Mass Spectrometry for Detection of Monoclonal Gammopathy of Undetermined Significance

A research team evaluated mass spectrometry-based methods of detection for monoclonal gammopathy of undetermined significance (MGUS) and, using monoclonal immunoglobulin rapid accurate mass measurement (miRAMM), estimated that MGUS was present in 5.1% of individuals aged 50 years or older in a screening cohort. The study results were reported in Blood Cancer Journal.

In this study, researchers compared methods to identify monoclonal immunoglobulins in samples from 226 patients diagnosed with MGUS or similar gammopathies. These patients were previously included in the Olmsted County MGUS study and had previously tested negative for MGUS; in addition, serum samples from these patients had been obtained and cryopreserved for later analyses.

Mass spectrometry-based detection assays that were compared in this study were matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) and miRAMM. Additionally, traditional immunofixation was carried out for comparisons.

From baseline samples, the researchers reported that immunofixation showed a monoclonal protein present in 10.6% of patients, compared with rates of 50% by MALDI-TOF and 65.9% by miRAMM. The miRAMM technique was also able to detect oligoclonal to monoclonal transitions.

The miRAMM approach enabled detection of MGUS in 5.1% of the members of the community tested in the Olmsted County screening study cohort in the age group of 50 years or older.

“The primary purpose of this study was to explore the epidemiology of MGUS using a more sensitive method,” wrote the researchers. “We found that a monoclonal protein can be detected by mass spectrometry (MALDI-TOF or miRAMM) in most patients several years prior to the diagnosis of clinical MGUS.”

The researchers concluded that MALDI-TOF is easier to perform than miRAMM is and that miRAMM is more sensitive but requires more resources. They noted that currently, miRAMM is used primarily for research purposes and suggested that it could be useful for measurable residual disease analysis.

Reference

1.     Murray D, Kmart SK, Kyle RA, et al. Detection and prevalence of monoclonal gammopathy of undetermined significance: a study utilizing mass spectrometry-based monoclonal immunoglobulin rapid accurate mass measurement [published online December 13, 2019]. Blood Cancer J. doi:10.1038/s41408-019-0263-z

This article originally appeared on Hematology Advisor