典型的白血病有很多不正常的细胞充满骨髓，取代正常的造血功能。这里的骨髓基本上100%是细胞，基本上是由白血病细胞组成的。由于取代正常组织或抑制干细胞的分裂，使得正常的造血功能降低。因此，白血病病人有贫血、血小板减少、粒细胞减少和所有继发并发症的倾向，明显的并发症是出血和感染。
Leukemias typically fill up the marrow with abnormal cells, displacing normal hematopoiesis. The marrow here is essentially 100% cellular, but composed almost exclusively of leukemic cells. Normal hematopoiesis is reduced via replacement (a "myelophthisic" process) or by suppressed stem cell division. Thus, leukemic patients are prone to anemia, thrombocytopenia, and granulocytopenia and all of the complications that ensue, particularly complications of bleeding and infection.
