Evaluation of assays for antibody to hepatitis E virus by a serum panel

Abstract

Few data are available to evaluate the performance of existing assays for antibody to the hepatitis E virus (anti-HEV). A panel of 164 randomized and coded sera was tested for anti-HEV by 12 different assays. The panel included a dilution series of an early convalescent human serum, known-positive sera (undiluted human sera obtained 2 months to 13 years after acute hepatitis E, and postinoculation chimpanzee sera), known-negative sera (preinoculation chimpanzee sera; sera from chimpanzees with hepatitis A virus, hepatitis B virus, or hepatitis C virus infection; and normal human sera), and sera obtained from previously tested U.S. blood donors without a history of hepatitis. Six tests detected anti-HEV in H90% of undiluted knownpositive sera. The sensitivity of all of the assays with known-positive sera ranged from 17% to 100%, and the limit of detection by endpoint dilution ranged from 1:5 to 1:160. Ten tests were nonreactive for all of the 22 knownnegative sera, one test was reactive for one serum, and one test was reactive for 5 sera. In pairwise comparisons of different tests in blood donor sera, the overall concordance ranged from 49% to 94% (median, 69%) and the concordance among reactive sera ranged from 0% to 89% (median, 32%). Several of these tests performed well in detecting anti-HEV in known positive sera. However, highly discrepant results among U.S. blood donor sera indicate that anti-HEV seroprevalence data in non-HEV-endemic countries may be unreliable and should be interpreted with caution. (HEPATOLOGY 1998;27:857-861.)The performance of tests for antibody to the hepatitis E virus (anti-HEV) is an important factor in assessing the epidemiology of hepatitis E virus (HEV) infection. The first serologic assays for anti-HEV included immune electron microscopy 1,2 and a fluorescent antibody blocking assay, 3,4 both of which utilize native HEV antigen as a target for detection. Although these assays are specific, they have limited sensitivity: anti-HEV has been detected in only 50% to 70% of patients with acute hepatitis during hepatitis E outbreaks, and anti-HEV titers decline to subdetectable levels within several months after acute infection. After HEV was cloned and sequenced, a variety of tests, including both Western blot assays and enzyme immunoassays (EIAs), were developed to detect anti-HEV by using recombinantexpressed proteins or synthetic peptides that model immunodominant epitopes of the putative structural regions of HEV [open reading frames (ORFs) 2 and 3]. [5][6][7][8][9][10][11][12][13][14][15][16] Several recombinant protein-based tests have demonstrated increased sensitivity compared to prior assays, detecting anti-HEV in 90% to 95% of patients with acute hepatitis during outbreaks of hepatitis E in HEV-endemic areas. 6,17 Recently, a number of cases of acute hepatitis E, diagnosed on the basis of serologic testing, have been reported among persons who had no history of travel to HEV-endemic areas. [18][19][20][21][22][23] However, the interpretation of these findings is problematic...

Bayesian estimation of hepatitis E virus seroprevalence for populations with different exposure levels to swine in The Netherlands

“…This observation has been reported previously [18,19] and complicates the interpretation of cross-sectional HEV seroprevalence estimates based on results from a single assay. Preferentially, true seroprevalence estimates are adjusted for sensitivity and specificity of assays [24], but true sensitivity and specificity of assays are always unknown.…”

“…Priors for sensitivity and specificity of each assay were based on the literature [19]. For assays based on similar antigens as E-2, sensitivity between 67 % and 91% was observed.…”

Characterization of hepatitis E-specific cell-mediated immune response using IFN-γ ELISPOT assay

“…Until recently, commercial tests for anti-HEV IgG have demonstrated inconsistent sensitivity and specificity. The in-house NIH assay used in this study has higher sensitivity when compared with commercial assays Fix et al, 2000;Ghabrah et al, 1998;Mast et al, 1998). In fact, community-based surveys in 6000 subjects demonstrated that different lots of a commercial anti-HEV IgG ELISA varied considerably (for example, a second lot increased community-wide prevalence by 25% from 60-to-85%) (Fix et al, 2000).…”

Population Seroprevalence of Hepatitis E Virus Antibodies in Rural Bangladesh

“…21,22 The Walter Reed Army Institute of Research (WRAIR, Bethesda, MD) has developed a quantitative anti-HEV total Ig EIA that is highly sensitive (96%) and specific (98%) to identify HEV infections in populations. 23,24 The assay uses a quantitative sandwich approach to capture and label human Ig antibodies to recombinant HEV ORF2 proteins (rHEV) of the Sar-55 Pakistani strain expressed in the baculovirus system, and the photometric result is compared with positive controls from a reference pool of Nepali HEV patients, reporting antibody concentrations in WRAIR units per milliliter (WRAIR U/mL).…”