Characteristics of macrolide responders in persistent post-surgical rhinosinusitis

Area of Science:

• Otolaryngology
• Rhinology
• Pharmacology

Background:

• Long-term, low-dose macrolide therapy demonstrates anti-inflammatory benefits, particularly in diffuse panbronchiolitis.
• While macrolides yield dramatic upper airway responses, the specific patient phenotypes predicting macrolide responsiveness in chronic rhinosinusitis (CRS) remain poorly understood.

Purpose of the Study:

• To identify patient phenotypes that predict a positive response to low-dose macrolide therapy in chronic rhinosinusitis (CRS) patients.
• To investigate the association between clinical characteristics, biomarkers, and treatment outcomes in CRS patients undergoing macrolide therapy.

Main Methods:

• A case-control study involving 28 CRS patients treated with 3-month clarithromycin post-surgery and corticosteroid irrigation failure.
• Patients were classified as responders (near-normal endoscopy) or non-responders.
• Comparison of smoking status, asthma, atopy, revision surgery, symptom severity (SNOT-22), serum biomarkers, and tissue histopathology between groups.

Main Results:

• 19 responders were compared to 9 non-responders, with no significant differences in age, gender, smoking, asthma, or atopy.
• Macrolide response correlated with lower tissue eosinophilia (≤10/HPF) and serum eosinophilia.
• Non-responders showed overexpression of tissue squamous metaplasia; neutrophil expression was similar in both groups.

Conclusions:

• Low tissue and serum eosinophilia may indicate a CRS phenotype suitable for macrolide therapy.
• Absence of tissue squamous metaplasia is another potential predictor of successful macrolide treatment in refractory CRS.
• These findings suggest a targeted approach for long-term macrolide therapy in specific CRS patient subgroups.