Humoral Immune Response Following COVID-19 Vaccination in Patients With Chronic Lymphocytic Leukemia and Other Indolent Lymphomas: A Large, Single-Center Observational Study

ABSTRACT

Background: Chronic lymphocytic leukemia (CLL) and other Non-Hodgkin's lymphomas (NHLs) are associated with broad immunosuppression, conferring a greater risk for infection-related morbidity and mortality. During the SARS-CoV-2 pandemic, patients with these conditions have been shown to be more susceptible to severe cases of infection. Vaccination against SARS-CoV-2 generally protects against severe disease, but there is scarce data on immune response in those with lymphoid malignancies. Our study aims to analyze antibody (Ab) response to vaccination against SARS-CoV-2 in patients with CLL, Waldenstrom macroglobulinemia (WM) and other NHLs. Methods: 398 patients with lymphoid malignancies seen between January and October 2021 were screened for eligibility. Ab titers using the Access SAR-COV-2 assay developed by Beckman Coulter Inc were obtained after the completion of a vaccination series with Pfizer (n=146), Moderna (n=90), Johnson & Johnson (n=1) or multiple brands (n=3). A response was defined as a positive total Ab or spike protein Ab. Groups were compared using chi-square tests, and a p-value of <0.05 was statistically significant. Results: 240 patients with postvaccination SARS-CoV-2 Ab results were included. Ab response was 50% in CLL, 67% in WM, and 71% in the remaining NHLs. In the CLL cohort (n=181), current or prior cancer therapy at any time led to a lower rate of positive Ab's compared to treatment-naïve patients (36% vs. 68%;p=0.000019), and response was particularly low in patients who had received anti-CD20 immunotherapy at any time (28% vs. 61%;p=0.000032). There was a trend towards lower Ab response in patients who received anti-CD20 agents within a year from vaccination compared to those who had these therapies more than one year prior (20% vs. 37%;p=0.14). For CLL patients, there was a significant difference in Ab response when receiving the Moderna series (61%) compared to Pfizer (44%) (p=0.028). More information is summarized in Table 1. Conclusions: This study provides data from a large cohort of patients with CLL and other NHLs on Ab response to SARS-CoV-2 vaccination. Active or prior therapy for CLL was associated with lower rates of Ab response to vaccination, especially when treated with anti-CD20 therapy, which is consistent with prior publications. However, we also found a significant increase in Ab response rates after Moderna SARS-CoV-2 vaccination in treated CLL patients compared to other vaccination series.