PDCD1 and mesothelioma: Compared with mesothelioma group, in the peripheral blood, higher percentages of circulating CD45 + PD-1 + lymphocytes, (18.62% vs. 24.21%; p = 0.045) and CD3 + PD-1 + T cells (19.83% vs. 23.83%; p = 0.048) were found in adenocarcinoma group (Fig. 6B).