Human PB B cell numbers uniquely correlate with Eos counts. A, PB lymphocyte counts were obtained from CBC analysis of HES patients and age- and gender-matched healthy controls. n=67. B-F, Peripheral blood B cell (B-C), NK cell (D), CD4 T cell (E), and CD8 T cell (F) counts were obtained from TBNK differential analysis of control subjects (n=21), patients with mild hypereosinophilia (n=58), and HES patients (n=16). Data were pooled from control subjects, patients with mild hypereosinophilia, and HES patients and plotted for PB Eos vs. B cell counts (C). * p<0.05; ** p<0.01; n.s., not significant.