TIM-3–Expressing Mast Cells Are Present in Chronic Rhinosinusitis with Nasal Polyps. (September 2018) - Corredera, Erica
Objectives: To identify whether TIM-3 expression is present in the mast cell population within nasal polyps and to determine its correlation with clinical severity in patients with chronic rhinosinusitis with nasal polyposis. Study Design: Basic science, translational study. Setting: Nasal polyp tissue collected from patients seen at a tertiary care hospital (2015-2016). Subjects and Methods: Nasal polyp tissue obtained during functional endoscopic sinus surgery (n = 24) was enzymatically digested into epithelial and stromal fractions. Viable mast cells expressing TIM-3 were identified using flow cytometry for the following: CD45, Live/Dead, c-kit, FcεR1, TIM-3. Disease severity was assessed using the Sino-Nasal Outcome Test, Lund-Mackay staging system, Lund-Kennedy staging system, and complete blood counts. Results: Mast cells were found in both the epithelial and stromal layers of polyps, with a greater %TIM-3 + mast cells in the epithelial layer compared with that of the stromal layer ( P = .001). As the percentage of mast cells increased, there was a comparative worsening in endoscopic severity after comparing pre- and postoperative LK scores (ρ = −0.455, P = .029). In a subgroup of patients with concomitant asthma, increased epithelial %TIM-3 + mast cells also correlated with worsening endoscopic appearance postoperatively (ρ = 0.866, P = .001, n = 11). Oral corticosteroid treatment did not change the viability of mast cells nor their influence on the increased postoperative endoscopic disease severity (ρ = −0.544, P = .020, n = 18). Conclusion: Viable mast cells were found to be present in polyps with increased TIM-3 expression at the epithelial layer. This suggests that TIM-3 may play a role in chronic inflammation in CRSwNP via mast cell activation.