[Effect of nasal microbial diversity on postoperative prognosis of patients with chronic sinusitis and nasal polyp]

Objective: To investigate the nasal microbial diversity in patients with chronic sinusitis with nasal polyps (CRSwNP), as well as the nasal microbiome characteristics, inflammatory cells and factors in postoperative relapses, in order to understand the effects of microbiome factors on the postoperative prognosis of CRSwNP. Methods: The nasal secretions and nasal polyp tissues from 77 patients with CRSwNP were collected in Department of Otorhinolaryngology Head and Neck Surgery, West China Hospital, Sichuan University from December 2017 to December 2018. The cohort consisted of 34 males and 43 females, aged from 29 to 76 years. Microbial DNA was extracted from cotton swabs for high-throughput sequencing based on 16SrRNA to detect bacterial community composition, and Luminex was used to analyze cytokines such as IL-5, IL-8, IL-17a, IL-17e, IL-18, IL-27, and IFN-γ in polyp tissue. Eosinophils and neutrophils in peripheral blood and polyp tissue were counted. Patients with CRSwNP were followed up for 1 year after surgery, and the recurrence of nasal polyps was recorded. The correlation between the recurrence of nasal polyps and inflammatory cytokines, inflammatory cell counts and nasal microbial diversity was analyzed. Chi-square test was used for bicategorical variables, Mann-Whitney U test was used for continuous variables, and Wilcoxon rank sum test was used to compare the difference in average relative abundance between the two groups. Results: At the one year follow-up, 12 patients experienced a recurrence, including 5 males and 7 females. There was no significant difference in age, sex, asthma, allergic rhinitis and eczema between the relapsing group and the non-relapsing group. The total nasal symptoms score (TNSS) in the recurrent group [42.3 (30.2, 67.1), M (Q₁, Q₃)] was significantly higher than that in the non-recurrent group [37.8 (29.4, 50.3)]. In nasal polyp tissue, the number of eosinophils [40.83 (22.33, 102.00)/HP] and neutrophils [30.83 (20.33, 56.44)/HP] in the recurrent group were significantly higher than those in the non-recurrent group [13.72 (13.50, 48.33)/HP] and [18.50 (12.00, 26.08)/HP], Z-values were -6.997 and -8.243, respectively, all P<0.001. The expression levels of IFN-γ, IL-17A, IL-17E and IL-18 in relapsed group were significantly higher than those in non-relapsed group, but there was no significant difference in positive rates. At the generic level, the mean relative abundance of Corynebacterium in the nasal passage of CRSwNP patients in the non-relapses group was (11.90±20.31)%, higher than that in the relapses group (0.15±0.20)%, but the difference was not statistically significant after correction (FDR P=0.638). The mean relative abundance of staphylococcus in the non-relapsed group was (8.17±27.70)%, significantly lower than that in the relapsed group (8.99±15.89)%, but the difference was not statistically significant (FDR P=0.638). Conclusions: Neutrophil-mediated inflammatory responses are associated with recurrent nasal polyps. The recurrence of nasal polyps after endoscopic surgery may be related to the decrease in the abundance of protective microorganisms and the increase in the number of pathogenic microorganisms.