Stem cell transplant is a procedure in which healthy or cancer-free stem cells are transfused into the patient. It is a curative treatment for many cancerous and non-cancerous diseases. Stem cell transplant blood-producing cells are collected in two ways.
One from peripheral blood another one from the bone of the patient. Both procedures are required differently based on the nature of the patient’s disease. Such as in blood cancers peripheral stem cell transplant is preferred and in diseases such as thalassemia or aplastic anemia whole bone marrow is effective.
What are stem cells?
Stem cells are blood-producing cells found in bone marrow. These are called progenitor cells that later make blood cells such as red blood cells, white blood cells, and platelets. Stem cells are counted in millions.
What stem cell dose is required for a safe transplant?
For a safe transplant and to avoid engraftment issues a safe cell dose is above three million to five million/kg of the patient’s body weight cells for an autologous transplant and five to 8 million/kg for an allogeneic transplant.
How stem cells are boosted?
Stem cells in the donor or patient’s bone marrow in boosted by an injection called filgrastim .dose of this injection depends upon the weight of the patient Moreover, for an autologous transplant and peripheral collection process the dose is given for four days consecutively whereas for bone marrow harvest dose is given for three days. The reason behind this is if the injection is given for four days, the stem cell moves from the bone marrow and comes into peripheral blood and if given three days the cells remain in the bone marrow and are then easily collected this injection is usually given subcutaneously.
How stem cells are stored?
In allogeneic bone marrow or stem cell transplant, cells are infused on the same day, whereas in autologous stem cell transplant, the cells are stored after cryopreservation with dimethyl sulfate and stored at -80C. Moreover, multiple stem cells can be stored at -2c to -8c due to the lesser type gap between chemotherapy and cell infusion. Furthermore, if the cells have to infuse after 72 hours, then cryopreservation is required.
Should you get a stem cell transplant?
Diseases that need stem cell transplants are as follow.
Hematological diseases/blood disorders such as aplastic anemia, thalassemia, Glanzman syndrome, and Bernard Solier syndrome.
Moreover, some other diseases related to platelet dysfunction or red cell dysfunctions need a stem cell transplant.
Oncological diseases such as leukemia and lymphoma (Hodgkin’s and non-Hodgkin’s and primary central nervous system lymphoma (PCNSL), multiple myeloma
What is the survival rate after stem cell transplant?
Survival of patients varies from patient to patient. Furthermore, it depends upon the overall health condition of the patient and response to treatment. Moreover, survival rates are higher in non-malignant diseases than in malignant diseases {cancerous). The second thing depends upon care after transplant. More care and good results.
What are the complications of stem cell transplant?
The more complex the transplant, the more complications it will cause. For example, a half-matched (haploid) transplant may have more challenges than a full HLA-matched transplant. Furthermore, autologous transplants will have fewer complications than other types of transplants. The following are the complications of a transplant.
Graft Versus Host Disease (skin, gut and liver)
Cytomegaylo virus reactivation:
This virus usually resides in the human body, but when a patient becomes immunocompromised, it reactivates and causes CMV viremia.
Pneumonia:
Patients with bone marrow transplants are at high risk due to very low immunity and restricted mobility due to physical weakness.
Graft failure:
It is possible that the stem cells of the donor do not start working. In this condition, the patient becomes aplastic meaning that the marrow of the patient does not work because the high-dose chemotherapy drug diminishes the bone marrow of the patient.so, if the infused cells do not start working patient becomes out of bone marrow and this becomes a very difficult situation. Furthermore patient becomes transfusion-dependent and at a very high risk of getting infections due to severely compromised immunity.
Selection criteria?
For a better outcome of a successful transplant, a patient must have physical as well as mental fitness. Patients with multiple co-morbid become complicated during transplant as transplant treatment has heavy doses of cancer-killing medicine such as chemotherapy and radiotherapy.
Healthy liver:
The liver of the patient must be healthy before transplant. All the medications are metabolized in the liver and if the liver is not healthy medicine has more effect on it and could end up with liver failure.
Patient with kidney problems:
Some chemotherapy drugs and some medications used in transplants have a very bad effect on kidney function.So, it is best to start the transplant with strong kidneys.
With cardiac issues:
Transplant becomes highly risky with low low-performing heart. Heart pumping power must be strong enough to tolerate the transplant medication Heart ejection fraction must be checked before stem cell transplant. Furthermore, some chemotherapeutic medications have direct side effects on the heart.
With active cancer:
A bone marrow transplant is always started when the cancer is in control. With active cancer, there are very poor results of transplant. So patient cancer status or disease status must be checked before proceeding to transplant. In leukemia, bone marrow biopsy and peripheral smear are the best ways to assess the disease status. In lymphoma, a PET scan is done and
With active infections:
Most patients become complicated if the transplant is preceded by any active infection such as pneumonia bloodstream infections or urine infections. When patients become severely immunocompromised these infections become more resistant and further weaken the immunity of patients.
Pregnancy:
It is very important to confirm pregnancy in transplant workup. A positive pregnancy test cannot precede transplantation. Furthermore, family planning is advised before and after the transplant. The chemotherapeutic drugs are cytotoxic and can harm the fetus.
How is the donor selected for stem cell transplant?
Donor for bone marrow transplants is selected based on a genetic test called HLA typing. The donor may be full, or matched partially usually a fully matched is the first option but if the matching is not matched half-matched transplant is done. Moreover, haploid transplant is a little more complicated than full-matched. Furthermore, a matched transplant has a greater risk of engraftment failure and graft versus Host disease. The younger the donor better the outcomes.
