title: Mucosal Regulatory T Cells and T Helper 17 Cells in HIV-Associated Immune Activation.
abstract: Residual mucosal inflammation along with chronic systemic immune activation is an important feature in individuals infected with human immunodeficiency virus (HIV), and has been linked to a wide range of co-morbidities, including malignancy, opportunistic infections, immunopathology, and cardiovascular complications. Although combined antiretroviral therapy (cART) can reduce plasma viral loads to undetectable levels, reservoirs of virus persist, and increased mortality is associated with immune dysbiosis in mucosal lymphoid tissues. Immune-based therapies are pursued with the goal of improving CD4(+) T-cell restoration, as well as reducing chronic immune activation in cART-treated patients. However, the majority of research on immune activation has been derived from analysis of circulating T cells. How immune cell alterations in mucosal tissues contribute to HIV immune dysregulation and the associated risk of non-infectious chronic complications is less studied. Given the significant differences between mucosal T cells and circulating T cells, and the immediate interactions of mucosal T cells with the microbiome, more attention should be devoted to mucosal immune cells and their contribution to systemic immune activation in HIV-infected individuals. Here, we will focus on mucosal immune cells with a specific emphasis on CD4(+) T lymphocytes, such as T helper 17 cells and CD4(+)Foxp3(+) regulatory T cells (Tregs), which play crucial roles in maintaining mucosal barrier integrity and preventing inflammation, respectively. We hypothesize that pro-inflammatory milieu in cART-treated patients with immune activation significantly contributes to enhanced loss of Th17 cells and increased frequency of dysregulated Tregs in the mucosa, which in turn may exacerbate immune dysfunction in HIV-infected patients. We also present initial evidence to support this hypothesis. A better comprehension of how pro-inflammatory milieu impacts these two types of cells in the mucosa will shed light on mucosal immune dysfunction and HIV reservoirs, and lead to novel ways to restore immune functions in HIV(+) patients.
authors.affiliation: Department of Biological Sciences, School of Dental Medicine, Case Western Reserve University , Cleveland, OH , USA.
authors.forename: Pushpa
authors.initials: P
authors.lastname: Pandiyan
authors.affiliation: Department of Medicine, Division of Infectious Diseases, University Hospitals, Case Western Reserve University , Cleveland, OH , USA.
authors.forename: Souheil-Antoine
authors.initials: SA
authors.lastname: Younes
authors.affiliation: Department of Pathology, Case Western Reserve University , Cleveland, OH , USA.
authors.forename: Susan Pereira
authors.initials: SP
authors.lastname: Ribeiro
authors.affiliation: Department of Pathology, Case Western Reserve University , Cleveland, OH , USA.
authors.forename: Aarthi
authors.initials: A
authors.lastname: Talla
authors.affiliation: Department of Microbiology and Molecular Biology, School of Medicine, Case Western Reserve University , Cleveland, OH , USA.
authors.forename: David
authors.initials: D
authors.lastname: McDonald
authors.affiliation: Department of Biological Sciences, School of Dental Medicine, Case Western Reserve University , Cleveland, OH , USA.
authors.forename: Natarajan
authors.initials: N
authors.lastname: Bhaskaran
authors.affiliation: Department of Pharmacology, School of Medicine, Case Western Reserve University , Cleveland, OH , USA.
authors.forename: Alan D
authors.initials: AD
authors.lastname: Levine
authors.affiliation: Department of Biological Sciences, School of Dental Medicine, Case Western Reserve University , Cleveland, OH , USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Weinberg
authors.affiliation: Department of Pathology, Case Western Reserve University , Cleveland, OH , USA.
authors.forename: Rafick P
authors.initials: RP
authors.lastname: Sekaly
keywords: Foxp3; HIV; Th17; Tregs; mucosal immunity