CD4 and lymphedema: To understand the role of the exhaustion marker on CD4+ T cells in lymphedema, we examined the expression patterns of programmed death-1 (PD-1), T cell immunoglobulin and mucin domain-containing-3 (Tim-3), lymphocyte activation gene-3 (Lag-3), and PD-1+Tim-3+, which is known as the exhaustion marker, on peripheral CD4+ T cells in lymphedema, post-LVA, and HCs.