Blood myeloid dendritic cells from HIV-1-infected individuals display a proapoptotic profile characterized by decreased Bcl-2 levels and by caspase-3+ frequencies that are associated with levels of plasma viremia and T cell activation in an exploratory study.

Reduced frequencies of myeloid and plasmacytoid dendritic cell (DC) subsets (mDCs and pDCs, respectively) have been observed in the peripheral blood of HIV-1-infected individuals throughout the course of disease. Accumulation of DCs in lymph nodes (LNs) may partly account for the decreased numbers observed in blood, but increased DC death may also be a contributing factor. We used multiparameter flow cytometry to evaluate pro- and antiapoptotic markers in blood mDCs and pDCs from untreated HIV-1-infected donors, from a subset of infected donors before and after receiving antiretroviral therapy (ART), and from uninfected control donors. Blood mDCs, but not pDCs, from untreated HIV-1-infected donors expressed lower levels of antiapoptotic Bcl-2 than DCs from uninfected donors. A subset of HIV-1-infected donors had elevated frequencies of proapoptotic caspase-3(+) blood mDCs, and positive correlations were observed between caspase-3(+) mDC frequencies and plasma viral load and CD8(+) T-cell activation levels. Caspase-3(+) mDC frequencies, but not mDC Bcl-2 expression, were reduced with viral suppression on ART. Apoptosis markers on DCs in blood and LN samples from a cohort of untreated, HIV-1-infected donors with chronic disease were also evaluated. LN mDCs displayed higher levels of Bcl-2 and lower caspase-3(+) frequencies than did matched blood mDCs. Conversely, LN pDCs expressed lower Bcl-2 levels than their blood counterparts. In summary, blood mDCs from untreated HIV-1-infected subjects displayed a proapoptotic profile that was partially reversed with viral suppression, suggesting that DC death may be a factor contributing to blood DC depletion in the setting of chronic, untreated HIV disease.

Biological, familial, and peer influences on dating in early adolescence.

The current study examined the joint contributions of pubertal maturation, parental monitoring, involvement in older peer groups, peer dating, and peer delinquency on dating in a sample of early adolescent boys and girls. The sample consisted of 784 adolescents (394 boys, 390 girls) enrolled in grades 5, 6, and 7 who were followed for one year. In addition to measures of pubertal maturation and parental monitoring, adolescents and their peer group members completed indices of dating and delinquency. Average dating and delinquency scores for each participant's peer group network were computed. Results indicated that it was the combination of pubertal maturation, peer delinquency, and peer dating that explained increases in early dating. For boys only, parental monitoring was a significant predictor. The more knowledgeable parents were about their boys' activities, the lower the number of dating activities reported. These results highlight the importance of considering the joint effects of these biological and social predictors in understanding early dating. When rapid changes occur in all three domains, early dating is most likely to ensue. The findings of this study have practical importance. Parents and professionals who work closely with youth should attend to the special vulnerability of early maturing adolescents in the face of peer pressure and to the important role of parental monitoring in regulating dating activities.