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Understanding the defects in innate immunity associated with perinatal HIV infection is a prerequisite for effective antiretroviral treatment. We therefore compared the innate immune response [dendritic cell (DC) phenotype and function] in peripheral blood by flow cytometry at baseline and 12 months in HIV-infected children to determine the defect associated with perinatal HIV infection. As compared with controls, patients had decreased numbers of total DCs including plasmacytoid (p)DCs and myeloid (m)DCs and impaired function based on induction of maturation markers (CD83, CD80, CCR7) and cytokines tumor necrosis factor-α and interferon-α (exclusive to pDC) upon stimulation with the TLR7/8 agonist Resiquimod. These abnormalities were evident in all three CD4 immune categories and persisted over 12 months; pDC function worsened in HIV+ children without treatment and improved slightly in those on highly active antiretroviral therapy (HAART). In conclusion, a majority of perinatally HIV-infected older children without HAART remain clinically stable in the short term, but have demonstrable immunologic abnormalities indicative of defects in the innate immune system. Children initiated on HAART showed improvement in CD4 counts but did not show improvement in DC function over the short term., (© 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.)

• BCG vaccination induces significantly enhanced frequencies of DC subsets • BCG vaccination induces diminished plasma levels of type I interferons but increased levels of type III interferons • BCG vaccination can potentially boost immune responses in a non -specific or off-target manner in elderly individuals. BCG can improve the response to vaccines directed against viral infections, and also, BCG vaccination reduces all-cause mortality, most likely by protecting against unrelated infections. However, the effect of BCG vaccination on dendritic cell (DC) subsets is not well characterized. We investigated the impact of BCG vaccination on the frequencies of DC subsets and type I and III interferons (IFNs) using whole blood and plasma samples in a group of elderly individuals (age 60-80 years) at one-month post-vaccination as part of our clinical study to examine the effect of BCG on COVID-19. Our results demonstrate that BCG vaccination induced enhanced frequencies of plasmacytoid DC (pDC) and myeloid DC (mDC). BCG vaccination also induced diminished plasma levels of type I IFNs, IFNα and IFNβ but increased levels of type III IFNs, IL-28A and IL-29. Thus, BCG vaccination was associated with enhanced DC subsets and IL-28A/IL-29 in elderly individuals, suggesting its ability to induce non-specific innate immune responses. [ABSTRACT FROM AUTHOR]