Antibody response against SARS-CoV-2 in convalescent plasma donors: can we predict subjects' eligibility?

Association between clinical symptoms during the COVID-19 infection and SARS-CoV-2 immunoglobulin G titers in COVID-19 convalescent whole-blood donors in China

BACKGROUND

Limited studies have explored the association between clinical symptoms and titers of SARS-CoV-2 antibodies.

STUDY DESIGN AND METHODS

In this cross-sectional study, whole-blood donors who had experienced a confirmed or suspected COVID-19 infection completed questionnaires at the time of blood donation. Plasma SARS-CoV-2 immunoglobulin G (IgG) titers were measured using an enzyme-linked immunosorbent assay. Logistic regression models were used to calculate odds ratios (ORs) for high-titer COVID-19 convalescent plasma (CCP) for each variable.

RESULTS

Among the total 386 donors, 120 (31%) donors with IgG titers ≥1:160 were classified as high-titer donors. The multivariable ORs (95% confidence intervals [CIs]) for high titers were 2.33 (1.45-3.75), 2.11 (1.29-3.43), 1.10 (1.01-1.21), 1.19 (1.00-1.43), and 1.97 (1.05-3.71) for sore throat, cough, symptom count, fever duration, and low fever (compared with non-fever), respectively. No significant association was observed between other symptoms and medical visits and the odds of high-titer CCP. The association between high-titer CCP and fever duration was restricted to confirmed COVID-19-infected donors, while associations with sore throat and cough remained significant in suspected infected donors. In addition, medical visit was positively associated with high-titer CCP in suspected donors, but not in confirmed donors. In bootstrapped logistic regression models, the associations remained significant and reproducible for medical visit in suspected donors and for sore throat and cough in both suspected donors and total donors.

DISCUSSION

Experiencing a sore throat and cough were associated with high-titer CCP in overall donors. We also identified sore throat, cough, and medical visits as potential predictors of high-titer CCP for suspected donors during the pandemic.

Simple prediction of COVID-19 convalescent plasma units with high levels of neutralization antibodies

BACKGROUND

Hyperimmune convalescent COVID-19 plasma (CCP) containing anti-SARS-CoV-2 neutralizing antibodies (NAbs) was proposed as a therapeutic option for patients early in the new coronavirus disease pandemic. The efficacy of this therapy depends on the quantity of neutralizing antibodies (NAbs) in the CCP units, with titers ≥ 1:160 being recommended. The standard neutralizing tests (NTs) used for determining appropriate CCP donors are technically demanding and expensive and take several days. We explored whether they could be replaced by high-throughput serology tests and a set of available clinical data.

METHODS

Our study included 1302 CCP donors after PCR-confirmed COVID-19 infection. To predict donors with high NAb titers, we built four (4) multiple logistic regression models evaluating the relationships of demographic data, COVID-19 symptoms, results of various serological testing, the period between disease and donation, and COVID-19 vaccination status.

RESULTS

The analysis of the four models showed that the chemiluminescent microparticle assay (CMIA) for the quantitative determination of IgG Abs to the RBD of the S1 subunit of the SARS-CoV-2 spike protein was enough to predict the CCP units with a high NAb titer. CCP donors with respective results > 850 BAU/ml SARS-CoV-2 IgG had a high probability of attaining sufficient NAb titers. Including additional variables such as donor demographics, clinical symptoms, or time of donation into a particular predictive model did not significantly increase its sensitivity and specificity.

CONCLUSION

A simple quantitative serological determination of anti-SARS-CoV-2 antibodies alone is satisfactory for recruiting CCP donors with high titer NAbs.

Convalescent plasma therapy against the emerging SARS-CoV-2 variants: Delineation of the potentialities and risks

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has resulted in a catastrophic pandemic and severely impacted people's livelihoods worldwide. In addition, the emergence of SARS-CoV-2 variants has posed a severe threat to humankind. Due to the dearth of therapeutic options during the commencement of the pandemic, convalescent plasma therapy (CPT) played a significant part in the management of patients with severe form of COVID-19. Several recent studies have proposed various protective effects of CPT, such as antiviral, anti-inflammatory, anti-thrombotic, and immunomodulatory actions, curtailing the devastating consequences of the SARS-CoV-2 infection. On the contrary, several clinical studies have raised some serious concerns about the effectiveness and reliability of CPT in the management of patients with COVID-19. The protective effects of CPT in severely ill patients are yet to be proved. Moreover, the emergence of SARS-CoV-2 variants has raised concerns about the effectiveness of CPT against COVID-19. Therefore, to establish concrete evidence of the efficacy of CPT and adjudicate its inclusion in the management of COVID-19, an updated review of present literature is required, which could help in the development of an efficient therapeutic regimen to treat COVID-19 amid the emergence of new viral variants.