USE OF IMMUNOBLOT IgM IN PATIENTS WITH SEROLOGICAL AND CLINICAL EVIDENCE OF PRIMARY EBV INFECTION AND REACTIVATION

Purpose: Anti-VCA IgM is a marker for establishing primary infection with Epstein-Barr Virus (EBV), it usually appears in combination with anti-VCA IgG. It has been shown that there is a risk of non-specific IgM reactivity due to cross-reactions, interference with rheumatoid factor or autoantibodies. These antibodies may also occur during reactivation. In these cases, Immunoblot based tests may be useful to confirm the ELISA result. We compared the results of anti-VCA IgM in ELISA and Immunoblot IgM in patients with evidence of primary EBV infection (infectious mononucleosis, IM) and/or reactivation/reinfection. Materials/Methods: We examined 32 serum samples with commercial immunoblot (Euroline Anti-EBV Profile 2 (IgM), Euroimmun, Germany). Samples were tested primarily for anti-VCA IgM/IgG in ELISA. Patients with IM were 11, and those with probable reactivation/reinfection - 21. Results: We found positive results at 31.3% (95% CI: 16.1% -50.0 %, n = 10) of all subjects. Patients with IM and isolated anti-VCA IgM in ELISA (81.8%) were negative in Immunoblot IgM. Positive in Immunoblot IgM was 38.1% (n = 8) of the patients with suspected reactivation. We confirmed a primary infection in three of them due to the low avidity of anti-VCA IgG and missing anti-EBNA1 IgG. In five of the patients, the presence of anti-VCA IgM may be interpreted as reactivation/reinfection. Conclusion: Patients with IM and isolated anti-VCA IgM models in ELISA were not confirmed in the Immunoblot test. Approximately 43% of patients of possible reactivation was also negative in the test