RESUMEN
A nosocomial cluster induced by co-infections with avian influenza A(H7N9) and A(H1N1)pdm09 (pH1N1) viruses occurred in 2 patients at a hospital in Zhejiang Province, China, in January 2014. The index case-patient was a 57-year-old man with chronic lymphocytic leukemia who had been occupationally exposed to poultry. He had co-infection with H7N9 and pH1N1 viruses. A 71-year-old man with polycythemia vera who was in the same ward as the index case-patient for 6 days acquired infection with H7N9 and pH1N1 viruses. The incubation period for the second case-patient was estimated to be <4 days. Both case-patients died of multiple organ failure. Virus genetic sequences from the 2 case-patients were identical. Of 103 close contacts, none had acute respiratory symptoms; all were negative for H7N9 virus. Serum samples from both case-patients demonstrated strong proinflammatory cytokine secretion but incompetent protective immune responses. These findings strongly suggest limited nosocomial co-transmission of H7N9 and pH1N1 viruses from 1 immunocompromised patient to another.
Asunto(s)
Infección Hospitalaria/transmisión , Huésped Inmunocomprometido , Gripe Aviar/transmisión , Gripe Humana/transmisión , Leucemia Linfocítica Crónica de Células B/inmunología , Policitemia Vera/inmunología , Enfermedades de las Aves de Corral/transmisión , Anciano , Animales , China , Infección Hospitalaria/diagnóstico , Infección Hospitalaria/patología , Infección Hospitalaria/virología , Citocinas/biosíntesis , Citocinas/inmunología , Resultado Fatal , Humanos , Subtipo H1N1 del Virus de la Influenza A/genética , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Subtipo H1N1 del Virus de la Influenza A/fisiología , Subtipo H7N9 del Virus de la Influenza A/genética , Subtipo H7N9 del Virus de la Influenza A/aislamiento & purificación , Subtipo H7N9 del Virus de la Influenza A/fisiología , Gripe Aviar/virología , Gripe Humana/complicaciones , Gripe Humana/inmunología , Gripe Humana/virología , Leucemia Linfocítica Crónica de Células B/complicaciones , Leucemia Linfocítica Crónica de Células B/virología , Masculino , Persona de Mediana Edad , Exposición Profesional , Policitemia Vera/complicaciones , Policitemia Vera/virología , Aves de Corral , Enfermedades de las Aves de Corral/virologíaRESUMEN
Endochondral ossification consists of successive steps of chondrocyte differentiation, including mesenchymal condensation, differentiation of chondrocytes, and hypertrophy followed by mineralization and ossification. Loss-of-function studies have revealed that abnormal growth plate cartilage of the Cdc42 mutant contributes to the defects in endochondral bone formation. Here, we have investigated the roles of Cdc42 in osteogenesis and signaling cascades governing Cdc42-mediated chondrogenic differentiation. Though deletion of Cdc42 in limb mesenchymal progenitors led to severe defects in endochondral ossification, either ablation of Cdc42 in limb preosteoblasts or knockdown of Cdc42 in vitro had no obvious effects on bone formation and osteoblast differentiation. However, in Cdc42 mutant limb buds, loss of Cdc42 in mesenchymal progenitors led to marked inactivation of p38 and Smad1/5, and in micromass cultures, Cdc42 lay on the upstream of p38 to activate Smad1/5 in bone morphogenetic protein-2-induced mesenchymal condensation. Finally, Cdc42 also lay on the upstream of protein kinase B to transactivate Sox9 and subsequently induced the expression of chondrocyte differential marker in transforming growth factor-ß1-induced chondrogenesis. Taken together, by using biochemical and genetic approaches, we have demonstrated that Cdc42 is involved not in osteogenesis but in chondrogenesis in which the BMP2/Cdc42/Pak/p38/Smad signaling module promotes mesenchymal condensation and the TGF-ß/Cdc42/Pak/Akt/Sox9 signaling module facilitates chondrogenic differentiation.