EARLY SPONTANEOUS-ABORTIONS AND FETAL THYMIC ABNORMALITIES IN MATERNAL-TO-FETAL HIV-INFECTION

The thymus is thought to play a major role in the immunopathogenesis o f human immunodeficiency virus (HIV) infection, particularly in matern al-to-fetal HIV transmission. Characteristic lesions of the HIV-infect ed thymus include a prominent CD4(+) CD8(+) T lymphocyte depletion at the corticomedullary junction, the region of the thymus where immune s election occurs. At least threefold excess early spontaneous abortions were noted in a cohort of 124 HIV-infected pregnant women. In these 1 3 abortuses a very high rate (54%) of HIV vertical transmission was do cumented, with the thymus gland particularly affected. It is possible that the thymic insult in HIV-infected fetuses contributes to immune r ejection of the fetus, possibly by an imbalance of maternal and fetal T1- and T2-type cytokines, known to be important in HN disease progres sion. We propose, therefore, that the early spontaneous abortions occu rring in HIV-infected pregnant women are due, at least in part, to abn ormal immune forces created by HIV infection of the thymus.