Parvovirus B19 infection in anemic children with AIDS using a nested polymerase chain reaction (PCR) assay: correlation with slot blot hybridization and antibody status by enzyme linked immunosorbent assay (ELISA)† 911

Abstract

Parvovirus B19 infection in patients with AIDS tends to be chronic and is associated with anemia and/or bone marrow failure. We looked for evidence of Parvovirus B19 infection in 21 children (mean age 7.24; median 9 years) with AIDS and anemia (mean Hb 9.6 g/dl; range 3.4 - 11.1). The reticulocyte count ranged from 0.6% to 7.1% (mean 2.3%). Absolute CD4 counts ranged from 2 to 1766/cu mm (mean 368.5). Anti Parvovirus IgG and IgM antibody levels were assayed by ELISA and slot blot hybridization was used to detect B19 DNA in the same sera. In addition, nested PCR assay was used to detect B19 DNA in the sera samples. B19 DNA was detected in 3/21 patients (14.3%) by the nested PCR method, but in none by the slot blot method. One patient of 21 (4.7%) was strongly positive for B19 IgM antibody indicative of recent infection; 10/21(47.6%) were anti B19 IgG positive suggesting past infection or recent transfusion. There was no difference in the hemoglobin level and reticulocyte counts in the three patients who were PCR positive compared to the group as a whole or with the patients who were IgG positive. The only patient who was IgM positive (PCR negative) had a hemoglobin level of 11 g/dl, a leukocyte count of 1860/cu mm, and a reticulocyte count of 1.3%. Thus, four patients had clear evidence of B19 infection: viremia in 3 (B19 DNA by PCR), and acute infection in 1 (anti B19 IgM). Of interest, all three patients with viremia had detectable IgG antibodies. Three of 10 (30%) who were IgG positive still had viremia detectable by PCR but not by the relatively less sensitive slot blot method, suggesting failure of the antibody to clear the virus. This study thus underscores the importance of more sensitive assays like nested PCR for detection of B19 Parvovirus infection in children with AIDS where an antibody response may be ineffective in clearing the viremia.