Heavy/light chain assay as a biomarker for diagnosis and follow-up of multiple myeloma.

Abstract

BACKGROUND:

The heavy-light chain (HLC) assay enables the accurate measurement of each isotype-specific heavy and light chain (i.e., IgGĸ, IgGλ, IgAĸ, and IgAλ) and the derivation of an HLC-pair ratio. However, to date, only limited data have validated the usefulness of serial HLC measurements in the routine follow-up of intact immunoglobulin multiple myeloma (MM) patients.

METHODS:

A total of 36 diagnostic and 671 post-treatment sera from 115 IgG and 61 IgA MM patients were assessed with capillary zone electrophoresis, immunosubtraction electrophoresis, total immunoglobulin measurement, free light chain, and HLC assay. The correlations between M-protein levels and the HLC and FLC assay-derived parameters were examined and the clinical significance of the biomarkers was evaluated according to patients' status.

RESULTS:

Involved HLC (iHLC) was the best biomarker correlating with M-protein concentration in both IgG and IgA MM, and could provide a surrogate marker substituting M-protein levels to follow the course of the disease, especially in β-migrating IgA M-proteins. The distribution of iHLC values as well as HLC-pair ratios (rHLC) yielded significantly different results among the various response categories in both IgG and IgA MM. In addition, we detected 2 cases in which an abnormal rHLC in a stringent complete remission (sCR) sample was a marker of early non-symptomatic relapse.

CONCLUSION:

In this study of a cohort of 176 patients in a routine clinical setting, we have provided evidence of the clinical utility of real world HLC assays for the identification of M-proteins and to monitor M-proteins with an emphasis on IgA monoclonal gammopathies.

• Authors: Hyojin Chae, Eunhee Han, Jaeeun Yoo, Jaewoong Lee, Jeong Joong Lee, Kyoungho Cha, Myungshin Kim, Yonggoo Kim, Sung-Eun Lee, Chang-Ki Min
• Journal: Clinica chimica acta; international journal of clinical chemistry (Clin Chim Acta) Vol. 479 Pg. 7-13 (Apr 2018) ISSN: 1873-3492 [Electronic] Netherlands
• PMID: 29324245 (Publication Type: Journal Article)
• Copyright: Copyright © 2018 Elsevier B.V. All rights reserved.

Chemical References

• Biomarkers, Tumor
• Immunoglobulin A
• Immunoglobulin G

Topics

• Aged
• Biomarkers, Tumor (blood)
• Female
• Humans
• Immunoglobulin A (blood)
• Immunoglobulin G (blood)
• Male
• Middle Aged
• Multiple Myeloma (blood, diagnosis)
• Retrospective Studies