Figure 7. Use of the maturity, exhaustion, antigen-experience, and activation markers PD-1, CD57, and HLA-DR on CD4 and CD8 cells as biomarkers for the risk, diagnosis, and prognosis of GvHD.

Blood samples were collected and analyzed as described in Materials and Methods and Supporting Materials and Methods. Tx indicates transplant. (A) Comparison of CD4+ and CD8+ expression of PD-1 expression in peripheral blood prior to implantation into the recipient in patients who later experienced GvHD vs. those who did not. Remarkably, there was a significantly higher expression of PD-1 by CD8+ cells in blood of patients who later had GvHD compared to those who did not, indicating that pre-transplant PD-1 expression by CD8+ cells in blood could be a biomarker for the risk of later developing GvHD. (B) Comparison of CD4+ and CD8+ phenotype and expression of PD-1, HLA-DR, and CD57 in GvHD patients who survived vs. those who did not. Blood samples were taken at the time of diagnosis of each GvHD episode. Patients who succumbed to GvHD compared to those who recovered had significantly higher percentages of PD-1, HLA-DR, and CD57, and lower percentages of naïve phenotype for CD4+ and significantly higher percentages of HLA-DR and CD57 and lower percentages of naïve phenotype for CD8+. Increases in CD4+T_EM and TEMRA approached statistical significance. Non-parametric Mann-Whitney test was used.