Nasal cytology produces results comparable to surgery in CRSwNP

Nasal cytology produces results comparable to surgery in CRSwNP

Investigators of a new study evaluated whether nasal cytology was a reliable method of identifying type 2 inflammation in patients with chronic rhinosinusitis with nasal polyps (CRSwNP), which could then facilitate patient selection for biologic agents at baseline. through endotyping.

Nasal cytology had proven reliability for the identification of biomarkers of type 2 inflammation in patients who have chronic rhinosinusitis with nasal polyps (CRSwNP), according to new study findings published in Journal of the World Allergy Organization.

This potential new method of endotyping, beyond the systemic and histologic biomarkers currently used for endotyping, would be used to facilitate patient selection for biologic agents, the authors noted. They evaluated the method using samples from the inferior nasal turbinate and polypoid tissue; Surgical polyp tissue was also collected and compared to nasal cytology samples.

Thirty-three consecutive patients with CRSwNP were included (mean [SD] age, 49.9 [13/3] years; 15.2% smokers; female patients, 42.2%); all were scheduled for functional endoscopic sinus surgery between June 2020 and 2021 at the Humanitas Clinical and Research Hospital for Personalized Medicine, Asthma and Allergies in Rozzano, Milan, Italy.

“Suggested type 2 inflammatory biomarkers include local but invasive methods,” the authors wrote. “It would be desirable to be able to use a non-invasive local biomarker, possibly cheap, and whose results can be obtained in a short time.”

Among the patient population, 39.4% were considered atopic, 51.5% had asthma, and 21.2% had nonsteroidal anti-inflammatory drugs that exacerbated respiratory disease. Mean measurements of nasal polyp score (NPS), blood eosinophil count, and neutrophil count were 6.1 (1.8), 410.0 (352.7) cells/mcL, and 4086.2 (1598.6 ) cells/mcL, respectively.

When the findings of the 3 sampling methods were compared, the researchers saw the following results:

  • Eosinophil counts:
    • Nasal polyp tissue: 43.7 (39.6) cells/hpf
    • Nasal polyp cytology: 32.8 (44.7) cells/hpf
    • Inferior turbinate cytology: 27.6 (58.0) cells/hpf
  • Neutrophil count:
    • Nasal polyp tissue: 24.4 (45.5) cells/hpf
    • Nasal polyp cytology: 30.0 (58.0) cells/hpf
    • Inferior turbinate cytology: 26.1 (54.8) cells/hpf

Among the 84.8% of patients shown to have high CRSwNP type 2 (at least 10 tissue eosinophils/HPF), age tended to be younger (47.8 [13.2] against 61.6 [5.0] years) and had a lower NPS (5.9 vs 7.2) compared with patients classified as low CRSwNP type 2. However, patients with high CRSwNP type 2 had significantly higher eosinophils on nasal polyp cytology (5.2.5 [67.0] against 12.2 [17.3] cells/hpf) and the mean number of eosinophils in the inferior turbinate cytology (32.0 [62.1] against 2.9 [2.9]).

Overall, the study investigators determined, the eosinophil count from the nasal polyp scraping cytology samples was comparable to the count they obtained from the surgical samples, but the nasal turbinate results were lower than those from the tissue samples. . In addition, Bland-Altman plots showed agreement between the eosinophil count derived from nasal polyp cytology and histological data.

The significant differences observed between these 2 measurements for especially high eosinophil counts was attributed to “the fact that cytology is capable of evaluating the presence of cells detached from polypoid tissue by means of the scraping maneuver which, in cases of very high eosinophilic tissue infiltrates, relevant, may partially underestimate the level of inflammation, while clearly highlighting the type 2 inflammatory nature of the nasal polyp,” the authors wrote.

“Nasal cytology is a simple, rapid, inexpensive, noninvasive, and potentially point-of-care diagnostic method,” they concluded. “Our results add an additional modality of using nasal cytology, showing that it provides results comparable to those obtained from the much more invasive collection of surgical biopsy samples.”

They added that their findings are especially relevant in the context of precision medicine, because they can add to the criteria used to identify patients with treatable inflammatory endotype disease who may be eligible for treatment with biologics, making nasal cytology on “a new and reliable biomarker of type 2 inflammatory involvement in patients with CRSwNP.”

Reference

Paoletti G, Malvezzi L, Riccio AM, et al. Nasal cytology as a reliable non-invasive procedure to phenotype chronic rhinosinusitis type 2 patients with nasal polyps. World Allergy Body J. Published online October 18, 2022. doi:10.1016/j.waojou.2022.100700

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