Investigating the correlation between mucus cytokine levels, inflammatory cell counts, and baseline quality-of-life measures in chronic rhinosinusitis

Background It is hypothesized that uncontrolled inflammation is responsible for many of the manifestations and symptoms of chronic rhinosinusitis (CRS). Although earlier work has demonstrated an association between olfactory loss and mucus cytokines, the impact on other symptoms is unknown. In this study we investigated the relationship between cytokines, inflammatory cell counts, and patient-reported outcomes measures to better understand how the inflammatory microenvironment correlates with CRS symptomatology. Methods The 22-item Sino-Nasal Outcome Test (SNOT-22) and 8-item Short Form Health Survey (SF-8) were administered to 76 patients undergoing endoscopic sinus surgery for CRS. Mucus was collected intraoperatively from the middle meatus and tested for 17 cytokines using a multiplex flow cytometric bead assay. Eosinophil/neutrophil counts were obtained from histopathologic slide review. Spearman correlations between cytokines, cell counts, and quality-of-life subdomain scores were assessed without multiple comparisons correction due to the small sample size. Results Interleukin-4 (IL-4) correlated significantly with the Rhinologic domain (R-s = 0.25, p = 0.03), whereas eosinophil and neutrophil counts were inversely correlated with the Extranasal Rhinologic domain (R-s = -0.32, p = 0.01; and R-s = -0.27, p = 0.03). Subgroup analysis for nasal polyposis (CRSwNP) showed significant correlations between IL-6 and Total SF-8 (R-s = 0.35, p = 0.02), General Health (R-s = 0.34, p = 0.03), and Emotional (R-s = 0.47, p = 0.002) scores. In patients without polyps (CRSsNP), IL-21 correlated positively with Extranasal Rhinologic Symptoms domain (R-s = 0.41, p = 0.01). Conclusion This pilot study identifies possible pairwise correlations between mucus cytokine levels and baseline quality-of-life measures that need confirmation in larger, targeted studies. Due to the exploratory methodology, positive results may be spurious and should only be used as a starting point for future confirmatory work.