Figure 1.

Potential effects of hormonal contraception on the pathogenesis of HIV infection. Arrows pointing down indicate decreases in immune response, arrows pointing up indicate increases in immune response, and question marks indicate unknown effects. The boxed sections denote processes in which hormonal effects may be significant. E, estrogens (effects of E on immune responses are shown in blue); IDO, indolamine 2,3-deoxygenase; P, progesterone (effects of P on immune response are shown in red).