SARS-CoV-2 Neutralization in Convalescent Plasma and Commercial Lots of Plasma-derived Immunoglobulin

Abstract

Introduction: Patients suffering from primary or secondary immunodeficiency face times of increased insecurity and discomfort in the light of the raging Covid-19 pandemic, not knowing if and to what extend their comorbidities impact a potential Covid-19 course of disease. Furthermore, recently available vaccination options might not be amenable or effective for all patients of this heterogeneous population. Therefore, these patients often rely on passive immunization with plasma-derived, intravenous or subcutaneous immunoglobulin (IVIG/SCIG). Whether the ongoing Covid-19 pandemic and/or the progress in vaccination programs lead to increased and potentially protective titers in plasma-derived immunoglobulins (Ig) indicated e.g. for humoral immunodeficiency remains a pressing question for this patient population. Purpose: Here we investigated SARS-CoV-2 reactivity of US plasma-derived IVIG/SCIG products from the end of 2020 until 06/2021 as well as in convalescent plasma (CP) from 05/2020 to 08/2020. Methods: Final containers of IVIG/SCIG and CP donations were analyzed by commercial ELISA for SARS-CoV-2 S1-RBD IgG as well as microneutralization assay using a patient-derived SARS-CoV-2 (D614G) isolate. Neutralization capacities of 313 plasma single donations and 119 plasma-derived IVIG/SCIG lots were determined. Results obtained from both analytical methods were normalized against the international WHO standard. Finally, based on dense pharmacokinetic profiles of an IVIG preparation from previously published investigations, possible steady-state plasma levels of SARS-CoV-2 neutralization capacities were approximated based on currently measured anti-SARS-CoV-2 potencies in IVIG/SCIG preparations. Results: CP donations presented with a high variability with regards to anti-SARS-reactivity in ELISA as well as in neutralization testing. While approximately 50% of convalescent donations were none/low neutralizing, approximately 10% were at or above 1000 IU/ml. IVIG/SCIG lots derived from pre-pandemic plasma donations did not show neutralizing capacities of SARS-CoV-2. Lots produced between 12/2020 and 06/2021, entailing plasma donations after emergence of SARS-CoV-2 showed a rapid and constant increase in anti-SARS-CoV-2 reactivity and neutralization capacity over time. Neutralization capacity increased from a mean of 20 IU/ml in 12/2020 to 505 IU/ml in 06/2021, while lot-to-lot variability was substantial. Pharmacokinetic (PK) extrapolations based on non-compartmental superposition principles using steady-state reference profiles from previously published PK investigations on IVIG in PID, yielded potential steady-state trough plasma levels of 16 IU/ml based on the average final container concentration from 05/2021 with 216 IU/ml. Maximum extrapolated trough levels could reach 64 IU/ml based on the latest maximal final container potency tested in 06/2021. Conclusions: SARS-CoV-2 reactivity and neutralization capacity in IVIG/SCIG produced from US plasma rapidly and in part exponentially increased in the first half of 2021. The observed increase of final container potencies is likely trailing the serological status of the US donor population in terms of Covid-19 convalescence and vaccination by at least 5 months due to production lead times and should in principle continue at least until fall 2021. In summary, the data support rapidly increasing levels of SARS-COV-2 antibodies in IVIG/SCIG products implicating that a certain level of protection could be possible against COVID-19 for regularly substituted PID/SID patients. Nevertheless, more research to confirm, which plasma levels are needed for protection against SARS-CoV-2 infection of immune-compromised patients is still needed.

Antibody response following the third and fourth SARS-CoV-2 vaccine dose in individuals with common variable immunodeficiency

“…During the pandemic, companies producing IgRT, such as Octapharma ® and Takeda ® , have reported rapidly increasing SARS-CoV-2 antibodies in commercial lots from pooled donated plasma (4,5). We showed high variation in the different IgRT products, with some products containing very low concentrations why a clinical effect seems unlikely.…”

“…We showed high variation in the different IgRT products, with some products containing very low concentrations why a clinical effect seems unlikely. Moreover, it takes at least 5-6 months to prepare a ready-touse IgRT product from donated plasma (4,5). Hence, products from different time periods (i.e., with high or low transmission and vaccination rate), may explain some of the variation in the product levels of antibodies.…”

“…Most CVID patients receive immunoglobulin replacement therapy (IgRT) from healthy donors to supplement the deficient antibody production (~passive immunization). The concentration of SARS-CoV-2-specific antibodies in the current IgRT preparations are unknown, but recent publications have indicated increasing amounts (4,5). Still, it is not known which levels are needed to confer protection against SARS-CoV-2 infection.…”