CYTOMEGALOVIRUS

Cytomegalovirus is a herpes virus transmitted by close human contact. No symptoms of infection are apparent in the majority of cases. However, the virus is very dangerous and may be fatal in immunodepressed patients. Serum-negative female patients who become infected during pregnancy may transmit the disease to the fetus. In 95% of cases this occurs without symptoms, but some neonates may present jaundice, hepato-splenomegaly and retarded psycho-motorial development. For this reason it is of great importance to determine the immunitary state of the patient and check for serum conversion. A significant increase in the anti-Cytomegalovirus IgG titer is indicative of a recent infection or reactivation of a latent infection.Sometimes it is not sufficient to test for IgM antibodies, as the presence of this class may be due to the persistence of IgM or asymptomatic reinfection by Cytomegalovirus, without risk for the fetus. For this reason it is useful to assay the avidity of the IgG antibodies, in as far as it has been demonstrated that avidity is low in the acute phase of infection and increases over a period of time. The presence of low avidity antibodies is therefore an indication of a recent or current infection.

Method:

Immunoenzymatic method for the quantitative determination of IgG-class antibodies, qualitative determination of IgM-antibodies and the qualitative determination of the avidity of IgG class antibodies to Cytomegalovirus in human serum. The test is based on the ELISA principle (Enzyme Linked ImmunoSorbent Assay) which uses the reaction between the antibodies present in the tested sample and the immobilized antigen bound to solid phases. The immunoglobulins bind to the antigen through incubation with diluted human serum. The result is expressed as an INDEX (ratio between the OD value of the sample and that of the Cut-off) for qualitative tests and in International Units (IU/mL) for quantitative tests.