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 αβ T-cell receptor, the thymus-derived αβ CD8 antigen heterodimer, and similar levels of the α4β7, α4β1, and αeβ7 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.