthmatic patients into likely‐eosinophilic phenotypes, based on accessible biomarkers: PBE, current treatment, FeNO, presence of nasal polyps (NP) and age of onset.Materials and Methods: We assessed the concordance between the algorithm proposed by Heany et al. with sputum examination, the gold standard, in 145 asthmatic patients of the MEGA cohort with varying grades of severity.Results: No correlation was found between both classifications 0.025 (CI = 0.013–0.037). Moreover, no relationship was found between sputum eosinophilia and peripheral blood eosinophilia count in the total studied population.Discussion and Conclusion: In conclusion, our results suggest that grouping the biomarkers proposed by Heany et al. are insufficient to diagnose eosinophilic phenotypes in asthmatic patients. Sputum analysis remains the gold standard to assess airway inflammation.

Key Clinical Message: An interesting case that shows an infrequent cause of cardiorespiratory arrest such as coronary vasospasm due to intravenous amiodarone induced Kounis syndrome. It highlights the usefulness of circulatory support with ECMO in the scenario of CPR. A patient with atrial fibrillation was admitted for an elective electrical cardioversion. He was given an amiodarone bolus that triggered Kounis syndrome with cardiac arrest due to vasospasm requiring emergency coronary angiography with infusion of nitroglycerin. Due to following refractory shock and severe refractory hypoxemia required mechanical circulatory support with ECMO and inhaled nitric oxide with favorable evolution. Allergy to amiodarone was later confirmed.