Differential plasma proteome profiles of mild versus severe β-thalassemia/Hb E

The severity of thalassemia is currently classified based on clinical manifestations and multiple tests. In the present study, we performed a plasma proteome analysis to identify differentially expressed proteins compared between normal subjects and patients with mild and severe forms of β-thalassemia/hemoglobin E (Hb E). Plasma samples were collected from patients with mild (n = 8) and severe (n = 12) forms as well as healthy normal individuals (n = 12). Clinical chemistry revealed that several parameters, i.e., hematological indices, oxidative stress markers, antioxidant enzymes, and erythropoietic activity, had significant differences among these three groups. After removal of seven major abundant proteins, the plasma proteome profiles were compared using two-dimensional gel electrophoresis. Spot matching, quantitative intensity analysis, and statistics revealed differential levels of 32 and 9 proteins when comparing normal vs. patients and mild vs. severe forms, respectively. These proteins were successfully identified by quadrupole time-of-flight mass spectrometry and/or tandem mass spectrometry. The decreased level of ADP-ribosylation factor guanine nucleotide-exchange factor 2 in β-thalassemia/Hb E patients compared to healthy individuals and the decreased level of endothelin-converting enzyme 2 in severe form compared to the mild form of the disease were validated by Western blot analysis. Our data provide a number of proteins that may lead to better understanding of the pathophysiology of thalassemia or for novel biomarkers which can be used to simply differentiate mild and severe forms of β-thalassemia/Hb E without any need for multiple tests.