Immune composition of peripheral blood and responsiveness to Toll-like receptor (TLR) ligands at Day 29 of induction chemotherapy for pediatric acute lymphoblastic leukemia (ALL)

Introduction: Although ALL has long been viewed as a poor target for immune therapy, peripheral blood (PB) absolute lymphocyte count (ALC) at end of induction chemotherapy (Day 29) seems to be prognostic for outcome. However, whether ALC is simply a marker of bone marrow recovery or whether certain immune cell subsets confer a beneficial effect is unknown. Methods: We collected D29 PB and i) performed an extensive phenotypic characterization of 20 leukocyte subsets, and ii) stimulated whole blood with a panel of TLR ligands to measure cytokine production. Results: To date we have evaluated 11 D29 patients for T…