Sensitivity and specificity of the new Bio-Rad HIV screening test, Access HIV combo V2.

Diagnosing of human immunodeficiency virus (HIV) types 1 and 2 requires a screening with a highly sensitive and specific enzyme immunoassay and a low detection limit for the HIV-1 p24 antigen to minimize the diagnostic window. The objective of the study was to determine the sensitivity, specificity, and p24 limit of detection of the Access HIV combo V2 assay. Retrospective part of sensitivity: 452 HIV-1 positive samples from 403 chronic (9 different HIV-1 group M subtypes, 22 different HIV-1 group M CRFs, and 3 HIV-1 group O), 49 primary HIV-1 infections, 103 HIV-2 positive samples assessed at Pitié-Salpêtrière Hospital, 600 untyped HIV-1, 10 subtype-D, and 159 untyped HIV-2 samples assessed in Bio-Rad Laboratories. Prospective part of clinical specificity: all consecutive samples in two blood donor facilities and Pitié-Salpêtrière (6,570 patients) tested with Access HIV combo V2 and respectively Prism HIV O Plus (Abbott) or Architect HIV Ag/Ab Combo (Abbott) for Ag/Ab screening, and Procleix Ultrio (Gen Probe) for HIV RNA screening. Limit of detection for p24 antigen was assessed on recombinant virus-like particles (10 HIV-1 group M subtypes/CRFs, HIV-1 group O). Sensitivity [95% confidence interval (CI)] of Access HIV combo V2 was 100% (99.63-100) for HIV-1 chronic infection, 100% (98.55-100) for HIV-2 chronic infection, and 100% (93.00-100) for HIV-1 primary infection. Specificity (95% CI) was 99.98 (99.91-100). Limit of detection for p24 antigen was around 0.43 IU/mL [interquartile range (0.38-0.56)], and consistent across the 11 analyzed subtypes/CRFs. Hence, with both high sensitivity and specificity, Access HIV combo V2 is a suitable screening assay for HIV-1/2 infection. IMPORTANCE: Bio-Rad is one of the leading human immunodeficiency virus (HIV) screening test manufacturers. This laboratory released in 2021 their new version of the Access combo HIV test. However, to date, there have been no studies regarding its performance, especially its limit of detection of the diverse p24 antigen. We present the sensitivity (chronic and primary HIV-1 infection and HIV-2 chronic infection), specificity (blood donors and hospitalized patients), and raw data for the p24/seroconversion panels the manufacturer gave to the European agencies.

Are Confirmatory Assays Reliable for HIV-1/HIV-2 Infection Differentiation? A Multicenter Study.

Immunoblots remain the gold standard for HIV-1/HIV-2 infection confirmation. However, their ability to differentiate HIV-1 from HIV-2 infection on an antigenically diversified HIV-1 and HIV-2 panel remain uncommon. We performed a multicenter study on 116 serum samples accounting for most of the diversity of HIV-1 (9 different subtypes in group M, 17 circulating recombinant forms (CRFs), and 3 group O) and HIV-2 (groups A and B), evaluating seven confirmatory assays (six commercially available assays and one in-house assay) with genotyping as the reference. The assays were INNO-LIA HIV I/II score, HIV-2 blot 1.2, HIV blot 2.2, New Lav blot I and II, Geenius, and an in-house serotyping enzyme-linked immunosorbent assay (ELISA). Among the HIV-1 samples, INNO-LIA, HIV blot 2.2, New Lav blot I, Geenius, and serotyping had comparable high sensitivities, from 98% to 100%, whereas HIV-2 blot 1.2 and New Lav blot II had high rates of "undetermined" results (85% and 95%, respectively). HIV-2 blot 1.2 and New Lav blot II misclassified 7% and 5% of HIV-1 samples as HIV-2, respectively, and HIV-2 blot 1.2 had an 8% false-negative rate. Among the HIV-2 samples, INNO-LIA, New Lav blot II, HIV-2 blot 1.2, and serotyping had high sensitivities, from 96% to 100%. HIV blot 2.2 misclassified 17% of HIV-2 samples as HIV-1/HIV-2 dual infections. New Lav blot I misclassified 19% of HIV-2 samples as HIV-1 with a high (81%) undetermined rate, and Geenius misclassified 2% as HIV-1 and 7% as untypeable HIV positive. For HIV-1/HIV-2 dual infection, the results were less sensitive, with at most 87.5% for INNO-LIA and Geenius and 75% for HIV blot 2.2 and serotyping. Overall, confirmatory assays remain useful for most cases, with the exception of HIV-1/HIV-2 dual-infection suspicion.

Comparison of two new HTLV-I/II screening methods, Abbott Alinity i rHTLV-I/II and Diasorin LIAISON® XL murex recHTLV-I/II, to Abbott architect rHTLVI/II assay.

BACKGROUND: Diagnosis of Human T-cell Lymphotropic Virus (HTLV) types I and II infection requires sequencial testing with firstly a screening using an Enzyme immunoassay followed by a confirmatory test. OBJECTIVES: To compare the performances of the Alinity i rHTLV-I/II (Abbott®) and LIAISON® XL murex recHTLV-I/II serological screening tests to the ARCHITECT rHTLVI/II test followed if positive by HTLV BLOT 2.4, MP Diagnostics as the reference. STUDY DESIGN: 119 serum samples from 92 known HTLV-I infected patients and 184 from uninfected patients with HTLV were analyzed in parallel with, Alinity i rHTLV-I/II, LIAISON® XL murex recHTLV-I/II and ARCHITECT rHTLVI/II. RESULTS: Alinity i rHTLV-I/II and LIAISON® XL murex recHTLV-I/II exhibited a total agreement with ARCHITECT rHTLVI/II for both positive and negative samples. Both tests are suitable alternatives for HTLV screening.

[Rapid SARS-CoV-2 antigenic test: definition, legislation of use, technological principles, analytical and clinical performance comparison]. / Tests rapides antigéniques SARS-CoV-2 : définition, législation d'utilisation, principes technologiques, comparaison des performances analytiques et cliniques.

The SARS-CoV-2 has emerged in China at the end of 2019. In order to meet the growing demand in laboratories for RT-PCR testing for viral genome detection, rapid tests detecting a SARS-CoV-2 protein (antigenic rapid test) have been developed. In this review, we present for different SARS-CoV-2 antigenic rapid tests authorized in France: legislation, technological principle, and analytical and clinical performances. Data bellow are those provided by the manufacturer/distributor. From the list of tests authorized by the French Ministry of Health, we have selected 25 for which the distributors/manufacturers have provided the technical data essential to their comparative analysis. The kits use immunochromatography technology, with detection of the nucleocapsid protein (n = 24) or the spike protein (n = 1). The matrix used is a nasopharyngeal (n = 23), oropharyngeal (n = 9) or nasal (n = 3) swab. According to the test, the reading of the result is done from 15 to 30 minutes after it is performed. The clinical sensitivity, for the more performant tests is conversely linked to the Ct of RT-PCR, ranging from 80.2% to 98.4%, according to the quantity of virus present in the sample. This percentage is inversely proportional to the Ct obtained using RT-PCR. The limit of detection ranges from 31.55 to 7200 TCID50/mL. The clinical specificity, compared to a negative result of RT-PCR, is between 99.2% and 100%. Analytical specificity evaluated on other microorganisms is 100%, except for 3 kits that show cross-reactivities with SARS-CoV-1 (n = 3) and MERS-CoV (n = 1). Positive and negative predictive values range from 96.3% to 100% and 95% to 99.4%, respectively.

Chronic persistent HHV-6B infection after sulfasalazine-induced DRESS with demonstration of HHV-6 encoded small noncoding RNAs (sncRNAs) in Crohn's-like colitis: Case report.

A sulfasalazine-induced DRESS (Drug Reactivation with Eosinophilia and Systemic Symptoms) was complicated by a Crohn's-like colitis. We demonstrated HHV-6 reactivation with presence of HHV-6 DNA and small noncoding RNA in colonic lesions. This observation confirms the major role of HHV-6 reactivation in DRESS manifestations and the importance of looking for HHV-6 reactivation in DRESS.

Donor-to-recipient transmission and reactivation in a kidney transplant recipient of an inherited chromosomally integrated HHV-6A: Evidence and outcomes.

Human herpesvirus (HHV)-6A can be inherited and chromosomally integrated (iciHHV-6A), and donor-to-recipient transmission has been reported in solid organ transplant. However, when HHV-6A reactivation happens after transplant, the source of HHV-6A is often not evident and its pathogenicity remains unclear. Here, we present an exhaustive case of donor-to-recipient transmission and reactivation of iciHHV-6A through kidney transplant. The absence of HHV-6A genome from the nails of the recipient excluded a recipient-related iciHHV-6A. Viral loads > 7 log10 copies/106 cells in donor blood samples and similarities of U38, U39, U69, and U100 viral genes between donor, recipient, and previously published iciHHV-6A strains are proof of donor-related transmission. Detection of noncoding HHV-6 snc-RNA14 using fluorescence in situ hybridization analysis and immunofluorescence staining of HHV-6A gp82/gp105 late proteins on kidney biopsies showed evidence of reactivation in the transplanted kidney. Because HHV-6A reactivation can be life threatening in immunocompromised patients, we provide several tools to help during the complete screening and diagnosis.

Evaluation of liver failure in a pediatric transplant recipient of a liver allograft with inherited chromosomally integrated HHV-6B.

BACKGROUND: Active infections of human herpesvirus 6B (HHV-6B) are frequent in immunocompromised recipients after transplantation. Nevertheless, they need to be distinguished from latent inherited chromosomally integrated genomes (iciHHV-6) present in about 1% of the population to avoid unnecessary administration of toxic antivirals. METHODS: A 5-year-old child presented with acute liver allograft rejection associated with HHV-6 DNA in plasma, which led to an unfavorable outcome. We investigated the possibility of HHV-6 infection derived from an iciHHV-6 present in the donor's liver using molecular and histopathology studies in various tissues, including quantification of HHV-6 DNA, genotyping, sequencing for antiviral resistance genes, relative quantification of viral transcripts, and detection of gB and gH viral proteins. RESULTS: The presence of iciHHV-6B was evidenced in the donor with signs of reactivation in the gallbladder and transplanted liver (detection of HHV-6B mRNA and late proteins). This localized expression could have played a role in liver rejection. Low viral loads in the recipient's plasma, with identical partial U39 sequences, were in favor of viral DNA released from the transplanted liver rather than a systemic infection. CONCLUSIONS: Determination of iciHHV-6 status before transplantation should be considered to guide clinical decisions, such as antiviral prophylaxis, viral load monitoring, and antiviral therapy.

Phenotypic and Functional Differences between Human Herpesvirus 6- and Human Cytomegalovirus-Specific T Cells.

Human herpesvirus 6 (HHV-6) infects >90% of the population and establishes a latent infection with asymptomatic episodes of reactivation. However, HHV-6 reactivation is associated with morbidity and sometimes mortality in immunocompromised patients. To date, control of the virus in healthy virus carriers and the failure to control it in patients with disease remain poorly understood. In particular, knowledge of HHV-6-specific T-cell responses is limited. Here, we characterized HHV-6A- and HHV-6B-specific CD4+ and CD8+ T-cell responses from peripheral blood mononuclear cells (PBMCs) of healthy donors. We studied the phenotype of effector HHV-6-specific T cells ex vivo, as well as of induced specific suppressive regulatory CD4+ T cells in vitro poststimulation, in comparison to human cytomegalovirus (HCMV) responses. Compared to that for HCMV, we show that ex vivo T-cell reactivity in peripheral blood is detectable but at very low frequency, both for HHV-6A and -6B viruses. Interestingly, the phenotype of the specific T cells also differs between the viruses. HHV-6A- and HHV-6B-specific CD4+ T lymphocytes are less differentiated than HCMV-specific T cells. Furthermore, we show a higher frequency of HHV-6-specific suppressive regulatory T cells (eTregs) than HCMV-specific eTregs in coinfected individuals. Despite the strong similarity of HHV-6 and HCMV from a virologic point of view, we observed immunological differences, particularly in relation to the frequency and phenotype of effector/memory and regulatory virus-specific T cells. This suggests that different immune factors are solicited in the control of HHV-6 infection than in that of HCMV infection.IMPORTANCE T cells are central to an effective defense against persistent viral infections that can be related to human cytomegalovirus (HCMV) or human herpesvirus 6 (HHV-6). However, knowledge of HHV-6-specific T-cell responses is limited. In order to deepen our knowledge of T-cell responses to HHV-6, we characterized HHV-6A- and HHV-6B-specific CD4+ and CD8+ T-cell responses directly ex vivo from healthy coinfected blood donors. Despite the strong similarity of HHV-6 and HCMV from a virologic point of view, we observed immunological differences, particularly in relation to the frequency and phenotype of effector/memory and regulatory virus-specific T cells. This suggests that different immune factors are solicited in the control of HHV-6 infection than in that of HCMV infection. Our findings may encourage immunomonitoring of patients with viral replication episodes to follow the emergence of effector versus regulatory T cells.

Vaginal Neoplasia Induced by an Unusual Papillomavirus Subtype in a Woman with Inherited Chromosomally Integrated Human Herpesvirus Type 6A.

We describe here a case of high-grade vaginal squamous lesion in a 54-year-old woman with a papillomaviruses (HPV) genital infection that developed from a cervical low-grade squamous intraepithelial lesion (SIL) to a high-grade SIL (H-SIL) on cytological examination. A colposcopy exam led to the detection of suspect vaginal lesions with granulomatous infiltrations, which were classified as a Vaginal Intra-Epithelial Neoplasia grade 2 after pathologists' analyses. After a laser vaginal surgery and a loop excision of the transformation zone, the analyses of the anatomical pieces using a near-complete HPV screening panel revealed an HPV-4 infection that was not detected before in cervical smears. This HPV-infection is associated with a high human herpesvirus type 6A (HHV-6A) viral load in the same anatomical piece. The presence of an inherited chromosomally integrated HHV-6A (iciHHV-6A) was proved in this patient by real-time polymerase chain reaction on hair follicles and nail. This case suggests reconsidering both the benign nature of low-grade lesions in the female genital tract and the well-known "good" prognosis of low-risk HPV infection, especially when iciHHV-6A is diagnosed. This clinical course insists on the benefits of the multiplex panel use or global sequencing in order to optimize biological testing sensitivity, and so enhance clinical management of infection-induced neoplasia.

Cytokine and cellular responses to human herpesvirus-6B in patients with B-acute lymphoblastic leukemia.

Primary infection with human herpesvirus-6 (HHV-6), is followed by its lifelong persistence in the host. Most T-cell responses to HHV-6 have been characterized using peripheral blood from healthy adults; however, the role of HHV-6 infection in immune modulation has not been elucidated for some diseases. Therefore, in this study the immune response to HHV-6 infection in patients with B-acute lymphoblastic leukemia (B-ALL) was analyzed. HHV-6 load was quantified in blood samples taken at the time of diagnosis of leukemia and on remission. The same concentrations of anti- and pro-inflammatory cytokines (IL-4, IL-1, IL-6, IL-8, IL-12p70, IL-17a, TNF-α and IFN-γ) were detected in plasma samples from 20 patients with and 20 without detectable HHV-6 virus loads in blood. Characterization of T-cell responses to HHV-6 showed low specific T-cells frequencies of 2.08% and 1.46% in patients with and without detectable viral loads, respectively. IFN-γ-producing T cells were detected in 0.03%-0.23% and in 0%-0.2% of CD4+T cells, respectively. Strong production of IL-6 was detected in medium supernatants of challenged T-cells whatever the HHV-6 status of the patients (973.51 ± 210.06 versus 825.70 ± 210.81 pg/mL). However, concentrations of TNF-α and IFN-γ were low. Thus, no association between plasma concentrations of cytokines and detection of HHV-6 in blood was identified, suggesting that HHV-6 is not strongly associated with development of B-ALL. The low viral loads detected may correspond with latently infected cells. Alternatively, HHV-6B specific immune responses may be below the detection threshold of the assays used.

Human Herpesviruses 6A, 6B, and 7.

Human roseoloviruses include three different species, human herpesviruses 6A, 6B, and 7 (HHV-6A, HHV-6B, HHV-7), genetically related to human cytomegalovirus. They exhibit a wide cell tropism in vivo and, like other herpesviruses, induce a lifelong latent infection in humans. In about 1% of the general population, HHV-6 DNA is covalently integrated into the subtelomeric region of cell chromosomes (ciHHV-6). Many active infections, corresponding to primary infections, reactivations, or exogenous reinfections, are asymptomatic. They also may cause serious diseases, particularly in immunocompromised individuals, including hematopoietic stem-cell transplant (HSCT) and solid-organ transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients. This opportunistic pathogenic role is formally established for HHV-6 infection and less clear for HHV-7. It mainly concerns the central-nervous system, bone marrow, lungs, gastrointestinal tract, skin, and liver. As the best example, HHV-6 causes both exanthema subitum, a benign disease associated with primary infection, and severe encephalitis associated with virus reactivations in HSCT recipients. Diagnosis using serologic and direct antigen-detection methods currently exhibits limitations. The most prominent technique is the quantification of viral DNA in blood, other body fluids, and organs by means of real-time polymerase-chain reaction (PCR). The antiviral compounds ganciclovir, foscarnet, and cidofovir are effective against active infections, but there is currently no consensus regarding the indications of treatment or specifics of drug administration. Numerous questions about HHV-6A, HHV-6B, HHV-7 are still pending, concerning in particular clinical impact and therapeutic options in immunocompromised patients.

[Diagnosis and practice of virological monitoring of infections by the human herpesviruses 6A and 6B]. / La pratique du diagnotic et du suivi virologiques des infections par les herpesvirus humains 6A et 6B.

The diagnosis of the infection by the human herpesviruses 6A and 6B (HHV-6A, HHV-6B) is based on a direct and an indirect approaches. Serological methods are mainly used to ask primary infection diagnosis and carry out epidemiological studies. However, limitations are numerous with, in particular, the existence of cross-reactivity with other herpesviruses, and the inability to differentiate the two kinds of HHV-6. Initially based on virus isolation in cell culture, direct diagnosis evolved with the development of gene amplification methods that provide sensitivity and specificity, and allow viral quantitation in many biological systems and the identification of present species. Its main current indications are the identification of active infection, the identification of the integrated form of HHV-6 (iciHHV-6, inherited chromosomally integrated HHV-6) and the monitoring of the effectiveness of antiviral treatment.

Performance of rapid tests for discrimination between HIV-1 and/or HIV-2 infections.

Major differences exist between HIV-1 and HIV-2 in terms of epidemiology, pathogenicity, sensitivity to antiretrovirals. Determining the type of HIV infecting a patient is essential for management. The aim of this study was to evaluate the ability of simple/rapid tests to differentiate between HIV-1 and/or HIV-2 infections. We analyzed 116 samples from patients infected with HIV-1 (n = 61), HIV-2 (n = 47), or HIV-1+HIV-2 (n = 8) at the chronic stage of infection. Each sample was tested with SD Bioline HIV-1/2 3.0, ImmunoFlow HIV1-HIV2, ImmunoFlow HIV1-HIV2 (WB), Genie III HIV-1/HIV-2, ImmunoComb HIV1&2 BiSpot. HIV-1, or HIV-2 single infection was identified with a sensitivity ranging from 90% to 100%. The ability to detect dual infection was less sensitive (12.5-100%). SD Bioline HIV-1/2 3.0, ImmunoFlow HIV1-HIV2, and Genie III were unable to detect HIV-1 group O infection in one, one and two cases, respectively. The specificity of detection of HIV-1, HIV-2, or HIV-1+HIV-2 antibodies differed greatly (36-100%). ImmunoComb BiSpot had the highest sensitivity values (99-100% for HIV-1, 98% for HIV-2, and 75-87.5% for dual infection) and specificity values (94-100% for HIV-1, 100% for HIV-2, and 97-100% for dual infection). In conclusion, this study showed that no single rapid test had a perfect sensitivity/specificity ratio, particularly in the case of the double infections.

Laboratory and clinical aspects of human herpesvirus 6 infections.

Human herpesvirus 6 (HHV-6) is a widespread betaherpesvirus which is genetically related to human cytomegalovirus (HCMV) and now encompasses two different species: HHV-6A and HHV-6B. HHV-6 exhibits a wide cell tropism in vivo and, like other herpesviruses, induces a lifelong latent infection in humans. As a noticeable difference with respect to other human herpesviruses, genomic HHV-6 DNA is covalently integrated into the subtelomeric region of cell chromosomes (ciHHV-6) in about 1% of the general population. Although it is infrequent, this may be a confounding factor for the diagnosis of active viral infection. The diagnosis of HHV-6 infection is performed by both serologic and direct methods. The most prominent technique is the quantification of viral DNA in blood, other body fluids, and organs by means of real-time PCR. Many active HHV-6 infections, corresponding to primary infections, reactivations, or exogenous reinfections, are asymptomatic. However, the virus may be the cause of serious diseases, particularly in immunocompromised individuals. As emblematic examples of HHV-6 pathogenicity, exanthema subitum, a benign disease of infancy, is associated with primary infection, whereas further virus reactivations can induce severe encephalitis cases, particularly in hematopoietic stem cell transplant recipients. Generally speaking, the formal demonstration of the causative role of HHV-6 in many acute and chronic human diseases is difficult due to the ubiquitous nature of the virus, chronicity of infection, existence of two distinct species, and limitations of current investigational tools. The antiviral compounds ganciclovir, foscarnet, and cidofovir are effective against active HHV-6 infections, but the indications for treatment, as well as the conditions of drug administration, are not formally approved to date. There are still numerous pending questions about HHV-6 which should stimulate future research works on the pathophysiology, diagnosis, and therapy of this remarkable human virus.