Humoral and cellular immune response to second and third severe acute respiratory syndrome coronavirus 2 mRNA vaccine in patients with plasma cell dyscrasia.

BACKGROUND: The recently developed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine has a short history of use and further information is needed regarding its efficacy, especially in immunocompromised conditions, such as plasma cell dyscrasia (PCD). METHODS: We retrospectively measured serum SARS-CoV-2 antibodies against the spike protein (S-IgG) after the second and third mRNA vaccine doses (doses 2 and 3, respectively) in 109 patients with PCD. We evaluated the proportion of patients with an adequate humoral response (defined as S-IgG titers ≥300 antibody units/mL). RESULTS: Although active anti-myeloma treatments prior to vaccination had a significantly negative impact on adequate humoral response, specific drug subclasses including immunomodulatory drugs, proteasome inhibitors, and monoclonal antibodies were not negatively associated, except for B-cell maturation antigen-targeted therapy. Dose 3 (booster vaccination) led to significantly higher S-IgG titers and more patients acquired an adequate humoral response. Furthermore, evaluation of vaccine-induced cellular immune response in patients using T-spot Discovery SARS-CoV-2 kit, revealed an enhanced cellular immune response after Dose 3. CONCLUSIONS: This study highlighted the significance of booster SARS-CoV-2 mRNA vaccination in patients with PCD with respect to humoral and cellular immunity. Moreover, this study highlighted the potential impact of certain drug subclasses on vaccine-induced humoral immune response.

A comprehensive evaluation of humoral immune response to second and third SARS-CoV-2 mRNA vaccination in patients with malignant lymphoma.

More information is needed regarding the efficacy of SARS-CoV-2 mRNA vaccines in immunocompromised populations, including patients with malignant lymphoma. This study aimed to evaluate humoral responses to the second and third mRNA vaccine doses in 165 lymphoma patients by retrospective analysis of serum SARS-CoV-2 spike protein antibody (S-IgG) titers. Patients with S-IgG titers ≥ 300, 10-300, and ≤ 10 binding antibody units (BAU)/mL were defined as adequate responders, low responders, and non-responders, respectively. S-IgG titers > 10 BAU/mL were considered to indicate seroconversion. After the second dose, 56%, 16%, and 28% of patients were adequate responders, low responders and non-responders, respectively. Multivariate analysis revealed that being an adequate responder after the second dose was associated with receiving the vaccine > 12 months after last chemotherapy, total peripheral lymphocyte count of ≥ 1000/µL, estimated glomerular filtration rate of ≥ 50 mL/min/1.73 m2, and vaccine type (mRNA-1273). After the third dose, patients had significantly higher S-IgG titers and a greater proportion achieved seroconversion. With this third dose, 26% of second-dose non-responders achieved seroconversion and 68% of second-dose low responders became adequate responders. Subsequent SARS-CoV-2 mRNA vaccinations may elicit an immune response in immunocompromised patients who do not initially respond to vaccination.