β-thal erythroblasts are characterized by abnormal proteomic signature and increased overall cysteine oxidation, resulting in upregulation of classic chaperones, such as HSP90 and HSP70, and upregulation of antioxidants, such as peroxiredoxins. Proteomics profile of erythroid precursors from patients with β-thal vs HCs. Specifically, the heat maps show the top 500 (A) and 50 (B) significant proteins by t test. (C) The volcano plot indicates proteins whose values are increased (red) or decreased (blue) in β-erythroblasts compared with healthy counterparts. (D) Heat map showing the relative abundance of all peroxiredoxins (Prdx) in the 2 groups. (E) Western blot analysis with specific antibodies against HSP70 and Prdx-2 of erythroid precursors, as in panel A, on day 14 of culture. Catalase was used as loading control. One representative immunoblot of 3 others with similar results. Densitometric analysis is shown in supplemental Figure 2. (F) Heat map showing cysteine redox modifications (colors were coded as follows: oxidation, orange; dioxidation, red; cysteine to dehydroalanine, magenta) between the 2 groups.