PLASMABLAST RESPONSE AFTER REVACCINATION WITH 13 VALENT CONJUGATED PNEUMOCOCCAL VACCIN IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA
Between 2013-2016, 126 treatment naïve chronic lymphocytic leukemia (CLL) patients (median age, 69 years; range, 46–87 years) were vaccinated in a randomized trial with PCV13 (n=63) or PPSV23 (n=63) at eight hematological clinics in Sweden. Antibody response, measured with ELISA and OPA was superior for PCV13. In the present study, we analyze the immune response, including plasmablasts, after revaccination with PCV13 and 3-6 years after primary vaccination.
In 2019-2020, 72 CLL patients were included for revaccination with PCV13. Immunophenotyping of peripheral plasmablasts (CD19+/CD38++/CD27++/CD138-/IgD-/IgM-) and plasma cells (CD19+/CD38++/ CD27++/ CD138+/ IgD-/IgM-) was performed before and seven days after revaccination using flow cytometry (n=13). Analyses of serotype specific antibodies (ELISA) and functionality (OPA) before and eight weeks, 16 weeks and 12 months after revaccination will be performed. Immunocompetent controls will be recruited.
Preliminary results show increased plasmablasts in 4/13 patients seven days after revaccination compared to baseline, previously vaccinated with PCV13 (n=3) and PPSV23 (n=1). Patients with detectable plasmablasts were still treatment naïve but those with previous/ongoing treatment (including two with Ibrutinib) had undetectable plasmablasts.
Preliminary results indicate a superior response after PCV13 revaccination in CLL patients if previously vaccinated with PCV13 than PPSV23. Further analyses will be conducted during 2020.