Prevalence of parvovirus B19 antibodies in pregnant women in northern Benin.

OBJECTIVES: Parvovirus B19 (B19V) infection in pregnancy is generally asymptomatic, but in about 3% it can cause complications, including miscarriage, severe foetal anaemia and foetal hydrops. The seroprevalence in pregnancy ranges from 20% to 82% in Africa, but there are no data for Benin. We therefore retrospectively assessed the seroprevalence of B19V in pregnant women attending the Saint Jean de Dieu Hospital in Tanguiéta, a rural district of Atacora, in northern Benin. METHODS: We searched for anti-B19V immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies in 227 sequential sera from as many women (mean age 26.3 years, range: 16-41) of whom 30 were in the first trimester, 66 in the second and 131 in the third. Samples that tested positive for IgM were analysed with an immunoblot test and the viral genome (DNA-B19V) was searched for using a polymerase chain reaction. RESULTS: Of the 227 women, 153 (67.4%) were positive for IgG anti-B19V, 7 (3.1%) for IgM and 73 (32.2%) were non-immune. Six IgM-positive women were also IgG positive. The difference in IgG seroprevalence between trimesters or ages was not statistically significant. Of the seven IgM-positive samples, three were confirmed positive by immunoblot (of which two were DNA-B19V positive), three were indeterminate (DNA-B19V negative) and one was negative (DNA-B19V negative). Of the three women with confirmed positive IgM, two were in the third trimester and one in the second trimester of pregnancy. CONCLUSIONS: The seroprevalence of anti-B19V IgG among pregnant women in Benin is high and in line with those reported in some African countries. IgM seroprevalence is also similar to that described in some African countries in non-epidemic periods. The low viral load observed depicts non-acute infections, but it is difficult to establish the precise time of the infection, especially for women tested in the second or third trimester of pregnancy, when the observed viremia could be a sign of an acute infection that occurred in the previous trimester. Consequently, clinical follow-up and further investigations to highlight possible foetal consequences are indicated.

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.

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.

Epidemiology of hepatitis E virus infection during pregnancy in Benin.

OBJECTIVES: Hepatitis E virus (HEV) is the cause of enterically transmitted non-A, non-C hepatitis (an infection that is particularly severe during pregnancy) in tropical and subtropical countries. As there are no published data concerning the prevalence of HEV antibodies in Benin, their presence was investigated in pregnant women undergoing routine HIV screening in a rural area in northern Benin and in pregnant women with acute non-A, non-C hepatitis. METHODS: A total of 278 serum samples were collected from asymptomatic pregnant women in 2011 were tested for HEV and hepatitis A virus (HAV) antibodies, and the HEV IgM-positive samples were further tested for HEV-RNA. A further seven samples of pregnant women with acute non-A, non-C hepatitis collected during episodes of acute hepatitis in 2005 were also analysed. RESULTS: Of the 278 samples collected in 2011, 16.19% were positive for HEV IgG and 1.44% for HEV IgM (none positive for HEV-RNA), and 99.64% were positive for total HAV antibodies (none positive for HAV IgM). Six of the seven samples collected in 2005 were positive for HEV IgG and IgM, and two were also positive for HEV-RNA. CONCLUSIONS: The circulation of HEV infection is significant among pregnant women in Benin, in whom the consequences may be fatal.

Prevalence of HBV, HDV, HCV, and HIV infection during pregnancy in northern Benin.

Pregnant women are not screened for HBsAg and anti-HCV antibodies in many African countries. As there are few data concerning the prevalence of HBV, HDV, and HCV serological markers in Benin, the aim of this study was to evaluate their 2011 prevalence in pregnant women undergoing HIV screening in a rural area of north Benin, and compare the data with those reported for the same area in 1986. The sera of 283 women were examined for HBsAg, anti-HBs, anti-HBc, anti-HCV, and anti-HIV 1/2 antibodies. In the case of HBsAg positivity, a search was made for the HBeAg, anti-HDV, and HBV genotypes; in the case of anti-HCV positivity, a search was made for the HCV genotypes. HBsAg, anti-HBs, anti-HBc, anti-HCV, and anti-HIV 1/2 were positive in respectively 44 (15.5%), 82 (29.0%), 234 (82.7%), 21 (7.4%), and nine samples (3.2%). Of the HBsAg-positive samples, five (11.4%) were positive for HBeAg, five (11.4%) for anti-HDV, and 19 for HBV genotype E. Of the anti-HCV-positive samples, five were positive for genotype 2a/2c and one for genotype 1a. The prevalence of anti-HBc alone (HBsAg and anti-HBs negative) was very high (41.3%). In comparison with the 1986 data, the prevalence of HBsAg and anti-HBc remained unchanged, that of HBeAg and anti-HDV had decreased, and that of anti-HIV 1/2 had increased. As these data confirm that HBV and HCV are highly endemic in the study area, it may be appropriate to introduce HBsAg and anti-HCV screening for pregnant women. J. Med. Virol. 86:1281-1287, 2014. © 2014 Wiley Periodicals, Inc.

Antenatal screening for Toxoplasma gondii, Cytomegalovirus, rubella and Treponema pallidum infections in northern Benin.

OBJECTIVES: Toxoplasma gondii, cytomegalovirus (HCMV) and rubella virus infections are among the most serious of those contracted during pregnancy in terms of foetal consequences. Toxoplasma, HCMV and rubella antibody screening is unusual in Africa, and there are few published data. The aim of this study was to evaluate the prevalence of these markers among pregnant women in northern Benin on the occasion of routine syphilis screening. METHODS: Toxoplasma, HCMV and rubella IgG and IgM antibodies were determined in the serum of 283 women attending Saint Jean de Dieu de Tanguiéta hospital, using an enzyme immunoassay, and IgM were confirmed using an enzyme-linked fluorescent assay (ELFA). In the case of IgM positivity, the avidity of anti-HCMV and anti-Toxoplasma IgG was measured. Total anti-Treponema pallidum antibodies were determined using an enzyme immunoassay and confirmed by immunoblotting. In the case of positivity, the Venereal Disease Research Laboratory (VDRL) test was used. RESULTS: The prevalence of anti-Toxoplasma, anti-HCMV, anti-rubella IgG and total anti-Treponema antibodies was, respectively, 30.0%, 100%, 94% and 2.5%. The VDRL test was positive in 62.5% of the anti-Treponema-positive samples. The prevalence of anti-Toxoplasma, anti-HCMV and anti-rubella IgM was, respectively, 0.4%, 1.4% and 0%. There were no statistically significant differences in terms of age class or trimester of pregnancy. Anti-Toxoplasma and anti-HCMV IgG avidity was always high. CONCLUSIONS: The prevalence of HCMV and rubella antibodies is high in northern Benin, whereas that of Toxoplasma antibodies is lower. As nearly two-thirds of the pregnant women were anti-Toxoplasma seronegative, antibody screening should be introduced.

Assessing SARS-CoV-2-specific T-cell reactivity in late convalescents and vaccinees: Comparison and combination of QuantiFERON and activation-induced marker assays, and relation with antibody status.

OBJECTIVES: Monitoring of SARS-CoV-2 spread and vaccination strategies have relied on antibody (Ab) status as a correlate of protection. We used QuantiFERON™ (QFN) and Activation-Induced Marker (AIM) assays to measure memory T-cell reactivity in unvaccinated individuals with prior documented symptomatic infection (late convalescents) and fully vaccinated asymptomatic donors (vaccinees). METHODS: Twenty-two convalescents and 13 vaccinees were enrolled. Serum anti-SARS-CoV-2 S1 and N Abs were measured using chemiluminescent immunoassays. QFN was performed following instructions and interferon-gamma (IFN-γ) measured by ELISA. AIM was performed on aliquots of antigen-stimulated samples from QFN tubes. SARS-CoV-2-specific memory CD4+CD25+CD134+, CD4+CD69+CD137+ and CD8+CD69+CD137+ T-cell frequencies were measured by flow cytometry. RESULTS: In convalescents, substantial agreement was observed between QFN and AIM assays. IFN-γ concentrations and AIM+ (CD69+CD137+) CD4+ T-cell frequencies correlated with each other, with Ab levels and AIM+ CD8+ T-cell frequencies, whereas AIM+ (CD25+CD134+) CD4+ T-cell frequencies correlated with age. AIM+ CD4+ T-cell frequencies increased with time since infection, whereas AIM+ CD8+ T-cell expansion was greater after recent reinfection. QFN-reactivity and anti-S1 titers were lower, whereas anti-N titers were higher, and no statistical difference in AIM-reactivity and Ab positivity emerged compared to vaccinees. CONCLUSIONS: Albeit on a limited sample size, we confirm that coordinated, cellular and humoral responses are detectable in convalescents up to 2 years after prior infection. Combining QFN with AIM may enhance detection of naturally acquired memory responses and help stratify virus-exposed individuals in T helper 1-type (TH1)-reactive (QFNpos AIMpos Abshigh), non-TH1-reactive (QFNneg AIMpos Abshigh/low), and pauci-reactive (QFNneg AIMneg Abslow).

A 12-month follow-up of the immune response to SARS-CoV-2 primary vaccination: evidence from a real-world study.

A real-world population-based longitudinal study, aimed at determining the magnitude and duration of immunity induced by different types of vaccines against COVID-19, started in 2021 by enrolling a cohort of 2,497 individuals at time of their first vaccination. The study cohort included both healthy adults aged ≤65 years and elderly subjects aged >65 years with two or more co-morbidities. Here, patterns of anti-SARS-CoV-2 humoral and cell-mediated specific immune response, assessed on 1,182 remaining subjects, at 6 (T6) and 12 months (T12) after the first vaccine dose, are described. At T12 median anti-Spike IgG antibody levels were increased compared to T6. The determinants of increased anti-Spike IgG were the receipt of a third vaccine dose between T6 and T12 and being positive for anti-Nucleocapside IgG at T12, a marker of recent infection, while age had no significant effect. The capacity of T12 sera to neutralize in vitro the ancestral B strain and the Omicron BA.5 variant was assessed in a subgroup of vaccinated subjects. A correlation between anti-S IgG levels and sera neutralizing capacity was identified and higher neutralizing capacity was evident in healthy adults compared to frail elderly subjects and in those who were positive for anti-Nucleocapside IgG at T12. Remarkably, one third of T12 sera from anti-Nucleocapside IgG negative older individuals were unable to neutralize the BA.5 variant strain. Finally, the evaluation of T-cell mediated immunity showed that most analysed subjects, independently from age and comorbidity, displayed Spike-specific responses with a high degree of polyfunctionality, especially in the CD8 compartment. In conclusion, vaccinated subjects had high levels of circulating antibodies against SARS-CoV-2 Spike protein 12 months after the primary vaccination, which increased as compared to T6. The enhancing effect could be attributable to the administration of a third vaccine dose but also to the occurrence of breakthrough infection. Older individuals, especially those who were anti-Nucleocapside IgG negative, displayed an impaired capacity to neutralize the BA.5 variant strain. Spike specific T-cell responses, able to sustain immunity and maintain the ability to fight the infection, were present in most of older and younger subjects assayed at T12.

Universal Newborn Screening for Congenital Cytomegalovirus Infection - From Infant to Maternal Infection: A Prospective Multicenter Study.

Introduction: Most infants at risk for cytomegalovirus (CMV)-associated sensorineural hearing loss (SNHL) are unrecognized because of the absence of a universal neonatal CMV screening. The search of CMV-DNA by molecular methods in salivary swabs was demonstrated to be a reliable approach. This study describes the results obtained by carrying out a universal screening for congenital CMV (cCMV) infection including all live-born newborns in three Italian sites, as well as the therapeutic interventions and clinical outcome of the CMV-infected neonates. Moreover, CMV maternal infection's characteristics were evaluated. Methods: To confirm or exclude cCMV infection, a CMV-DNA-positive result on a first salivary swab was followed by repeated saliva and urine samples collected within 21 days of age. Breast milk samples were also collected. The search of CMV-DNA was performed with a single automated quantitative commercial real-time PCR assay, regardless of the type of samples used. Results: A total of 3,151 newborns were enrolled; 21 (0.66%) of them were congenitally infected (median saliva viral load at screening, 6.65 [range, 5.03-7.17] log10 IU/ml). Very low/low viral load in screening saliva samples (median value, 1.87 [range, 1.14-2.59] log10 IU/ml) was associated with false-positive results (n = 54; 1.7%). CMV-DNA was detected in almost half of the breast milk samples of mother-infant pairs with a false-positive result, suggesting that contamination from breast milk may not be the only explanation in the study population. cCMV infection confirmation with the search of CMV-DNA in a urine sample proved to be the gold standard strategy, since false-positive results were observed in 4/54 (7.5%) of the repeated saliva samples. Symptomatic cCMV infection was observed in 3/21 (14.3%) infants; notably, one (4.7%) developed moderate unilateral SNHL at 5 months after birth. Finally, two symptomatic cCMV infections were associated with primary maternal infection acquired in the first trimester of gestation; one newborn with severe cCMV symptoms was born to a mother with no CMV checkups in pregnancy. Conclusion: Without universal neonatal CMV screening, some infected infants who develop late neurological sequelae may not be recognized and, consequently, they are not able to benefit early from instrumental and therapeutic interventions to limit and/or treat CMV disease.

Evaluation of humoral and cellular response to four vaccines against COVID-19 in different age groups: A longitudinal study.

To date there has been limited head-to-head evaluation of immune responses to different types of COVID-19 vaccines. A real-world population-based longitudinal study was designed with the aim to define the magnitude and duration of immunity induced by each of four different COVID-19 vaccines available in Italy at the time of this study. Overall, 2497 individuals were enrolled at time of their first vaccination (T0). Vaccine-specific antibody responses induced over time by Comirnaty, Spikevax, Vaxzevria, Janssen Ad26.COV2.S and heterologous vaccination were compared up to six months after immunization. On a subset of Comirnaty vaccinees, serology data were correlated with the ability to neutralize a reference SARS-CoV-2 B strain, as well as Delta AY.4 and Omicron BA.1. The frequency of SARS-CoV-2-specific CD4+ T cells, CD8+ T cells, and memory B cells induced by the four different vaccines was assessed six months after the immunization. We found that mRNA vaccines are stronger inducer of anti-Spike IgG and B-memory cell responses. Humoral immune responses are lower in frail elderly subjects. Neutralization of the Delta AY.4 and Omicron BA.1 variants is severely impaired, especially in older individuals. Most vaccinees display a vaccine-specific T-cell memory six months after the vaccination. By describing the immunological response during the first phase of COVID-19 vaccination campaign in different cohorts and considering several aspects of the immunological response, this study allowed to collect key information that could facilitate the implementation of effective prevention and control measures against SARS-CoV-2.

Characterisation of AIDS presenters and their response to antiretroviral therapy at legnano general hospital (Italy) during the period 2000-2008.

The aim of this study was to characterise the AIDS presenters diagnosed between 2000 and 2008 in Legnano (Italy), and describe their initial response to highly active antiretroviral therapy (HAART) and trends over time. Seventy-six (48.7%) of 156 patients diagnosed as having AIDS in the period 2000-2008 were AIDS presenters. The proportion of AIDS presenters increased from 23.8% in 2000 to 70.6% in 2008 (p = 0.009). The major risk factors were heterosexual transmission and a foreign place of birth, and did not significantly change over time. The median CD4+ cell count at diagnosis was 30 cells/microl and the median level of HIV RNA was 5.38 log copies/ml, with no differences between the transmission risk groups. Fifteen AIDS presenters died of AIDS-defining diseases; the others started HAART (72% with 2 NRTIs + boosted PI), and 40% after a drug resistance test. The median duration of the initial HAART was 107 days. After three months, 34% of the patients had undetectable HIV-RNA levels and the median CD4+ cell count was 140 cells/microl; the corresponding figures after 12, 24 and 48 months were respectively 84%, 82.3% and 94.1%, and 310, 370 and 380 cells/microl. In conclusion, the AIDS presenters were mainly heterosexual men and immigrants. Their proportion increased significantly over time, and a substantial proportion maintained an immunovirological response to HAART.

Seroepidemiology of EBV and interpretation of the "isolated VCA IgG" pattern.

The presence of VCA IgG in the absence of VCA IgM and EBNA-1 IgG antibodies makes classifying EBV infection more difficult as this serological picture can be seen in the case of past infection with EBNA-1 IgG loss or non-appearance, or acute infections with the early disappearance or delayed onset of VCA IgM. The aim of this study was to assess the prevalence of this pattern in 2,422 outpatients with suspected EBV infection examined in 2005-2006, and to interpret its significance by means of immunoblotting. One hundred and seventy-seven (7.3%) of the patients were VCA IgG-positive, VCA IgM-negative and EBNA-1 IgG-negative, 15 of whom (8.5%) presented with heterophile antibodies. Analysis by age class showed that the prevalence of isolated VCA IgG ranged from 4.5% in the subjects aged 1-10 years to 9% in those aged >60 years. Immunoblotting allowed 18.9% of the cases to be classified as acute and 81.1% as past infections, the latter being observed in about 37% of the patients aged less than 10 years and in 100% of those aged >30 years. Therefore, in our case series, the presence of isolated VCA IgG was associated usually with past infection, particularly among adults. In children aged less than 10 years, it was associated mainly with acute infection but as past infection may be present in about one-third of such children, this possibility should not be overlooked.

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.

Revision of the positive predictive value of IgM anti-Toxoplasma antibodies as an index of recent infection.

The severity of congenital Toxoplasma gondii infection underlines the need for a precise diagnosis of acute infection during pregnancy. The search for specific IgM has been widely used for this purpose, but their possible early disappearance or persistence over time limits their meaning. In order to estimate the positive predictive value of anti-Toxoplasma IgM testing, we made an epidemiological analysis of the presence of anti-Toxoplasma IgG and IgM using ELISA in 4786 subjects attending the Hospital of Legnano in 2004-2005: 1360 seen for a clinical check-up and 3426 pregnant women for serological screening. In relation to IgG avidity, the positive predictive value of IgM was 45.98% (95% CI: 35.51-56.45) as a whole: this increased to 83.87% (95% CI: 70.92-96.82) in the patients with a highly positive test for IgM, but decreased to 9.52% (95% CI: 0.00-22.07) in pregnant women with a weakly positive test for IgM. Our results indicate that a highly positive IgM value in patients can be a good index of recent infection, but its poor predictive value in pregnant women underlines the need for additional tests with a follow-up if necessary.

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.

Microbiology laboratory and the management of mother-child varicella-zoster virus infection.

Varicella-zoster virus, which is responsible for varicella (chickenpox) and herpes zoster (shingles), is ubiquitous and causes an acute infection among children, especially those aged less than six years. As 90% of adults have had varicella in childhood, it is unusual to encounter an infected pregnant woman but, if the disease does appear, it can lead to complications for both the mother and fetus or newborn. The major maternal complications include pneumonia, which can lead to death if not treated. If the virus passes to the fetus, congenital varicella syndrome, neonatal varicella (particularly serious if maternal rash appears in the days immediately before or after childbirth) or herpes zoster in the early years of life may occur depending on the time of infection. A Microbiology laboratory can help in the diagnosis and management of mother-child infection at four main times: (1) when a pregnant woman has been exposed to varicella or herpes zoster, a prompt search for specific antibodies can determine whether she is susceptible to, or protected against infection; (2) when a pregnant woman develops clinical symptoms consistent with varicella, the diagnosis is usually clinical, but a laboratory can be crucial if the symptoms are doubtful or otherwise unclear (atypical patterns in immunocompromised subjects, patients with post-vaccination varicella, or subjects who have received immunoglobulins), or if there is a need for a differential diagnosis between varicella and other types of dermatoses with vesicle formation; (3) when a prenatal diagnosis of uterine infection is required in order to detect cases of congenital varicella syndrome after the onset of varicella in the mother; and (4) when the baby is born and it is necessary to confirm a diagnosis of varicella (and its complications), make a differential diagnosis between varicella and other diseases with similar symptoms, or confirm a causal relationship between maternal varicella and malformations in a newborn.

Serological diagnosis of Epstein-Barr virus infection: Problems and solutions.

Serological tests for antibodies specific for Epstein-Barr virus (EBV) antigens are frequently used to define infection status and for the differential diagnosis of other pathogens responsible for mononucleosis syndrome. Using only three parameters [viral capsid antigen (VCA) IgG, VCA IgM and EBV nuclear antigen (EBNA)-1 IgG],it is normally possible to distinguish acute from past infection: the presence of VCA IgM and VCA IgG without EBNA-1 IgG indicates acute infection, whereas the presence of VCA IgG and EBNA-1 IgG without VCA IgM is typical of past infection. However, serological findings may sometimes be difficult to interpret as VCA IgG can be present without VCA IgM or EBNA-1 IgG in cases of acute or past infection, or all the three parameters may be detected simultaneously in the case of recent infection or during the course of reactivation. A profile of isolated EBNA-1 IgG may also create some doubts. In order to interpret these patterns correctly, it is necessary to determine IgG avidity, identify anti-EBV IgG and IgM antibodies by immunoblotting, and look for heterophile antibodies, anti-EA (D) antibodies or viral genome using molecular biology methods. These tests make it possible to define the status of the infection and solve any problems that may arise in routine laboratory practice.

Prevalence of markers of hepatitis B virus infection or vaccination in HBsAg-negative subjects.

BACKGROUND: The implementation of mass vaccinations against hepatitis B virus (HBV) has significantly reduced the prevalence of HBsAg-positive subjects. At the same time, the prevalence of the other markers of infection has decreased, but there has been an increase in the percentage of subjects with markers of a successful vaccination. It has been suggested that increasing immigration from countries in which this virus is highly endemic is changing the epidemiology of HBV infection. The aim of this study was to assess the prevalence of the serological markers of HBV in Italian and non-Italian HBsAg-negative subjects. MATERIALS AND METHODS: In the years 2007-2008, 8,018 samples from HBsAg-negative subjects (7,521 Italians and 497 non-Italians) were received for detection of anti-HBs and/or anti-HBc. The findings in the 1,358 samples from candidate blood donors were compared with those obtained in 1991 and 1999. RESULTS: The rate of anti-HBc positivity was 18.3% in the Italian samples and 32.8% in the non-Italian samples; the corresponding percentages of anti-HBs/anti-HBc positive samples (indicating past infection), anti-HBs positive only samples (vaccination) and anti-HBc positive only were, 11.3% vs. 22.5%, 25.8% vs. 17.2%, and 6.9% vs. 9.9% in Italians and non-Italians, respectively. The differences were more marked when stratified by age. In relation to candidate blood donors, simultaneous positivity for anti-HBs and anti-HBc decreased from 11.0% in 1991 to 8.1% in 1999 and 3.9% in 2007-2008, whereas isolated anti-HBs positivity increased from 2.2% in 1991 to 21.4% in 1999 and 42.9% in 2007-2008. CONCLUSIONS: The frequency of markers of past infection among Italians has decreased over time as a result of mass vaccination and is significantly lower than that observed in non-Italians. The increasing number of immigrants from countries in which HBV is highly endemic is changing the epidemiology of HBV infection in Italy.