Enzyme-linked immunosorbent assay for detection of virus-specific IgM antibodies to varicella-zoster virus.

A sensitive enzyme-linked immunosorbent assay (ELISA) is described for detection of varicella-zoster virus (VZV) IgM antibodies. The antigen consisted of a sonically disrupted extract of VZV-infected human embryo cells. The tested sera were absorbed with Staphylococcus aureus (strain Cowan I) before analysis. Rabbit anti-human IgM peroxidase conjugate was used to detect human IgM bound to viral antigen. The results were compared with those obtained by the indirect fluorescent antibody to membrane antigen (IFAMA) technique. Comparison of titers obtained by ELISA with those obtained by IFAMA for sera of chickenpox patients showed agreement between the results in 8 of 9 patients. In 1 chickenpox patient, no VZV IgM antibodies could be detected by IFAMA, while a titer of 3,200 was obtained by ELISA. The ELISA technique described gave titers more than 100 times higher than those obtained by IFAMA. VZV IgM antibody was detected by ELISA and IFAMA in only 1 of 5 zoster patients. No VZV IgM antibodies were found by ELISA in 45 control sera (healthy adults and hospitalized patients with various other diseases). Neither were they found in paired sera of 6 patients with acute herpes simplex infections, 2 patients with Epstein-Barr virus infections, and 3 patients with human cytomegalovirus infections.