Normal Absolute Monocyte Count at the Time of Relapse is Associated with Improved Survival After First Salvage Therapy in Adult Patients with Early Relapsed B-Lineage Acute Lymphoblastic Leukemia.

Background: Peripheral monocytes, a key cell type for innate immunity, have been shown to be associated with survival in various types of hematological malignancies. However, no previous studies regarding the prognostic impact of peripheral absolute monocyte count (AMC) in early relapsed B-lineage acute lymphoblastic leukemia (B-ALL) have been reported.

Methods: Forty-nine cases of early relapsed adult B-ALL were reviewed. The upper (0.80 × 10/L) and lower limits (0.12 × 10/L) of the normal value for AMC were used as cut-off points. Kaplan-Meier curves and Log rank test were used for comparison of overall survival (OS). The univariate and multivariate Cox proportional hazards models were used for investigating the factors associated with OS.

Results: More than half (59.2%) of all patients showed a normal AMC (0.12-0.80 × 10/L). The median follow-up was 5.3 months from the start of first salvage therapy. Univariate analysis revealed that normal AMC (versus low/high AMC) at the time of relapse was a prognostic factor for improved OS (P = 0.021). On multivariate analysis, normal AMC (versus low/high AMC) at the time of relapse remained an independent prognostic factor for improved OS (hazard ratio = 0.43, P = 0.030).

Conclusion: AMC at the time of relapse, which can be easily derived from routine clinical laboratory testing of complete blood count, might be used as a prognostic marker for survival outcomes in adult patients with early relapsed B-ALL.