COVID‑19 antibody production by vaccination in chemotherapy with CD20 antibody for B‑cell lymphoma.

Most hematologic diseases are immunosuppressed, either by the disease itself or by treatment. As such, the implementation of vaccination is largely at the discretion of the attending physician. In this context, an objective measure is needed, therefore the index of vaccination against coronavirus disease 2019 (COVID-19) in B-cell lymphomas treated with antibody therapy against CD20 (including after the completion of therapy) was examined. A total of 40 patients with B-cell lymphoma during or after antibody therapy against CD20 were vaccinated twice with the BNT162b2 messenger RNA (mRNA) COVID-19 vaccine (Pfizer, Inc. and BioNTech SE.) at 3-week intervals and then again six months later with the same vaccine or mRNA-1273 (Moderna, Inc.). Antibody testing was conducted ~1 month after the third vaccination. Analysis was performed using the antibody titers to the anti-spike immunoglobulin assay, with a titer of 0.8 U/ml or higher (considered positive) and a titer of 264 U/ml or higher (considered the value at which the efficacy of the vaccine can be fully expected). Significant factors of antibody acquisition were identified when i) antibody titers were 0.8 U/ml or higher (CD4 ≥400/µl), ii) no anti-CD20 antibody maintenance therapy was undertaken (CD19 ≥100/µl), iii) patients were not on treatment (CD4 ≥400/µl), or 4) at least six months had passed since treatment ended (CD19 ≥100/µl). When antibody titers were 264 U/ml or higher, the treatment method, the stage of the primary disease and other factors related to the condition treatment method of the patient were relevant. When these were analyzed by multivariate analysis, the significant factor when antibody titers were set to 0.8 U/ml was CD19 ≥100/µl. In contrast, when setting them to 264 U/ml or higher, CD4 ≥400/µl was not significant, but there was a tendency for it to be related. The findings of the present study on vaccine-induced antibody acquisition in patients with B-cell lymphoma indicated that it is desirable to have a CD19 titer of at least 100/µl and a CD4 titer of at least 400/µl (both conditions should be met), and that no maintenance therapy with anti-CD20 antibody should be administered for at least six months after the last treatment or completion of the treatment. Interestingly, when the criteria for antibody titers were compared between 0.8 U/ml, where antibody titer is detected, and 264 U/ml, where vaccine efficacy is expected, several key factors were different. It is possible that these key factors may change depending on the antibody titer used as a criterion.