Different antibodies can be engineered to glow in different colors, allowing two or three different markers to be measured simultaneously. By looking at these charts, it is possible to see if certain populations of immune cells are missing or deficient, resulting in specific immune defects. Two patients can be very different in reality, even if their usual blood-count numbers are the same. Some previous studies have failed to find a selective loss of naive T-cells. Naive cells have the CD45RA marker.
Many important questions remain.
For example, nobody knows why the naive cells are selectively depleted. One theory is that they are killed by HIV before they get out of the thymus gland, where they develop. Damage to or deficiency of the thymus might also contribute. But a completely different possibility is that the immune system is overstimulated, and abnormally causing naive cells to mature into memory cells. More basic research will be needed to answer these questions.