Cytomegalovirus (CMV) Infection in Transplant Patients
Matthew P. Cheng, MDCM, FRCPC, FACP
Assistant Professor, McGill University
Dr. Cheng obtained his medical degree from McGill University, and then subsequently completed his residency in internal medicine at the University of British Columbia. He then returned to McGill to complete a combined fellowship in infectious diseases and medical microbiology. Afterwards, he completed a postdoctoral fellowship at the Harvard Medical School-affiliated Brigham and Women’s Hospital and Dana-Farber Cancer Institute before establishing his clinical research program at the McGill University Health Centre. His research program is funded by research operating grants from the US National Institutes of Health, the Canadian Institutes for Health Research, and the Australian National Health and Medical Research Council. His research focuses on patients with potentially lethal infections, including those with severe manifestations of sepsis, bloodstream infections, and opportunistic infections in immunocompromised hosts.
He has received numerous awards including Top Influential Article in Blood Advances (2021), and the prestigious Terry Fox Humanitarian Award.
In the year 2021, doctors performed a total of 2,782 organ transplants in Canadian patients. However, for every one Canadian that received a transplant in 2021, 1.5 patients were still waiting to receive one, with a total of 4,043 Canadians on the wait list for an organ transplant by the end of 2021. Unfortunately, approximately 247 Canadians died that year while waiting for an organ transplant.
Cytomegalovirus, or CMV, is a type of herpes virus that is very common worldwide. If infected with CMV, most people with a healthy immune system may either experience no symptoms, or mild, short-lived symptoms similar to having a cold or mononucleosis. Once the symptoms subside, the person may live with CMV in their bodies their whole lives without it causing any further health problems (in other words, the virus goes dormant).
However, CMV is problematic for transplant recipients, as they are required to take medications that weaken their immune system to prevent their bodies from rejecting the organ or tissue. If the person has a dormant CMV infection, it can be reactivated and cause serious health complications, including CMV-related organ rejection or even death.
We talked to Dr. Matthew Cheng, Infectious Disease Physician and Assistant Professor at McGill University, and asked him how CMV affects transplant patients: “It can cause severe issues to the colon, to the liver, to the lungs, to the brain, to the eye. It can also affect the transplanted organ itself and increases the risk of rejecting a solid organ. It can also linger for a long period of time and significantly affect that patient’s quality of life.” If left untreated, it can even cause a patient’s death.
According to Dr. Cheng, “CMV really needs to be treated properly to make sure that a patient doesn’t develop any of those complications. Furthermore, we know that after a transplant patient has been treated for CMV, they are unfortunately at risk of the disease recurring. They therefore need to be followed even after the treatment phase to make sure they don’t develop subsequent complications from CMV.”
Treatment Options for CMV Infection in Transplant Patients
Drugs currently exist to treat CMV in transplant patients, which help to reduce negative outcomes associated with CMV infection in this group. However, some CMV infections are resistant to available treatments, and these treatments come with their own set of negative side effects for patients.
When asked about his experience treating transplant patients with CMV infection, Dr. Cheng said: “The problem with the existing treatments is that they often come at a potential cost, for example one treatment that’s commonly available can suppress the bone marrow and another one may affect the kidney…it’s quite common for patients to develop complications on some of the existing therapies.”
New treatments are being developed to help patients with CMV infections that do not respond well to existing treatments. Dr. Cheng says, “One of the reasons a lot of us in the infectious disease community are so excited about these new treatment options is that they’re safe – along with being effective for the management of CMV. With the advancement of a completely new drug and mechanism of action, we now have more options at our disposal, and it really feels a lot better knowing that if one treatment doesn’t work, or isn’t ideal for a patient, there are others we can turn to.”
Supporting Transplant Patients and Caregivers in the Workplace
How does receiving an organ transplant affects someone’s life?
Dr. Cheng states, “In the short-term, it’s important to recognize that patients need to adopt completely new habits. The obvious thing is that they need to take medications to prevent their immune system from rejecting the new organ or tissue. But in addition to that, they need to be careful in their day-to-day life because they’re now at increased risk of infections specifically because they are taking those medications to suppress their immune system in the long term.”
He goes on to say, “The transplant, while absolutely lifesaving and a phenomenal advancement in medicine, does predispose them to increased risks of adverse events. Especially after transplant, their immune system is weakened and therefore they are at increased risk of infection. This was really highlighted during the pandemic where a lot of transplant recipients who had occupations where they were facing the public directly, needed to take additional precautions to protect themselves, because a respiratory infection, that may not seriously affect you or me, could be potentially lethal in a transplant recipient."
Dr. Cheng cautions against focusing on doom and gloom when describing the effects of a transplant on someone’s life: “It’s not to say that transplant recipients cannot live a normal life, that is not the picture I want to paint. But I do want to stress that they need to be more cautious, because receiving a transplant puts someone at increased risk of bad outcomes from infections.”
When specifically asked how employers can support patients who have gone through a transplant, Dr. Cheng says, “I think that it would be great for those employees to be able to have additional flexibility. And the reason I say that is because even in the best-case scenarios when a transplant goes incredibly well, there is still very close follow up with the medical team to ensure that they’re progressing as they should post-transplant. In addition, it’s important to recognize that the patient is already at increased risk of several kinds of complications, and they may require additional assistance for medical leave or other things as they come up.”
This is the case for individuals receiving a transplant but also their caregivers, as the average age for transplant is around 50 years old, and caregivers can experience stress and burnout during the transplant journey.
– Hannah Baker bh