Anti-CD20 monoclonal antibodies are widely used for the treatment of hematological malignancies or autoimmune disease but may be responsible for a secondary humoral deficiency. In the context of COVID-19 infection, this may prevent the elicitation of a specific SARS-CoV-2-antibody response. We report a series of 17 consecutive patients with profound B-cell lymphopenia and prolonged COVID-19 symptoms, negative IgG-IgM SARS-CoV-2 serology and a positive RNAemia measured by digital PCR who were treated with four units of COVID-19 convalescent plasma. Within 48 hours following transfusion, all patients except one experienced an amelioration of their clinical symptoms. The inflammatory syndrome abated within a week. Only one patient who needed mechanical ventilation for severe COVID-19 disease died of bacterial pneumonia. SARS-CoV-2 RNAemia decreased to below the sensitivity threshold in 9 out of 9 evaluated patients. Analysis of virus-specific T-cell responses using T-cell enzyme linked immunoSpot (ELISPOT) assay was analyzed before convalescent plasma transfusion in 3 patients. All showed a conserved SARS-CoV-2 T-cell response and poor cross-response to other coronaviruses. No adverse event was reported. In COVID-19 patients unable to mount a specific humoral response to SARS-CoV-2, convalescent plasma with anti-SARS-CoV-2 antibodies appears to be a very promising approach in the context of protracted COVID-19 symptoms.

This study evaluated the safety and immunogenicity of BNT162b2 vaccine in patients with hematological malignancies. Antibodies blocking spike binding to immobilized ACE-2 (NAb) correlated with anti-Spike (S) IgG d42 titers (Spearman r = 0.865, p < 0.0001), and an anti-S IgG d42 level ≥3100 UA/mL was predictive of NAb ≥ 30%, the positivity cutoff for NAb (p < 0.0001). Only 47% of the patients achieved an anti-S IgG d42 level ≥3100 UA/mL after the two BNT162b2 inocula, compared to 87% of healthy controls. In multivariable analysis, male patients, use of B-cell targeting treatment within the last 12 months prior to vaccination, and CD19+ B-cell level <120/uL, were associated with a significantly decreased probability of achieving a protective anti-S IgG level after the second BNT162b2 inoculum. Finally, using the IFN-γ ELISPOT assay, we found a significant increase in T-cell response against the S protein, with 53% of patients having an anti-S IgG-positive ELISPOT after the second BNT162b2 inoculum. There was a correlation between the anti-S ELISPOT response and IgG d42 level (Spearman r = 0.3026, p = 0.012). These findings suggest that vaccination with two BNT162b2 inocula translates into a significant increase in humoral and cellular response in patients with hematological malignancies, but only around half of the patients can likely achieve effective immune protection against COVID-19.