SLC15A4 and systemic lupus erythematosus: On the contrary, SLC15A4 was found to be required for the production of antibodies in B cells in a mouse model of lupus, and the lack of SLC15A4 in B cells led to reduced production of IgG2a and IgG2c auto-antibodies such as anti-snRNP and anti-DNA antibodies (Kobayashi et al., 2014).