Asunto(s)
COVID-19 , Eritema Pernio , Eritema Pernio/epidemiología , Brotes de Enfermedades , Humanos , Pandemias , SARS-CoV-2Asunto(s)
Metotrexato , Prurigo , Alitretinoína , Ciclosporina , Humanos , Metotrexato/uso terapéutico , Prurigo/tratamiento farmacológico , PruritoAsunto(s)
Infecciones por Coronavirus/epidemiología , Control de Infecciones/organización & administración , Pandemias/estadística & datos numéricos , Neumonía Viral/epidemiología , Enfermedades de la Piel/diagnóstico , Telemedicina , COVID-19 , Estudios de Cohortes , Infecciones por Coronavirus/prevención & control , Dermatología/métodos , Femenino , Humanos , Masculino , Evaluación de Resultado en la Atención de Salud , Pandemias/prevención & control , Neumonía Viral/prevención & control , Derivación y Consulta/estadística & datos numéricos , Estudios RetrospectivosRESUMEN
To emphasize the requirement for a J chain in native polymeric immunoglobulins for their selective transport into exocrine secretions, IgG, purified from two different antisera specific for the human J chain, was shown to: (i) bind in vitro to human polymeric IgA (pIgA) by density gradient ultracentrifugation; (ii) inhibit binding in vitro of rat secretory component to human pIgA; (iii) inhibit hepatic transport of human pIgA into rat bile in vivo; and (iv) inhibit apical transcytosis of pIgA in vitro by polarized human polymeric immunoglobulin receptor (pIgR)-expressing Madin-Darby canine kidney cells. Inhibition of biliary transport increased with the molar ratio of anti-J chain antibodies against pIgA and their incubation time. Anti-J chain F(ab')2 and Fab fragments also inhibited biliary transport, excluding a role for phagocytic clearance or excessive size of the immune complexes. Anti-human-Fc alpha Fab, bound to human pIgA in complexes of larger size than those with anti-J chain Fab, did not inhibit biliary transport of human pIgA. Propionic acid-denatured human pIgA, although containing J chains, was very poorly transported into rat bile. Altogether, our data strongly support, now also by in vivo experiments, the crucial role of the J chain of native pIgA in its selective pIgR-mediated transport into secretions, as suggested long ago by in vitro data only. Recent data on J chain-knockout mice, with low IgA levels in bile and feces, cannot explain the role of the J chain in contributing to the secretory component/pIgR-binding site of normal pIgA, but otherwise agree with our study.