IKZF1 and systemic lupus erythematosus: Given that IKZF1 has been convincingly associated with SLE in previous studies [35]–[37], and that functional studies in heterozygous knock-out mice in our study showed clear differences in profiles of several IgG N-glycan traits, we explored an intriguing hypothesis: whether the same IgG N-glycan traits that were significantly affected in Ikzf1 knock-out mice could be demonstrated to differ between human SLE cases and controls.