Allergic rhinitis and chronic rhinosinusitis (CRS) are both upper airway diseases with high prevalence rates in Japan. Because these diseases significantly reduce patients' quality of life, new treatments are being researched every day. In this paper, we focused on allergic rhinitis, eosinophilic chronic rhinosinusitis (ECRS), and CRS with IgG4-related disease (CRS with IgG4-RD), their underlying pathogenic mechanisms, and treatments that have been recently attracting attention.

Allergic rhinitis is a type 1 hypersensitivity reaction that induces chemical mediators, such as histamine, and type 2 cytokines, such as IL-5. The effectiveness of biologic agents, such as Omalizumab, an anti-IgE antibody, and sublingual immunotherapy have already been assessed and approved.

ECRS, caused by type 2 inflammation, is a refractory disease. Its pathogenic conditions are formed mainly by type 2 cytokines, such as IL-4, IL-5, and IL-13. Dupilumab, an anti-IL-4α receptor antibody, inhibits the function of IL-4 and IL-13, has recently been reported to improve disease-control of ECRS.

IgG4-RD has been reported to complicate CRS. In this study, activation-induced cytidine deaminase (AID) -positive cells and regulatory T cells were found to increase in the sinus mucosa of CRS with IgG4-RD. The results implied that the pathogenesis of CRS with IgG4-RD and IgG4-RD are possibly of the same mechanism.

Clarifying the pathogenesis of these refractory diseases is necessary to improve disease-control and gain insights from which better treatments can be developed.

Background: Inflammation is associated with increased perioperative morbidity and mortality. Perioperative expression of neutrophil extracellular traps (NETs), innovative measures for inflammatory immune response, are proposed as a potential predictor of postoperative outcomes. Here, we investigated perioperative NET expression using flow cytometry in a clinical setting.

Methods: This study included 46 adult patients who underwent elective gastrointestinal surgery or cardiovascular surgery with extracorporeal circulation, in Tokyo Women's Medical University between August 2020 and September 2021. Perioperative NET expression was measured in serial blood samples collected from the preoperative period until the first postoperative day (POD1) with flow cytometry.

Results: The highest level of NET expression, as measured by the release of NETs using flow cytometry, was detected at POD1. Additionally, NET expression commenced during surgery and intraoperative NET expression dynamics differed depending on the type of surgery.

Conclusions: Our findings suggest a relationship between NET expression and perioperative factors, including postoperative outcomes. These results highlight the potential utility of flow cytometry in measuring NET expression to evaluate perioperative inflammatory response. Further studies are required for the clinical application of this method.