The role of immunoregulator CD200 and CD47 in childhood acute lymphoblastic leukemia

Background: About 30% of all pediatric cancers are acute lymphoblastic leukemia (ALL). Leukemia cells capacity to avoid immune system destruction contributes to the disease's onset and spread. One of the adaptive immune response's regulators is CD47. The immunoglobulin superfamily inhibitory receptor CD200R, which is mostly expressed on myeloid/monocyte lineage cells and a subset of T cells, interacts with CD200. CD200R inhibits immunological responses mediated by T cells and monocytes. The existence of post-therapeutic leukemia cells in the bone marrow is known as minimal residual disease (MRD). Aim of study: In the current study we aimed to spotlight the role of CD200 and CD47 in pediatric ALL which may help in the understanding of the roles played by them, and highlight their possible role in MRD. Patients and Methods: This study was carried out on 52 childhood ALL cases from both B cell and T cell types. Expression pattern of CD200 and CD47 on blasts was assessed by flowcytometry. The MRD was detected at day 42. The cut of value of MRD is 0.01%. Results: CD200 blast expression was significantly upregulated in B-ALL group compared to T-ALL group (P =0.017). There was statistically significant increase in hepatomegaly, splenomegaly, para aortic lymphadenopathy and anterior mediastinal mass in T-ALL group when compared with B-ALL group (P=0.026, P=0.011, P=0.042 and P > 0.001) respectively. Conclusion: T-All cases were presented with more metastatic course. B-ALL patients presented initially with significant increase in CD200 expression on blasts. No significant difference was shown in MRD levels at day 42 between B-ALL and T-ALL patients