CD4 and delirium: Some lymphocyte subsets were significantly higher in the delirium than non-delirium group: CD19+ B cell count (median 145.5 cells/μL, IQR 160 cells/μL vs. median 105 cells/μL, IQR 111 cells/μL, p = 0.004); and CD4+ T cell count (median 566 cells/μL, IQR 182 cells/μL vs. median 339 cells/μL, IQR 253 cells/μL, p < 0.001).