We measured the fold change of IgG and IgM production and found that the inhibition of IL-21R decreased the production of both IgM (SLE, non-treated vs. αIL-21R: p = 0.0028; IgG1 vs. αIL-21R: p = 0.0027) and IgG (SLE, non-treated vs. αIL-21R: p = 0.0001; IgG1 vs. αIL-21R: p = 0.0148; non-treated vs. IgG1: p = 0.0353) in lupus similarly to controls (Figure 4C,D). This evidence concerns the gene IL21R and systemic lupus erythematosus.