Actually, in patients, SCL transcription initiated at promoter 1b is restricted to primitive CD34+CD41- progenitor cells, while it is detectable in both cell subsets from healthy subjects; (iii) the full-length isoform of SCL protein is present in patients' CD34+ cells and in PBMC; in the latter the SCL-expressing cells mainly belong to the MK lineage in which its sublocalization is both nuclear and cytoplasmic, which contrasts with the sole nuclear staining observed in normal MK cells.