CLL mAb reactivity with MEACs correlates with IGHV mutation and clinical survival. (A) MEAC reactivity, measured as MFIR in Figure 3C, was plotted versus percentage of CLL mAb IGHV mutation, showing a moderate inverse correlation, where a decrease in MFIR correlated with an increase in percentage of mutation (Spearman nonparametric correlation coefficient equals −.556 with P value as shown). (B) Kaplan-Meier survival plot comparing patients with CLL with mAbs having low (Lo) versus high (Hi; MFIR ≥ 1.5) binding to MEACs. Clinical information was available for patients from 24 of 26 tested CLL mAbs. Patients with CLL whose mAb had Hi binding to MEACs (n = 15) had a median survival time of 99 months, whereas median survival for those with Lo binding (n = 9) was not reached. The statistical difference (P value) between these curves is shown. (C) Kaplan-Meier survival plot comparing the same patients on the basis of unmutated (UM) versus mutated (Mut; > 2.0%) IGHV. Patients with CLL with UM mAb (n = 18) had a median survival time of 118 months, whereas median survival for those with Mut mAb (n = 6) was not reached. The statistical difference (P value) between these curves is shown.