Following a bone marrow (stem cell) transplant, the immune system's reconstitution and the production of healthy new blood cells can take a significant amount of time. Post-transplant immune recovery is influenced by various factors. These include the source of the stem cells, immunosuppressive treatments administered, potential complications, and the varying recovery timelines of different immune cell subsets. Consequently, full immune reconstitution can extend up to five years. During this prolonged recovery period, patients undergoing bone marrow transplantation are at an elevated risk of infection and must adhere to strict preventive measures. Furthermore, temporary decreases in blood cell counts (cytopenia) are common. This can lead to complications such as anemia, excessive bleeding, bruising, and an increased susceptibility to infections. Blood transfusions may be necessary for some patients during this period.