CD4 and sarcoidosis: However, the frequency of PB Ki-67+CD4+ and Ki-67+CD8+ T cells we found in the included patients with sarcoidosis is higher than 0.8%, which is the frequency for both Ki-67+CD4+ and CD8+ T cells reported from healthy controls.25 Thus, our finding of the lower PB lymphocyte concentration, the higher expression of Ki-67 in both CD4+and CD8+ T cells, may speak for an increased turn-over and activation of PB T cells in sarcoidosis.