Thrombopoietin receptor agonists shift the balance of Fcγ receptors toward inhibitory receptor IIb on monocytes in ITP.

Elevated expression of the activating Fcγ receptor (FcγR) I and FcγRIIa together with decreased expression of the inhibitory FcγRIIb are involved in the pathogenesis of primary immune thrombocytopenia (ITP). Thrombopoietin receptor agonists (TPO-RAs) have been used clinically for the management of ITP; however, little is known about the effect of TPO-RAs on FcγR modulation in ITP. In this prospective study, we measured the alteration in monocyte FcγR expression from 21 corticosteroid-resistant/relapsed patients with chronic ITP receiving eltrombopag therapy. Results showed that the mRNA and protein levels of FcγRIIb were significantly elevated after 6-week eltrombopag treatment. Concurrently, FcγRI and IIa levels decreased remarkably, whereas FcγRIII expression did not change. In vitro phagocytosis assays indicated that a shift in the balance of FcγR toward inhibitory FcγRIIb on monocytes was accompanied with a considerable decrease in monocyte/macrophage phagocytic capacity. The response to eltrombopag therapy in patients with ITP was associated with FcγR phenotype and functional changes of monocytes/macrophages. Moreover, the plasma transforming growth factor-β1 (TGF-β1) concentrations increased significantly in eltrombopag responders. Modulation of monocyte FcγR balance by TPO-RAs was also found in a murine model of ITP established by transferring splenocytes from immunized CD61 knockout mice into CD61(+) severe combined immunodeficient mice. Romiplostim administration in ITP mice significantly upregulated inhibitory FcγRII expression and downregulated activating FcγRI expression. These findings showed that recovery of platelet counts after TPO-RA treatment in ITP is associated with the restoration of FcγR balance toward the inhibitory FcγRIIb on monocytes, and suggested that thrombopoietic agents have a profound effect on immune modulation in ITP. This study is registered at ClinicalTrials.gov as #NCT01864512.

Liu XG ，Liu S ，Feng Q ，Liu XN ，Li GS ，Sheng Z ，Chen P ，Liu Y ，Wei Y ，Dong XY ，Qin P ，Gao C ，Ma C ，Zhang L ，Hou M ，Peng J ... -  《-》

Eltrombopag modulates the phenotypic evolution and potential immunomodulatory roles of monocytes/macrophages in immune thrombocytopenia.

Yang F ，Zong H ，Li F ，Luo S ，Zhang X ，Xu Y ，Zhang X ... -  《-》

High-dose dexamethasone shifts the balance of stimulatory and inhibitory Fcgamma receptors on monocytes in patients with primary immune thrombocytopenia.

Liu XG ，Ma SH ，Sun JZ ，Ren J ，Shi Y ，Sun L ，Dong XY ，Qin P ，Guo CS ，Hou M ，Peng J ... -  《-》

Real-world use of thrombopoietin receptor agonists for the management of immune thrombocytopenia in adult patients in the United Kingdom: Results from the TRAIT study.

Few studies have reported the real-world use of both romiplostim and eltrombopag in immune thrombocytopenia (ITP). TRAIT was a retrospective observational study aimed to evaluate the platelet responses and adverse effects associated with the use of these thrombopoietin receptor agonists (TPO-RAs) in adult patients with ITP in the United Kingdom. Of 267 patients (median age at diagnosis, 48 years) with ITP (primary ITP [n = 218], secondary ITP [n = 49]) included in the study, 112 (42%) received eltrombopag and 155 (58%) received romiplostim as the first prescribed TPO-RA. A platelet count ≥30 × 109/L was achieved in 89% of patients with the first TPO-RA treatments, while 68% achieved a platelet count ≥100 × 109/L. Treatment-free response (TFR; platelet count ≥30 × 109/L, 3 months after discontinuing treatment) was achieved by 18% of the total patients. Overall, 61 patients (23%) switched TPO-RAs, most of whom achieved platelet counts ≥30 × 109/L with the second TPO-RA (23/25 who switched from eltrombopag to romiplostim [92%]; 28/36 who switched from romiplostim to eltrombopag [78%]). TFR was associated with secondary ITP, early TPO-RA initiation after diagnosis, the presence of comorbidity and no prior splenectomy or treatment with steroids or mycophenolate mofetil. Both TPO-RAs had similar efficacy and safety profiles to those reported in clinical studies.

Cooper N ，Scully M ，Percy C ，Nicolson PLR ，Lowe G ，Bagot CN ，Thachil J ，Grech H ，Nokes T ，Hill QA ，Bradbury C ，Talks K ，Dutt T ，Evans G ，Pavord S ，Wexler S ，Charania A ，Collington SJ ，Ervin A ，Ramscar N ，Provan D ... -  《-》

Thrombopoietin Receptor Agonists in Children with Immune Thrombocytopenia: A New Therapeutic Era.

Immune thrombocytopenia (ITP) is a common bleeding disorder in childhood. The management of ITP in children is controversial, requiring personalized assessment of patients and therapeutic choices. Thrombopoietin receptor agonists (TPO-RAs), eltrombopag and romiplostim, have been shown to be safe and effective for the treatment of pediatric ITP. The aim of our research is to define the role of thrombopoietin receptor agonists in the management of pediatric ITP. This review focuses on the use of TPO-RAs in pediatric ITP, in randomized trials and in clinical routine, highlighting their key role in the management of the disease. Eltrombopag and romiplostim appear effective treatment options for children with ITP. Several clinical studies have assessed that the use of TPO-RAs increases platelet count, decreases bleeding symptoms and improves health-related quality of life. Moreover, TPO-RAs are well tolerated with minor side effects. Although long term efficacy and safety of TPO-RAs still require further investigations, their use is gradually expanding in the clinical practice of children with ITP.

Lassandro G ，Palladino V ，Vecchio GCD ，Palmieri VV ，Corallo PC ，Faienza MF ，Giordano P ... -  《-》