TNFSF13 and rheumatoid arthritis: In contrast to the normal levels of APRIL in the patients with SLE, the patients with RA had significantly higher levels of APRIL at baseline (p < 0.05) (median 96.7 ng/ml, range 5.04 to 409 ng/ml) (Figure 1d, Table 2), and also had higher levels than the healthy controls (p < 0.001).