PDCD1 and infection: Furthermore, in our study CD4+ and CD8+ T-cells expressing Tim-3 and co-expressing PD-1 and Tim-3 decreased after successful treatment and this was accompanied by increased frequency of PD-1−Tim-3− CD4+ and CD8+ T-cells, suggesting that the immune exhaustion induced by prolonged infection may be at least partially reversed once the infecting pathogen is eliminated.