Anti-phospholipid antibodies are elevated and functionally active in chronic rhinosinusitis with nasal polyps

Background: Polyps from patients with chronic rhinosinusitis with nasal polyps (CRSwNP) contain increased levels of autoreactive antibodies, B cells and fibrin deposition. Anti-phospholipid antibodies (APA) are autoantibodies known to cause thrombosis but have not been implicated in chronic rhinosinusitis (CRS). Objective: To compare APA levels (anti-cardiolipin, anti-phosphatidylethanolamine (anti-PE), and anti-β₂-glycoprotein (anti-B2GP)) in nasal polyp (NP) tissue with tissue from control and CRS without nasal polyp (CRSsNP) patients, we tested whether NP antibodies affect coagulation, and correlate APAs with anti-dsDNA IgG and markers of coagulation. Methods: Patient specimens were assayed for APA IgG, anti-dsDNA IgG and thrombin-anti-thrombin (TaT) complex by ELISA. Antibodies from a subset of specimens were tested for modified activated partial thromboplastin time (aPTT) measured on an optical-mechanical coagulometer. Results: Anti-cardiolipin IgG in NP was 5-fold higher than control tissue (p <.0001). NP antibodies prolonged aPTT compared to control tissue antibodies at 400 µg/mL (36.7 s vs. 33.8 s, p =.024) and 600 µg/mL (40.9 s vs. 34.7 s, p =.0037). Anti-PE IgG antibodies were increased in NP (p =.027), but anti-B2GP IgG was not significantly higher (p =.084). All APAs correlated with anti-dsDNA IgG levels, which were also elevated (R =.77,.71 and.54, respectively, for anti-cardiolipin, anti-PE, and anti-B2GP; all p <.001), but only anti-cardiolipin (R =.50, p =.0185) and anti-PE (R = 0.45, p =.037) correlated with TaT complex levels. Conclusions: APA IgG antibodies are increased in NP and correlate with autoreactive tissue antibodies. NP antibodies have in vitro anti-coagulant activity similar to those observed in anti-phospholipid syndrome, suggesting that they may have pro-coagulant effects in polyp tissue.