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The erythropoietin (Epo)-erythroferrone (ERFE)-hepcidin axis coordinates erythropoiesis and iron homeostasis. While mouse studies have established that Epo-induced ERFE production represses hepcidin synthesis by inhibiting hepatic BMP/SMAD signaling, evidence for the role of ERFE in humans is limited. To investigate the role of ERFE as a physiological erythroid regulator in humans, we conducted two studies. First, 24 males were given six injections of saline (placebo), recombinant Epo (rhEpo) at a dose of 20 IU/kg (micro-dose) or rhEpo at 50 IU/kg (low dose). Second, we quantified ERFE in 22 subjects exposed to high altitude (3800 m) for 15 h. In the first study, total hemoglobin mass (Hbmass) increased after low- but not after micro-dose injections, when compared to the mass after placebo injections. Serum ERFE levels were enhanced by rhEpo, remaining higher than after placebo for 48 h (micro-dose) or 72 h (low-dose) after injections. Conversely, hepcidin levels decreased when Epo and ERFE rose, before any changes in serum iron parameters occurred. In the second study, serum Epo and ERFE increased at high altitude. The present results demonstrate that in healthy humans ERFE responds to slightly increased Epo levels not associated with Hbmass expansion and downregulates hepcidin in an apparently iron-independent way. Notably, ERFE flags micro-dose Epo, thus holding promise as a novel biomarker of doping.

We describe a rapid and simple flow cytometry technique for the detection and quantification of p53 in several human cell lines, including an adenocarcinoma cell line (SW 626) having a mutant (m) p53, and a pre-B leukemia cell line (NALM-6) having wild-type (wt) p53. By introducing a second antibody coupled to RPE-fluorescence, the discrimination between control and specific peaks was improved over that achieved with methods used previously. To quantify the content of p53 molecules in the cells, we used a series of beads with the capability to bind mouse monoclonal IgG antibodies. p53 cell content, expressed as antibody binding capacity (ABC), was directly quantified from logarithmic scattergrams; the results were reproducible in all cell lines tested. Flow cytometric results were compared with those of a standard immunocytochemistry method routinely used for the detection of p53 in cells, and found to be in correlation. Furthermore, cytometric data also reflect ELISA determinations. In summary, we showed for the first time that (i) p53 can be clearly detected by flow cytometry in various cell lines, (ii) p53 can be quantitated in terms of number of molecules per cell, and (iii) it can be easily monitored as a function of time after stimulation. Cytometry 31:180–186, 1998. © 1998 Wiley-Liss, Inc.

Background: Genomic complexity can predict the clinical course of patients affected by chronic lymphocytic leukemia (CLL) with a normal FISH. However, large studies are still lacking. Here, we analyzed a large series of CLL patients and also carried out the so far largest comparison of FISH versus single-nucleotide polymorphism (SNP) array in this disease. Patients and methods: SNP-array data were derived from a previously reported dataset. Results: Seventy-seven of 329 CLL patients (23%) presented with a normal FISH. At least one large (>5 Mb) genomic aberration was detected by SNP array in 17 of 77 patients (22%); this finding significantly affected TTT. There was no correlation with the presence of TP53 mutations. In multivariate analysis, including age, Binet stage, IGHV genes mutational status and large genomic lesion, the latter three factors emerged as independent prognosticators. The concordance between FISH and SNP array varied between 84 and 97%, depending on the specific genomic locus investigated. Conclusions: SNP array detected additional large genomic aberrations not covered by the standard FISH panel predicting the outcome of CLL patients.