Retrospective analysis of vaccine antibody titers in patients with different stages of monoclonal plasma cell disorders

ABSTRACT

Background: Infections occur with up to twofold increased risk in patients with monoclonal gammopathy of undetermined significance (MGUS) and tenfold increased risk in multiple myeloma (MM). To reduce risk, revaccination following autologous hematopoietic cell transplantation (AHCT) is recommended to restore humoral immunity. We have previously shown that vaccine titers after AHCT have prognostic significance. In the COVID era, reliable clinical data about antibody titers is relevant yet scarce. We investigated the significance of different vaccine titers in newly diagnosed patients in different stages of the disease. Methods: The study population comprised of 77 patients with MGUS, smoldering multiple myeloma (SMM) and MM who were seen at a tertiary cancer center from 2018- 2022. All patients had antibody titers (B. pertussis, Diptheria, H. Influenzae B, Hepatitis, Influenza, Meningitis, Mumps, Rubeola, Rubella, Poliovirus, S. pneumoniae, Varicella Zoster and Tetanus) tested at the time of diagnosis, prior to start of treatment if indicated. Titers were interpreted in accordance with the manufacturers' recommendations. Patient characteristics were compared using the Kruskal- Wallis and Fisher's exact tests. Associations with % titer positivity were evaluated using the Kruskal- Wallis test. Results: There was significant difference in antibody titer positivity between the different patient groups (51.4% in MGUS, 40.5% in SMM and 34.2% in MM) (p < 0.001). There was no difference in antibody titer positivity depending on age, sex or race. Among individual pathogens, there was a significant difference between the three groups in regards to titers for Diphtheria, Mumps, Poliovirus 3, Strep pneumoniae 19, Strep pneumoniae 56 and Varicella Zoster. Conclusions: Antibody titers for vaccine preventable diseases are significantly different between patients with MGUS, SMM and MM at the time of diagnosis, with MGUS having the highest and MM having the lowest positivity. Patient related factors such as age, sex or race were not associated with antibody titer positivity. Current guidelines for revaccination are not extended to patients with MGUS and SMM and can be considered in prospective trials.