FCRL5 and Miyoshi myopathy: Recognition and lysis of NCI-H929 cells by FcRH5 CAR-T cells was not hampered by secreted IRTA2a protein in concentrations of over 10-fold higher than the median FcRH5 protein levels found in the serum of MM patients24, as indicated by equivalent 6-hour cytotoxicity and IFN-γ secretion (Fig. 5b, c).