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Background: Anti-spike monoclonal antibodies represent one of the most tolerable prophylaxis and therapies for COVID-19 in frail and immunocompromised patients. Unfortunately, viral evolution in Omicron has led all of them to failure., Objectives: We review here the current pipeline of anti-spike mAb's, discussing in detail the most promising candidates., Sources: We scanned PubMed, ClinicalTrials.gov and manufacturers' press releases for clinical studies on anti-spike monoclonal antibodies., Content: We present state-of-art data clinical progress for AstraZeneca's AZD3152, Invivyd's VYD222, Regeneron's REGN-17092 and Aerium Therapeutics' AER-800., Implications: The anti-spike monoclonal antibody clinical pipeline is currently limited to few agents (most being single antibodies) with unknown efficacy against the dominant JN.1 sublineage. The field of antibody-based therapies requires boosting by both manufacturers and institutions., (Copyright © 2024 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Background: Plasma collected from recovered patients with COVID-19 (COVID-19 convalescent plasma [CCP]) was the first antibody-based therapy employed to fight the COVID-19 pandemic. While the therapeutic effect of early administration of CCP in COVID-19 outpatients has been recognized, conflicting data exist regarding the efficacy of CCP administration in hospitalized patients., Objectives: To examine the effect of CCP compared to placebo or standard treatment, and to evaluate whether time from onset of symptoms to treatment initiation influenced the effect., Data Sources: Electronic databases were searched for studies published from January 2020 to January 2024., Study Eligibility Criteria: Randomized clinical trials (RCTs) investigating the effect of CCP on COVID-19 mortality in hospitalized patients with COVID-19., Participants: Hospitalized patients with COVID-19., Interventions: CCP versus no CCP., Assessment of Risk of Bias: Cochrane risk of bias tool for RCTs., Methods of Data Synthesis: The random-effects model was used to calculate the pooled risk ratio (RR) with 95% CI for the pooled effect estimates of CCP treatment. The Grading of Recommendations Assessment, Development and Evaluation was used to evaluate the certainty of evidence., Results: Twenty-seven RCTs were included, representing 18,877 hospitalized patients with COVID-19. When transfused within 7 days from symptom onset, CCP significantly reduced the risk of death compared to standard therapy or placebo (RR, 0.76; 95% CI, 0.61-0.95), while later CCP administration was not associated with a mortality benefit (RR, 0.98; 95% CI, 0.90-1.06). The certainty of the evidence was graded as moderate. Meta-regression analysis demonstrated increasing mortality effects for longer interval to transfusion or worse initial clinical severity., Conclusions: In-hospital transfusion of CCP within 7 days from symptom onset conferred a mortality benefit., (Copyright © 2024 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Objectives: After the third year of the COVID-19 pandemic, most of the severe COVID-19 burden falls upon immunocompromised patients who cannot mount an endogenous immune response after both vaccination and/or natural infection. They also experience persistent SARS-CoV-2 infection with high viral loads often unsuccessfully managed by the standard antiviral monotherapy regimen initially validated for treatment of COVID-19 immunocompetent patients, only. The off-label prescription of such monotherapy regimens in immunocompromised patients is likely to drive the emergence of treatment-related immune escape, relapses, excess morbidity, and mortality from both COVID-19 and delayed treatment of the underlying disorders. A possible treatment approach to mitigate such consequence is based on combined antiviral therapies., Methods: We searched PubMed for case reports, case series and clinical trials reporting the usage of combined antiviral therapies for COVID-19., Results: In this narrative review, we show that combinations of either small molecule antivirals or small molecule antiviral plus passive immunotherapies are safe and effective in small cohorts reported so far., Conclusion: Considering the progressive loss of efficacy of all authorized anti-spike monoclonal antibodies, promising regimen options are reserved to combinations of small molecule antivirals and COVID-19 convalescent plasma from vaccinated donors., Competing Interests: Declarations of competing interest DJS reports AliquantumRx Founder and Board member with stock options (macrolide for malaria), Hemex Health malaria diagnostics consulting and royalties for malaria diagnostic test control standards to Alere- all outside of submitted work., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Competing Interests: DF was an investigator in the TSUNAMI randomised controlled trial of COVID-19 convalescent plasma. AC reports being part of the scientific advisory board of SabTherapeutics, has received personal fees from Ortho Diagnostics, outside of the submitted work, and is an investigator in the CSSC-004 randomised controlled trial.

The Delta variant of concern (VOC) of SARS-CoV-2 has become dominant worldwide. In this article, we report a cluster caused by B.1.617.2 harboring the additional mutation of concern (MOC) F490S. We observed that 5 fully vaccinated subjects aged between 47 and 84 years were infected with this variant. The immune escape mutation F490S, first identified in the Lambda VOI, appears to impair vaccine efficacy and is rapidly increasing in prevalence worldwide., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Massive usage of antiviral compounds during a pandemic creates an ideal ground for emergence of resistant strains. Remdesivir, a broad-spectrum inhibitor of the viral RNA-dependent RNA polymerase (RdRp), was extensively prescribed under emergency use authorization during the first 18 months of the COVID19 pandemic, before randomized controlled trials showed poor efficacy in hospitalized patients. RdRp mutations conferring resistance to remdesivir are well known from in vitro studies, and the huge SARS-CoV-2 sequencing effort during the ongoing COVID19 pandemic represents an unprecedented opportunity to assess emergence and fitness of antiviral resistance in vivo. We mined the GISAID database to extrapolate the frequency of remdesivir escape mutations. Our analysis reveals very low levels of remdesivir resistance worldwide despite massive usage., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) is being extensively investigated as a treatment, with mixed results to date. Overall, there has been a generalized lack of appropriateness in prescriptions, which, in the field of transfusion medicine, is termed patient-blood management., Objectives: We aimed to separate study design variables that could affect clinical outcome after CCP therapy. We focus here on variables such as pretransfusion antibody testing in recipients, dose adjustments and antibody affinity measurements., Sources: We searched PubMed and preprint servers for relevant preclinical and clinical studies discussing each of these variables in the field of CCP therapy., Content: We show evidence that neglecting those variables has affected the outcomes of the vast majority of CCP clinical trials to date., Implications: A better understanding of such variables will improve the design of the next generation of CCP clinical trials. This will likely lead to better clinical outcomes and will minimize risks of immune evasion from subneutralizing doses of neutralizing antibodies., (Copyright © 2021 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

COVID-19 convalescent plasma (CCP) is widely used as a treatment. While safety data are enough, high-level evidences of efficacy are still missing. We summarize here the results from randomized controlled trials (RCT) published to date and analyze their flaws and biases. We then provide suggestions for next round of CCP RCTs, discussing specification of CCP, therapeutic dose, timing, control arm, disease stage, and outcome measures., (Copyright © 2020. Published by Elsevier Ltd.)

Objectives: Torquetenovirus (TTV) is an emerging marker of functional immune competence with the potential to predict transplant-related adverse events. A large-scale epidemiological study was performed to understand how basal values vary in healthy individuals according to age and gender., Methods: We tested plasma from 1017 healthy blood donors aged 18-69 years. The presence and load of TTV were determined by a real-time PCR assay. A sub-cohort of 384 donors was tested for anti-cytomegalovirus IgG antibodies, and 100 participants were also tested for TTV viraemia on a paired whole blood sample., Results: The overall prevalence of TTV was 65% (657/1017) with a mean (±SD) growth of 5 ± 4% every 10 years of age increase, but stably higher in males (465/690, 67%) than in females (192/327, 59%). Mean (±SD) TTV load was 2.3 ± 0.7 Log copies/mL with no sex difference. TTV viraemia showed modest increases along 10-year age intervals (mean ± SD: 0.3 ± 0.1). TTV viraemia in donors sampled 2 years later remained stable (mean ± SD: 2.3 ± 0.8 versus 2.2 ± 0.7 Log copies between samples). Twenty-six per cent (9/34) of blood donors with TTV-negative plasma scored positive when whole blood was tested, and the donors with positive plasma showed a mean (±SD) 1.4 ± 0.5 Log increase in copy numbers when whole blood was tested., Conclusions: This study establishes the mean value of TTV viraemia in plasma in healthy blood donors and suggests that ageing causes only minimal increases in TTV viraemia., (Copyright © 2020 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Torquetenovirus (TTV) is the most abundant component of human virome. Virologists have long ignored this orphan and highly divergent virus, in part because TTV cannot be cultured and because it lacks serology reagents and animal models. Nevertheless, it is almost endemic worldwide and is insensitive to current antiviral drugs, so its monitoring is useful in various conditions. To date, TTV as a marker has proved useful in at least two circumstances: to identify anthropogenic pollution and to assess functional immune competence in immunosuppressed individuals. This review summarizes recent findings about TTV and discusses the main hurdles in translating them into clinical diagnostics., (Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Background Aims: Mesenchymal stromal cells (MSCs) modulate the immune response and represent a potential treatment for inflammatory and autoimmune diseases. We hypothesized that this feature could be potentiated by co-administering anti-inflammatory cytokines. In this article, we asked whether engineering of Wharton Jelly-derived human MSCs (WJ-hMSCs) to express an anti-inflammatory cytokine increases cell immunomodulatory properties without altering their native features., Methods: We used Epstein-Barr virus-derived interleukin-10 (vIL-10), which shares some immunosuppressive properties with human IL-10 but lacks immunostimulatory activity. Engineering was accomplished by transducing WJ-hMSCs with a self-inactivating feline immunodeficiency virus-derived vector co-expressing vIL-10 and herpes simplex virus type-1 thymidine kinase (TK). TK was added to allow future tracking of WJ-hMSC in vivo by positron electron tomography (PET)., Results: The results show that (i) expression of TK and/or vIL-10 does not change WJ-hMSC phenotypic and functional properties; (ii) vIL-10 is secreted, biologically active and enhances the immunosuppressing functions of WJ-hMSCs; (iii) v-IL10 and TK can be produced simultaneously by the same cells and do not interfere with each other., Discussion: WJ-hMSCs engineered to secrete vIL-10 could be a powerful tool for adoptive cell therapy of immune-mediated diseases, and therefore, additional studies are warranted to confirm their efficacy in suitable animal disease models., (Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Background & Aims: We investigated whether improving 25-hydroxyvitamin D status in young type 1A diabetic patients reduces reactivity of peripheral blood mononuclear cells against islet autoantigens and associates with beta-cell functional changes., Methods: Eight patients with 25-hydroxyvitamin D deficiency (<20 ng/ml), out of 15 consecutive young type 1A diabetic subjects received 25-hydroxyvitamin D3 to achieve and maintain levels above 50 ng/ml for up to one year. Peripheral blood mononuclear cell reactivity (Interferon-γ spots) against beta-cell autoantigens (glutamic acid decarboxylase 65-kD isoform, proinsulin and tyrosine phosphatase-like protein IA-2) and C-peptide during mixed meal were assessed before and after 25-hydroxyvitamin D3 replenishment., Results: Target 25-hydroxyvitamin D blood levels were safely reached and maintained. Peripheral blood mononuclear cell reactivity against glutamic acid decarboxylase 65-kD isoform (3.8 ± 4.0 vs. 45 ± 16) and proinsulin (3.5 ± 3.2 vs. 75 ± 51) decreased significantly (p < 0.001 and p < 0.02) upon 25-hydroxyvitamin D3 replenishment, which was correlated with 25-hydroxyvitamin D concentrations. C-peptide values remained stable after one year of treatment., Conclusions: Safely restored and maintained 25-hydroxyvitamin D levels associated with reduced peripheral blood mononuclear cell reactivity against beta-cell autoantigens with no significant decrease of beta-cell function in this cohort of patients., (Copyright © 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

The biological significance of donor-specific microchimerism (DSM) in solid organ transplantation is unresolved. It has been reported both as a favourable feature, which may facilitate induction and maintenance of tolerance, and as a sign of graft-vs-host disease. Here, we applied a quantitative real-time PCR assay (qRT-PCR) to a selected series of kidney transplant recipients to measure the level of microchimerism in relation to allograft function and survival. DSM level was assessed by scoring the HLA-DRB1 locus in 54 patients (42 males, 12 females) with more than 2 years of follow-up after transplantation; 38 patients were considered to have stable renal function (SRF) and 16 had allograft dysfunction (AD). Among patients with AD, 12 (75%) showed detectable level of microchimerism, compared to 11 (29%) SRF patients (Odds Ratio 7.36, 95% CI 1.7-35.2; p<0.01). In addition, AD patients showed a higher mean donor genome equivalents (6.5×10(-5) vs. 2.4×10(-5); p<0.001). SRF patients were re-evaluated two years later; 2 out of 27 DSM negative vs. 2 out of 11 DSM positive had lost their transplanted organ. In conclusion, qRT-PCR applied to peripheral blood shows significant association between DSM and allograft dysfunction in kidney transplant patients., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The human pathogen xenotropic murine leukaemia virus-related virus (XMRV) has been tentatively associated with prostate cancer and chronic fatigue syndrome. Unfortunately, subsequent studies failed to identify the virus in various clinical settings. To determine whether XMRV circulates in humans and the relationship with its host, we searched for the virus in 124 human immunodeficiency virus-infected patients who might have been exposed to XMRV, might be prone to infection as a result of progressive immunodeficiency, and had not yet been treated with antiretroviral drugs. Using nested PCR and single-step TaqMan real-time PCR, both designed on the XMRV gag gene, we could not find any positive samples. These findings add to the growing amount of scepticism regarding XMRV., (© 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.)

Monoclonal antibodies (mAbs) are well-established therapeutics, as evidenced by the large number of Food and Drug Administration-approved mAbs for the treatment of cancers, and inflammatory or autoimmune diseases, and for the prevention and treatment of solid organ transplant rejection. Although, in many cases, mAbs have improved patient survival, they are also associated with an increased incidence of opportunistic infections. We review here the current and next generation of mAbs and the risks that infectious disease specialists should be aware of., (© 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.)

We report here a 50-years old female with multiple myeloma-associated chronic renal failure who underwent high-dose chemotherapy supported by autologous hematopoietic stem cell transplantation. She developed progressive encephalopathy on day 5 progressing to coma despite hemodialysis and no obvious organ failure. She finally recovered after a single 1-liter plasma exchange. The final diagnosis was metabolic encephalopathy due to hypercytokinemia, particularly high serum TNF levels. We discuss here the pathogenesis and raise an alert for monitoring cytokine levels in patients with renal failure undergoing high-dose chemotherapy.

Rituximab improves outcomes for persons with lymphoproliferative disorders and is increasingly used to treat immune-mediated illnesses. Recent reports describe 2 patients with systemic lupus erythematosus and 1 with rheumatoid arthritis who developed progressive multifocal leukoencephalopathy (PML) after rituximab treatment. We reviewed PML case descriptions among patients treated with rituximab from the Food and Drug Administration, the manufacturer, physicians, and a literature review from 1997 to 2008. Overall, 52 patients with lymphoproliferative disorders, 2 patients with systemic lupus erythematosus, 1 patient with rheumatoid arthritis, 1 patient with an idiopathic autoimmune pancytopenia, and 1 patient with immune thrombocytopenia developed PML after treatment with rituximab and other agents. Other treatments included hematopoietic stem cell transplantation (7 patients), purine analogs (26 patients), or alkylating agents (39 patients). One patient with an autoimmune hemolytic anemia developed PML after treatment with corticosteroids and rituximab, and 1 patient with an autoimmune pancytopenia developed PML after treatment with corticosteroids, azathioprine, and rituximab. Median time from last rituximab dose to PML diagnosis was 5.5 months. Median time to death after PML diagnosis was 2.0 months. The case-fatality rate was 90%. Awareness is needed of the potential for PML among rituximab-treated persons.

JC virus (JCV) is a double-stranded DNA virus belonging to family Polyomaviridae. It causes progressive multifocal leukoencephalopathy (PML), mainly in immunosuppressed people. JCV had been shown to require the serotonin 2A receptor for host cell entry. We report a case of clinical, neuroradiological and virological response of biopsy-proven PML in a 33-year-old comatose woman after treatment with the anti-psychotic drug risperidone. Since risperidone is the tightest binding of current drugs to this receptor we think this may have blocked JCV entry in our patient, allowing her immune recovery and viral clearance.