FCGR1A and myeloid sarcoma: In aCD20-treated MS patients, we observed positive correlations between anti-S1 IgG antibody production and three myeloid cell sub-clusters (M11: CD14-CD16-CD64+; M15: CD14loCD16+; M17: CD14+CD16+CD68hi), as well as one NK cell sub-cluster (N7: CD56+CD16+CD8hi) (Fig. 4I).