Treatment course of patients receiving BCMA-, GPRC5D-, and FcRL5-targeted CAR-T therapies. (A) Serum M-spike and clonal plasmas in the BM aspirate. (B) Top, positron emission tomography–computed tomography (CT; left) scan of the extramedullary soft mass in the left neck and head CT scan (right) during BCMA CAR-T infusion; middle, head CT scan of the extramedullary soft mass behind the left ear before and after GPRC5D CAR-T infusion; and bottom, cranial magnetic resonance imaging of the extramedullary soft mass in the left temporal region before and after FcRL5 CAR-T infusion. (C) The schematic of structure of FcRL5 CAR. (D) Immunofluorescence indicating the expression of FcRL5 in extramedullary myeloma cells. The lower panel as control and CD138 as positive control; scale bar, 50 μm. (E) Serum cytokines and CAR-T numbers in PB during FcRL5 CAR-T infusion. (F) The cell numbers of leukocyte and lymphocyte in PB during FcRL5 CAR-T infusion. BM, bone marrow; DAPI, 4′,6-diamidino-2-phenylindoleIFN-γ, interferon gamma; IL-6, interleukin-6; Ixa, ixazomib; LTR, long terminal repeats; PB, peripheral blood; PD1, anti-PD1 antibody; Sel, selinexor; TNF-α, tumor necrosis factor- α; Ven, venetoclax.