G T Maine1, René Stricker2, Martin Schüler2, Jack Spesard1, S. Brojanac1, Beimar Iriarte1, Karl R. Herwig1, T. Gramins1, B. Combs1, J. Wise1, Hugh Simmons1, T. Gram1, J. Lonze1, D. Ruzicki1, Barry J. Byrne1, J. D. Clifton1, Linda E. Chovan1, Dawnell Wachta3, Cindy Holas3, D. Wang3, Tracy Wilson3, Susan Tomazic-Allen3, Mary Ann Clements4, George L. Wright4, Tiziana Lazzarotto5, Alessandro Ripalti5, Maria Paola Landini5
1Department of Congenital Infectious Disease Diagnostics1 and
2Dianalab, Geneva, Switzerland2;
3Department of Clinical Research,3 Abbott Laboratories, Abbott Park, Illinois;
4Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia4; and
5Department of Clinical and Experimental Medicine, Section of Microbiology, University of Bologna, Bologna, Italy5
Tóm tắt
ABSTRACT
A new microparticle enzyme immunoassay (MEIA), the Cytomegalovirus (CMV) Immunoglobulin M (IgM) test, was developed on the Abbott AxSYM analyzer. This test uses recombinant CMV antigens derived from portions of four structural and nonstructural proteins of CMV: pUL32 (pp150), pUL44 (pp52), pUL83 (pp65), and pUL80a (pp38). A total of 1,608 specimens from random volunteer blood donors (
n
= 300), pregnant women (
n
= 1,118), transplant recipients (
n
= 6), and patients with various clinical conditions and disease states (
n
= 184) were tested during development and evaluation of this new assay. In a preliminary clinical evaluation we tested specimens collected prospectively from pregnant women (
n
= 799) and selected CMV IgM-positive archived specimens from pregnant women (
n
= 39). The results from the new CMV IgM immunoassay were compared to the results of a consensus interpretation of the results obtained with three commercial CMV IgM immunoassays. The results for specimens with discordant results were resolved by a CMV IgM immunoblot assay. The relative sensitivity, specificity, and agreement for the AxSYM CMV IgM assay were 94.29, 96.28, and 96.19%, respectively, and the resolved sensitivity, specificity, and agreement were 95.83, 97.47, and 97.37%, respectively. We also tested serial specimens from women who experienced seroconversion or a recent CMV infection during gestation (
n
= 17) and potentially cross-reactive specimens negative for CMV IgM antibody by the consensus tests (
n
= 184). The AxSYM CMV IgM assay was very sensitive for the detection of CMV IgM during primary CMV infection, as shown by the detection of CMV IgM at the same time as or just prior to the detection of CMV IgG. Specimens from individuals with lupus (
n
= 16) or parvovirus B19 infection (
n
= 6) or specimens containing hyper IgM (
n
= 9), hyper IgG (
n
= 8), or rheumatoid factor (
n
= 55) did not cross-react with the AxSYM assay. One specimen each from individuals infected with Epstein-Barr virus (
n
= 26), measles virus (
n
= 10), herpes simplex virus (
n
= 12), or varicella-zoster virus (
n
= 13) infection, one specimen from an influenza vaccinee (
n
= 14), and one specimen containing antinuclear antibody cross-reacted with the assay. The overall rate of cross-reactivity of the specimens with the assay was 3.3% (6 of 184). The AxSYM CMV IgM assay is a sensitive and specific assay for the detection of CMV-specific IgM.
