Predictive Value of Blood Eosinophils for MAST Positivity in CRSwNP Versus CRSsNP

Article information

J Rhinol. 2025;32(1):64-65

Publication date (electronic) : 2025 March 21

doi : https://doi.org/10.18787/jr.2024.00035

Jae Yoon Lee, MD, PhD

Department of Otolaryngology-Head and Neck Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

Address for correspondence: Jae Yoon Lee, MD, PhD, Department of Otolaryngology- Head and Neck Surgery, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea Tel: +82-2-2258-6335, Fax: +82-2-2258-1354, E-mail: leejaeyooon@gmail.com

Received 2024 October 17; Accepted 2024 October 22.

Dear Editor,

The article by Yoon et al. [1] reported that the eosinophil count and eosinophil cationic protein (ECP) have statistically insignificant predictive value for multiple allergen simultaneous test (MAST) positivity in chronic rhinosinusitis (CRS), with area under the curve (AUC) values below 0.6.

Building on their methodology, we analyzed a larger cohort of patients using similar criteria and methods. Our findings reveal that the results in CRS with nasal polyp (CRSwNP) group had minimal predictive value. In contrast, CRS without nassal polyps (CRSsNP) group showed statistically significant AUC values (eosinophil proportion [EO%] AUC=0.730, p=0.013; eosinophil count [EO count] AUC=0.710, p=0.024), as illustrated in the Fig. 1. This suggests that eosinophilic parameters may hold predictive value in CRSsNP when evaluated with larger sample sizes.

Fig. 1.

Receiver operating characteristic (ROC) curves for MAST positivity. A: In the CRSwNP group (n=70), the AUC values for predicting MAST positivity were 0.469 for EO% (p=0.682), 0.515 for EO count (p=0.845), and 0.608 for ECP (p=0.160). B: In the CRSsNP group (n=53), the AUC values were 0.730 for EO% (p=0.013), 0.710 for EO count (p=0.024), and 0.585 for ECP (p=0.363). EO, eosinophil; ECP, eosinophil cationic protein; AUC, area under the curve; MAST, multiple allergen simultaneous test.

We hypothesized three potential reasons for the difference in the predictive value of eosinophilic markers between CRSwNP and CRSsNP:

1) Differences in inflammatory pathways: CRSwNP is primarily associated with type 2 inflammation, characterized by elevated levels of eosinophils, interleukins (IL-4, IL-5, and IL13), and IgE. In this type of inflammation, eosinophils may participate in a chronic inflammatory process that is independent of immediate allergen sensitization (MAST positivity). Conversely, CRSsNP typically exhibits non-eosinophilic or neutrophilic inflammation, whereas eosinophils might directly reflect an allergic response. This could explain why EO counts in CRSsNP correlate more closely with MAST positivity, indicating an allergic etiology, whereas in CRSwNP, eosinophils contribute to a broader, more complex inflammatory environment [2].

2) Tissue remodeling and barrier dysfunction in CRSwNP: CRSwNP is characterized by significant tissue remodeling, which includes fibrosis, epithelial damage, and the formation of polyps. This extensive tissue damage can disrupt the functioning of eosinophils and the exposure to allergens in the nasal mucosa, resulting in a weaker correlation between eosinophil counts and MAST positivity [3]. In contrast, patients with CRSsNP experience less severe tissue remodeling, which allows eosinophils to more accurately reflect local allergic sensitization. Therefore, in CRSwNP, the predictive value of eosinophil counts may be obscured by the extensive tissue changes.

3) MAST positivity reflects systemic allergy in CRSwNP, not local inflammation: In patients with CRSwNP, MAST positivity is likely indicative of systemic allergic sensitization rather than local eosinophilic inflammation. The increased eosinophil count observed in CRSwNP could stem from a broader type 2 immune response, rather than being a direct response to allergens identified by the MAST [4]. Consequently, eosinophils may not be reliable indicators of local allergic activity in CRSwNP, whereas in CRSsNP, they may more accurately reflect localized allergic inflammation.

We believe that the differences in findings between CRSwNP and CRSsNP populations may underscore the distinct roles of eosinophils in these conditions. Our results suggest that both eosinophil count and percentage could play a role in predicting MAST positivity in CRSsNP patients, although they appear to be less significant in CRSwNP.