Changes in RANKL, OPG, and 25(OH)D Levels in Children with Leukemia from Diagnosis to Remission.

Simple Summary: Advances in the treatment of acute lymphoblastic leukemia (ALL) have led to a marked improvement in the survival rate of patients. Nevertheless, these patients may develop adverse effects during and after treatment, such as bone abnormalities and vitamin D deficiency. Bone remodeling allows for bone volume and structure to be maintained, which is controlled by the receptor activator of the nuclear factor-kB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system-determining pathway in the balance between bone formation and resorption. Some reports have explored the role of corticosteroids in modulating the RANKL and OPG levels and RANKL/OPG ratio in pediatric patients. Nevertheless, studies evaluating the role of RANKL and OPG in the bone health of pediatric ALL patients during treatment are limited. During remission, we observed an increase in the RANKL/OPG ratio, increased RANKL levels, and decreased OPG levels in ALL patients. These changes may predispose such patients to the development of bone health disorders in their adult lives. Background: The receptor activator of the nuclear factor-kB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) pathway is a determining pathway in the balance between bone formation and resorption, and disruptions in this complex can affect bone metabolism. Methods: This study analyzes the changes in RANKL, OPG, and 25(OH)D levels; the RANKL/OPG ratio; and other bone turnover markers (BTMs) from diagnosis to complete remission in children with acute lymphoblastic leukemia (ALL). This is a prospective observational cohort study, carried out at the Instituto Mexicano del Seguro Social, Mexico City, including 33 patients (4–17 years) with newly diagnosed B-cell ALL. The patients were treated with the HP09 chemotherapy protocol. Children who had previously been treated with corticosteroids were excluded. A peripheral blood sample at diagnosis and remission was collected to determine the 25(OH)D and BTM concentrations. Results: Increased RANKL (p = 0.001) and osteocalcin (p < 0.001) levels and RANKL/OPG ratio (<0.001) and a decreased OPG level (p = 0.005) were observed at remission, predominantly in the high-risk (HR) relapse and vitamin D deficiency groups. A negative association between RANKL and OPG (r = −0.454, p = 0.008) was observed. Conclusions: we suggest that the RANKL/OPG ratio could serve as a bone remodeling marker in ALL patients. [ABSTRACT FROM AUTHOR]