Prevalence of anti-parvovirus B19 IgG and IgM and parvovirus B19 viremia in pregnant women in an urban area of Northern Italy.

Parvovirus B19 (B19V) infection in pregnancy is mostly asymptomatic, but can cause complications including abortion and fetal hydrops. Although its infection is ubiquitous, seroprevalence among pregnant women varies according to different geographical areas. Since seroprevalence data in Italy are limited, the prevalence of antibodies and DNA in pregnant women was evaluated retrospectively, correlating the clinical situation of mothers and newborns. One thousand eight hundred and ninety-three sequential sera were examined from pregnant women (60.8% in the first trimester, 16.6% in the second one, and 22.6% in the third one, respectively) for anti-B19V IgG and IgM (confirmed by immunoblot); 1402 (74.1%) were of Italian origin and 491 (25.9%) non-Italian women. Molecular tests were used to search for viral genome. One thousand three hundred and fifteen (69.5%) samples were IgG-positive, 21 (1.1%) IgM-positive, and 578 (30.5%) nonimmune. The difference in IgG seroprevalence between Italian (71.1%) and non-Italian women (64.8%) was statistically significant. Of the 21 IgM-positive women, 16 were confirmed positive also by immunoblot (prevalence: 0.8%), of which 11 were viraemic (prevalence: 0.6%; mean 1.3 × 104 geq/ml). Mothers were asymptomatic, and the newborns had no clinical signs of congenital infection. IgG seroprevalence in Italy is high, with differences between Italian women and non-Italian women from geographic areas with lower endemic levels of B19V. The consistent migratory flows in place could lead to an increase in the number of susceptible women. The prevalence of viremia is low, and has not been associated with evident fetal damage at birth.

Evaluation of the vitros hiv combo 4th generation test for the identification of HIV infections.

BACKGROUND: Simultaneous detection of HIV 1 and 2 antibodies and HIV-1 p-24 antigen in the 4th generation tests is particularly effective for the identification of early acute HIV infections while maintaining accurate detection of long-established infections. OBJECTIVES: The aim of this study was to evaluate the new 4th generation VITROS HIV Combo test from Ortho-Clinical Diagnostics by comparing its results with those obtained using a 3rd generation HIV 1/2 antibody test (VITROS Anti HIV 1 + 2 from Ortho-Clinical Diagnostics) and a 4th generation test (LIAISON XL HIV Ab/Ag, DiaSorin) currently used in the Microbiology Unit of Legnano Hospital. STUDY DESIGN: One thousand and three samples of the normal daily routine (Group 1) were analyzed simultaneously with the three systems. The concordant and discordant sample results were further tested using Western blot and HIV-RNA assay (Roche). One hundred samples (Group 2) of known HIV positive subjects (63 of subtype B, 37 subtype non-B, and 51 with positive viraemia) and 50 samples (Group 3) with indeterminate Western blot were also examined using the three systems. From Group 3, 24 samples were collected from patients diagnosed with acute infection. RESULTS: The overall agreement between the three systems was 99.4% (99.5% in group 1, 100% in group 2 and 96.6% in group 3) with a coefficient Fleiss Kappa of 0.9814. Notably, the VITROS HIV Combo test was positive in all known HIV positive samples of group 2 without any statistically significant difference in the values of the sample/cut off ratios between the B and non-B subtypes and between the positive and negative viraemia samples in established infections. The VITROS HIV Combo test was also positive in all samples of patients with acute infection in group 3. CONCLUSIONS: The VITROS HIV Combo test has shown comparable performance to the other two assays in use of 3rd and 4th generation tests and is able to correctly identify both acute and established HIV infections independently of viraemia and HIV subtype.

Threshold value of LIAISON XL anti-HCV screening assay predicting positive immunoblotting results.

Some international guidelines recommend evaluating the need to confirm positive anti-hepatitis C virus (HCV) antibody screening results by means of a more specific antibody or molecular biology test on the basis of a screening threshold value (such as the sample signal/cut-off ratio) that can predict the positivity of additional antibody testing in at least 95% of cases. The aim of this study was to determine the threshold value of the DiaSorin LIAISON XL chemiluminescence test. Two hundred and twenty-eight routine laboratory samples that were chemiluminescence positive for anti-HCV antibodies but had different signal/cut-off ratios were assayed using immunoblotting, which indicated that 155 (68.0%) were positive, 40 (17.5%) were negative, and 33 (14.5%) were indeterminate. When the samples were divided on the basis of their signal/cut-off ratios, 95.5% of the samples with a ratio of ≥3.5 were positive as against 74.1% of the positive or indeterminate samples with a ratio of <3.5. Statistical analysis using Youden's index and a receiver operating characteristic curve showed that the optimum cut-off value was 3.65. These findings indicate that, when using the LIAISON XL system for anti-HCV antibody screening, a signal/cut-off ratio of ≥3.65 makes further confirmatory tests unnecessary.

Evaluation of LIAISON® XL system for HBsAg, and anti-HCV and anti-HIV/Ag p24.

The aim of this study was to compare the data obtained using the new LIAISON® XL chemiluminescence system to search for HBsAg, anti-HCV, and anti-HIV1-2/p24 Ag with those obtained using the VITROS system currently adopted by the Microbiology Unit of the Hospital of Legnano. Routine samples of patients who were referred by practitioners for the determination of HBsAg (1,000 samples) and/or anti-HCV (1,002 samples) and/or anti-HIV1-2 (995 samples) were simultaneously analyzed using both systems. The concordant positive and discordant samples were re-examined for confirmation by means of an HBsAg neutralization assay, anti-HCV immunoblot, or anti-HIV1-2 Western blot; HBV-DNA, or HCV-RNA or HIV-RNA was also sought in the discordant samples. Samples of patients known to be positive were tested (100 HBsAg positive, 100 anti-HCV positive, and 100 HIV 1-2 positive) as well throughout treatment, with viremia levels becoming undetectable after treatment. The HBsAg, anti-HCV, and anti-HIV1-2 concordance between the two systems in routine series was respectively 99.8%, 98.5% and 99.7%, and 100% for all markers in samples known positive. The various molecular biology and confirmatory tests of the discordant samples were all negative (except for one anti-HCV positive sample). Measure of Cohen's kappa coefficient for HBsAg, anti-HCV, and anti-HIV gave K values of respectively 0.992, 0.946, and 0.980. In conclusion, the performance of the LIAISON® XL system in the routine laboratory determination for all three markers was comparable with that of the VITROS system. J. Med. Virol. 89:489-496, 2017. © 2016 Wiley Periodicals, Inc.

Rubella antibody screening during pregnancy in an urban area of Northern Italy.

Various countries have implemented anti-rubella vaccination campaigns with the main aim of preventing congenital infection. In 2003, Italy joined the European WHO programme for the elimination of congenital rubella and issued a special healthcare plan, one of the objectives of which was to reduce the proportion of rubella-susceptible pregnant women to less than 5% by 2005. The aim of this study was to determine the percentage of seronegative pregnant women after the implementation of this plan. Anti-rubella IgG and IgM antibodies were sought in 2385 pregnant women who attended our hospital for serological screening between 1 July 2008 and 30 June 2010. They included 750 women of foreign origin (31.4%). Eight percent of the women were anti-rubella seronegative: 6.2% of the Italians and 11.7% of the non-Italians. Among the women of foreign origin, the percentage of seronegativity ranged from 5.6% of those coming from Eastern Europe to 17.7% of those coming from Latin America. The level of seropositivity among women of Italian origin is high, although the objective of ensuring less than 5% of susceptible pregnant women has not yet been quite reached in our area. However, particular attention needs to be given to women coming from geographical areas characterised by different epidemiologies and vaccination strategies because the percentage of seronegativity is in some cases double that of Italian women.

Incidence and risk of cytomegalovirus infection during pregnancy in an urban area of Northern Italy.

The fetal consequences of CMV infection make it one of the most serious infections contracted during pregnancy, but the scientific community is divided over the proposed implementation of preventive screening for anti-CMV antibodies. The aim of this study was to assess the incidence and risk of infection during pregnancy in 2817 women who underwent anti-CMV IgG and IgM antibody screening during the period 2005-2007. The prevalence of anti-CMV IgG antibodies was 68.3% (95% CI: 66.6-70.0); the seroconversion rate in the 892 seronegative women was 0.32%; the results of IgG avidity testing revealed an cumulative incidence of 1.4% (95% CI: 0.97-1.83), density incidence of 0.8% (as cases/pregnant woman-trimester) (95% CI: 0.47-1.13), and a risk of infection of 0.5% (95% CI: 0.24-0.76). The screening identified 13 cases of primary infection (84.6% of which occurred in the first trimester of pregnancy). The possibility to identify these cases and consequently to plan appropriate interventions, supports the use of screening during pregnancy, especially in the first trimester when the risk of infection is greater.