The ratio of absolute lymphocyte count at interim of therapy to absolute lymphocyte count at diagnosis predicts survival in childhood B-lineage acute lymphoblastic leukemia.

Absolute lymphocyte count (ALC) after therapy has been reported to be an independent prognostic factor for clinical outcome in leukemia. This study mainly analyzed ALC at interim of therapy on day 22 (ALC-22) and the ratio of ALC-22 to ALC at diagnosis (ALC-0) on the impact of survival and the relation of ALC to lymphocyte subsets in 119 pediatric B-lineage acute lymphoblastic leukemia (B-ALL) patients. Univariate analysis revealed that ALC-22/ALC-0 ratio <10% was significantly associated with inferior overall survival (OS) (hazard ratio (HR)=12.24, P=0.0014) and event-free survival (EFS) (HR=3.3, P=0.0046). In multivariate analysis, ALC-22/ALC-0 ratio remained an independent prognostic factor for OS (HR=6.92, P=0.0181) and EFS (HR=2.78, P=0.0329) after adjusting for age, white blood cell (WBC) count and minimal residual disease (MRD) status. A Spearman correlation test showed that CD3+ T cells had a negative correlation with ALC-0 (r=-0.7204, P<0.0001) and a positive correlation with ALC-22 (r=0.5061, P=0.0071). These data suggest that ALC-22/ALC-0 ratio may serve as a more effective biomarker to predict survival in pediatric B-ALL and ALC is mainly associated with CD3+ T cells.