In patients ≥ 6 years old, stages are as follows: Stage 1: ≥ 500 cells / mcL Stage 2: 200 to 499 cells / mcL Stage 3: < 200 cells / mcL The CD4 count after 1 to 2 years of treatment provides an indication of ultimate immune recovery; CD4 counts may not return to the normal range despite prolonged suppression of HIV.