Diagnosis of parvovirus B19 infection in hematological patients with partial red cell aplasia of the bone marrow

AIM: To assess diagnosis of parvovirus B19 infection (PI) in patients with aplastic crises by combined use of polymerase chain reaction (PCR) and enzyme immunoassay (EIA) of specific IgM and IgG. MATERIAL AND METHODS: A total of 159 serum samples from 77 PI suspects were examined. The examination for virus DNA was conducted with modified "net" PCR in 108 samples, for specific IgM and IgG with EIA in 110 samples. RESULTS: The percentage of patients infected with parvovirus detected by PCR or EIA reached 60%. 21 of 77 patients with hemolytic anemias were infected with parvovirus B19, the virus persisting in 8 cases (40%). persistence of the virus was registered if viremia occurred in immunodeficiency due to the disease or immunosuppressive therapy. Immunity to parvovirus has not developed: IgM expression was the same as in patients without hemopoietic abnormalities, while IgG was not detected. The absence of specific immunity to parvovirus B19 occurred in patients treated with immunosuppressive drugs early after the end of viremia period in high IgM level and at the initial phase of IgG synthesis. IgM levels also remained unchanged; the level of IgG declined and was not identified furthermore. There were cases of reinfection. CONCLUSION: Combined use of PCR and EIA is optimal for diagnosis of parvovirus B19 infection in patients with hemolytic anemias. It was found that there are correlations between defects in specific immunity, persistence and immunodeficiency onset regarding viremia. Abnormal for the disease course levels of IgM and IgG indicate the persisting virus, the condition of specific immune response to parvovirus B19 and feasibility of reinfection. Reliable diagnosis of parvovirus infection is possible only in simultaneous use of PCR and EIA.