Haploidentical Transplant
Haploidentical Transplant
A haploidentical transplant is a type of allogeneic bone marrow transplant that uses a half-matched donor. While traditional transplants usually require a 100% HLA match, this procedure utilizes a donor who is a 50% match, significantly expanding the donor pool for patients who cannot find a perfect match in international registries.
When You Should Consider Haploidentical Transplant
When a 100% HLA-matched sibling or unrelated donor is not available.
For patients requiring an urgent transplant where a family member can be screened and ready in days.
When the "mismatch" effect is desired to help new cells identify and eliminate remaining cancer (Graft-vs-Leukemia effect).
For those who have a biological parent, child, or half-matched sibling available to donate.
Methods of Haploidentical Transplant
Parental Donation: Utilizing a biological parent as the 50% HLA match.
Child Donation: Utilizing a biological child as the 50% HLA match.
Sibling Half-Match: Utilizing a biological sibling who shares half of the inherited HLA markers.
Post-Transplant Cyclophosphamide (PTCy): A specialized protocol using high-dose chemotherapy after infusion to ensure safety.
How Haploidentical Transplant Is Performed
Conditioning: Administration of chemotherapy or radiation to eliminate diseased marrow.
Stem Cell Infusion: Infusing donor stem cells through a central line, similar to a blood transfusion.
PTCy Administration: Delivering high-dose Cyclophosphamide on days 3 and 4 post-infusion to selectively kill cells that cause rejection.
Engraftment waiting period: A 2 to 3-week phase where the new cells begin producing white blood cells, red cells, and platelets.
Immunosuppression: Using specific medications to maintain balance in the new immune system.
Pre-Procedure Preparation
Identifying and screening a biological family member who is a 50% HLA match.
Educating the patient on the unique PTCy safety phase following the stem cell infusion.
Baseline health assessments to ensure the patient can handle the intensive conditioning phase.
Preparing for a longer hospital stay, typically between 3 to 5 weeks.
Tests Before Haploidentical Transplant
HLA Typing: Identifying the 50% match markers inherited from parents.
Donor Screening: Rapid testing and medical clearance of the identified family member.
Viral Screening: Detailed testing for viruses like CMV, as there is a higher infection risk post-procedure.
Marrow Assessment: Evaluating the status of the diseased marrow prior to the conditioning phase.
Life After Haploidentical Transplant
Most patients remain in the hospital for 3 to 5 weeks following the procedure.
Close outpatient monitoring is required for at least the first 100 days.
A slightly longer recovery period for the immune system compared to a full-match transplant.
Ongoing use of immunosuppressant medications to prevent Graft-versus-Host Disease (GVHD).
Benefits of Haploidentical Transplant
Provides a nearly universal donor source since most people have a half-matched family member.
Allows for a much faster donor identification and screening process compared to unrelated registries.
Utilizes the Graft-vs-Leukemia effect, where the mismatch helps kill residual cancer cells.
Modern PTCy protocols have made half-matched transplants as safe as traditional full-match procedures.