VpreB expression in standard- and high-risk B-ALL at diagnosis (day 0) and end induction (day 29). (A-B) VpreB-PE and VpreB-FITC in standard (A) and high risk (B) showed a spectrum of expression, but brighter expression for the PE conjugate (P < .001; unpaired Student t test) at the time of diagnosis. (C-D) VpreB-PE and VpreB-FITC in standard (C) and high risk (D) showed a spectrum of expression but trended to show brighter expression for the FITC conjugate (P < .001; unpaired Student t test) at end induction, suggesting that the FITC conjugate might detect recovering marrow populations that include B-lymphoblast populations with hematogones. Statistical comparisons were calculated between combined *PE and **FITC groups.