CD4+ T-lymphocyte percentage

Method

CD4+ T lymphocytes expressed as a percentage of total lymphocytes in peripheral blood by flow cytometry. Gating strategy and antibody panel recorded on the edge.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

Confused with the CD4+ absolute count in cells per microlitre — same marker, same cytometer, same direction of benefit, different denominator. The percentage moves whenever the total lymphocyte count moves, so it can rise while the absolute count is flat or falling, and the two dissociate in exactly the immunosuppressed populations where both are reported. Also an INPUT to the CD4/CD8 ratio: recording this percentage and that ratio from one panel as independent endpoints double-counts the same cells.