3.4 Treatment of Acute Aplastic Anemia

3.4 Treatment of Acute Aplastic Anemia

3.4.1 Immunosuppressive Therapy

3.4.1.1 Anti-Lymphocyte Globulin (ALG) and Anti-Thymocyte Globulin (ATG): These drugs have the function of targeting immune-active T-suppressor cells to mediate immune suppression. They can induce T-cell proliferation, thereby restoring hematopoiesis.

3.4.1.2 Cyclosporine A (CSA): This is a cytotoxic agent that targets Ts cells and Tc cells, correcting immune dysregulation in patients with aplastic anemia and promoting the recovery of bone marrow hematopoietic function in severe cases [18].

3.4.2 Bone Marrow Transplantation (BMT)

Bone marrow transplantation has been widely used abroad for treating aplastic anemia. However, since it is difficult to find donors with closely matched HLA typing, and it requires significant human and material resources, indications for transplantation should be strictly selected. Regarding indications, the following views exist:

Severe aplastic anemia (excluding elderly patients), with neutrophil count below 0.5×10⁹/L, platelet count below 20×10⁹/L, and lymphocyte proportion in bone marrow above 75%; ideally performed within 3 months after diagnosis; among those under 20 years old, the best results are achieved in patients who received fewer blood transfusions before transplantation (or did not receive any). Before bone marrow transplantation, a high-dose cyclophosphamide regimen combined with anti-human thymocyte globulin (ATG)/anti-human lymphocyte globulin (ALG) can be used as a pre-treatment protocol for allo-BMT, which not only achieves the purpose of pre-treatment but also reduces transplant rejection, thereby increasing the success rate of transplantation [19].

3.4.3 Peripheral Blood Stem Cell Transplantation

Although healthy individuals have hematopoietic stem cells in their peripheral blood, the quantity is extremely limited and cannot be collected. In the 1990s, hematopoietic stimulating factors (G-CSF, GM-CSF, EPO) were widely used in clinical practice, and it was discovered that they have a strong mobilizing effect with few side effects, making it possible to collect hematopoietic stem cells from healthy donors for transplantation. This method is mainly used for SAA, administered concurrently with or after immunosuppressants, to promote the recovery of blood counts, and is an indispensable supportive treatment.

3.4.4 Umbilical Cord Blood Transplantation

Umbilical cord blood contains more early-stage stem cells than bone marrow, making it another ideal source for hematopoietic stem cell transplantation. Compared with peripheral blood stem cell transplantation, umbilical cord blood transplantation has developed more slowly, mainly because the number of stem cells contained in a single unit of umbilical cord blood is limited, sufficient only for children of smaller body weight. In addition, obtaining umbilical cord blood from HLA-matched donors for adult patients is also difficult. To solve the problem of unrelated donor umbilical cord blood sources, Europe and the United States have now established umbilical cord blood banks of a certain scale, and China is also in the process of establishing its own umbilical cord blood bank. With the resolution of multi-potent hematopoietic stem cell ex vivo expansion technology, umbilical cord blood transplantation may soon be widely used in clinical practice [20].