Adequate Antibody Response to COVID-19 Vaccine in Patients with Monoclonal Gammopathies and Light Chain Amyloidosis

Objective: Determine the COVID-19 seroconversion rate for patients with multiple myeloma receiving a COVID-19 vaccine.

Materials and methods: After 45 patients received their second COVID-19 vaccine dose, their serum IgG antibodies were measured: 22 with monoclonal gammopathy (MG) of unknown significance, 3 with smoldering myeloma, 2 with light chain amyloidosis, and 18 with MG (9 in remission, 6 out of remission, and 3 with free light-chain gammopathy alone). A second serum specimen was retained for 16 patients with MG. Their antibody levels were compared to those of 78 uninfected healthy vaccinated control patients.

Results: Three patients with MG had low antibody levels on blood collected 98, 100, and 113 days after the initial vaccine dose (2 with MG of unknown significance and 1 with hypogammaglobulemia). The other 40 patients with MG (seroconversion rate 93%) and both patients with amyloidosis produced antibodies. Relative to days after vaccination, patients with MG had lower antibody levels than control patients.

Conclusion: After receiving a COVID-19 vaccine, most patients with MG produce anti-SARS-CoV-2 antibodies comparable to levels in uninfected vaccinated healthy control patients.