CD4 and infection: Compared to patients who did not have any post-operative infection, patients who developed an infection had an increase in monocyte count (p = 0.0037) and CD4+ lymphocyte IL-7R (p < 0.0001) and a decrease in monocyte CD80 (p = 0.0279) and CXCR4 expression (p = 0.0220) (Figures 4, 5; Supplementary Table 4).