Costimulation molecule expression and subset distribution of blood dendritic cells in normal children and newly diagnosed pediatric leukemia and lymphoma patients

Abstract

To characterize dendritic cell (DC) numbers, subset distribution, phenotype, and costimulation molecule expression in a normal pediatric population and in a lymphoblastic malignant pretherapy pediatric population. DC are potent antigen-presenting cells and are crucial for initiating specific immune responses. We first analyzed peripheral blood samples of healthy pediatric controls (n=72). Once a range of normal parameters was established, we compared these to newly diagnosed pediatric leukemia and lymphoma patients prior to receiving therapy (n=69). Using flow cytometry, we examined blood DC cell-surface expression of CD80, CD86, CD40, CD18, CD50, CD83, CD123, CD58, CD54, and CD11c. Expression of each of these molecules was significantly altered except for CD80, CD83, and CD58. When compared to healthy children, absolute blood DC were reduced in children with leukemia or lymphoblastic lymphoma (p<0.0001) and children with Hodgkin's disease (p=0.0028). Additionally, lymphocyte function in vitro, was impaired (p=0.0489) for children with lymphoblastic malignancies, while patients with Hodgkin's disease had normal proliferative function. Our results show that peripheral blood DC from children with newly diagnosed leukemia or lymphoma are significantly altered in number, subset distribution, and costimulation molecule expression, and that lymphocyte function is impaired compared to healthy pediatric controls.