Unexpected kinetics of anti-SARS-CoV-2 total antibodies in two patients with chronic lymphocytic leukemia

Evaluation of Neutralizing Capacity of Tixagevimab plus Cilgavimab (AZD7442) against Different SARS-CoV-2 Variants: A Case Report Study with Comparison to a Vaccinated Population

AZD7442 (150 mg of tixagevimab plus 150 mg of cilgavimab) has been approved for the preexposure prophylaxis of COVID-19 and for the treatment of adults and adolescents with COVID-19 who do not require supplemental oxygen and who are at increased risk of severe COVID-19. Thus, the aim of the present study is to evaluate the neutralizing capacity of tixagevimab and cilgavimab across different SARS-CoV-2 variants in two patients who received AZD7442 for immunoprophylaxis. A cohort of subjects (n = 45) who had received the BNT162b2 mRNA COVID-19 vaccine has been included to compare these two preventive strategies. Neutralizing antibody (NAb) titers against several variants were assessed against the wild-type, alpha, beta, gamma, delta, omicron BA.5, and XBB.1.5 variants. Binding antibodies have also been measured. NAbs T 1/2 for AZD7442 was 8.1 days (95% CI: 5.1-19.5 days) and was 11.8 days (95% CI: 7.9-23.7 days) for the primo-vaccination cohort. The time to reach neutralization negativity was 108.3 days (95% CI: 66.9-130.7) for AZD7442 compared to 95.4 days (95% CI: 31.0-119.7 days) for the primo-vaccination cohort. The time to reach NAbs' negativity differs between variants with the maximum value obtained for alpha (i.e., 101.1 days (95% CI: 30.0-135.4 days)) and the minimum obtained for beta (i.e., 61.2 days (95% CI: 37.8-77.1 days)). Our results reinforce the need of reviewing the use of AZD7442 in relation to variants of concern and potentially adapting its administration schedule. AZD7442 could be indicated for short-term prophylaxis in frail patients who may be acutely exposed to SARS-CoV-2.

Management of patients with chronic lymphocytic leukemia during the SARS-CoV-2 pandemic

Oncohematological patients are prone to develop infections due to immunosuppression caused by the disease and chemo-immunotherapy. The aim of this review was to outline the details of the management of patients with chronic lymphocytic leukemia (CLL) during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Patients with CLL often exhibit inadequate humoral and cellular immune responses to various infections and vaccinations. Patients under the 'watch and wait' strategy have a lower risk of infections, including with SARS-CoV-2, compared with those undergoing therapeutic interventions, but they still have a higher risk than age-matched controls. Patients with CLL have a high risk of developing severe forms of coronavirus disease-2019 (COVID-19), particularly if they are undergoing chemo-immunotherapy. The total anti-SARS-CoV-2 antibody titer demonstrates a slower increase in patients with CLL infected with the virus, and the antibody levels tend to decrease after reaching a maximum level sooner than in healthy individuals. This leads to a late negativation of the PCR tests and a longer duration of hospitalization. In total, ~1/3 of patients with CLL do not develop a persistent titer of antiviral antibodies, and this is associated with the presence of hypogammaglobulinemia. It appears that patients with CLL have the worst outcomes amongst patients with malignant hemopathies and SARS-CoV-2 infection. Bruton tyrosine kinase inhibitors reduce the hyperinflammatory status of patients with CLL with COVID-19, which is accompanied by decreased levels of serum inflammatory markers, ferritin and D-dimer, and serum levels of pro-inflammatory cytokines, but they increase the risk of infections and impaired humoral immunity. An abrupt discontinuation of these may promote the rapid decompensation of CLL, which may even mimic the clinical manifestations of COVID-I9, including a significant increase in cytokine release. In conclusion, therapeutic decisions must be personalized to each patient with CLL and each at risk patient must be quarantined during the SARS-CoV-2 pandemic to reduce their risk of contraction.

Transient disappearance of CD19+/CD5+ B-lymphocyte clone in peripheral blood in a patient with CLL during SARS-CoV-2-related mild disease

Although lymphopenia is currently considered a good predictor for the prognosis of COVID-19, it must be critically evaluated in patients with CLL, where other clinical markers should be considered to define the prognosis and treatment.

Concurrent chronic lymphocytic leukemia and COVID-19: A comprehensive review of epidemiological, diagnostic, and therapeutic challenges

A comprehensive review of the literature on chronic lymphocytic leukemia (CLL) patients and recommendations regarding the evaluation and treatment of these patients was conducted. The overall prevalence of CLL and COVID-19 concurrence was found to be 0.6% (95%CI: 0.5% to 0.7%). Diagnostic interaction between CLL and COVID-19 remains a major challenge. Also, CLL patients have a lower rate of anti-SARS-CoV-2 IgG development. Evidences show the unacceptable therapeutic outcome in these patients. Although the CLL-COVID-19 occurrence is associated with adverse clinical consequences, no general and standard agreement has yet been presented for the management and treatment of this disease.

Clinical performance of three fully automated anti-SARS-CoV-2 immunoassays targeting the nucleocapsid or spike proteins

This study assesses the clinical performance of three anti‐SARS‐CoV‐2 assays, namely EUROIMMUN anti‐SARS‐CoV‐2 nucleocapsid (IgG) ELISA, Elecsys anti‐SARS‐CoV‐2 nucleocapsid (total antibodies) assay, and LIAISON anti‐SARS‐CoV‐2 spike proteins S1 and S2 (IgG) assay. One hundred and thirty‐seven coronavirus disease 2019 (COVID‐19) samples from 96 reverse‐transcription polymerase chain reaction confirmed patients were chosen to perform the sensitivity analysis. Non‐SARS‐CoV‐2 sera (n = 141) with a potential cross‐reaction to SARS‐CoV‐2 immunoassays were included in the specificity analysis. None of these tests demonstrated a sufficiently high clinical sensitivity to diagnose acute infection. Fourteen days since symptom onset, we did not find any significant difference between the three techniques in terms of sensitivities. However, Elecsys performed better in terms of specificity. All three anti‐SARS‐CoV‐2 assays had equivalent sensitivities 14 days from symptom onset to diagnose past‐COVID‐19 infection. We also confirmed that anti‐SARS‐CoV‐2 determination before Day 14 is of less clinical interest.

Antibody response and therapy in COVID-19 patients: what can be learned for vaccine development?

The newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected millions of people and caused tremendous morbidity and mortality worldwide. Effective treatment for coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 infection is lacking, and different therapeutic strategies are under testing. Host humoral and cellular immunity to SARS-CoV-2 infection is a critical determinant for patients' outcomes. SARS-CoV-2 infection results in seroconversion and production of anti-SARS-CoV-2 antibodies. The antibodies may suppress viral replication through neutralization but might also participate in COVID-19 pathogenesis through a process termed antibody-dependent enhancement. Rapid progress has been made in the research of antibody response and therapy in COVID-19 patients, including characterization of the clinical features of antibody responses in different populations infected by SARS-CoV-2, treatment of COVID-19 patients with convalescent plasma and intravenous immunoglobin products, isolation and characterization of a large panel of monoclonal neutralizing antibodies and early clinical testing, as well as clinical results from several COVID-19 vaccine candidates. In this review, we summarize the recent progress and discuss the implications of these findings in vaccine development.

An Original ELISA-Based Multiplex Method for the Simultaneous Detection of 5 SARS-CoV-2 IgG Antibodies Directed against Different Antigens

Strategies to detect SARS-CoV-2 are increasingly being developed. Among them, serological methods have been developed. Nevertheless, although these may present an interesting clinical performance, they are often directed against only one antigen. This study aims at evaluating the clinical performance of an innovative multiplex immunoassay (i.e., CoViDiag assay) detecting simultaneously the presence of antibodies directed against N, S1, S2, RBD and NTD antigens. Sensitivity was evaluated in 135 samples obtained from 94 rRT-PCR confirmed coronavirus disease 2019 (COVID-19) patients. Non-SARS-CoV-2 sera (n = 132) collected before the COVID-19 pandemic with potential cross-reactions to the SARS-CoV-2 immunoassay were included in the specificity analysis. The antibody signature was also studied in hospitalized and non-hospitalized patients. The specificity of the CoViDiag assay was excellent for all antibodies (99.2 to 100%) using adapted cut-offs. None of the false positive samples were positive for more than one antibody. The sensitivity obtained from samples collected 14 days since symptom onset varied from 92.0 to 100.0% depending on the antibody considered. Among samples collected more than 14 days after symptom onset, 12.8, 66.3, 3.5, 9.3, 5.8 and 2.3% were positive for 5, 4, 3, 2, 1 or 0 antibodies, respectively. A trend toward higher antibody titers was observed in hospitalized patient in the early days since symptom onset. However, no significant difference was observed compared to non-hospitalized patients after 14 days since symptom onset. The clinical performance of the CoViDiag 5 IgG assay is sufficient to recommend its use for the detection and the characterization of the antibody signature following SARS-CoV-2 infection. The combination of several antigens in the same test improves the overall specificity and sensitivity of the test. Further research is needed to investigate whether this strategy may be of interest to identify severe disease outcome in patients with SARS-CoV-2 infection.

Comparison of 2 fully automated tests detecting antibodies against nucleocapsid N and spike S1/S2 proteins in COVID-19

Automated assays for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in coronavirus disease 2019 (COVID-19) diagnostics have recently come available. We compared the performance of the Elecsys® Anti–SARS-CoV-2 and LIAISON® SARS-CoV-2 S1/S2 IgG tests. The seroconversion panel comprised of 120 samples from 13 hospitalized COVID-19 patients. For the sensitivity and specificity testing, samples from COVID-19 outpatients >15 days after positive nucleic acid amplification test (NAAT) result (n = 35) and serum control samples collected before the COVID-19 era (n = 161) were included in the material. Samples for the detection of possible cross-reactions were also tested. Based on our results, the SARS-CoV-2 antibodies can be quite reliably detected 2 weeks after NAAT positivity and 3 weeks after the symptom onset with both tests. However, since some COVID-19 patients were positive only with Elecsys®, the antibodies should be screened against N-antigen (Elecsys®) and reactive samples confirmed with S antigen (LIAISON®), but both results should be reported. In some COVID-19 patients, the serology can remain negative.

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Elecsys® and LIAISON® SARS-CoV-2 antibody tests performed reliably.

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SARS-CoV-2 antibodies should be confirmed with different antigens to increase accuracy.

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In some patients, the COVID-19 serology may remain completely negative.

Evaluation of three fully-automated SARS-CoV-2 antibody assays

Objectives Serological assays for detection of SARS-CoV-2 antibodies are increasingly used during the COVID-19 pandemic caused by the SARS-Coronavirus-2. Here we evaluated the analytical and clinical performance of three commercially available SARS-CoV-2 antibody assays. Methods A total of 186 samples from 58 patients with PCR-confirmed COVID-19 infection were measured using SARS-CoV-2 antibody assays by Siemens Healthineers, Roche Diagnostics and Euroimmun. Additionally, 123 control samples, including samples collected before December 2019 and samples with potential cross-reactive antibodies were analyzed. Diagnostic specificity, sensitivity, agreement between assays and ROC curve-derived optimized thresholds were determined. Furthermore, intra- and inter-assay precision and the potential impact of interfering substances were investigated. Results SARS-CoV-2 antibody assays by Siemens and Roche showed 100% specificity. The Euroimmun assay had 98 and 100% specificity, when borderline results are considered as positive or negative, respectively. Diagnostic sensitivity for samples collected ≥14 days after PCR-positivity was 97.0, 89.4 and 95.5% using the Siemens, Roche and Euroimmun assay, respectively. Sensitivity of the Roche assay can be increased using an optimized cut-off index (0.095). However, a simultaneous decrease in specificity (98.4%) was observed. Siemens showed 95.8 and 95.5% overall agreement with results of Euroimmun and Roche assay, respectively. Euroimmun and Roche assay exhibited 92.6% overall agreement. Discordant results were observed in three COVID-19 patients and in one COVID-19 patient none of the investigated assays detected antibodies. Conclusions The investigated assays were highly specific and sensitive in detecting SARS-CoV-2 antibodies in samples obtained ≥14 days after PCR-confirmed infection. Discordant results need to be investigated in further studies.