Cytomegalovirus, or CMV, is a moderately infectious herpes group virus. It is rarely associated with symptoms in healthy individuals, but like other members of the herpes family it remains in the body until death. During this period of time in the body it is contained by the normal immune system and doesn’t normally produce an acute infection. It is found all over the world, and typically 75-80% of a country’s population are CMV positive by the age of 40. It is most common virus passed between mother and unborn child, and after birth can be contracted from any exchange of body fluids.
CMV, although normally unnoticed by the carrier, can cause serious health problems in immunocompromised patients. CMV pneumonia is one of the leading causes of morbidity and mortality among immunosuppressed patients after bone marrow transplant (BMT) procedures.
Before a BMT can be carried out, the patient’s own bone marrow is wiped out with heavy chemotherapy. This has the unfortunate consequence of effectively destroying the patient’s entire immune system. When the donor bone marrow is transplanted, it takes it several weeks to begin building the patient’s immune cell numbers back to normal levels. During this period, the patient is kept in relative isolation and great care is taken to prevent infection with any pathogens from medical staff and so forth. However, if the patient is CMV positive, they already have a virus capable of causing serious illness in their body.
During the period of rebuilding the patient’s immune system, all specific immune responses have to be redeveloped from scratch. This of course includes the specific immune cells that have been keeping the patient’s CMV infection under control. The virus can multiply and can cause a serious illness. CMV can cause pneumonia or other serious illnesses. Your doctors will monitor the activity of CMV in your body and give you treatment to prevent it causing these serious complications.
Treatment comprises of an intravenous drug which will be either ganciclovir or foscarnet.
Ganciclovir is given twice a day and a hospital stay can range from 2 to 6 weeks depending on the patient’s CMV levels becoming negative. This can be very frustrating for the patient especially when they may be feeling quite well as it is normal with CMV to be well and without symptoms. Where possible when the patient is feeling well they will be able to be away from the hospital when the drug is not being given. Ganciclovir can effect the white blood count so sometimes the dose needs to be reduced.
Foscarnet is given 3 times a day and has similar side effects to ganciclovir. Both of these treatments are effective ways of managing CMV reactivation.
In time the patient’s own immune system will control the CMV reactivation. However until then the patient may need multiple admissions to hospital.
For patients living outside Leeds the treatment cannot usually be given by the local hospital due to the level of monitoring needed. Additionally patients would normally reactivate early after the transplant and most local areas are unfamiliar with the care and treatment needed.