Individual baseline titers are plotted by cohort for (A) the neutralization assay to A(H1N1), and the hemagglutination inhibition (HAI) assay to (B) A(H1N1), (C) A(H3N2), (D) B(Victoria), and (E) B(Yamagata). Data have been jittered to allow viewing of overlapping values. Horizontal bars represent geometric mean titers (GMTs). Points on or above the dashed horizontal lines represent baseline HAI titers ≥40. For both assays, titers to A(H1N1) were significantly lower in the CAR-T cohorts when compared to the control cohort as indicated with a * (neutralization assay: pre-CAR-T vs controls, P=.01; post-CAR-T vs controls, P=.02. HAI assay: pre-CAR-T vs controls, P=.009; post-CAR-T vs controls, P=.001; based on Dunn’s test with the Holm stepwise procedure for multiple comparisons). There were no significant differences between cohorts based on the HAI assay to A(H3N2), B(Victoria), or B(Yamagata) (Kruskal-Wallis, P=.46, P=.21 and P=.40, respectively), although in general, a higher proportion of individuals in the control cohort had HAI titers ≥40. GMTs and the proportion of individuals with an HAI titer ≥40 are detailed in Table 2.