Research Progress of Desialylation in Immune Thrombocytopenia -Review / 中国实验血液学杂志

Some patients diagnosed as immune thrombocytopenia(ITP) have poor response to common first-line therapy such as corticosteroid and immunoglobulin. Studies in recent years have found a FC-independent platelet clearance pathway exists, which is characterized by desialylation of platelet surface glycoprotein(GP), recognition and phagocytosis by Ashwell-Morell receptor(AMR) on hepatocytes, independent on Fc receptors of the reticuloendothelial system. The up-regulation of neuraminidase-1(Neu1) expression on platelet caused by various factors, such as cold storage of platelet, septicemia and ITP could desialylate GPs. It has been found that ITP with positive anti-GPIbα antibody mostly has a poor response to first-line therapy and indicated that such antibody may lead to FC-independent platelet clearance. It also has been proved that anti-GPIbα antibody could desialylate GPs on platelet in animal experiments. Researchers have tris to use sialidase inhibitor agent to treat ITP and got a persistent response of platelet. Here, the desialylation of platelet and its role in ITP pathogensis and therapy are reviewed.

Clinical analysis of recombinant humanized thrombopoietin for treating 25 children with severe immune thrombocytopenia / 中国实验血液学杂志

This study was aimed to evaluate the efficacy and safety of recombinant humanized thrombopoietin (rhTPO) for treating children with severe immune thrombocytopenia (ITP). A total of 25 patients with severe ITP who accepted rhTPO treatment for 14 days between December, 2009 and November, 2012 in Beijing Children's Hospital was retrospectively analyzed. The results showed that the median platelet counts of all 25 patients increased from the lowest level 4.0×10(9)/L (0×10(9)/L-10×10(9)/L) to the highest level 71×10(9)/L (14×10(9)/L-439×10(9)/L) on median 11 days (range from 3 days to 15 days). After rhTPO discontinuation, the platelet counts of patients gradually decreased. Complete response rate was 44% (11/25), response rate was 32% (8/25), non-response rate was 24% (6/25) and total response rate was 76% (19/25). The platelet count in the patients who showed complete response to rhTPO therapy reached the highest 112×10(9)/L (43×10(9)/L-439×10(9)/L) on median 12 days(range from 7 days to 15 days). The patients showed response to rhTPO treatment on median 4 days (range from 1 days to 11 days). The platelet count decreased gradually after the discontinuation of rhTPO administration but still significantly higher on 28 days than the level before the treatment (P < 0.05). 12 patients who did not respond to γ-globulin before rhTPO treatment showed response to γ-globulin after the discontinuation of rhTPO therapy. 2 patients showed mild clinical adverse reaction. It is concluded that rhTPO is an effective and safe treatment method for children with severe ITP. It will help the patient smoothly through the dangerous period of severe bleeding, but the platelet count decreases gradually after rhTPO discontinuation. Maintenance treatment is needed to consolidate the curative efficacy.

Relationship between platelet specific antibodies and the onset, clinical manifestation, treatment and prognosis of ITP / 中国实验血液学杂志

Immune thrombocytopenia (ITP) is an autoimmune hemorrhagic disease. It is considered that production of platelet auto-antibodies was one of the pathogenesis of ITP, first-line therapy including corticosteroid and immunoglobulin could reduce destruction of platelets by inhibiting production of auto-antibodies and blocking Fc-receptor of reticuloendothelial system, but some of the patients were refractory to first-line therapy and have persistent duration of the disease, having worse prognosis and developing into chronic/refractory ITP(C/RITP) . Platelet membrane glycoprotein like GPIIb/IIIa and GPIbα are the most common antigen targets, but first-line therapy was less effective to patients whose anti-GPIbα antibodies are positive. Further studies revealed that the way causing platelet destruction by anti-GPIIb/IIIa antibodies and anti-GPIbα antibodies are different: the former is mainly dependent to Fc-pathway, and the latter mainly cleared platelet by Fc-independent way. Results above indicated that detection of type of platelet auto-antibodies maybe potential to treatment and prognosis of ITP. This article summarizes relationship between platelet specific antibodies and the onset, clinical manifestation, treatment and prognosis of ITP.

Advance in thrombopoietic drugs used in treatment of children's immune thrombocytopenia / 中国实验血液学杂志

Immune thrombocytopenia (ITP) is a common acquired hemorrhagic disease. Conventional view considered its pathogenesis as the destruction of platelets induced by platelet associated antibodies, the target of treatment are inhibiting the production of antibodies and blocking the destruction of platelets in reticuloendothelial system, but they are ineffective in part of ITP patients, who transform to chronic/refractory ITP (C/RITP). As to children's C/RITP, the effect of first-line therapy is low, while the second-line therapy isn't effective definitely and has obvious side effects. The safe and effective second-line drugs to prevent disease progressing are urgently required. Recently, a pathogenesis that decrease the platelet production has been confirmed, thrombopoietic drugs, including thrombopoietin (TPO) and its receptor agonist (TRA), are under research and clinical application gradually. Recombinate human TPO (rhTPO) has accomplished Phase III clinical trails in adult C/RITP and tumor children. The Phase III clinical trails of romiplostim and eltrombopag, as the representative of TRA, in adult C/RITP have been performed. There are also two clinical trails of TRA for children's C/RITP, the efficacy and safety have been approved, with the convenience for using. In pediatric population, they have a good clinical application. In this article the research and development of thrombopoietic drugs and their perspective in pediatric clinical use are reviewed.