Whilst other studies have observed increased TNFSF13 expression in reactive astrocytes in multiple sclerosis [53] and in cells surrounding tumor tissue [54], the absence of TNFSF13 expression changes in patients with bipolar disorder suggests at least a degree of diagnostic specificity for the TNFSF13 mRNA change between the two psychiatric groups. Here, TNFSF13 is linked to multiple sclerosis.