Cytomegalovirus Antibody Scree... Health Article

Definition

Cytomegalovirus (CMV) is a common human virus. When first exposed to CMV, a healthy person's immune system is triggered and quickly makes antibodies to fight the virus. Specialized screening tests can be done to document the presence or absence of antibodies specific to the cytomegalovirus. Antibodies to CMV can be evidence of a current or a past infection.

Purpose

Up to 85% of people have antibodies to CMV by the time they are 40 years old. In a healthy, nonpregnant person, CMV infection is almost never serious. Symptoms, if present, are mild, often resembling infectious mononucleosis caused by the Epstein-Barr virus. However, consequences of CMV infection can be devastating to the fetus, transplant patients, patients with human immunodeficiency virus (HIV) and other patients with suppressed immune systems. People with weakened immune systems are vulnerable to infection from several routes, including from another person, from a donated organ or transfused blood, or from reactivation of a past infection. CMV is related to the herpes simplex and varicella (chickenpox) viruses in that it remains dormant in the body but can resurface with or without symptoms.

Antibody screening helps control the infection risk for high risk groups. For instance, before a transplant, both the recipient and donor are usually tested for anti- bodies. A recipient who has never had CMV (negative for antibodies) should not receive an organ from a donor who has had CMV (positive for antibodies) because active infection could be acquired by the recipient. CVM infection in this context can be associated with organ rejection, or can cause illness such as pneumonia, hepatitis, or death. In some transplant patients, particularly after bone marrow transplantation, testing may be done as often as every week to screen for new or recurrent infection.

Women who do not have evidence of previous CMV infection (i.e. antibody screen negative) should try to avoid exposure to CMV in pregnancy. CMV infection is the most common congenital infection (existing at birth). The infection, passed from mother to baby, can cause permanent mental or physical damage, or death. However, CMV antibody screening is not routinely ordered as part of prenatal care.

Blood is usually screened for CMV antibodies before being transfused into a person with a weakened immune system. CMV infection can be very similar to illness due to Epstein-Barr virus. If there is a need to know the specific source of a patient's symptoms, antibody screening distinguishes between these two infections.