Houston Methodist Hospital Houston, Texas, United States
Background/Case Studies: COVID-19 vaccine-induced anti-SARS-CoV-2 antibodies have been shown to provide crucial protection against COVID-19 infection. Therapeutic plasma exchange (TPE) is an effective treatment for antibody-mediated disorders, including autoimmune neurological diseases and solid organ transplant rejection. However, TPE also removes protective immunoglobulins. Its effect on anti-SARS-CoV-2 antibody levels is not known, and COVID-19 infection in patients with autoimmune disease or in solid organ transplant recipients can be devastating. The goal of this study is to investigate the pre- and post-TPE SARS-CoV-2 antibody levels in patients with antibody-mediated rejection (AMR) or autoimmune neurological diseases.
Study
Design/Methods: In this prospective study, 8 patients with AMR and 7 patients with autoimmune neurological diseases who underwent TPE and met the following inclusion criteria were enrolled: >18 years old, received SARS-CoV-2 mRNA vaccines, no history of COVID-19 infection, and confirmed positive anti-SARS-CoV-2 Spike IgG before initiation of TPE. Among them, 4 patients with AMR and 2 patients with neurological diseases underwent a course of 5 TPEs on an every-other-day schedule. Plasma samples were collected before the first TPE, immediately after the first TPE, and after the last TPE for those receiving a course of 5 TPEs. Samples were also collected 2-3 weeks after completion of the 5 TPE series in 2 AMR and 1 neurology patients. Anti-SARS-CoV-2 spike IgG titers were measured with a clinically validated quantitative assay. Results were analyzed by comparing individual patients' antibody titers after TPE to their pre-TPE values. All TPEs were performed with one blood volume exchange using 5% albumin or fresh frozen plasma. No patients received vaccine boosters or reported COVID-19 related symptoms during the study period. All AMR patients received common immunosuppressive therapy, but no intravenous immunoglobulins or B cell depletion therapy. Neurology patients received no immunosuppressive therapy.
Results/Findings: Days between vaccination to TPE varied from 47 to 260, with a median of 81 days. The average reduction of anti-Spike IgG from the pre-TPE level was 63% after one TPE and 88% after the last TPE in those receiving a course of 5 TPEs. No statistical difference was found in the reduction of anti-Spike IgG between AMR patients and neurology patients after one TPE (65 ± 7% vs. 63 ± 7%; p = 0.633) or after completion of the 5 TPE series (88 ± 3% vs. 78 ± 14%; p = 0.206). Of those with 2-3 week follow up, anti-Spike IgG recovered to 41% of pre-TPE levels in the 2 AMR patients, and to 119% of pre-TPE level in the neurology patient (Figure A). Conclusions: TPE significantly reduced COVID vaccine-induced antibody titers, especially after a series of 5 TPEs, raising the possibility of an increased risk of COVID-19 infection while patients undergo TPE.
Importance of research: The results from this prospective study clearly show a significant reduction of anti-SARS-CoV-2 antibody levels in patients undergoing TPE. Based on this knowledge, at-risk patients may benefit from COVID-19 convalescent plasma and/or additional vaccine boosters during TPE. Although the COVID-19 pandemic appears to be nearing an end, these findings still apply to any vaccine-induced protective antibodies, especially in susceptible patients or during times of high disease prevalence.
