The net change in viral epitopes to which serum IgG antibodies were directed. For each participant depicted in a column, the panels are colored according to the change in the number of epitopes (range indicated in the legend) recognized by IgG for a given virus (indicated in rows) between the pre– and last post–CD19-CARTx samples. The participants are grouped by prior HCT status. Empty cells indicate that the participant did not have any IgG directed against an epitope for a given virus in the pre– and post–CD19-CARTx samples or that there was only a change of 1 epitope recognition. This figure includes data for 28 participants with serum sample results from both the pre– and post–CD19-CARTx time periods; 2 participants who did not have data for both periods were excluded. Participant 8 had the greatest losses in IgG responses to specific viruses and viral epitopes. There were no distinct clinical features of this individual who had NHL, did not receive a prior HCT, received dose level 2 of CAR T cells with cyclophosphamide and fludarabine conditioning, had grade 1 CRS, never received IVIG, never had a total IgG concentration <400 mg/dL, and had 1 mild upper respiratory tract infection after CARTx.