Gingival tissue as a reservoir for human immunodeficiency virus type-1: Preliminary results of a cross-sectional observational study

J Periodontol. 2021 Aug 15. doi: 10.1002/JPER.21-0345. Online ahead of print.

Abstract

Background: Despite combined antiretroviral therapy (cART), total cure of immunodeficiency virus type 1 (HIV-1) infection remains elusive. Chronic periodontitis (CP) is strongly associated with HIV-1 infection. This condition is characterized by an intense inflammatory infiltrate mainly constituted of immune cells which in turn may be a valuable source of HIV-1 reactivation. This study aimed to determine if gingival tissue could act as a reservoir for HIV-1.

Methods: Twelve HIV-1-infected patients with CP and 12 controls (no HIV-1-infection and no CP) were evaluated in a cross-sectional study. RNA viral load and interleukin (IL) levels were determined in blood plasma and saliva. Histological sections of gingival tissue were stained with fluorescent antibodies against p24 antigen and different cellular biomarkers.

Results: In 6 of the 12 patients, HIV RNA load was detected, despite cART; in three of them, expression of viral RNA was also detected in saliva. The levels of IL-2, IL-6 and IL-12 were higher in blood and saliva of HIV-infected patients with CP than controls. HIV-1 p24 antigen was detected by Immunostaining in gingival biopsies of 10 of the 12 patients but in no control. Immune markers for T cells and antigen-presenting cells were also identified in most patients and some controls.

Conclusion: These preliminary data showing the detection of HIV-1 p24 antigen in the gingival biopsies of a significant part of HIV-1 infected patients with CP under cART together with the presence of immune cells, plead for the existence of a HIV-1 reservoir in the gingival tissue of this population. This article is protected by copyright. All rights reserved.

Keywords: HIV-1; gingiva; inflammation; mouth; mucous membrane; periodontitis; saliva.