Abstract

Regeneration and tolerance factor (RTF) plays a pivotal role in successful pregnancy outcome and has potent immunomodulating properties. During pregnancy, it is abundantly expressed in the placenta and on peripheral B lymphocytes. Several lines of evidence suggest that both successful pregnancy outcome and progression from human immunodeficiency virus (HIV) infection to AIDS are associated with a Th2-type response. As a result, we hypothesized that the cellular expression of RTF may also be increased during infection with HIV. Using flow cytometric analysis, we showed a significantly ( P < 0.01) increased expression of RTF on CD3 + cells obtained from individuals with HIV over that for individuals without HIV. On average, 32.1% of the CD3 + cells from individuals with HIV expressed high levels of RTF. In contrast, an average of only 6.7% of the CD3 + cells from individuals without HIV expressed high levels of RTF. Similar results were obtained when CD19 + cells from individuals with (mean, 44.1%) and without (mean, 25.8%) HIV were evaluated. Linear regression analysis suggested that high levels of RTF expression by CD3 + cells correlated better with viral load ( r value, 0.46) than with absolute CD4 count ( r value, 0.09). While additional experiments are necessary to delineate the precise immunologic role of RTF, our current data suggest that RTF expression during HIV infection may be a useful marker of immune activation.