Treatment of COVID-19 patients with the anti-CD6 antibody itolizumab

CD6 Regulates CD4 T Follicular Helper Cell Differentiation and Humoral Immunity During Murine Coronavirus Infection

During activation the T cell transmembrane receptor CD6 becomes incorporated into the T cell immunological synapse where it can exert both co-stimulatory and co-inhibitory functions. Given the ability of CD6 to carry out opposing functions, this study sought to determine how CD6 regulates early T cell activation in response to viral infection. Infection of CD6 deficient mice with a neurotropic murine coronavirus resulted in greater activation and expansion of CD4 T cells in the draining lymph nodes. Further analysis demonstrated that there was also preferential differentiation of CD4 T cells into T follicular helper cells, resulting in accelerated germinal center responses and emergence of high affinity virus specific antibodies. Given that CD6 conversely supports CD4 T cell activation in many autoimmune models, we probed potential mechanisms of CD6 mediated suppression of CD4 T cell activation during viral infection. Analysis of CD6 binding proteins revealed that infection induced upregulation of Ubash3a, a negative regulator of T cell receptor signaling, was hindered in CD6 deficient lymph nodes. Consistent with greater T cell activation and reduced UBASH3a activity, the T cell receptor signal strength was intensified in CD6 deficient CD4 T cells. These results reveal a novel immunoregulatory role for CD6 in limiting CD4 T cell activation and deterring CD4 T follicular helper cell differentiation, thereby attenuating antiviral humoral immunity.

Importance

CD6 monoclonal blocking antibodies are being therapeutically administered to inhibit T cell activation in autoimmune disorders. However, the multifaceted nature of CD6 allows for multiple and even opposing functions under different circumstances of T cell activation. We therefore sought to characterize how CD6 regulates T cell activation in the context viral infections using an in vivo murine coronavirus model. In contrast to its role in autoimmunity, but consistent with its function in the presence of superantigens, we found that CD6 deficiency enhances CD4 T cell activation and CD4 T cell help to germinal center dependent antiviral humoral responses. Finally, we provide evidence that CD6 regulates transcription of its intracellular binding partner UBASH3a, which suppresses T cell receptor signaling and consequently T cell activation. These findings highlight the context dependent flexibility of CD6 in regulating in vivo adaptive immune responses, which may be targeted to enhance anti-viral immunity.

Long-term therapy with itolizumab is safe and effective for patients with moderate to severe psoriasis: Results from an expanded-access program

Itolizumab is a humanized monoclonal antibody that selectively targets the CD6-ALCAM pathway. This article reports on the safety and efficacy of itolizumab in the treatment of moderate-to-severe plaque psoriasis in a clinical study conducted in Cuba in the setting of an expanded-access program (EAP). The study included 84 patients who had previously received conventional anti-psoriatic systemic therapies but were either intolerant, had an inadequate response, or had contraindications to these therapies. It consisted of multiple phases, including a 12-week induction phase, a 40-week maintenance phase, and a 24-week off-treatment follow-up phase, using either a 0.4 or 1.6 mg/Kg dose. The results showed that itolizumab monotherapy was safe and effective during 52 weeks of continuous treatment and the subsequent 24 follow-up weeks. Itolizumab treatment resulted in a significant improvement (PASI 75) in 80 % of patients at the end of the induction phase, and this effect was sustained till week 52 during the maintenance phase. Moreover, 24 weeks after treatment stopped nearly two-thirds of patients still showed a PASI ≥ 75. The observed effects were dose-dependent, with 1.6 mg/kg being the most convenient dose. This study further supports the strategy of targeting the CD6-ALCAM signaling pathway for the treatment of psoriasis and the use of itolizumab as a valuable asset in the armamentarium of anti-psoriasis drugs.

Immune-Based Therapy for Hospitalized Patients With COVID-19 and Risk of Secondary Infections: A Systematic Review and Meta-analysis

Background

Immune-based therapies are standard-of-care treatment for coronavirus disease 2019 (COVID-19) patients requiring hospitalization. However, safety concerns related to the potential risk of secondary infections may limit their use.

Methods

We searched OVID Medline, Ovid EMBASE, SCOPUS, Cochrane Library, clinicaltrials.gov, and PROSPERO in October 2020 and updated the search in November 2021. We included randomized controlled trials (RCTs). Pairs of reviewers screened abstracts and full studies and extracted data in an independent manner. We used RevMan to conduct a meta-analysis using random-effects models to calculate the pooled risk ratio (RR) and 95% CI for the incidence of infection. Statistical heterogeneity was determined using the I ² statistic. We assessed risk of bias for all studies and rated the certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation methodology. We conducted a meta-regression using the R package to meta-explore whether age, sex, and invasive mechanical ventilation modified risk of infection with immune-based therapies. The protocol is registered with PROSPERO (CRD42021229406).

Results

This was a meta-analysis of 37 RCTs including 32 621 participants (mean age, 60 years; 64% male). The use of immune-based therapy for COVID-19 conferred mild protection for the occurrence of secondary infections (711/15 721, 4.5%, vs 616/16 900, 3.6%; RR, 0.82; 95% CI, 0.71-0.95; P = .008; I ² = 28%). A subgroup analysis did not identify any subgroup effect by type of immune-based therapies (P = .85). A meta-regression revealed no impact of age, sex, or mechanical ventilation on the effect of immune-based therapies on risk of infection.

Conclusions

We identified moderate-certainty evidence that the use of immune-based therapies in COVID-19 requiring hospitalization does not increase the risk of secondary infections.

Significant perspectives on various viral infections targeted antiviral drugs and vaccines including COVID-19 pandemicity

A virus enters a living organism and recruits host metabolism to reproduce its own genome and proteins. The viral infections are intricate and cannot be completely removed through existing antiviral drugs. For example, the herpes, influenza, hepatitis and human immunodeficiency viruses are a few dreadful ones amongst them. Significant studies are needed to understand the viral entry and their growth in host cells to design effective antivirals. This review emphasizes the range of therapeutical antiviral drugs, inhibitors along with vaccines to fight against viral pathogens, especially for combating COVID-19. Moreover, we have provided the basic and in depth information about viral targets, drugs availability, their mechanisms of action, method of prevention of viral diseases and highlighted the significances of anticoagulants, convalescent plasma for COVID-19 treatment, scientific details of airborne transmission, characteristics of antiviral drug delivery using nanoparticles/carriers, nanoemulsions, nanogels, metal based nanoparticles, alike the future nanosystems through nanobubbles, nanofibers, nanodiamonds, nanotraps, nanorobots and eventually, the therapeutic applications of micro- and nanoparticulates, current status for clinical development against COVID-19 together with environmental implications of antivirals, gene therapy etc., which may be useful for repurposing and designing of novel antiviral drugs against various dreadful diseases, especially the SARS-CoV-2 and other associated variants.

Immune, inflammatory and prothrombotic parameters in COVID-19 patients treated with an anti EGFR antibody

SARS-CoV-2 infection causes a range of clinical presentations and induces changes in both innate and adaptive branches of the immune system. Furthermore, direct viral action to the cells of the lung promotes over-expression of the epidermal growth factor receptor (EGFR) which triggers pro-inflammatory response, contributes to coagulopathy and intravascular thrombi as well as lung fibrosis. Based on the role of this signaling pathway in the pathophysiology of the disease, nimotuzumab, an anti-EGFR monoclonal antibody, was used to treat patients with COVID-19. The aim of this study was to determine IL-6 and PAI-1 concentrations and lymphocyte subpopulations profiles in moderately and severely ill COVID-19 patients diagnosed during the B.1.617.2 variant wave in Cuba and included in a phase I/II trial to evaluate the safety and preliminary effect of nimotuzumab in COVID-19 disease. We observed high serum levels of IL-6, elevated plasma concentration of PAI-1, mean values of neutrophils to lymphocytes ratio (NLR) above three and CD4+ lymphopenia in both groups of patients. PAI-1 and IL-6 circulating levels decreased in patients treated with nimotuzumab. More than 95% of patients in which IL-6 decreased or increased slightly, were alive within 14 days after the monoclonal antibody administration. Patients with moderate and severe disease, were no different regarding the studied parameters, addressing the idea that several immune alterations could be present before the infection becomes clinically relevant. These findings suggest that nimotuzumab could be an attractive therapeutic option to interfere with the negative relationship between cytokines and procoagulant mediators in the inflammatory and prothrombotic phases of the disease.

CD6-mediated inhibition of T cell activation via modulation of Ras

BACKGROUND

CD6 is one of many cell surface receptors known to regulate signal transduction upon T cell activation. However, whether CD6 mediates costimulatory or inhibitory signals is controversial. When T cells engage with antigen presenting cells (APCs), CD6 interacts with its ligand CD166 at the cell-cell interface while the cytosolic tail assembles a complex signalosome composed of adaptors and effector enzymes, that may either trigger activating signaling cascades, or instead modulate the intensity of signaling. Except for a few cytosolic adaptors that connect different components of the CD6 signalosome, very little is known about the mechanistic effects of the cytosolic effectors that bind CD6.

METHODS

Jurkat model T cells were transfected to express wild-type (WT) CD6, or a cytoplasmic truncation, signaling-disabled mutant, CD6Δcyt. The two resulting cell lines were directly activated by superantigen (sAg)-loaded Raji cells, used as APCs, to assess the net signaling function of CD6. The Jurkat cell lines were further adapted to express a FRET-based unimolecular HRas biosensor that reported the activity of this crucial GTPase at the immunological synapse.

RESULTS

We show that deletion of the cytosolic tail of CD6 enhances T-cell responses, indicating that CD6 restrains T-cell activation. One component of the CD6-associated inhibitory apparatus was found to be the GTPase activating protein of Ras (RasGAP), that we show to associate with CD6 in a phosphorylation-dependent manner. The FRET HRas biosensor that we developed was demonstrated to be functional and reporting the activation of the T cell lines. This allowed to determine that the presence of the cytosolic tail of CD6 results in the down-regulation of HRas activity at the immunological synapse, implicating this fundamental GTPase as one of the targets inhibited by CD6.

CONCLUSIONS

This study provides the first description of a mechanistic sequence of events underlying the CD6-mediated inhibition of T-cell activation, involving the modulation of the MAPK pathway at several steps, starting with the coupling of RasGAP to the CD6 signalosome, the repression of the activity of Ras, and culminating in the reduction of ERK1/2 phosphorylation and of the expression of the T-cell activation markers CD69 and IL-2R α chain. Video abstract.

Antibody Therapy for COVID-19: Categories, Pros, and Cons

COVID-19 is a life-threatening respiratory disease triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has been considered a pandemic viral infection since December 2019. The investigation of the effective prophylaxis or therapeutic strategies for emergency management of the current condition has become a priority for medical research centers and pharmaceutical companies. This article provides a comprehensive review of antibody therapy and its different categories with their advantages and disadvantages for COVID-19 over the last few years of the current pandemic. Antibodies can be generated by active immunization, including natural infection with a pathogen and vaccination, or by the passive immunization method such as convalescent plasma therapy (CPT) and antibody synthesis in laboratories. Each of these ways has its characteristics. Arming the immune system with antibodies is the main aim of antiviral therapeutic procedures toward SARS-CoV-2. Collecting and discussing various aspects of available data in this field can give researchers a better perspective for the production of antibody-based products or selection of the most appropriate approach of antibody therapies to improve different cases of COVID-19. Moreover, it can help them control similar viral pandemics that may happen in the future appropriately.

Recent advances in passive immunotherapies for COVID-19: The Evidence-Based approaches and clinical trials

In late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged, causing a global pandemic called COVID-19. Currently, there is no definitive treatment for this emerging disease. Global efforts resulted in developing multiple platforms of COVID-19 vaccines, but their efficacy in humans should be wholly investigated in the long-term clinical and epidemiological follow-ups. Despite the international efforts, COVID-19 vaccination accompanies challenges, including financial and political obstacles, serious adverse effects (AEs), the impossibility of using vaccines in certain groups of people in the community, and viral evasion due to emerging novel variants of SARS-CoV-2 in many countries. For these reasons, passive immunotherapy has been considered a complementary remedy and a promising way to manage COVID-19. These approaches arebased on reduced inflammation due to inhibiting cytokine storm phenomena, immunomodulation,preventing acute respiratory distress syndrome (ARDS), viral neutralization, anddecreased viral load. This article highlights passive immunotherapy and immunomodulation approaches in managing and treating COVID-19 patients and discusses relevant clinical trials (CTs).

Nimotuzumab for COVID-19: case series

Background: In COVID-19, EGFR production is upregulated in the alveolar epithelial cells. EGFR overexpression further activates STAT-3 and increases lung pathology. The EGFR pathway is also one of the major nodes in pulmonary fibrosis. Methods: Nimotuzumab, a humanized anti-EGFR antibody, was used to treat three patients with severe or moderate COVID-19. The antibody was administered in combination with other drugs included in the national COVID-19 protocol. Results: Nimotuzumab was well tolerated. IL-6 decreased from the first antibody infusion. Clinical symptoms significantly improved after nimotuzumab administration, and the CT scans at discharge showed major resolution of the lung lesions and no signs of fibrosis. Conclusion: Safe anti-EGFR antibodies like nimotuzumab may modulate COVID-19-associated hyperinflammation and prevent fibrosis. Clinical Trial Registration: RPCEC00000369 (RPCEC rpcec.sld.cu).

Immunomodulatory therapies for SARS-CoV-2 infection: a systematic literature review to inform EULAR points to consider

OBJECTIVE

To summarise the available information on efficacy and safety of immunomodulatory agents in SARS-CoV-2 infection.

METHODS

As part of a European League Against Rheumatism (EULAR) taskforce, a systematic literature search was conducted from January 2019 to 11 December 2020. Two reviewers independently identified eligible studies according to the Population, Intervention, Comparator and Outcome framework and extracted data on efficacy and safety of immunomodulatory agents used therapeutically in SARS-CoV-2 infection at any stage. The risk of bias was assessed with validated tools.

RESULTS

Of the 60 372 records, 401 articles were eligible for inclusion. Studies were at variable risk of bias. Randomised controlled trials (RCTs) were available for the following drugs: hydroxychloroquine (n=12), glucocorticoids (n=6), tocilizumab (n=4), convalescent plasma (n=4), interferon beta (n=2), intravenous immunoglobulins (IVIg) (n=2) and n=1 each for anakinra, baricitinib, colchicine, leflunomide, ruxolitinib, interferon kappa and vilobelimab. Glucocorticoids were able to reduce mortality in specific subsets of patients, while conflicting data were available about tocilizumab. Hydroxychloroquine was not beneficial at any disease stage, one RCT with anakinra was negative, one RCT with baricitinib+remdesivir was positive, and individual trials on some other compounds provided interesting, although preliminary, results.

CONCLUSION

Although there is emerging evidence about immunomodulatory therapies for the management of COVID-19, conclusive data are scarce with some conflicting data. Since glucocorticoids seem to improve survival in some subsets of patients, RCTs comparing glucocorticoids alone versus glucocorticoids plus anticytokine/immunomodulatory treatment are warranted. This systematic literature review informed the initiative to formulate EULAR 'points to consider' on COVID-19 pathophysiology and immunomodulatory treatment from the rheumatology perspective.

Disease-drug and drug-drug interaction in COVID-19: Risk and assessment

COVID-19 is announced as a global pandemic in 2020. Its mortality and morbidity rate are rapidly increasing, with limited medications. The emergent outbreak of COVID-19 prompted by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) keeps spreading. In this infection, a patient's immune response plays pivotal role in the pathogenesis. This inflammatory factor was shown by its mediators that, in severe cases, reach the cytokine at peaks. Hyperinflammatory state may sparks significant imbalances in transporters and drug metabolic machinery, and subsequent alteration of drug pharmacokinetics may result in unexpected therapeutic response. The present scenario has accounted for the requirement for therapeutic opportunities to relive and overcome this pandemic. Despite the diminishing developments of COVID-19, there is no drug still approved to have significant effects with no side effect on the treatment for COVID-19 patients. Based on the evidence, many antiviral and anti-inflammatory drugs have been authorized by the Food and Drug Administration (FDA) to treat the COVID-19 patients even though not knowing the possible drug-drug interactions (DDI). Remdesivir, favipiravir, and molnupiravir are deemed the most hopeful antiviral agents by improving infected patient’s health. Dexamethasone is the first known steroid medicine that saved the lives of seriously ill patients. Some oligopeptides and proteins have also been using. The current review summarizes medication updates to treat COVID-19 patients in an inflammatory state and their interaction with drug transporters and drug-metabolizing enzymes. It gives an opinion on the potential DDI that may permit the individualization of these drugs, thereby enhancing the safety and efficacy.

Life-long passion for antiviral research and drug development: 80th birthday of Prof. Dr. Erik De Clercq

Since the 1950s, great efforts have been made to develop antiviral agents against many infectious diseases such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), human cytomegalovirus (HCMV), herpes simplex virus (HSV), and varicella-zoster virus (VZV). Among the list of nearly 106 antiviral agents approved in the past five decades, Prof. Erik De Clercq has contributed to the development of 7 antiviral drugs: tenofovir disoproxil fumarate (Viread®) for HIV and HBV treatment, tenofovir alafenamide (Vemlidy®) for HIV and HBV treatment, brivudine (Zostex®) for HSV-1 and VZV treatment, valacyclovir (Valtrex®) for HSV and VZV treatment, adefovir dipivoxil (Hepsera®) for HBV treatment, stavudine (Zerit®) for HIV treatment, and cidofovir (Vistide®) for treating HCMV retinitis in AIDS patients. In addition to the above antiviral drugs, his contributions include two anti-cancer drugs: rabacfosadine (Tanovea®-CA1) for canine lymphoma and plerixafor (Mozobil®) for multiple myeloma and non-Hodgkin's lymphoma. These achievements are driven by his life-long passions for antiviral research and successful collaborations worldwide. To honor the 80th birthday of Prof. Erik De Clercq, this study highlights his scientific achievements and the importance of life-long passions and collaborations in the success of antiviral research and drug development.