On the other hand, CLL patients displayed significantly increased levels of serum APRIL compared to healthy controls (median, IQR: 5.1 ng/mL, 3.7–7.8 versus 3.5 ng/mL, 2.5–4.7; P = 0.003) (Figure 3). Here, TNFSF13 is linked to B-cell chronic lymphocytic leukemia.