July 21, 2013 | by Darrin Joy
Bone marrow transplantation has evolved to be the standard of care for leukemia, lymphoma and several other cancers. When a transplantation uses stem cells from a donor, finding donor cells that match the recipient’s as closely as possible is key. That’s where the experts in the histocompatibility lab (HLA lab) come in.
David Senitzer, Ph.D., directs City of Hope’s HLA lab. He recently explained the lab's role and its impact on patients undergoing bone marrow transplantation.
What does the HLA lab do?
Bone marrow transplantation (BMT) is a lifesaving and life-altering treatment for patients with malignancies such as leukemia and lymphoma. The job of the HLA laboratory is to find the best-matched donor. Matching for the HLA genes ensures a better outcome. The better the match, the better the quality of life for the transplanted patient.
We test potential donors that are related to the patient; e.g., siblings, parents, cousins. If none are found, then we look for unrelated donors. An unrelated donor search depends on the millions of volunteer donors in data banks of bone marrow registries around the world. The registry in the U.S. is the National Marrow Donor Program. That registry coordinates these searches for HLA-matched donors throughout the world.
How does HLA lab work affect how transplant patients are treated?
The origin of the matched donor will determine the type of transplant that is performed. If a relative were identified, then he or she would be the first choice. A matched unrelated person would be the donor if no related donor were found.
Has matching donors and patients changed over the years?
The HLA genes control the making of protein molecules that are part of the surface of nearly every cell in the body. These molecules help in defending the body against bacteria, viruses and even tumors. We originally look for the type of proteins a patient displays on the surface of their cells. Then we test potential donors to see if they have the same types of proteins (matching donor with patient). Today we look at the genes that are the blueprints for the cell’s proteins. This method involves “reading” the nucleotide sequence of the genes themselves. It is the most accurate way of matching donors and patients.
What improvements has City of Hope’s HLA lab brought to BMT?
We have developed methods for determining if the transplant is a success. We want only the donor cells to be circulating in the blood of the patient. The method we helped pioneer can detect the presence, in the blood, of very small numbers of the patient’s own cells. There should be no patient cell in circulation; if there is it could signal the return of the disease.
What should people know about City of Hope’s HLA lab?
Our transplant program has a higher patient survival rate than 95 percent of the transplant centers in the U.S. Not only do we have a higher-than-expected patient survival rate than other centers, but we have exceeded expectations for the last eight years in a row. This record of patient survival is not duplicated by any other transplant center in the U.S. Our HLA laboratory and our City of Hope physicians provide the basis for this enviable record.
If you’d like to learn more about joining the bone marrow registry and other ways you can help, visit our website or call 626-301-8483.