CD4 percentage, CD4 number, and CD4:CD8 ratio in HIV infection: which to choose and how to use.

Data from a 3 year longitudinal study of CD4 levels in 813 untreated HIV-seropositive men are presented. Baseline CD4 levels were used to stratify the men for the severity of HIV disease at the outset of the study, and each man's CD4 levels and progression to AIDS were evaluated. These data can be used to advise patients who are HIV seropositive on the likelihood that they will deteriorate immunologically or progress to AIDS based on their own CD4 cell level obtained from laboratory evaluation. Graphs are presented here for 1, 2, and 3 years of follow-up. As expected, each individual's absolute CD4 lymphocyte number, CD4 lymphocyte percent, and CD4:CD8 ratio were strongly correlated, and were similar in their ability to predict the development of AIDS. In this sense, all three are useful markers for monitoring individuals with HIV infection, and for many clinical situations from a practical point of view there is little to choose between the markers. However, the CD4 percent has slightly greater prognostic significance and shows slightly less variability on repeated measurements. Because of this, the CD4 percent may be preferable to the CD4 absolute number for use in stratifying individuals who are candidates for antiviral or immunotherapy for HIV infection, and for monitoring patients in clinical trials.