Chemotherapy alters the increased numbers of myeloid-derived suppressor and regulatory T cells in children with acute lymphoblastic leukemia.

INTRODUCTION

Acute lymphoblastic leukemia (ALL) is the most common cancer diagnosed in children. The precise mechanism behind the relapse in this disease is not clearly known. One possible mechanism could be the accumulation of immunosuppressive cells, including myeloid-derived suppressor cells (MDSCs) and T regulatory cells (T) which we and others have reported to mediate suppression of anti-tumor immune responses.

AIM

In this study, we aimed to analyze the numbers of these cells in a population of B-ALL pediatric patients.

METHODS

Peripheral blood samples withdrawn from B-ALL pediatric patients (n = 45 before, during and after the induction phase of chemotherapy. Using multi parametric flow cytometric analysis. MDSCs were identified as LinHLA-DRCD33CD11b; and T cells were defined as CD4CD25CD127.

RESULTS

Early diagnosed B-ALL patients showed significant increases in the numbers of MDSCs and T as compared to healthy volunteers. During induction of chemotherapy, however, the patients showed higher and lower numbers of MDSCs and T cells, respectively as compared to early diagnosed patients (i.e., before chemotherapy). After induction of chemotherapy, the numbers of MDSCs and T cells showed higher increases and decreases, respectively as compared to the numbers in patients during chemotherapy.

CONCLUSION

Our results indicate that B-ALL patients harbor high numbers of both MDSCs and T cells. This pilot study opens a new avenue to investigate the mechanism mediating the emergence of these cells on larger number of B-ALL patients at different treatment stages.