Effect of raltegravir-containing intensification on HIV burden and T-cell activation in multiple gut sites of HIV-positive adults on suppressive antiretroviral therapy

Abstract

Objective: To determine whether raltegravir-containing antiretroviral therapy (ART) intensification reduces HIV levels in the gut.

Design: Open-label study in HIV-positive adults on ART with plasma HIV RNA below 40 copies/ml.

Methods: Seven HIV-positive adults received 12 weeks of ART intensification with raltegravir alone or in combination with efavirenz or darunavir. Gut cells were obtained by upper and lower endoscopy with biopsies from duodenum, ileum, colon, and rectum at baseline and 12 weeks. Study outcomes included plasma HIV RNA, HIV DNA and RNA from peripheral blood mononuclear cells (PBMC) and four gut sites, T-cell subsets, and activation markers.

Results: Intensification produced no consistent decrease in HIV RNA in the plasma, PBMC, duodenum, colon, or rectum. However, five of seven participants had a decrease in unspliced HIV RNA per 10 CD4(+) T cells in the ileum. There was a trend towards decreased T-cell activation in all sites, which was greatest for CD8(+) T cells in the ileum and PBMC, and a trend towards increased CD4(+) T cells in the ileum.

Conclusion: Most HIV RNA and DNA in the blood and gut is not the result of ongoing replication that can be impacted by short-term intensification with raltegravir. However, the ileum may support ongoing productive infection in some patients on ART, even if the contribution to plasma RNA is not discernible.

Figure 1

Blood HIV levels as a function of time through week 16. 1A shows the plasma HIV RNA, as measured by the high volume plasma HIV RNA assay. 1B shows the cell-associated unspliced HIV RNA in peripheral blood mononuclear cells (PBMC), as measured by real time reverse transcriptase PCR. 1C-D show the cell-associated HIV DNA in PBMC (1C) and sorted peripheral CD4+ T cells (1D), as measured by real time PCR. The x-axis shows the study week. Intensification was started after week 0 and stopped at week 12.

Figure 2

Change in cell-associated unspliced HIV RNA (2A-B) and HIV DNA (2C) per 10⁶ CD4+ T cells. HIV copy numbers were measured by real time PCR, normalized for the total cell input into the PCR (by μg RNA or DNA), and then normalized to the percent of all cells that were CD4+ T cells (by flow cytometry). 2B shows the HIV RNA values in the ileum for each subject at weeks 0 and 12. In 2A and 2C, column heights indicate the average of the changes (week 12-week 0) in HIV copy number per 10⁶ CD4+ T cells, as measured from peripheral blood mononuclear cells or total gut cells (obtained by collagenase digestion of endoscopic biopsies) from each of the four gut sites. Error bars indicate the standard error of measurement (SEM).

Figure 3

Change in CD4+ T cells as a percent of all cells (3A) and as a percent of T cells (3B) by site. The y-axis shows the average difference between the percent of CD4+ T cells at week 12 and the percent at week 0, as measured by flow cytometry from peripheral blood mononuclear cells (PBMC) or total gut cells (obtained by collagenase digestion of endoscopic biopsies) from each of the four gut sites. Error bars indicate the SEM.

Figure 4

Change in T cell activation by site. Using flow cytometry, T cell activation was measured by the percent of CD4+ T cells (left column) or CD8+ T cells (right column) that express both CD38 and HLA-DR (4A-B) as well as the percent of the total that express CD38 (4C-D) and the percent of the total that express HLA-DR (4E-F). The y-axis shows the average difference between the percent of activated T cells at week 12 and the percent at week 0, as measured from peripheral blood mononuclear cells (PBMC) or total gut cells (obtained by collagenase digestion of endoscopic biopsies) from the indicated gut sites. Error bars indicate the SEM.