Editorial
Pathogenesis and Biomarkers of Eosinophilic Chronic Rhinosinusitis
2023 Volume 116 Issue 4 Pages 289-296
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2023 Volume 116 Issue 4 Pages 289-296
Chronic rhinosinusitis (CRS) is divided into CRS with nasal polyp formation (CRSwNP) and CRS without NP formation (CRSsNP) according to the phenotype classification. CRS is also divided into type 1/type 2/type 3 according to the endotype classification. CRSwNP and type 2 CRS are caused by eosinophilic inflammation in most cases, and are intractable. Useful biomarkers for such cases of eosinophilic CRS (eCRS) are desired for predicting their severity and postoperative courses.
In our recent study, we demonstrated that the number of IgG4-positive cells in the NP tissue and serum IgG4 levels could be potential novel biomarkers for evaluating the disease severity and predicting the risk of postoperative recurrence in cases of eCRS. Combined use of serum IgG4 and serum periostin levels can further improve the predictive ability.
Traditionally, peripheral blood eosinophilia and tissue eosinophilia have been used as biomarkers of eosinophilic inflammation. These biomarkers are used as diagnostic markers in the JESREC study. Charcot-Leyden crystals (CLCs), which are formed from galectin-10 released after extracellular trap cell death (ETosis) of activated eosinophils, also reflect eosinophilic inflammation.
Nasal nitric oxide (nasal NO) can also be a noninvasive biomarker of eCRS. NO is constantly produced in the nasal and paranasal cavity, and nasal NO levels are much higher than fractional exhaled nitric oxide (FeNO) levels. Nasal NO is reduced in eCRS patients, although the mechanism of this reduction has not yet been clarified.
Other biomarkers, such as IgE and leukotriene (LT) levels have been reported to be associated with the severity of eCRS and the risk of postoperative recurrence. The efficacy of anti-IgE antibody and LT receptor blockers in patients with eCRS suggests that IgE and LT receptors are important factors in the pathogenesis of eCRS.
I would like to emphasize here that rhinologists should use noninvasive biomarkers wisely to better manage patients with eCRS.
