FIG. 5.

Hypothetical defects in host defenses against oroesophageal candidiasis in HIV infection. Progressive depletion and functional dysregulation of mucosal Langerhans' cells alters normal processing and presentation of C. albicans antigens to CD4⁺ cells, which are themselves depleted in HIV infection, resulting in diminished numbers of CD4⁺ Th1 cells and perturbed adaptive immunity to C. albicans. However, substantially preserved innate defense mechanisms (calprotectin, PMNs, and γδ T cells) and cytotoxic T lymphocytes prevent systemic dissemination.