Background: Although the importance of ectopic lymphoid tissues (eLTs) in the pathophysiology of nasal polyps (NPs) is increasingly appreciated, the mechanisms underlying their formation remain unclear. Objective: To study the role of IL-17A, CXCL13 and lymphotoxin (LT) in eLT formation in NPs. Methods: The expression of CXCL13 and LT as well as their receptors, and the phenotypes of stromal cells in NPs were studied by flow cytometry, immunostaining, and RT-PCR. Purified nasal stromal cells and polyp B cells were cultured and a murine model with nasal type 17 inflammation was established for the mechanistic study. Results: Excessive CXCL13 production was found in NPs and correlated with enhanced IL-17A expression. Stromal cells, with an expansion of CD31-Pdpn+ fibroblastic reticular cell (FRC) type, were the major source of CXCL13 in NPs without eLTs. IL-17A induced FRC expansion and CXCL13 production in nasal stromal cells. In contrast, B cells were the main source of CXCL13 and LTα1β2 in NPs with eLTs. CXCL13 upregulated LTα1β2 expression on polyp B cells, which in turn promoted CXCL13 production from polyp B cells and nasal stromal cells. LTα1β2 induced expansion of FRCs and CD31+Pdpn+ lymphoid endothelial cells, corresponding to the phenotypic characteristic of stromal cells in NPs with eLTs. IL-17A gene knockout, and CXCL13 and LTβR blockage diminished nasal eLT formation in the murine model. Conclusion: We identified an important role of IL-17A-induced stromal cell remodeling in the initiation, and crosstalk between B and stromal cells via CXCL13 and LTα1β2 in the enlargement of eLTs in NPs.

Safety and efficacy of tracheostomy in COVID-19 patients: a preliminary retrospective study of 14 casesKeypointsThe outbreak of COVID-19 in Wuhan, China, since December, 2019, has become a pandemic.This highly infectious disease increases the risk of converting to acute progressive respiratory failure, which needs the treatment with invasive mechanical ventilation, including tracheostomy.Up to now, there is no data describing tracheostomy cases in COVID-19 pandemic.we retrospectively analyzed 14 cases of critically ill COVID-19 patients with tracheostomy, concentrating on surgical indication, complication, procedure and precaution.Bedside open tracheostomy in COVID-19 patients is a relatively safe procedure for skilled surgeons under appropriate precautions, and the critically ill patients may benefit from it.Introduction The outbreak of Corona Virus Disease 2019 (COVID-19) has become a pandemic. It has been reported that in an early study, about 20% COVID-19 hospitalized patients developed into acute respiratory distress syndrome (ARDS) and required invasive mechanical ventilation.1 For some patients on prolonged intubation, tracheostomy may be considered as an important option for optimal respiratory care. Although recent several articles described the principles and procedures of tracheostomy on COVID-19 patients,2,3 there is no data describing tracheostomy cases in COVID-19 pandemic. In this study, we retrospectively analyzed 14 cases of COVID-19 patients with tracheostomy in [removed for blind peer review], the only designated hospital which still has a dozen intubated patients in [removed for blind peer review], concentrating on surgical indication, complication, procedure and precaution.