title: Diagnosis of recent primary rubella virus infections: significance of glycoprotein-based IgM serology, IgG avidity and immunoblot analysis.
abstract: Reliable serodiagnosis of rubella virus (RV) infections requires discrimination of specific IgM induced by primary rubella from persistent, reactivated or non-specific IgM reactivity. Sera from 130 pregnant women with recent or past RV infection/vaccination, persistent IgM or negative rubella serology, 26 patients with other acute infections and 5 patients with rheumatoid factor-positivity were analyzed for RV-specific IgM by ELISA coated with whole-virus lysate or native glycoprotein, followed by determination of IgG avidity and E2-specific IgG using lysate-coated ELISA and non-reducing immunoblot. Compared to a reference μ-capture IgM ELISA, the sensitivity for diagnosing recent rubella infection/vaccination was 90.0% and 100% for the lysate-based and glycoprotein-based IgM ELISA, respectively. With respect to women with past RV infections or negative histories of RV infection/vaccination, both assays were 97.5-100% specific, whereas for patients with other acute infections the glycoprotein substrate provided a specificity of 92.3% compared to only 80.8% using whole-virus antigen. Analyzing anti-RV IgG avidity and anti-E2 IgG reactivity allowed the time point of primary infection to be determined unambiguously in >86% of samples. In conclusion, using RV glycoprotein antigen improves the specificity of indirect IgM ELISA. In cases of RV-specific IgM reactivity, recent primary rubella infection can be confirmed or excluded efficiently by specific IgG avidity and immunoblot analysis.
authors.affiliation: Institute of Experimental Immunology, Affiliated to EUROIMMUN AG, Seekamp 31, D-23560 Luebeck, Germany.
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Wandinger
authors.forename: Sandra
authors.initials: S
authors.lastname: Saschenbrecker
authors.forename: Katja
authors.initials: K
authors.lastname: Steinhagen
authors.forename: Thomas
authors.initials: T
authors.lastname: Scheper
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Meyer
authors.forename: Uwe
authors.initials: U
authors.lastname: Bartelt
authors.forename: Gisela
authors.initials: G
authors.lastname: Enders
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D000915:Antibody Affinity; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006023:Glycoproteins / Q000276:immunology; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D007074:Immunoglobulin G / Q000097:blood*; D007075:Immunoglobulin M / Q000097:blood*; D008875:Middle Aged; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis* / Q000276:immunology; D012409:Rubella / Q000175:diagnosis* / Q000276:immunology; D012412:Rubella virus / Q000276:immunology*; D012680:Sensitivity and Specificity; D012699:Serology / Q000379:methods; D015678:Viral Structural Proteins / Q000276:immunology; D014773:Virology / Q000379:methods*
chemical_list: D000914:Antibodies, Viral; D006023:Glycoproteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015678:Viral Structural Proteins