A role for apoptosis in the pathogenesis of AIDS-related idiopathic esophageal ulcers

Lack of understanding of the mechanism of tissue destruction associated with idiopathic esophageal ulcers (IEUs) poses a diagnostic and therapeutic dilemma for the clinician. The possible role of apoptosis in IEUs, as suggested by endoscopic and histologic observations, was investigated by examination of archival tissues for apoptosis-related DNA fragmentation using in situ nick end labeling (TUNEL). High levels of apoptosis were observed in mucosal cells immediately adjacent to IEUs. Apoptotic cells were virtually absent in normal control tissues, while the edges and bases of lesions and sloughed-off tissues in IEUs in human immunodeficiency virus (HIV)-infected patients showed elevated levels of apoptotic cell death. However, tissue samples from patients with esophageal ulcerations of known etiology showed no apoptosis of mucosal cells. These data support a role for apoptosis in the pathogenesis of IEUs and suggest a mechanism involving HIV-associated bystander killing of uninfected mucosal cells.