Increased apoptosis in cervical intraepithelial neoplasia associated with HIV infection: implication of oncogenic human papillomavirus, caspases, and Langerhans cells.

PURPOSE: Increasing risk of squamous cervical intraepithelial neoplasia (CIN) exits in HIV-infected women. However, the relatively low incidence of invasive carcinoma in the untreated HIV-infected population suggests an imbalance between cell proliferation and apoptosis. We investigated apoptosis and caspases in cervical samples from this population comparatively to non-HIV-infected and control subjects. EXPERIMENTAL
DESIGN: Apoptotic terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method, immunohistochemistry for caspase-2, caspase-3, caspase-8, caspase-9, and other apoptosis markers were done on 12 normal cervical samples and 103 low- and high-grade cervical lesions, containing human papillomavirus(es) from 35 HIV-negative and 33 HIV-positive women before tritherapy advent.
RESULTS: (a) The apoptotic index (AI) in epithelial cells did not vary between normal mucosa and condyloma acuminata infected or not with HIV. (b) AI augmented with the CIN severity in HIV-positive and HIV-negative women. (c) AI dramatically increased in oncogenic human papillomavirus-infected CIN of HIV-positive population compared with the CIN of similar grade in HIV-negative one. This was associated with a greater expression of caspase-8, active caspase-9, and active caspase-3 in those samples. Moreover, densities of Langerhans' cells, involved in apoptotic bodies engulfment, were greatly reduced in CIN of HIV-positive women. In samples, these densities were highly inversely correlated with AI (r = -0.88, P < 0.002).
CONCLUSIONS: This study provides the first evidence for the strongly enhanced apoptosis levels and caspase expression in CIN of untreated HIV-infected women. We suggest that the reduction in Langerhans' cell number could contribute at least partly to apoptotic cell accumulation.