Patterns of seroconversion for SARS-CoV-2 IgG in patients with malignant disease and association with anticancer therapy

Patients with cancer have been identified in several studies to be at high risk of developing severe COVID-19; however, rates of SARS-CoV-2 IgG seroconversion and its association with cancer types and anticancer therapy remain obscure. We conducted a retrospective cohort study in patients with cancer who underwent SARS-CoV-2 IgG testing. Two hundred and sixty-one patients with a cancer diagnosis underwent SARS-CoV-2 IgG testing and demonstrated a high rate of seroconversion (92%). However, significantly lower seroconversion was observed in patients with hematological malignancies (82%), patients who received anti-CD-20 antibody therapy (59%) and stem cell transplant (60%). Notably, all 17 patients who received immunotherapy, including 16 that received anti-PD-1/PD-L1 monoclonal antibodies, developed SARS-CoV-2 IgG antibodies (100% seroconversion). These data show differential rates of seroconversion in specific patient groups and bear importance for clinical monitoring and vaccination strategies that are being developed to mitigate the COVID-19 pandemic.