Figure 4.

Representative T-cell lymphocyte counts (solid lines and points) for three men who were: (a) HIV−, (b) HIV+ without AIDS onset, and (c) HIV+ with AIDS onset. The best-fit segmented regression model is denoted by the dashed line with the ∗ denoting the estimated IP. “A” indicates the date of onset of clinical AIDS. The fitted regression lines are curved because of the linear structure used to model the log₁₀ transformed values, and we have exponentiated the values to plot the data and the regression estimates in the original scale (cells per mm³).