Summary Eosinophils are innate immune cells typically associated with allergic and parasitic diseases. However, in recent years, eosinophils have also been ascribed a role in keeping homeostasis and in fighting several infectious diseases. Indeed, these cells circulate as mature cells in the blood and can be quickly recruited to the infected tissue. Moreover, eosinophils have all the necessary cellular equipment such as pattern recognition receptors (PRRs), pro-inflammatory cytokines, anti-bacterial proteins, and DNA traps to fight pathogens and promote an efficient immune response. This review summarizes some of the updated information on the role of eosinophils’ direct and indirect mediated interactions with pathogens.

<b><i>Introduction:</i></b> The pathogenesis of chronic rhinosinusitis (CRS) with nasal polyps (CRSwNPs) is not yet completely understood. Based on current knowledge, the infiltration of mast cells and eosinophils in nasal polyps (NPs) plays an important role. This study aimed to investigate the interplay of asthma and allergy etiopathology in CRSwNPs patients by specifically studying tissue mast cells and eosinophils and the pro-inflammatory marker CD48. <b><i>Methods:</i></b> Immunohistochemistry was used to assess eosinophils, mast cells, and CD48 expressing eosinophils infiltrating NPs, and flow cytometry was used to assess surface receptors expression on eosinophils from digested NPs. <b><i>Results:</i></b> Immunohistochemical analyses showed that mast cell infiltration in NPs is higher in allergic patients in comparison to nonallergic patients; eosinophils infiltration in asthmatic NPs was significantly elevated in comparison to the nonasthmatic NPs, and membrane CD48 (mCD48) expression on eosinophils infiltrating nonallergic asthmatic NPs was highly elevated in comparison to the other subgroups. Similarly, mCD48 and its high-affinity ligand m2B4’s expression on eosinophils from enzymatically digested NPs were significantly higher in nonallergic asthmatics in comparison to allergic asthmatics. <b><i>Conclusions:</i></b> Eosinophil infiltration in NPs for asthmatic patients, and mast cell infiltration for allergic patients, may be used as reliable biomarkers for endotyping CRSwNPs. In addition, CD48 in asthmatic patients who developed CRSwNPs could be regarded as a potential target for treatment.

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Bilateral internal carotid artery agenesis is a very rare congenital anomaly. Intracranial blood circulation in the affected internal carotid artery side is provided by collateral vasculature, contralateral internal carotid artery through the anterior communicating artery, and from the vertebrobasilar system through the posterior communicating artery. People with this abnormality may be asymptomatic for many years. However, patients may also be present with ischemic stroke orsubarachnoid hemorrhage, headache, and blurred vision. Diagnosis is usually incidental by the performance of carotid artery doppler ultrasonography or cervical/cranial magnetic resonance imaging owing to other symptoms. We report a case of bilateral internal carotid artery agenesis with pulsatile tinnitus lasting five years in the light of clinical presentation and imaging findings.