Immunoglobulin M to the membrane of uninfected fibroblasts in primary human cytomegalovirus infections.

Thirty-two patients with primary human cytomegalovirus (HCMV) infection were examined for presence of antibody to the membrane (Me) of uninfected human embryonic lung fibroblasts (HELF) using an anti-complement immunofluorescence (ACIF) test. Patients were divided into three groups according to age: less than or equal to 12 months (11 cases), 2-6 years (8 cases), greater than or equal to 13 years (13 cases). Convalescent-phase sera from 13 out of 13 of the older and 6 out of 8 of the middle-aged group gave positive fluorescence staining of the membrane of living uninfected HELF monolayers, whereas only one out of 11 younger patients showed antibody reactivity to HELF Me. ACIF performed on IgM and IgG fractions of randomly selected Me antibody-positive sera, showed a reactivity to HELF Me restricted to antibody of the IgM class (Me IgM). HELF Me IgM were first detected during the second week after the onset of symptoms of primary HCMV infection and disappeared usually within 4-6 months. Me IgM were not detected in sera from patients with HCMV infections other than primary (i.e. recurrent or congenital), or with other herpesvirus infections and were not detected in sera from patients with severe immunological diseases. HELF Me IgM were shown not to be related to rheumatoid factor and their reactivity was shown to be restricted to HELF cells, for it was not observed in any of the other cell types tested. The determination of HELF Me IgM antibody appears to be a new, practical and useful serological tool for the diagnosis of primary infections in patients over 2 years.