CD34 and hydrops fetalis: Considering that in our study, increased levels of TNF-α were associated with impaired endothelial function measured by FMD, as well as with a lower number of CD34+ cells after stimulation with G-CSF, we suggest that high TNF-α levels are one of the main factors affecting both the endothelium and the bone marrow function in patients with HF regardless of the cause of HF.