BACH2 and systemic lupus erythematosus: At the same time, HLA–DQ2A/B and BACH2 genetic loci are associated with IgG galactosylation 8, and thus their association with SLE could reflect subdued immunosuppressive activity of IgG in SLE, which suggests that changes in IgG glycosylation could be one molecular mechanism by which these genes affect SLE.