ПЦР. Эпштейна-Барр вирус (EBV), кровь

Epstein-Barr Virus (EBV), DNA Probe testing identifies EBV nucleic acid in clinical specimens or tissue. The assay serves as a molecular adjunct to routine histopathology when EBV involvement is in question and may be performed as EBV in situ hybridization or as an EBV DNA assay. It supports the evaluation of suspected EBV-related disease when serology is noninformative or unavailable. Clinically, this test assists with the early assessment of infectious mononucleosis before antibody titers increase, helps distinguish EBV from other herpesvirus infections and bacterial causes of tonsillopharyngitis, and is used to evaluate possible EBV reactivation in recipients of solid-organ or hematopoietic stem cell transplants.

Epstein-Barr virus is a ubiquitous member of the Herpesviridae that primarily targets B lymphocytes but can also infect T cells and epithelial cells. Transmission occurs via respiratory secretions, and the peak incidence of clinically apparent disease is in individuals 15–25 years of age. Primary exposure usually occurs in childhood and is frequently asymptomatic or pauci-symptomatic, leading to latent infection. In adults, primary infection often manifests as infectious mononucleosis with fever, systemic symptoms, tonsillar and pharyngeal inflammation, and generalized lymphadenopathy. Hepatosplenomegaly is common, and petechiae may appear on the soft palate. Reported complications include hepatitis, pneumonia, hemolytic anemia, thrombocytopenia, aplastic anemia, splenic rupture, myocarditis, and neurologic syndromes such as Guillain–Barré syndrome, encephalitis, and meningitis. Rarely, chronic active EBV infection develops, with symptoms persisting longer than 6 months, histologic evidence of organ involvement (eg, pneumonitis, hepatitis, bone marrow hypoplasia, uveitis), and detection of EBV antigens or DNA in tissues accompanied by very high virus-specific antibody titers. By contrast, chronic fatigue syndrome typically shows only modest antibody elevations. More than 90% of adults are lifelong EBV carriers, with persistence in memory B cells. In the setting of impaired immunity (eg, HIV infection or iatrogenic immunosuppression), EBV can contribute to lymphoproliferative disorders, nasopharyngeal carcinoma, or recurrent symptomatic infection. EBV nucleic acid detection uses molecular methods such as real-time PCR to amplify virus-specific DNA targets and in situ hybridization on tissue sections as an adjunct to histopathology. A negative result does not exclude EBV if sampling is suboptimal, the specimen is improperly handled or fixed, or the viral burden is below the assay’s analytical sensitivity.