Interestingly, treatment with IL6 antibody prevented the decrease in proliferation (Ki67) and increase in apoptosis (CC3) caused by treatment with serum from delirium patients, when compared with treatment with serum from non-delirium patients (Time point 1, delirium vs delirium + IL6 antibody; for Ki67, 40.2% vs 61.3%, p < 0.0001; for CC3, 10.2% vs. 3.4%, p < 0.0001), with no differences between cells treated with serum samples collected at Time point 2 (Fig. 4a–d). Here, IL6 is linked to delirium.