Research Paper Volume 13, Issue 16 pp 20131—20148

Figure 6. Identification of “sub-healthy individuals” with PD-1 expression in PBMCs. (A) Proportion of CD3⁺PD-1⁺ cells was <4% in the PBMCs of healthy individuals. PBMCs of 95 individuals (aged >50 years) were analyzed, of which 16.84% of samples had a proportion of CD3⁺PD-1⁺ cells >4%. (B) Proportion of CD3⁺CD4⁺PD-1⁺ cells was <10% in the CD3⁺CD4⁺ T cells of healthy individuals. In these 95 individuals, 9.47% of samples had a proportion of CD3⁺CD4⁺PD-1⁺ cells >10%. (C) Proportion of CD3⁺CD8⁺PD-1⁺ cells was <10% in the CD3⁺CD8⁺ T cells of healthy individuals. In these 95 individuals, 37.9% of samples had a proportion of CD3⁺CD8⁺PD-1⁺ cells >10%. We defined CD3⁺PD-1⁺ cells/PBMCs >4% and CD3⁺CD8⁺PD-1⁺ cells/CD3⁺CD8⁺ cell >10% as “sub-healthy individuals” (4.21%).