At the age of 3, Antek became ill with aplastic anemia. This disease involves damage to the bone marrow, which causes reduced production of red and white blood cells and platelets, leading to anemia. The only solution for patients is a stem cell transplant.

At the time of Antek's illness, his sister was 7 months old and, although she was genetically compatible with him, she could not become a bone marrow donor for her brother, because she was too small. Fortunately, the boy's parents secured his stem cells from umbilical cord blood during delivery. Despite the low content of leukocytes in the collected biological material, it was sufficient for transplantation and saved Antek's life.