Convalescent plasma treatment of persistent severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in patients with lymphoma with impaired humoral immunity and lack of neutralising antibodies.

Abstract

Since the first outbreak in Hubei, China in December 2019, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has rapidly spread across the globe. The broadly prescribed anti-CD20 monoclonal antibody rituximab induces B-cell depletion and may affect anti-viral immunity, including the development of SARS-CoV-2 antibodies, risk of re-infection, and impaired vaccine efficacy.1 Recently, Hueso et al.2 reported on protracted coronavirus disease 2019 (COVID-19) in patients with profound B-cell lymphopenia. In their study, they focussed on SARS-CoV-2 RNAaemia and pretreatment T-cell responses. As they could not exclude spontaneous recovery, we investigated the humoral immune response kinetics in B-cell-depleted patients with protracted COVID-19 in more detail using a functional SARS-CoV-2 plaque-reduction neutralisation test (PRNT). All adult B-cell-depleted patients with protracted COVID-19 between 1 April and 1 August 2020 were included in our single-centre study. COVID-19 was defined as a positive respiratory sample reverse transcriptase-polymerase chain reaction (RT-PCR) result in symptomatic patients. Each patient received two consecutive ABO-compatible COVID-19 convalescent plasma (CCP) transfusions (all units had a neutralising antibody titre of 1:160). Clinical response was defined as a temperature of <38°C, C-reactive protein (CRP) of <10 mg/l, and hospital discharge within 7 days after the first CCP administration. The present study was approved by the Ethics Committee of the University Hospitals Leuven (S64533) and all participants provided informed consent. Serum anti-SARS-CoV-2 nucleoprotein immunoglobulin G (IgG) antibodies were assessed using the Abbott ARCHITECT SARS-CoV-2 IgG chemiluminescent microparticle immunoassay following the manufacturer’s instructions (Abbott Park, IL, USA). PRNT assays were conducted with a passage 5 Belgium clinical isolate (SARS-2-CoV/Belgium/GHB-03021/2020, GISAID accession number EPI_ISL_407976) in a certified biosafety level 3+ laboratory: after incubating serial dilutions of inactivated patient’s serum and 400 plaque-forming units (pfu) SARS-CoV-2 in 96-well plates seeded with Vero E6 wells (1 h, 37°C, humidified 5% CO2 atmosphere), a 1% agarose (SeaKem LE agarose, Lonza, Belgium) overlay was added (4 days, 37°C). Following overlay with 1% neutral red/1% agarose (24 h, 37°C), plaques were counted. Virus neutralisation titres were reported as 50% reduction (NT50) or 90% reduction (NT90) in the number of plaques in comparison to a non-neutralising antibody control. SARS-CoV-2 RT-PCR was performed using an in-house method complying with the World Health Organization (WHO) guidelines.3 Five severely B-cell-depleted patients with mild-to-moderate respiratory symptoms and fever were identified (Table I, Fig 1A). Inflammatory parameters were persistently elevated in the absence of microorganisms other than SARS-CoV-2. Four patients had hypogammaglobinaemia (IgG <7·51 g/l). Two patients required continuous oxygen supplementation via nasal cannula (1–3 l/min). Prior to CCP administration [median (range) illness duration 56 (47–116) days], (neutralising) SARS-CoV-2 antibodies were low or undetectable (Fig 1B). Only after administration of CCP moderate neutralising antibody titres were measured up to day 6. Semi-quantitative SARS-CoV-2 RT-PCR measurements (Fig 1C) showed a clear association between waxing and waning COVID-19 symptoms, nasopharyngeal viral load and presence of neutralising antibodies. CCP treatment was associated with a clinical response in four patients. One lung transplant patient did not make a complete recovery of COVID-19 pneumonia and had persistently positive bronchoalveolar SARS-CoV-2 RT-PCR results despite an initial clinical improvement after CCP therapy. A negative bronchoalveolar RT-PCR was finally obtained after retreatment with CCP and initiation of remdesivir. Nevertheless, the patient died from invasive pulmonary aspergillosis and antibody-mediated transplant rejection. Even though SARS-CoV-2 IgG antibodies were absent at follow-up in all patients, no relapse was observed after a median (range) follow-up of 117·5 (88–148) days in the four surviving patients. The impact of rituximab treatment and B-cell depletion on the incidence and severity of SARS-CoV-2 infection remains to be fully elucidated. Montero-Escribano et al.4 did not find an increased risk of SARS-CoV-2 infection in 60 patients with multiple sclerosis receiving anti-CD20 treatment. However, SARS-CoV-2 infection was not confirmed by RT-PCR in most of the patients. Other authors did report a more severe, even fatal, COVID-19 disease course in patients with inflammatory rheumatic diseases treated with rituximab.5, 6 Hueso et al.2 were the first to report protracted COVID-19 in 17 consecutive patients with B-cell lymphopenia. In their study, intact T-cell function before CCP therapy was verified, but data on the hypothesised impaired neutralising antibody formation were lacking. Their study did not answer the question of whether administration of CCP had an immunomodulatory effect. Our present study demonstrates that protracted COVID-19 in patients with B-cell lymphoma is associated with a lack of significant neutralising antibody titres and impaired clearance of SARS-CoV-2. Treatment with CCP resulted in an increase in neutralising antibody titres in all patients and a clinical response in four out of the five patients. One patient had an initial clinical improvement, but was readmitted 34 days after CCP with repeated imaging suggestive of COVID-19 pneumonia and SARS-CoV-2 RT-PCR positivity, which required repeated CCP administration and remdesivir treatment. The present report has several limitations. First, all patients received other immunocompromising agents in addition to rituximab. Second, as all patients in our study had a history of lymphoma, the results should not be extrapolated to patients receiving anti-CD20 treatment for other conditions, including non-infectious inflammatory disorders. Furthermore, not all patients with B-cell depletion appear to be at risk for a protracted COVID-19 disease course, and further research will be required to identify the best candidates for CCP therapy early in the disease course. Third, the retrospective nature of our report and the limited follow-up time does not allow us to draw firm conclusions on the efficacy of CCP therapy in this patient cohort. However, our present study is the first to demonstrate that B-cell depletion is associated with an impaired humoral immune response in COVID-19, and that the consequent absence of neutralising antibodies may result in an inability to clear SARS-CoV-2 and a protracted disease course. In conclusion, B-cell depletion may be associated with decreased neutralising antibody titre formation, reduced viral clearance and protracted clinical manifestations of SARS-CoV-2 infection. Patients with B-cell-depleted lymphoma with protracted SARS-CoV-2 infection may be excellent candidates for passive transfer of immunity by COVID-19 CCP therapy. Albrecht Betrains and Steven Vanderschueren designed the study. Albrecht Betrains and Wouter Rosseels analysed the data. Albrecht Betrains, Laurent Godinas, F. J. Sherida H. Woei-A-Jin, Wouter Rosseels and Steven Vanderschueren drafted the manuscript. All the co-authors contributed to data collection and critically revised the manuscript. All the authors gave final approval for the version to be published. The authors thank Lies Laenen, PhD, Laboratory of Clinical and Epidemiological Virology (Rega Institute, Belgium), for her contributions with regard to molecular virological data. This study was not financially supported. None of the authors have competing interests.