Identification of gamma heavy chain disease using MALDI-TOF mass spectrometry

• Published in: Clinical biochemistry Vol. 77; pp. 57 - 61
• Main Authors: Thoren, Katie L., Eveillard, Marion, Chan, Patrick, Doddi, Sital, Cho, Sun, Murata, Kazunori
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-03-2020
• Subjects: Heavy chain disease; Heavy Chain Disease - diagnosis; Humans; MALDI-TOF mass spectrometry; Monoclonal immunoglobulin; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; MALDI-TOF mass spectrometry; Heavy chain disease; Monoclonal immunoglobulin
• ISSN: 0009-9120; 1873-2933
• DOI: 10.1016/j.clinbiochem.2019.12.010

We describe the use of MALDI-TOF mass spectrometry in the analysis of a suspected case of gamma heavy chain disease. The patient had an abnormal serum immunofixation result where a monoclonal gamma heavy chain band was present without a corresponding light chain. Analysis by MALDI-TOF mass spectrometry revealed large peaks in the spectrum following IgG-specific purification. The m/z values of the peaks were outside the expected range for normal heavy chains or light chains. Corresponding peaks were not present in mass spectra of the kappa- or lambda-specific purifications. MALDI-TOF MS confirmed the presence of a truncated heavy chain without associated light chains. This case report demonstrates the value of mass spectrometry in interpreting challenging cases such as the identification of heavy chain disease.