Matrix-assisted Laser Desorption Ionization Mass Spectrometry for Detection of α/β-Chain Changes From Human Hemoglobin: An Exploratory Study

In this work, we developed a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) method to directly analyze human whole blood samples. 1.0 µL of whole blood samples and 1.0 µL of optimized organic matrix were directly loaded onto the sample plates for MALDI-TOF-MS detection. A total of 59 whole blood samples were investigated in this work, including 23 healthy control samples, 28 α-globin gene triplication carriers with α-chain repetition, and eight deletional hemoglobin H disease (HbH) patients with α-chain deficiency. Human hemoglobin (Hb) chains with high signal-to-noise were directly observed. It is found that there is a change in signal ratios of α/β-chains of Hb from blood samples in thalassemia subtypes by comparing the ratios obtained from healthy blood samples. Analytical variability (n = 6) of signal ratios of α/β-chains was found to be 3.33%–12.86% (intra-day), 4.02%–13.39% (inter-day), and 6.41%–15.32% (inter-laboratory), respectively. Furthermore, the results were validated using different MALDI-TOF MS approaches. Our results suggest that α/β-chains ratios of Hb could be an indicator for investigating thalassemia by MALDI-TOF-MS.