The impact of pre-existing influenza antibodies and inflammatory status on the influenza vaccine responses in older adults.

Age-associated immune changes and pre-existing influenza immunity are hypothesized to reduce influenza vaccine effectiveness in older adults, although the contribution of each factor is unknown. Here, we constructed influenza-specific IgG landscapes and determined baseline concentrations of cytokines typically associated with chronic inflammation in older adults (TNF-α, IL-10, IL-6, and IFN-γ) in 30 high and 29 low influenza vaccine responders (HR and LR, respectively). In a background of high H3 antibody titers, vaccine-specific H3, but not H1, antibody titers were boosted in LRs to titers comparable to HRs. Pre-vaccination concentrations of IL-10 were higher in LRs compared with HRs and inversely correlated with titers of pre-existing influenza antibodies. Baseline TNF-α concentrations were positively correlated with fold-increases in antibody titers in HRs. Our findings indicate that baseline inflammatory status is an important determinant for generating post-vaccination hemagglutinin-inhibition antibodies in older adults, and IgG responses can be boosted in the context of high pre-existing immunity.

Acquisition and transmission of HIV-1 among migrants and Chinese in Guangzhou, China from 2008 to 2012: Phylogenetic analysis of surveillance data.

BACKGROUND: Post-migration infection and domestic transmission of HIV-1 between immigrants and local population are critical for the HIV epidemic, but have not been addressed thus far in China. METHODS: Transmission clusters were analyzed with two cluster reconstruction methods, HIV-TRACE and Cluster Picker, using 1695 HIV-1 pol sequences obtained from 139 HIV-infected foreigners and 1556 Chinese natives in Guangzhou, China from 2008 to 2012. The geographic origin of the HIV-1 sequences was further determined by PastML while the factors associated with recent HIV-1 transmission were documented by logistic regression analysis. RESULTS: HIV-1 genotypes that are prevalent in African and East Asian countries were identified in HIV-infected Chinese subjects and vice versa. In addition, more NRTI drug resistance mutations were found in HIV-infected foreigners than in native Chinese (p < 0.001). HIV-1 transmission between HIV-infected foreigners and native Chinese individuals was documented in 12.95% (18/139) of the HIV-infected foreigners. Furthermore, Asian (odds ratio [OR] = 3.45), male (OR = 16.88) and those with known HIV-1 infection routes (OR = 3.23) were more likely associated with recent HIV-1 transmission in China. The Chinese natives linked to recent HIV-1 transmission were more likely to be infected through men who have sex with men (OR = 3.05) or people who inject drugs (OR = 3.05), rather than by heterosexual transmission. CONCLUSION: Our study demonstrates the impact of recent HIV-1 transmission between HIV-infected foreigners and Chinese natives on the HIV-1 epidemic in Guangzhou, China. Moreover, the results highlight the importance of phylogenetic analysis of HIV-1 surveillance data and the need for specific prevention strategies that target the immigrant population.