Reduced Frequency of CD4+CD25++CD127low/-FOXP3+ Regulatory T Cells in Patients with Primary Myelofibrosis

Background. Primary myelofibrosis (PMF) is a clonal, neoplastic disorder of the hematopoietic stem cell, categorized among the Ph-negative myeloproliferative neoplasms (MPNs). Available evidence indicates that enhanced activation of JAK-STAT pathway is the main molecular mechanism of myeloproliferation due to somatic mutations in JAK2, CALR or MPL genes. However, imbalanced immune responses that lead to chronic inflammation has been hypothesized to play an important role in the pathogenesis of the disease (Hasselbalch HC et al. Leuk Res 2013;37:214-20). Study design. In the attempt to explain the mechanism of immune dysregulation, and to explore how it could influences the disease phenotype, we examined the frequency of circulating CD4+CD25++CD127low/-FOXP3+ regulatory T cells (Tregs), as measured by cytofluorimetric technique, in 193 consecutive patients with PMF and 16 healthy controls (HCs). Results. The percentage of Treg cells between PMF patients and HCs was significantly different [median, 0.87% (range 0% to 10.2%) vs. 2.09% (range 0.54% to 6.5%); Mann-Whitney U test, P Disclosures No relevant conflicts of interest to declare.