Lymphoma patients receiving anti-CD20 therapy have inferior seroconversion rates after COVID-19 vaccination but do exhibit T-cell responses, according to research published in Blood.

“[P]atients with recent or ongoing anti-CD20 treatments who suffer from insufficient humoral immune responses after 2 COVID-19 vaccinations might still benefit from vaccination due to the cellular immune response,” the researchers suggested.

The team evaluated responses to vaccination in 80 patients with lymphoma. Most were diagnosed with an aggressive (n=32) or indolent (n=32) B-cell lymphoma. Of the remaining patients, 11 had chronic lymphocytic leukemia, 4 had nodular lymphocyte-predominant Hodgkin lymphoma, and 1 had hairy cell leukemia.

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There were 25 patients on active anti-CD20 treatment and 55 who had prior anti-CD20 therapy. Most patients received anti-CD20 treatment with chemotherapy (n=33), as monotherapy (n=23), or with novel agents (n=12).

Patients received the Pfizer-BioNTech COVID-19 vaccine (n=63), the Moderna vaccine (n=4), the AstraZeneca vaccine (n=2), or a heterologous regimen (n=7). There were 4 patients who had received only 1 vaccination by the data cutoff.

The median time to serological testing was 15 days from the first vaccination (interquartile range [IQR], 14-17 days) and 16 days from the second vaccination (IQR, 14-24.2 days).

With a median follow-up of 151 days (range, 88-239 days) from the first vaccination, there were no breakthrough infections.

Seroconversion, Antibody Levels

The overall seroconversion rate was 41% after 2 vaccine doses and 9% after 1 dose (P <.001). The seroconversion rate was 41% (26/67) after homologous mRNA-based vaccination, 0% after non-mRNA-based vaccination (0/2), and 71% after heterologous vaccination (5/7).

The median antibody levels were significantly higher after the second vaccine dose than the first dose — 0.2 and 0.09, respectively (P =.004). However, the median antibody levels in patients with seroconversion after the second vaccination were considerably lower than levels reported in vaccinated patients without lymphoma — 67.7 and 116.2, respectively.

A multivariate analysis revealed the following factors as independent predictors of seroconversion after the second vaccination in the lymphoma patients:

  • Age, per 10 years — odds ratio (OR), 0.5 (95% CI, 0.2-0.8; P =.008)
  • The interval between the last anti-CD20 treatment and first vaccination, per year — OR, 2.2 (95% CI, 1.3-4.7; P =.02)
  • CD4 cell count, per 100 cells/mL — OR, 1.6 (95% CI, 1.2-2.3; P =.005). 

T-Cell Response

The researchers assessed T-cell responses in 50 of the lymphoma patients and in 7 healthy vaccinated control individuals. The response rate was 58% (29/50) in the lymphoma patients and 71% (5/7) in the controls.

Among the lymphoma patients, T-cell responses were seen in 70% (14/20) of those with seroconversion and 50% (15/30) of those without (P =.2).

The researchers noted that T-cell responses “are essential for viral clearance,” so even if SARS-CoV-2 infections cannot be prevented, T-cell responses may be sufficient to ensure a mild course of COVID-19.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Liebers N, Speer C, Benning L, et al. Humoral and cellular responses after COVID-19 vaccination in anti-CD20-treated lymphoma patients. Blood. Published online January 6, 2022. doi:10.1182/blood.2021013445.