[Blood antioxidant defense in children with malignant disease. I. Plasma antioxidant activity and level of ceruloplasmin and transferrin].

In this study we examined selected elements of the antioxidant defence system in the plasma of children with the most common solid tumors (nephroblastoma, neuroblastoma, rhabdomyosarcoma, osteosarcoma). We observed a significant increase of plasma antioxidant activity (AOA) in the majority of the examined children. This factor changed during clinical treatment, i.e. induction of chemotherapy, surgery and/or radiotherapy and during maintenance chemotherapy. We conclude that the elevated plasma antioxidant activity in children with malignancy may be due to the higher concentration of ceruloplasmin in affected children than in their healthy counterparts.