Performance evaluation of the Access anti-HBc Total assay on the DxI 9000 Access Immunoassay Analyzer.

This study evaluated the diagnostic and analytical performances of the Access anti-HBc Total assay on the DxI 9000 Access Immunoassay System (Beckman Coulter Inc.). The multicenter study involved both prospective and retrospective sample collection from non-selected blood donors, hospitalized patients, or presumed anti-HBc Total positive individuals. Fresh/previously-frozen samples were tested with the Access and comparator assays to determine concordance; discrepant samples were tested with a second CE-marked assay. Among the 5983 non-selected fresh blood donor samples deemed anti-HBc Total negative, clinical specificity of the Access assay was 99.58% (95%CI: 99.38-99.72%). Clinical specificity was 99.27% (97.37-99.80%) among 273 anti-HBc Total negative hospitalized patient samples. Clinical sensitivity on 450 anti-HBc Total positive samples was 99.78% (98.75-99.96%). Evaluation in seroconversion panels revealed an average 1.4-day earlier detection versus a comparator assay. The Access assay demonstrated excellent clinical and analytical performances comparable to existing CE-marked anti-HBc Total assays. NCT04904835.

Performance evaluation of the Access HBsAg and Access HBsAg confirmatory assays on the DxI 9000 Access Immunoassay Analyzer.

Introduction: This study evaluated the clinical and analytical performances of the Access HBsAg and the Access HBsAg Confirmatory assays on the DxI 9000 Access Immunoassay Analyzer (Beckman Coulter, Inc.). Materials and methods: Diagnostic specificity and sensitivity of the Access HBsAg and Access HBsAg Confirmatory assays were evaluated by comparing the Access assays to the final HBsAg sample status determined using the Architect, PRISM, or Elecsys HBsAg assays, along with Architect or PRISM HBsAg Confirmatory assays. Imprecision, sensitivity on seroconversion panels, analytical sensitivity on WHO, and recognition of HBV variants were also evaluated. Results: A total of 7534 samples were included in the analysis (6047 blood donors, 1032 hospitalized patients, 455 positive patients' samples). Access HBsAg assay sensitivity and specificity were at 100.00% (99.19-100.0) and 99.92% (99.82-99.97), respectively. Sensitivity of Access HBsAg Confirmatory assay was 100.00% (99.21-100.0) on the 464 HBsAg positive samples. The use of a high positive algorithm for the Access HBsAg assay, wherein samples with S/CO ≥ 100.00 were considered positive without requiring repeat or confirmatory testing, was successfully evaluated with all 450 specimens with S/CO greater than 100.00 (sensitivity 100.00%; 99.19-100.0). Access HBsAg assay demonstrated good analytical performance, equivalent recognition of seroconversion panels compared to Architect assay, and an analytical sensitivity between 0.022 and 0.025 IU/mL. All HBV genotypes, subtypes and mutants were well detected without analytical sensitivity loss. Conclusion: Access HBsAg and Access HBsAg Confirmatory assays demonstrated robust performances. They provide low samples volume requirements and a simplified process, no systematic retesting for high positive samples.

Evaluation of T Cell Response to SARS-CoV-2 in Kidney Transplant Recipients Receiving Monoclonal Antibody Prophylaxis and the Utility of a Bivalent mRNA Vaccine Booster Dose.

Monoclonal antibodies have been administered to kidney transplant recipients (KTRs) with a poor or non-responder status to SARS-CoV-2 vaccination. The cellular response to SARS-CoV-2 has been poorly studied in this context. We assessed the T cell response to SARS-CoV-2 in 97 patients on the day of the injection of tixagevimab/cilgavimab using an IFNγ enzyme-linked immunospot assay (ELISPOT). Among the 97 patients, 34 (35%) developed COVID-19 before the injection. Twenty-nine (85.3%) had an ELISPOT compatible with a SARS-CoV-2 infection. There was no difference between KTRs under belatacept or tacrolimus treatment. Sixty-three patients (64.9%) had no known COVID-19 prior to the ELISPOT, but nine (14.3%) had a positive ELISPOT. In 21 KTRs with a positive ELISPOT who received a booster dose of a bivalent mRNA vaccine, median antibody titers and spike-reactive T cells increased significantly in patients under tacrolimus but not belatacept. Our study emphasizes the potential usefulness of the exploration of immune cellular response to SARS-CoV-2 by ELISPOT. In KTRs with a positive ELISPOT and under CNI therapy, a booster dose of mRNA vaccine seems effective in inducing an immune response to SARS-CoV-2.

Evaluation of the ELITechGroup solution for plasma HIV-1 RNA quantification.

In the last few years, many manufacturers have developed new kits for plasma HIV-1 RNA quantification. Recently, a solution consisting of the ELITe InGenius® instrument and the HIV1 ELITe MGB®kit has been commercialized worldwide. Our aim was to compare its clinical performance with the Aptima® HIV-1 Quant Dx kit by Hologic, on a panel of HIV-1 group M circulating variants, representative of viral load levels found during the pre- and post-treatment follow-up of patients. The linearity was evaluated on the AcroMetrix® HIV-1 Panel. Clinical specificity was evaluated on 100 plasma samples negative for HIV; and clinical sensitivity and sequential follow-up were evaluated on 166 HIV-1 positive plasma samples from 126 patients. The linearity data showed a difference obtained for each point of less than 0.2 Log cp/mL. No amplification was found for the 100 HIV negative clinical specimens. The overall agreement between the two kits was 83.7 %; the differences corresponded to a slightly higher detection for the Aptima kit (with more samples detected below the lower limit of quantification). A Bland & Altman analysis of the quantifiable samples showed a mean difference of -0.05 Log and Spearman's coefficient was 0.975. Only six samples presented discrepancies (above 0.5 Log), but these differences were overall similar between the two kits. Our study has shown that the HIV1 ELITe MGB® Kit can be successfully used for the monitoring of patients infected with various epidemic HIV-1 strains, and for the precise quantification of the viral load.

Anti SARS-CoV-2 Monoclonal Antibodies in Pre-Exposure or Post-Exposure in No- or Weak Responder to Vaccine Kidney Transplant Recipients: Is One Strategy Better than Another?

Background: Kidney transplant recipients (KTRs) are likely to develop severe COVID-19 and are less well-protected by vaccines than immunocompetent subjects. Thus, the use of neutralizing anti-SARS-CoV-2 monoclonal antibodies (mAbs) to confer a passive immunity appears attractive in KTRs. Methods: This retrospective monocentric cohort study was conducted between 1 January 2022 and 30 September 2022. All KTRs with a weak antibody response one month after three doses of mRNA vaccine (anti spike IgG < 264 (BAU/mL)) have received tixagevimab-cilgavimab in pre-exposure (group 1), post-exposure (group 2) or no specific treatment (group 3). We compared COVID-19 symptomatic hospitalizations, including intensive care unit hospitalizations, oxygen therapy, and death, between the three groups. Results: A total of 418 KTRs had SARS-CoV-2 infection in 2022. During the study period, we included 112 KTRs in group 1, 40 KTRs in group 2, and 27 KTRs in group 3. The occurrence of intensive care unit hospitalization, oxygen therapy, and COVID-19 death was significantly increased in group 3 compared to group 1 or 2. In group 3, 5 KTRs (18.5%) were admitted to the intensive care unit, 7 KTRs (25.9%) needed oxygen therapy, and 3 KTRs (11.1%) died. Patients who received tixagevimab-cilgavimab pre- or post-exposure had similar outcomes. Conclusions: This retrospective real-life study supports the relative effectiveness of tixagevimab-cilgavimab on COVID-19 infection caused by Omicron, used as a pre- or post-exposure therapy. The continued evolution of Omicron variants has made tixagevimab-cilgavimab ineffective and reinforces the need for new therapeutic monoclonal antibodies for COVID-19 active on new variants.

Severe and fatal neonatal infections linked to a new variant of echovirus 11, France, July 2022 to April 2023.

We report nine severe neonatal infections caused by a new variant of echovirus 11. All were male, eight were twins. At illness onset, they were 3-5 days-old and had severe sepsis and liver failure. This new variant, detected in France since April 2022, is still circulating and has caused more fatal neonatal enterovirus infections in 2022 and 2023 (8/496; 1.6%, seven associated with echovirus 11) compared with 2016 to 2021 (7/1,774; 0.4%). National and international alerts are warranted.

Antibody and T Cell Response to SARS-CoV-2 Messenger RNA BNT162b2 Vaccine in Kidney Transplant Recipients and Hemodialysis Patients.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with a high rate of mortality in patients with ESKD, and vaccination is hoped to prevent infection. METHODS: Between January 18 and February 24, 2021, 225 kidney transplant recipients (KTRs) and 45 patients on hemodialysis (HDPs) received two injections of mRNA BNT162b2 vaccine. The postvaccinal humoral and cellular response was explored in the first 45 KTRs and ten HDPs. RESULTS: After the second dose, eight HDPs (88.9%) and eight KTRs (17.8%) developed antispike SARS-CoV-2 antibodies (P<0.001). Median titers of antibodies in responders were 1052 AU/ml (IQR, 515-2689) in HDPs and 671 AU/ml (IQR, 172-1523) in KTRs (P=0.40). Nine HDPs (100%) and 26 KTRs (57.8%) showed a specific T cell response (P=0.06) after the second injection. In responders, median numbers of spike-reactive T cells were 305 SFCs per 106 CD3+ T cells (IQR, 95-947) in HDPs and 212 SFCs per 106 CD3+ T cells (IQR, 61-330) in KTRs (P=0.40). In KTRs, the immune response to BNT162b2 seemed influenced by the immunosuppressive regimen, particularly tacrolimus or belatacept. CONCLUSION: Immunization with BNT162b2 seems more efficient in HDPs, indicating that vaccination should be highly recommended in these patients awaiting a transplant. However, the current vaccinal strategy for KTRs may not provide effective protection against COVID-19 and will likely need to be improved.

Invasive meningoencephalitis as the first manifestation of hepatitis A.

Since mid-2016, Europe has been facing a major hepatitis A epidemic, with more than 25 000 cases reported to the European CDC, in 2018. We describe herein a rare case of invasive HAV meningoencephalitis as a prodrome of the classic hepatitis, which largely explains a delay in diagnosis.

HIV rapid screening tests and self-tests: Be aware of differences in performance and cautious of vendors.

BACKGROUND: Rapid tests for HIV testing are essential tools to achieve the 90-90-90 target of the World Health Organization. Many tests are available, some directly from websites. Evaluation of the performance of rapid tests, under close to real-life usage, is therefore needed to ensure accurate diagnosis in the context of the recommendation for their more widespread use. METHOD: Nine third- (3G) or fourth-generation (4G) rapid screening tests or self-tests (two bought on websites), were evaluated on an extensive panel of 200 HIV-negative and 312 HIV-positive samples, representative of a wide variety of clinical situations and HIV genetic diversity. A whole blood reconstitution protocol was designed to simulate real-life usage of these tests in community-based and private settings. FINDINGS: The specificity was high (98.5-100%) and sensitivity excellent (100%) for samples from patients chronically infected with the pandemic strains. The performance for infrequent situations with a major epidemiological and clinical impact, such as infection with divergent viruses or primary infection, was highly variable, depending on the test. One of the two 4G tests allowed detection of additional positive samples from early stages of infection, whereas the second (sold as a 4G test on a website) corresponded in reality to a 3G test. INTERPRETATION: Our study showed that not all tests are equal for the detection of major HIV variants or early stages of HIV infection; adding the detection of specific p24Ag improved the latter point. This study also showed, for the first time, that buying through web-based vendors can be risky, due to the varying performance of the tests and questionable sales practices. Our results are of particular importance in the context of the increasing use of rapid tests in an "outside laboratory" settings. FUND: Santé Publique France, COREVIH - Normandie, and Rouen University Hospital.

Confirmation of HCV viremia using HCV RNA and core antigen testing on dried blood spot in HIV infected peoples who inject drugs in Vietnam.

BACKGROUND: Nucleic acid tests performed on blood samples collected on Dried Blood Spot (DBS) and detection of HCV core antigen (HCVcAg) are two approaches that may facilitate access to HCV diagnosis in low and middle incomes countries. In this study we evaluate HCV RNA and HCV antigen testing on DBS in HIV/HCV co-infected peoples who inject drugs in Vietnam. METHOD: One hundred and four HIV/HCV seropositive patients managed in outpatient care at the Haiphong Viet Tiep hospital were included in this study from February to March, 2014 (ANRS 12262 study). RESULTS: Eighty-six subjects were tested positive for HCV RNA in serum, median (IQR): 6.9 log10 IU/ml (5.6-7.4 log10 IU/ml). Genotypes consisted of 57 G1 (69%), 3 G3 (4%), and 22 G6 (27%). HCV RNA was detected on DBS specimens in 79 out 86 subjects with chronic hepatitis C (sensitivity 92.5%; 95% CI: 85.1-96.9%). HCV RNA level on DBS and serum was moderately correlated (r = 0.24; p = 0.05) suggesting a degradation of HCV RNA due to transportation and storage conditions. HCVcAg was detected in 75/86 dB specimens (sensitivity: 87.2%; 95% CI: 78.3-93.4%), with a strong positive relationship between DBS HCVcAg and serum HCV RNA levels (r = 0.80; P < 0.0001). CONCLUSIONS: Quantification of HCVcAg on DBS appears to benefit from substantial stability under prolonged storage conditions but with a lower analytical sensitivity compared to DBS HCV RNA testing. Detection of HCV RNA on DBS is an interesting approach for confirming viral replication in HCV seropositive persons but the impact of pre-analytical conditions on the integrity of HCV RNA needs to be controlled.

Detection of numerous HIV-1/MO recombinants in France.

BACKGROUND: The broad genetic divergence of HIV-1/O relative to HIV-1/M has important implications for diagnosis, monitoring and treatment. Despite this divergence, some HIV-1/M+O dual infections and HIV-1/MO recombinant forms have been reported, mostly in Cameroon, where both groups are prevalent. Here, we describe the characteristics of such infections detected in France in 10 new patients, and discuss their implications for biological and clinical practice, owing to the presence of group O species. METHODS: The French National Reference Centre for HIV received samples within the framework of mandatory notification of HIV infections, and for expert analysis. A strategy combining serotyping, viral quantification, group-specific molecular amplification and whole-genome sequencing was used for strain characterization and complementary investigations. RESULTS: We identified one patient with M+O infection, three patients with M+O infection associated with an MO recombinant, and six patients with only an MO recombinant. These atypical infections were detected upon strain characterization (n = 4) or because of anomalies during patient monitoring (n = 6). We identified eight new URF_MO, all but one originating from Cameroon. Interestingly, two distinct recombinant strains were found in two unrelated patients, representing possible precursors of a CRF_MO. CONCLUSION: Our work highlights the fact that the continuous evolution of HIV can hinder diagnosis and complicate clinical practice. We stress that unexpected results during diagnosis or monitoring necessitate further serological and molecular exploration, these atypical infections influence biological and therapeutic management and necessitate appropriate tools, and specific surveillance is necessary, especially as the frequency of such infections may be underestimated.