Manufacturing of convalescent plasma of COVID-19 patients: Aspects of quality

Cytokine, Anti-SARS-CoV-2 Antibody, and Neutralizing Antibody Levels in Conventional Blood Donors Who Have Recovered from COVID-19

Background

At the beginning of the pandemic, COVID-19 convalescent plasma (CCP) containing anti-SARS-CoV-2 antibodies was suggested as a source of therapy. In the last 3 years, many trials have demonstrated the limited usefulness of CCP therapy. This led us to the hypothesis that CCP could contain other elements, along with the desired neutralizing antibodies, which could potentially prevent it from having a therapeutic effect, among them cytokines, chemokines, growth factors, clotting factors, and autoantibodies.

Methods

In total, 39 cytokines were analyzed in the plasma of 190 blood donors, and further research focused on the levels of 23 different cytokines in CCP (sCD40L, eotaxin, FGF-2, FLT-3L, ractalkine, GRO-α, IFNα2, IL-1β, IL-1RA, IL-5, IL-6, IL-8, IL-12, IL-13, IL-15, IL-17E, IP-10, MCP-1, MIP-1b, PDGF-AA, TGFα, TNFα, and TRAIL). Anti-SARS-CoV-2 antibodies and neutralizing antibodies were detected in CCP.

Results

We found no significant differences between CCP taken within a maximum of 180 days from the onset of the first COVID-19 symptoms and the controls. We also made a comparison of the cytokine levels between the low neutralizing antibodies (<160) group and the high neutralizing antibodies (≥160) group and found there were no differences between the groups. Our research also showed no correlation either to levels of anti-SARS-CoV-2 IgG Ab or to the levels of neutralizing antibodies. There were also no significant changes in cytokine levels based on the period after the start of COVID-19 symptoms.

Conclusions

No elements which could potentially be responsible for preventing CCP from having a therapeutic effect were found.

Convalescent plasma (hyperimmune immunoglobulin) for COVID-19 management: An update

The pandemic COVID-19 has spread widely throughout the globe and has been responsible for millions of deaths worldwide. Recently, it has been identified that there is no specific and 100% effective treatment available to manage the infection especially for the severe cases. A significant amount of research efforts and clinical trials have been undertaken globally and many more are underway to find the potential treatment option. Earlier, convalescent plasma or hyperimmune immunoglobulin was effectively used in the treatment of many endemic or epidemic viral infections as a part of passive immunization. In this article, we have touched upon the immunopathology of COVID-19 infection, a basic understanding of convalescent plasma, it's manufacturing as well as evaluation, and have reviewed the scientific developments focussing on the potential of convalescent plasma vis-à-vis other modalities for the management of COVID-19. The article also covers various research approaches, clinical trials conducted globally, and the clinical trials which are at various stages for exploring the efficacy and safety of the convalescent plasma therapy (CPT) to predict its future perspective to manage COVID-19.

A Review on Effectiveness of Plasma Therapy in Severe COVID-19 Patients

Coronavirus 2019 has created a big threat to the modern world. Many researchers and scientists had taken the burden of finding information about this entity, its structure, its transmission, and also about the treatment that can be given to individuals infected by it. There has been use of different medicines at different times simultaneously researching about them, starting with only symptomatic and supportive treatment, then antimalarial agents like chloroquine and hydroxychloroquine, then going to favipavir, and other antivirals, then came the use of vaccines and also convalescent plasma therapy for COVID-19. The most advanced is convalescent plasma use for the treating coronavirus. Using plasma of patients who have remitted from this disease and putting it into those individuals who are dealing with the disease or are critically ill for improvement of their health status. This treatment has been used for many other diseases too and has been proven efficacious. So, this technique is being used and studied for coronavirus 2019 as well. There have been set certain criteria for those who can donate plasma and also criteria for the recipients of this technique. Also, there can be adverse reactions or even side effects with this, like transfusion-related acute lung injury (TRALI), so they should also be kept in mind during treatment with this method. So, though there are many methods to date to treat these individuals but one of the latest ones is using plasma, which is proven to be efficacious but still many studies are under process for the same.

Association between Reactogenicity and Immunogenicity after Vaccination with BNT162b2

It is not clear whether there is an association between adverse reactions and immune response after vaccination. Seven hundred and thirty-five vaccinees from our University Medical Center vaccination clinic provided information about sex, age and adverse reactions after first and second vaccination with BNT162b2. Adverse reactions were categorized into three groups: no or minor on the injection side, moderate (not further classified) and severe-defined as any symptom(s) resulting in sick leave. We chose 38 vaccinees with the most severe adverse reactions and compared their humoral and T-cell-mediated immune responses after second vaccination with those of 38 sex and age matched controls without or only minor injection-side related adverse reactions. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) anti-receptor binding domain (RBD) IgG titers were detectable in all participants (median 5528; range 958-26,285). Men with severe adverse reactions had 1.5-fold higher median SARS-CoV-2 RBD IgG titers compared to men without adverse reactions (median 7406 versus 4793; p < 0.001). Similarly; neutralization activity was significantly higher in men with severe adverse reactions (half maximal inhibitory concentrations (IC50) median 769 versus 485; p < 0.001). Reactogenicity did not influence humoral immune response in women nor T-cell-mediated immune response in any sex. To conclude; adverse reactions after vaccination with BNT162b2 do influence humoral immune response yet only in men and are not a prerequisite for a robust antibody response.

Detection of SARS-CoV-2-independent immunoregulatory activity of COVID-19 convalescent plasma

BACKGROUND

Convalescent plasma has emerged as a potential specific treatment for coronavirus disease 2019 (COVID-19), since it contains severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. Several studies are currently investigating the efficacy of convalescent plasma for treatment of COVID-19, with a focus on neutralizing antibodies. However, there is little information on whether convalescent plasma may contain additional immunoregulatory constituents produced by the blood donor during convalescence. Therefore, using a standardized whole blood assay employing synthetic toll-like receptor (TLR) ligands, we have investigated the immunoregulatory capacity of convalescent plasma in direct comparison to ABO-matched allogeneic control plasma.

STUDY DESIGN AND METHODS

Whole blood samples from healthy blood donors were collected, and autologous plasma was replaced by convalescent plasma or ABO-matched control plasma. Standardized innate immune triggering and monitoring was performed by adding different TLR ligands (Pam3CsK4 [TLR1/2], HKLM [TLR2], LPS [TLR4], flagellin [TLR5], ssRNA40 [TLR8], imiquimod [TLR7], and FSL-1 [TLR2/6]) and subsequent quantitative analysis of pro- and anti-inflammatory cytokines (IP-10, IL-1β, TNF-α, MCP-1, IL-6, IL-10, and IFN-γ) by cytometric bead array. Negative controls included unstimulated samples as well as samples spiked with autologous plasma.

RESULTS

COVID-19 convalescent plasma (CCP) significantly decreased pro-inflammatory cytokines production triggered by different TLR ligands in healthy donors as compared with healthy control plasma. IL-6, MCP-1, and IFN-γ represented the cytokines that are most frequently downregulated by convalescent plasma.

CONCLUSION

Our experiments reveal a potential novel, SARS-CoV-2-independent immunomodulatory activity of CCP, which may be beneficial for COVID-19 patients.

Donors for SARS-CoV-2 Convalescent Plasma for a Controlled Clinical Trial: Donor Characteristics, Content and Time Course of SARS-CoV-2 Neutralizing Antibodies

Background

Convalescent plasma is one of the treatment options for COVID-19 which is currently being investigated in many clinical trials. Understanding of donor and product characteristics is important for optimization of convalescent plasma.

Methods

Patients who had recovered from CO­VID-19 were recruited as donors for COVID-19 convalescent plasma (CCP) for a randomized clinical trial of CCP for treatment of severe COVID-19 (CAPSID Trial). Titers of neutralizing antibodies were measured by a plaque-reduction neutralization test (PRNT). Correlation of antibody titers with host factors and evolution of neutralizing antibody titers over time in repeat donors were analysed.

Results

A series of 144 donors (41% females, 59% males; median age 40 years) underwent 319 plasmapheresis procedures providing a median collection volume of 850 mL and a mean number of 2.7 therapeutic units per plasmapheresis. The majority of donors had a mild or moderate course of COVID-19. The titers of neutralizing antibodies varied greatly between CCP donors (from <1:20 to >1:640). Donor factors (gender, age, ABO type, body weight) did not correlate significantly with the titer of neutralizing antibodies. We observed a significant positive correlation of neutralization titers with the number of reported COVID-19 symptoms and with the time from SARS-CoV-2 diagnosis to plasmapheresis. Neutralizing antibody levels were stable or increased over time in 58% of repeat CCP donors. Mean titers of neutralizing antibodies of first donation and last donation of repeat CCP donors did not differ significantly (1:86 at first compared to 1:87 at the last donation). There was a significant correlation of neutralizing antibodies measured by PRNT and anti-SARS-CoV-2 IgG and IgA antibodies which were measured by ELISA. CCP donations with an anti-SARS-CoV-2 IgG antibody content above the 25th percentile were substantially enriched for CCP donations with higher neutralizing antibody levels.

Conclusion

We demonstrate the feasibility of collection of a large number of CCP products under a harmonized protocol for a randomized clinical trial. Titers of neutralizing antibodies were stable or increased over time in a subgroup of repeat donors. A history of higher number of COVID-19 symptoms and higher levels of anti-SARS-CoV-2 IgG and IgA antibodies in immunoassays can preselect donations with higher neutralizing capacity.

Evaluation of a Broad Panel of SARS-CoV-2 Serological Tests for Diagnostic Use

Serological testing is crucial in detection of previous infection and in monitoring convalescent and vaccine-induced immunity. During the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) pandemic, numerous assay platforms have been developed and marketed for clinical use. Several studies recently compared clinical performance of a limited number of serological tests, but broad comparative evaluation is currently missing. Within this study, a panel of 161 sera from SARS-CoV-2 infected, seasonal CoV-infected and SARS-CoV-2 naïve subjects was enrolled to evaluate 16 ELISA/ECLIA-based and 16 LFA-based tests. Specificities of all ELISA/ECLIA-based assays were acceptable and generally in agreement with the providers' specifications, but sensitivities were lower as specified. Results of the LFAs were less accurate as compared to the ELISAs, albeit with some exceptions. We found a sporadic unequal immune response for different antigens and thus recommend the use of a nucleocapsid protein (N)- and spike protein (S)-based test combination when maximal sensitivity is necessary. Finally, the quality of the immune response in terms of neutralization should be tested using S-based IgG tests.

COVID-19 convalescent plasma composition and immunological effects in severe patients

Convalescent plasma (CP) has emerged as a treatment for COVID-19. However, the composition and mechanism of action are not fully known. Therefore, we undertook a two-phase controlled study in which, first the immunological and metabolomic status of recovered and severe patients were evaluated. Secondly, the 28-day effect of CP on the immune response in severe patients was assessed. Nineteen recovered COVID-19 patients, 18 hospitalized patients with severe disease, and 16 pre-pandemic controls were included. Patients with severe disease were treated with CP transfusion and standard therapy (i.e., plasma recipients, n = 9) or standard therapy alone (n = 9). Clinical and biological assessments were done on day 0 and during follow-up on days 4, 7, 14, and 28. Clinical parameters, viral load, total immunoglobulin (Ig) G and IgA anti-S1-SARS-CoV-2 antibodies, neutralizing antibodies (NAbs), autoantibodies, cytokines, T and B cells, and metabolomic and lipidomic profiles were examined. Total IgG and IgA anti-S1-SARS-CoV-2 antibodies were key factors for CP selection and correlated with NAbs. In severe COVID-19 patients, mostly interleukin (IL)-6 (P = <0.0001), IL-10 (P = <0.0001), IP-10 (P = <0.0001), fatty acyls and glycerophospholipids were higher than in recovered patients. Latent autoimmunity and anti–IFN–α antibodies were observed in both recovered and severe patients. COVID-19 CP induced an early but transient cytokine profile modification and increases IgG anti-S1-SARS-CoV-2 antibodies. At day 28 post-transfusion, a decrease in activated, effector and effector memory CD4⁺ (P < 0.05) and activated and effector CD8⁺ (P < 0.01) T cells and naïve B cells (P = 0.001), and an increase in non-classical memory B cells (P=<0.0001) and central memory CD4⁺ T cells (P = 0.0252) were observed. Moreover, IL-6/IFN-γ (P = 0.0089) and IL-6/IL-10 (P = 0.0180) ratios decreased in plasma recipients compared to those who received standard therapy alone. These results may have therapeutic implications and justify further post-COVID-19 studies.