Introduction: Bone disorders observed commonly after haematopoietic stem cells transplantation (HSCT) can be caused by several factors,but their detailed pathomechanism is still not well known, especially in childhood.The aim of this study was to evaluate: IGF-I, RANKL-OPG system, IL-6, and IL1β levels and their association with bone mineral density(BMD) in children and adolescents after HSCT.

Material and methods: Thirty five patients after allogeneic (N = 21) and autologous (N = 14) HSCT, mean age 8.48 ± 5.18 years, wereincluded in the study. Blood samples were taken before HSCT, on the transplantation day, three and six months after HSCT, then eachyear after HSCT for 2–8 years. RANKL, OPG, and IL-1β, IGF-1, and IL-6 were measured by immunochemistry. Total BMD was evaluatedsix months after HSCT using dual energy X-ray absorptiometry, then annually.

Results: All Z-core values for BMD were negative in all patients. It was significantly higher in patients after auto HSCT than after allo HSCT.Serum levels of IGF-1 and IL-6 significantly changed after HSCT. IGF-I levels started to increase in the second year after transplantation.IL-6 increased up to 12 months after transplantation. Dynamic although not significant changes of OPG and RANKL levels were observedafter HSCT. RANKL and IGF-1 values correlated with BMD. IL-6 correlated positively with IL-1β but both did not correlate with BMD.

Conclusions: Our data indicates that factors influencing bone remodelling change dynamically in the post-transplantation period.It suggests that serum RANKL and IGF-1 levels could be markers of bone metabolism after HSCT in paediatric patients.