ABSTRACT
The impact of the microbiome on HIV disease is widely acknowledged although the mechanisms downstream of fluctuations in microbial composition remain speculative. We detected rapid, dynamic changes in translocated microbial constituents during two years after cART initiation. An unbiased systems biology approach revealed two distinct pathways driven by changes in the abundance ratio of Serratia to other bacterial genera. Increased CD4 T cell numbers over the first year were associated with high Serratia abundance, pro-inflammatory innate cytokines, and metabolites that drive Th17 gene expression signatures and restoration of mucosal integrity. Subsequently, decreased Serratia abundance and downregulation of innate cytokines allowed re-establishment of systemic T cell homeostasis promoting restoration of Th1 and Th2 gene expression signatures. Analyses of three other geographically distinct cohorts of treated HIV infection established a more generalized principle that changes in diversity and composition of translocated microbial species influence systemic inflammation and consequently CD4 T cell recovery.
Subject(s)
Gastrointestinal Microbiome , HIV Infections/immunology , HIV Infections/microbiology , Antiretroviral Therapy, Highly Active , Biodiversity , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Chemokines/blood , Cohort Studies , Glycolysis , HIV Infections/blood , HIV Infections/drug therapy , Humans , Inflammation/genetics , Inflammation/pathology , Mitochondria/metabolism , Monocytes/metabolism , Nucleic Acids/blood , Principal Component Analysis , Serratia/physiology , Th1 Cells/immunology , Th2 Cells/immunology , Transcription, Genetic , Uganda , Viral Load/immunologyABSTRACT
Vaccine responses vary by geographic location. We have previously described how HIV-associated inflammation leads to fibrosis of secondary lymph nodes (LNs) and T cell depletion. We hypothesized that other infections may cause LN inflammation and fibrosis, in a process similar to that seen in HIV infection, which may lead to T cell depletion and affect vaccine responses. We studied LNs of individuals from Kampala, Uganda, before and after yellow fever vaccination (YFV) and found fibrosis in LNs that was similar to that seen in HIV infection. We found blunted antibody responses to YFV that correlated to the amount of LN fibrosis and loss of T cells, including T follicular helper cells. These data suggest that LN fibrosis is not limited to HIV infection and may be associated with impaired immunologic responses to vaccines. This may have an impact on vaccine development, especially for infectious diseases prevalent in the developing world.
