Prognostic Significance of Serum Complement Component 3 in Chronic Rhinosinusitis with Nasal Polyps.

Objective: The aim of this study was to assess the relationship between serum complement component 3 (C3) levels and disease recurrences in patients with chronic rhinosinusitis with nasal polyps (NPs). Methods: Ninety-seven patients with NPs and 30 controls were recruited. Clinical features were collected. Serum concentrations of C3 and C4 were measured before and after endoscopic sinus surgery. Results: Compared to the controls, increased C3 levels were found in patients with NPs. Patients with polyp recurrences had higher pre- and postoperative serum C3 levels than patients without polyp recurrences. Serum C3 levels dropped after surgery. After polyp regrowth, the mean C3 level in the recurrent group elevated again to the degree similar to that before surgery. When patients were stratified by tissue eosinophilia, no significant difference was seen in pre-/postoperative, absolute change after surgery, and post-recurrent C3 levels between patients without and with eosinophilic NPs in the group with disease recurrences. Conclusion: Serum C3 may be involved in the pathogenesis of NPs. Higher serum C3 levels may pinpoint patients at high risk of recurrence as an independent factor. Furthermore, the change in C3 levels after surgery may have the potential to serve as a predictor for polyp progression. Adding serum C3 measurement to the routine walk-up in the clinical management of NPs is worth further investigation and may help physicians make a more rational diagnostic and/or therapeutic decision regarding this disease.