Biases related to periostin levels in chronic rhinosinusitis with nasal polyposis: a systematic review

Background: The role of periostin in the pathophysiology of chronic rhinosinusitis with nasal polyposis (CRSwNP) has been debated in the literature, with several authors proposing periostin as a potential biomarker or theurapeutical target. However, the mechanisms regulating the systematic or local periostin production in both CRSwNP patients and controls remain elusive. Methodology: Any factors reported to affect periostin expression in polyp tissue samples, nasal mucosa samples, serum and nasal secretions were considered as primary outcomes in this systematic review. Interactions or synergistic effects between bias factors were considered as secondary outcomes. Results: Eosinophilic CRSwNP, large polyp size and radiological severity were found to be high -risk, positive bias factors for periostin levels in polyp tissue samples, while the role of atopy and asthma has been debated. Immunotherapy and eosinophilic endotype were identified as biases for serum periostin measurements, while steroids and non-steroidal anti-inflammatory drug exacerbated respiratory disease remain of unclear risk. Bronchal asthma, eosinophilic endotype and immunotherapy have been reported to bias periostin measurements in nasal secretions. Conclusions: The relevant literature is extremely limited and little is actually known about the intrinsic or extrinsic factors affecting periostin measurements. The synthesis of the existing literature should be done with cautiousness.