Bone Marrow Transplantation 101

Two main types of BMT: Auto vs Allo.  Basic idea is you receive high dose chemo and XRT to destroy cancer cells and progenitor cells, then reintroduce stem cells, either from your own stored stems cells (Auto) or a donor (Allo).

1) Autologous HSCT – harvest patient’s own stem cells before chemo/XRT, freeze cells, then thaw and return to the patient. 

• Benefit – Fewer side effects than allo-HSCT, including NO Graft vs Host Disease à thus, patient’s do not need immune suppression for GVHD and are only immunocompromised during the peritransplant period.
• Downside – Likely less effective than allo-HSCT, as you do not get the benefit of Graft vs Tumor effect.
• Main Indications:  Lymphoma (Hodgkins and NHL, most commonly DLBCL), Multiple Myeloma, and Testicular Cancer

2) Allogeneic HSCT – stem cells harvested from a donor (Matched Donor = siblings, Matched Unrelated, or Mismatched Related or Unrelated) and infused into patient after preparative regimen of chemo +/-XRT.

• Benefit – Gain Graft vs Tumor effect
• Downside – Main complication is Graft vs Host Disease, for which patients need to be on long-term immunosuppression. 
• Main Indications:  Basically, certain high risk leukemias do better with BMT (i.e. relapsed leukemia, or high risk cytogenetics) - AML, ALL, CML.  Also: CLL, MDS, some types of Lymphoma, Aplastic Anemia, Hemoglobinopathies, Immunodeficiencies

Two types of Allo-HSCT:

• Myeloablative – typical, intensive regimen of chemo and XRT prior to the transplant to completely eradicate disease and patient’s bone marrow
• Nonmyeloablative – receive less intensive chemo and radiation, for patients who cannot tolerate myeloablative regimens due to age or comorbidities.  Results in a “mixed chimerism state” with stem cells from both the donor and the host. 

Main Complications after BMT
1) Infections – patients are among the most immuncompromised hosts we will ever see, and are susceptible to a huge variety of infections.

2) Graft Vs Host Disease – again, only occurs with Allogeneic BMT.  Divided into Acute (<100 days) and Chronic (>100 days) which have slightly different presentations.  Acute GVHD manifests in the skin (rash), liver (elevated LFTs and obstructive picture), GI tract (abdominal pain, diarrhea), and Hematopoietic system (persistent cytopenias).

3) Chemo-related toxicities, especially mucositis

4) Veno-occlusive disease of the liver

5) Diffuse Alveolar Hemorrhage - see below

(Chanu Rhee MD, 1/25/11)