A, Plasma levels of human Ig κ and B, Ig λ FLC, as measured by ELISA. Results are provided for each experimental group and included are the combined results of two-independent experiments for mice implanted EBV− and EBV+ B-cells, and treated with ch128.1/IgG1 or IgG1 control. Bars are geometric mean values. Also shown are mean values of human Ig κ and λ FLC in healthy human plasma samples (Lab QC). Nonparametric, unpaired Mann-Whitney tests were conducted, where *p = 0.01–0.05, ***p = 0.0001–0.001, ****p < 0.0001, and ns, not significant.