FCGR2A and myasthenia gravis: To evaluate whether Fc-gamma receptors (FcγRs) or neonatal Fc-receptor (FcRn) mediates indirect lysis by MuSK-CAART after binding anti-MuSK antibodies, primary human monocytes (which express high-affinity FcγR/CD64, CD32 and FcRn)21 and natural killer (NK) cells (which express low-affinity FcγR/CD16)21 were cocultured with MuSK-CAART and normal human IgG, mixed anti-MuSK IgG4 mAbs, purified plasma IgG from patients with MuSK MG or anti-CD3 positive-control antibody (Fig. 2e,f).