Measles, Mumps & Rubella Titers Post Autologous Stem Cell Transplant in Multiple Myeloma Patients Induced with Modern Therapy

Multiple Myeloma (MM) is a hematological malignancy resulting in abnormal plasma cells proliferating in the bone marrow. One of the most common treatment strategies for newly diagnosed MM is the combination of induction therapy followed by autologous stem cell transplant (ASCT). Due to the underlying disease and/or the effect of the treatment regimens administered, immunosuppression is a common clinical consequence. It has been shown that ASCT recipients, treated with traditional compounds, have a reduction in the levels of antibody titers to vaccine-preventable diseases such as measles, mumps and rubella (MMR), between one and four years post-transplant. Therefore, re-vaccination is recommended at least two years after ASCT. Therapeutic options have expanded in the past decade, with the introduction of novel agents that have significantly improved MM patient outcomes; however, this may also arguably have new and different implications on a patient's immune system. In this study we sought to analyze the presence of IgG antibodies against MMR in 110 patients with MM post-ASCT. All patients received ASCT between 2014 and 2019 at Mayo Clinic Arizona. Plasma samples were collected approximately 100 days after ASCT (median 92 days) and the antibody titers were tested using the Bio-Rad MMR IgG multiplex flow immunoassay. Sample antibody index values were compared with the assay-specific calibration to determine positivity. For a control population, we utilized the results of fully vaccinated and presumptively immune healthcare workers (HCWs) that were evaluated for the presence of antibodies to measles (n=199), mumps (n=197) and rubella (n=209), using the same method, instrument and laboratory. Overall, 70% of the MM patients were positive for antibodies against measles, compared with 77.4% of HCWs. For mumps, the MM cohort had a positivity of 49.1% versus 84.8% of HCWs. Finally, rubella antibodies were found in 64.5% and 83.7% of MM and HWCs, respectively. Next, we performed testing on serial samples collected from 45 MM patients, comparing the presence of MMR antibodies pre-ASCT (median 130 days) and post-ASCT. The number of patients with positive titers detected pre- and post-transplant was unchanged for each of the three viruses. In summary, our findings do not indicate a significant reduction in relative MMR antibody levels in ASCT recipients. This suggests that earlier re-vaccination is not required post-ASCT in the era of novel MM compounds. However, further validation studies in larger cohorts are necessary prior to considering a change in current vaccination guidelines.