The microbiome in the blood of HAART-Naive HIV positive patients

Abstract

Introduction: Infection with HIV results in the loss of gut mucosal CD4 T cells of the Th17 subtype responsible for maintaining integrity of the mucosa well as antimicrobial immunity. This results in an upset in the balance of the microbiome in the gut characterised by more pathobionts being more abundant. The dysbiosis leads to translocation of these organisms into the sterile tissues and eventually into the general circulation. The microbial components circulating in blood contribute to immune activation thus hindering the return of normal immune status even with suppression of viral replication and elimination of opportunistic infections. The products of translocation can be detected by measuring lipopolysaccharide, endotoxin core antibodies, soluble CD14 and 16S rRNA. Objectives: To characterise the blood microbiome of HIV positive patients based on 16S rRNA gene sequencing and to find an association between the detection of a blood microbiome based on the level of immune suppression. Methods: 89 patients were recruited from The AIDS Support Organisation and Makerere University Joint AIDS Project. Blood was drawn in EDTA vacutainers, transported to the Makerere University College of Health Sciences where DNA was extracted. Polymerase chain reaction was carried out using 16S rRNA universal primers and agarose gel electrophoresis done to detect amplicons prior to sequencing. Results: The patients recruited had high CD4 T cell counts, with 51.2% having between 400 and 800 cells/ul. Polymerase chain reaction did not yield any amplicons for the 16S rRNA gene. Conclusions: Our findings showed that in this population there is no blood microbiome detected based on the 16S rRNA marker. We recommend that this study be done in other sub-populations of HIV infected individuals, such as those with established severe immune suppression and those on HAART as well as including measurement of gut immune suppression.