Characterization of CD8⁺ T Cells and Microenvironment in Oral Lesions of Human Immunodeficiency Virus-Infected Persons with Oropharyngeal Candidiasis

Oropharyngeal candidiasis (OPC), the most common oral infection in human immunodeficiency virus-positive persons, correlates with reduced blood CD4⁺ T cells. In those with OPC, CD8⁺ T cells accumulate at the lamina propria-epithelium interface at a distance from the organism at the outer epithelium. The present study aimed to characterize the tissue-associated CD8⁺ T cells and tissue microenvironment in both OPC⁺ and OPC⁻ persons. The results show that the majority of CD8⁺ T cells possess the [alpha]{szligbeta} T-cell receptor, the thymus-derived [alpha]{szligbeta} CD8 antigen heterodimer, and similar levels of the [alpha]₄{szligbeta}₇, [alpha]₄{szligbeta}₁, and [alpha][subscript e]{szligbeta}₇ homing receptors. Studies to evaluate the tissue microenvironment showed that in OPC⁺ persons, the adhesion molecule for T cells to enter mucosa, mucosal addressin cell adhesion molecule, is significantly increased, whereas E-cadherin, which allows T cells to migrate through mucosa, is significantly decreased compared to OPC⁻ persons. These results continue to support a role for CD8⁺ T cells against OPC under conditions of reduced numbers of CD4⁺T cells, with susceptibility to infection potentially associated with a dysfunction in mucosal CD8⁺ T-cell migration by reduced tissue-associated E-cadherin.