RESUMO
The differentiation between influenza and coronavirus disease 2019 (COVID-19) could constitute a diagnostic challenge during the ongoing winter owing to their clinical similitude. Thus, novel biomarkers are required to enable making this distinction. Here, we evaluated whether the surfactant protein D (SP-D), a collectin produced at the alveolar epithelium with known immune properties, was useful to differentiate pandemic influenza A(H1N1) from COVID-19 in critically ill patients. Our results revealed high serum SP-D levels in patients with severe pandemic influenza but not those with COVID-19. This finding was validated in a separate cohort of mechanically ventilated patients with COVID-19 who also showed low plasma SP-D levels. However, plasma SP-D levels did not distinguish seasonal influenza from COVID-19 in mild-to-moderate disease. Finally, we found that high serum SP-D levels were associated with death and renal failure among severe pandemic influenza cases. Thus, our studies have identified SP-D as a unique biomarker expressed during severe pandemic influenza but not COVID-19.
Assuntos
COVID-19/genética , Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Vírus da Influenza A Subtipo H1N1 , Influenza Humana/genética , Proteína D Associada a Surfactante Pulmonar/genética , SARS-CoV-2 , Adulto , Idoso , Biomarcadores , COVID-19/sangue , COVID-19/diagnóstico , COVID-19/virologia , Coinfecção , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Influenza Humana/diagnóstico , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Proteína D Associada a Surfactante Pulmonar/sangue , Índice de Gravidade de Doença , Avaliação de Sintomas , Adulto JovemRESUMO
The yellow fever 17D (YF-17D) vaccine is one of the most efficacious vaccines developed to date. Interestingly, vaccination with YF-17D induces IFN-γ production early after vaccination (days 5-7) before the development of classical antigen-specific CD8(+) and CD4(+) T cell responses. Here we investigated the cellular source of this early IFN-γ production. At days 5 and 7 post-vaccination activated CD8(+) gamma-delta TCR T cells produced IFN-γ and TNF-α. Activated CD4(+) T cells produced IFN-γ and TNF-α at day 7 post-vaccination. This early IFN-γ production was also induced after vaccination with recombinant YF-17D (rYF-17D), but was not observed after recombinant Adenovirus type 5 (rAd5) vaccination. Early IFN-γ production, therefore, might be an important aspect of yellow fever vaccination.