Production of beta-defensin antimicrobial peptides by maxillary sinus mucosa

beta-Defensins are endogenous cationic peptides with broad-spectrum antimicrobial activity that are thought to play a role in the innate immune response. Two human beta-defensins, beta-defensin-1 (HBD-1) and beta-defensin-2 (HBD-2), have been identified. These peptides have recently been characterized in several human tissues. The presence of these peptides in the paranasal sinuses has not been investigated. We examined maxillaary sinus secretions from six patients with sinusitis and 10 patients without signs, symptoms, or radiologic evidence of sinus disease for the presence of beta-defensins. Cationic peptides were extracted from antral lavage specimens and examined for the presence of HBD-1 and HBD-2 by Western blot. Normal maxillary sinus epithelium was obtained from two patients and analyzed by RT-PCR for the presence of HBD-1 and HBD-2 mRNA. Tissue immunostaining for the two peptides was also used. Western blot analysis identified HBD-1 in two of 10 patients in the control group and in three of six patients in the sinusitis group. HBD-2 was identified in one of 10 patients in the control group and in four of six patients in the sinusitis group. RT-PCR revealed HBD-1 mRNA in one of two normal controls tested. Immunostaining localized HBD-1 and HBD-2 to the epithelial cell cytoplasm. This is the first demonstration of HBD-1 and HBD-2 production in the paranasal sinuses. In the present study, HBD-1 and HBD-2 were detected more frequently in the maxillary sinus fluid of patients with inflamed sinuses than in normal controls.