CMV
In addition to determining the HLA typing, a donor's cheek swabs are also used to determine their CMV status. Knowing a donor's so-called CMV status (i.e. whether they have ever been infected with the CMV virus) makes it easier to determine if they are a potential match for a patient. What is CMV, exactly, and how does this status affect the stem cell donation process?
Page content
What is CMV?
CMV is short for cytomegalovirus. This is a virus that occurs all over the world. More than half of the Dutch population has been infected with CMV at some point. Most people experience no symptoms when they get infected. If any symptoms do occur, they are usually flu-like in nature and generally go away on their own. When you contract a CMV infection, you carry the virus with you for the rest of your life, but your immune system is able to contain the virus.
Why is the CMV status important?
Whether or not someone has been infected with CMV is an important factor in the stem cell transplantation process. It is important that the patient and donor have the same CMV status; either both positive (infected) or both negative (not infected). A donor's CMV status is particularly relevant if the patient is CMV positive.
If a patient who has been infected with the CMV virus receives stem cells from a donor who has not contracted this virus, they will no longer be protected against a CMV (re)infection after their stem cell transplantation. This is because the donor cells have never come into contact with the CMV virus before and have therefore not developed a resistance against the virus. This can lead to a reactivation of the virus that still resides in the patient's body after their original infection. That, in turn, can lead to health risks for the patient. For this reason, testing for CMV is an important factor when searching for a suitable stem cell donor for a patient.
On the other hand, a CMV-positive donor may transmit the virus to a CMV-negative patient. As the donor cells have already developed a resistance against the CMV virus, they may effectively combat the virus inside the patient's body. This situation is therefore less dangerous than matching a CMV-positive patient with a CMV-negative donor. However, a CMV-negative donor is still the best option for a CMV-negative patient.
Am I more likely to be called up as a donor if my CMV status is known?
Yes, that is certainly possible. If there are two potential donors with equal suitability, the donor whose CMV status is known will be preferred over the donor whose CMV status is unknown at the time.
