Xiaochun Li, Wenwen He2, Yifang Wen3, Wei Jiang4,5 and Lei Huang6*
1Sixth People’s Hospital of Xinjiang, Antiviral Treatment Center for HIV/AIDS, China
2The Sixth People’s Hospital of Xinjiang, Clinical Laboratory Center, the Sixth People’s hospital, China
3The Sixth People’s Hospital of Xinjiang, Hepatitis Treatment Center, China
4Department of Microbiology and Immunology, Medical University of South Carolina, USA
5Divison of Infectious Diseases, Department of Medicine, USA
6The 302 Hospital of PLA, Treatment and Research Center for Infectious Diseases, China
*Corresponding author:Lei Huang, The 302 Hospital of PLA, Treatment and Research Center for Infectious Diseases, China
Submission: November 09, 2020;Published: November 20, 2020
ISSN 2639-0531Volume2 Issue5
Circulation has been considered in a sterile condition in individuals without live microbial infections. However, recent publications from our group and others highlight detection of blood microbiome or microbial molecules in healthy individuals and individuals with various diseases, as well as their potential roles in disease pathogenesis. In this review, we introduce the published studies and research advancement in the field of blood microbial and microbial translocation in disease immunopathogenesis.
Keywords: Blood microbiome; Microbial product translocation; Disease pathogenesis
Circulation has been considered in a sterile condition in individuals without live microbial
infections. However, recent publications highlight detection of blood microbiome or microbial
molecules in healthy individuals and individuals with various diseases without a live infection
or sepsis. Due to the low blood levels of microbial biomass and background contaminations
from experimental procedures, blood microbiome analysis has been met with technical
challenges. Nonetheless, blood microbiome provides important information to study the
interactions of microbiome and hosts, which is potentially critical for investigating their
effects on host immune perturbations in various disease conditions.
Blood and tissue microbiome have been studied in some fields. In a recent study, blood
and tissue microbiome has been assessed and cancer-specific microbial sequences have been
identified in different types of cancer in humans . In another study with seven different
type of cancer, evidence was found that cancer-specific bacteria were detected within both
immune cells and cancer tissues .
We have extensively investigated both quantity and quality of blood microbial translocation
and their roles in HIV pathogenesis. In HIV, the magnitude of blood microbial translocation
correlates with T cell activation, B cell activation and apoptosis, autoantibody production,
persistent immune activation and inflammation, immune recovery after antiretroviral
therapy, and organ complications [3-9]. Notably, not only the total amount of microbial
translocation, but also the specific bacterium or its molecule translocation plays a role in HIV
disease pathogenesis. In a recent study, we found that translocation of Staphylococcus aureus
plays a role in autoantibody production in HIV, and provide evidence of systemic exposure of
Staphylococcus aureus drove germinal central autoreactive B cell activation and autoantibody
production in mice .
In autoimmune diseases, studies from Silverman’s group and Kriegel’s group reveal
that translocation of gut pathobionts drive autoimmune diseases [10-13]. Our recent studies in systemic lupus erythematosus (SLE) disease show that
plasma microbial dysbiosis in the first-degree relatives of lupus
patients compared to unrelated healthy controls, and plasma
levels of microbial product translocation correlated with levels
of autoantibodies in lupus patients and first-degree relatives of
Studies in humans with chronic inflammatory diseases show that blood microbiome was detected and suggest that blood microbiome may play a role in the production of inflammation [16-18]. Moreover, blood and adipose tissue microbiome has been identified and suggest its role in tissue inflammation in obesity and type 2 diabetes; gut microbial translocation to the pancreatic lymph nodes triggered NOD2 singling pathway and contributed to type 1 diabetes [19,20]. Blood microbiome and microbial translocation have been studied in central nervous system diseases as well. An oral bacterium, Porphyromonas gingivalis, has detected to translocate to the brain and plays a role in Alzheimer’s disease . Moreover, bacterial LPS has shown to play a role in neurodegenerative diseases [22-24].
In summary, solid evidence has shown the detection of blood microbiome and microbial product translocation in humans without live infection. Further studies need to explore the mechanisms and causality using animals as well as in humans with treatment against specific microbes.
This work was supported by the National Natural Science Foundation of China (81772185, Huang).
© 2020 Lei Huang. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and build upon your work non-commercially.