RESUMEN
Patients who are severely affected by coronavirus disease 2019 (COVID-19) may develop a delayed onset 'cytokine storm', which includes an increase in interleukin-6 (IL-6). This may be followed by a pro-thrombotic state and increased D-dimers. It was anticipated that tocilizumab (TCZ), an anti-IL-6 receptor monoclonal antibody, would mitigate inflammation and coagulation in patients with COVID-19. However, clinical trials with TCZ have recorded an increase in D-dimer levels. In contrast to TCZ, colchicine reduced D-dimer levels in patients with COVID-19. To understand how the two anti-inflammatory agents have diverse effects on D-dimer levels, we present data from two clinical trials that we performed. In the first trial, TCZ was administered (8 mg/kg) to patients who had a positive polymerase chain reaction test for COVID-19. In the second trial, colchicine was given (0·5 mg twice a day). We found that TCZ significantly increased IL-6, α-Defensin (α-Def), a pro-thrombotic peptide, and D-dimers. In contrast, treatment with colchicine reduced α-Def and Di-dimer levels. In vitro studies show that IL-6 stimulated the release of α-Def from human neutrophils but in contrast to colchicine, TCZ did not inhibit the stimulatory effect of IL-6; raising the possibility that the increase in IL-6 in patients with COVID-19 treated with TCZ triggers the release of α-Def, which promotes pro-thrombotic events reflected in an increase in D-dimer levels.
Asunto(s)
Antiinflamatorios/uso terapéutico , Anticuerpos Monoclonales Humanizados/uso terapéutico , Tratamiento Farmacológico de COVID-19 , Colchicina/uso terapéutico , Productos de Degradación de Fibrina-Fibrinógeno/análisis , alfa-Defensinas/inmunología , Anciano , Coagulación Sanguínea/efectos de los fármacos , COVID-19/sangre , COVID-19/inmunología , Síndrome de Liberación de Citoquinas/sangre , Síndrome de Liberación de Citoquinas/tratamiento farmacológico , Síndrome de Liberación de Citoquinas/inmunología , Femenino , Productos de Degradación de Fibrina-Fibrinógeno/inmunología , Humanos , Interleucina-6/sangre , Interleucina-6/inmunología , Masculino , Persona de Mediana Edad , Neutrófilos/efectos de los fármacos , Neutrófilos/inmunologíaRESUMEN
The inflammatory response to SARS/CoV-2 (COVID-19) infection may contribute to the risk of thromboembolic complications. α-Defensins, antimicrobial peptides released from activated neutrophils, are anti-fibrinolytic and prothrombotic in vitro and in mouse models. In this prospective study of 176 patients with COVID-19 infection, we found that plasma levels of α-defensins were elevated, tracked with disease progression/mortality or resolution and with plasma levels of interleukin-6 (IL-6) and D-dimers. Immunohistochemistry revealed intense deposition of α-defensins in lung vasculature and thrombi. IL-6 stimulated the release of α-defensins from neutrophils, thereby accelerating coagulation and inhibiting fibrinolysis in human blood, imitating the coagulation pattern in COVID-19 patients. The procoagulant effect of IL-6 was inhibited by colchicine, which blocks neutrophil degranulation. These studies describe a link between inflammation and the risk of thromboembolism, and they identify a potential new approach to mitigate this risk in patients with COVID-19 and potentially in other inflammatory prothrombotic conditions.