Changes of histopathological and hematological characteristics in recurrent chronic rhinosinusitis with nasal polyps

Objective: To investigate the histopathological and hematological changes in reoperation of recurrent chronic rhinosinusitis with nasal polyps (CRSwNP). Methods: A total of 41 patients with CRSwNP who underwent two consecutive endoscopic sinus surgeries in Peking Union Medical College Hospital from February 1999 to April 2019 were included retrospectively, including 25 males and 16 females, aged (40.7±13.6) years at the former surgery and (47.0±13.2) years at the recurrent surgery. The peripheral blood cell count results were collected. Differential inflammatory cells in nasal polyp tissue sections were counted and characteristics of tissue remodeling were scored. Paired t test was used to compare the hematological and histological data of the two surgeries in the same cohort. Spearman's rank correlation coefficient was used to determine the correlation between tissue and peripheral blood eosinophil contents. Results: In histopathological tissue sections of nasal polyps, the mean tissue eosinophil, lymphocyte and total inflammatory cell counts per high power field significantly decreased (54.04±34.67 vs 76.97±65.59, 35.27±16.61 vs 50.01±26.94, 128.88±41.32 vs 176.38±80.59, t value was 2.413, 2.923, 3.445, respectively, all P<0.05), whereas the percentages of different inflammatory cell types remained unchanged when comparing the recurrent surgery with the former surgery. There was a significant reduction of basement membrane thickness and goblet cell hyperplasia score in the recurrent surgery (1.29±0.84 vs 2.00±0.84, 1.81±1.31 vs 2.44±1.10, t value was 5.367, 2.714, respectively, all P<0.05). Subgroup analysis suggested that changes in asthmatic cases, younger cases and cases without previous surgery were more remarkable than non-asthmatics, older cases and cases with previous surgery, respectively. There was no significant change in peripheral white blood cell counts and differential cell percentages, except a small increase of blood monocyte percentage. Correlation analysis showed that tissue eosinophil content correlated positively with blood eosinophil content at each surgery. Conclusions: In the recurrent surgery of CRSwNP, tissue eosinophil, lymphocyte and total inflammatory cell counts decrease significantly compare with that of the former surgery. The histological inflammatory load decreases with improvement of tissue remodeling, which could be attributed to the integrated treatment with surgery and medications.