Frequency of targeted mutations within hotspot motifs during IL-6R and TNF-α inhibition. (A) A significant reduction in frequency of targeted mutations within RGWY/WRCY is found in Ig-VH gene rearrangements of DN B cells during TCZ therapy (*
P = 0.046, **
P = 0.004). (B) During TNF-α inhibition, a comparable mutational hotspot targeting of VH gene rearrangements of DN B cells were observed at all time points. (C) A significant reduction in frequency of targeted mutations within RGWY/WRCY is found in all three isotypes specific to DN B cells during IL-6R inhibition. P values were determined by Wilcoxon test using GraphPad Prism 5. DN, double negative; Ig, immunoglobulin; IL-6R, interleukin-6 receptor; TCZ, tocilizumab; TNF-α, tumor necrosis factor alpha.