IL27RA and systemic lupus erythematosus: Similarly, IL-27rα−/−Roquinsan/san mice had an elevated percentage of GC B cells switching to IgG1 and fewer cells switching to IgG2a(c), and these mice showed a lower number of CD4+ and CD44+ cells, and lower ICOS levels, demonstrating that IL-27 promoted GC B-cell activity and potentiated lupus in Sanroque mice (114).