Usefulness of Plasma SARS-CoV-2 RNA Quantification by Droplet-based Digital PCR to Monitor Treatment Against COVID-19 in a B-cell Lymphoma Patient

Szwebel, Tali-Anne; Veyer, David; Robillard, Nicolas; Eshagh, Deborah; Canoui, Etienne; Bruneau, Thomas; Contejean, Adrien; Azoulay, Celia; Serrano, Thomas; Hueso, Thomas; Izquierdo, Laure; Rozenberg, Flore; Terrier, Benjamin; Vignon, Marguerite; Laurent-Puig, Pierre; Taly, Valérie; Bélec, Laurent; Kernéis, Solen; Lacombe, Karine; Péré, Hélène

We report the case of an HIV-1-infected patient, treated with anti-CD20 monoclonal antibody for a B-cell lymphoma previously treated by autologous stem cell transplant. He suffered from chronic COVID19 and we monitored by plasma SARS-CoV-2 RNA by highly sensitive droplet-based digital PCR technology (ddPCR). Under tocilizumab therapy and despite a first clinical improvement biologically associated with decreasing inflammatory markers, a slight increase of SARS-CoV-2 RNAaemia quantified by ddPCR was highlighted, confirming the absence of viral efficacy of this treatment and predicting the subsequent observed deterioration. As expected, his complete recovery, finally achieved after COVID-19 convalescent plasmatherapy, strictly paralleled plasma SARS-CoV-2 RNA clearance. With these results, we confirmed the interest of SARS-CoV-2 RNAaemia monitoring by ddPCR in COVID-19 patients, particularly during treatment, and firstly showed that this new and specific biomarker could be helpful to select eligible patient for anti-IL6 receptors therapy considering the variable levels of efficacy recently observed with such therapy.