Blood or Colon in HIV-1 Patients on ART ... Greathead1, Hannah Cheeseman2, Robert Goldin3, Alan Steel4 Mark Nelson5 Brian Gazzard5 and Peter Kelleher.1.
CD4 TH17 Cytokine Secretion is not Depleted in the Blood or Colon in HIV-1 Patients on ART Louise Greathead1, Hannah Cheeseman2, Robert Goldin3, Alan Steel4 Mark Nelson5 Brian Gazzard5 and Peter Kelleher.1 1Immunology
Section, Chelsea and Westminster Campus, , 2IAVI, Chelsea and Westminster Campus, 3Department of Cellular Pathology, St Mary’s Campus, Faculty of Medicine, Imperial College London 4Gastroenterology Unit, Chelsea and Westminster NHS Trust 5HIV Sexual Health Directorate, Chelsea and Westminster Hospital NHS Trust.
4. RESULTS
1. INTRODUCTION & OBJECTIVES The gastrointestinal tract is a major site of CD4 T cell depletion during acute HIV-1 infection (1). Recent work identified a preferential loss of the pro-inflammatory TH17 subset in both the blood and mucosa of HIV-1 patients and further work has correlated reduction of this subset with increased markers of immune activation (2). The effect of anti retroviral therapy (ART) on the restoration of mucosal CD4 subsets has yielded conflicting results (3).
A significant depletion of %CD4 MMC was found in both the viremic and aviremic ART treated HIV groups compared to controls.
This work examined CD4 subsets in the peripheral blood (PBMC) and mucosal mononuclear cells (MMC) of HIV-1 patients on ART (median treatment time 3 years) and compared them to levels in HIV-1 patients with detectable viremia, uninfected controls and in patients with Crohn’s disease (CD) (a mucosal inflammatory control).
Numbers Recruited
CONTROLS CROHN’S DISEASE
VIREMIC HIV
Median Age Sex (Female/ (IQR) Male)
Median CD4 count (IQR)
No preferential depletion of IL-17a in the MMC of aviremic HIV
CD4+ IL-17a is restored on ART
Median CD8 count (IQR)
14
47 (40-55)
2/12
524 (498-768)
313 (285-457)
9
32 (25-36)
7/2
889 (735-1050)
410 (375-505)
4
37 (32-44)
0/4
474 (429-578)
825 (588-1290)
AVIREMIC HIV
10
48 (42-52)
0/10
500 (371-589)
721 (597-860)
CD4+ IL-22 is restored on ART
2. METHODS Mucosal biopsies
MMCs
1. Fine mincing 2. Collagenase II digestion 3. Mechanical disruption 4. Cell straining
PBMCs
5. Fix/Perm intracellular staining 6. Acquisition on custom built LSRII
Blood CD8 immune activation is not increased in aviremic HIV
TH1/TH17 is restored on ART
7. Robust gating strategy to minimise non-specific staining
3. FLOW CYTOMETRY C y t o k i n e staining on CD4 memory subsets in mucosal mononuclear cells (MMC)and PBMC’s in a healthy control.
ACKNOWLEDGEMENTS We would like to acknowledge the section of Infection and Immunity, Imperial NHS Trust for measuring absolute lymphocyte counts. Funding for this project was provided by the Joint Research Committee (JRC) of the Westminster Medical School, St Stephen’s AIDS Trust and Pfizer.
5. DISCUSSION We have demonstrated that viremic HIV infection is accompanied by a reduction of IL-17a and IL-22 producing CD4 T cells in the MMC. This is accompanied by increased levels of CD8 activation. Patients on successful ART have mucosal IL-22 and IL-17a responses similar to controls and normal immune activation levels indicating that ART can lead to restoration of mucosal TH17 cells. These results may have implications in the understanding of HIV related enteropathy and in the progressive immune deficiency seen in untreated infection. REFERENCES 1. Brenchley, J. M., T. W. Schacker, L. E. Ruff, D. A. Price, J. H. Taylor, G. J. Beilman, P. L. Nguyen, A. Khoruts, M. Larson, A. T. Haase & D. C. Douek (2004) CD4+ T cell depletion during all stages of HIV disease occurs predominantly in the gastrointestinal tract. J Exp Med, 200, 749-59. 2. Elhed, A. & D. Unutmaz (2010) Th17 cells and HIV infection. Curr Opin HIV AIDS, 5, 146-50. 3. Chege, D., P. M. Sheth, T. Kain, C. J. Kim, C. Kovacs, M. Loutfy, R. Halpenny, G. Kandel, T. W. Chun, M. Ostrowski, R. Kaul & t. T. M. I. Group (2011) Sigmoid Th17 populations, the HIV latent reservoir, and microbial translocation in men on long-term antiretroviral therapy. AIDS, 25, 741-749.
