Increased serum amyloid A in nasal polyps is associated with systemic corticosteroid insensitivity in patients with chronic rhinosinusitis with nasal polyps: a pilot study

Serum amyloid A (SAA) was involved in the pathogenesis of glucocorticoid resistance in lung diseases. However, their association with systemic corticosteroid insensitivity in chronic rhinosinusitis with nasal polyps (CRSwNP) patients remains to be assessed.

This study enrolled 32 CRSwNP patients to evaluate the association between SAA expression in NP and corticosteroid insensitivity, and the value of polyp SAA level for predicting the response to oral corticosteroids in CRSwNP patients. All patients were given a course of oral prednisone (30 mg daily for 2 weeks) and subdivided into glucocorticoid(GC)-sensitive and -insensitive subgroup according to the change in polyp size scores. The polyp specimens were obtained before and after corticosteroid treatment. SAA levels in polyp tissues were evaluated by enzyme-linked immunosorbent assay and quantitative reverse transcription polymerase chain reaction. Regression analysis was performed to analyze the association between SAA protein levels and corticosteroid insensitivity.

13/32 (40.62%) CRSwNP patients were insensitive to the oral corticosteroid therapy. SAA mRNA and protein levels were significantly increased in GC-insensitive NP compared to those in GC-sensitive NP. Tissue SAA protein levels were positively correlated with tissue neutrophil numbers. Regression analysis revealed tissue SAA levels were significantly correlated with corticosteroid insensitivity (P < 0.01). ROC curves indicated that the area under the curve was 0.87. When the polyp SAA protein level was 122.2 ng/ml or higher, the sensitivity and specificity were 76.92 and 73.68%, respectively.

Our findings suggest that increased SAA in NP is associated with reduced response to oral corticosteroids in CRSwNP. SAA levels in NP may have potential value in predicting corticosteroid insensitivity in CRSwNP patients.