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.

Pharmacokinetic Studies of Factor VIII in Chinese Boys with Severe Hemophilia A: A Single-Center Study / 中华医学杂志(英文版)

<p><b>Background</b>Although much attention has been paid to the pharmacokinetics (PKs) of different factor VIII (FVIII) concentrates in persons with hemophilia A (HA), limited information is available in young boys with severe HA. In this study, we aimed to assess the PK parameters of FVIII products in boys with severe HA in China.</p><p><b>Methods</b>A total of 36 boys (plasma-derived [pd]-FVIII, n = 15; recombinant [r] FVIII, n = 21) were enrolled between January 2015 and May 2016 in Beijing Children's Hospital. PK characteristics of FVIII products were studied according to a reduced 4-sampling time point design (1 h, 9 h, 24 h, and 48 h postinfusion).</p><p><b>Results</b>The mean FVIII half-life (t) was 10.99 ± 3.45 h (range 5.52-20.02 h), the mean in vivo recovery (IVR) was 2.01 ± 0.42 IU/dl per IU/kg (range 1.24-3.02 IU/dl per IU/kg) and mean clearance (CL) of FVIII is 4.34 ± 1.58 ml·kg·h (range 2.29-7.90 ml·kg·h). We also analyzed the influence of several parameters that potentially modulate FVIII PK. The age was closely associated with FVIII half-life (R = 0.32, P < 0.01). The tof FVIII increased by 0.59 h per year. Besides age, von Willebrand factor antigen (VWF:Ag) also was associated with FVIII half-life (R = 0.52, P < 0.01). Patients with blood Group O had a shorter FVIII half-life than patients with non-O blood group (9.40 ± 0.68 h vs. 12.3 ± 0.79 h, t = 2.70, P = 0.01). The FVIII IVR correlated with age (R = 0.21, P < 0.01) and VWF:Ag level (R = 0.28, P < 0.01). CL rates were faster in young patients and in those with low-VWF:Ag levels. CL rates of FVIII are higher in blood Group O versus non-blood Group O persons (5.02 ± 0.38 vs. 4.00 ± 0.32 ml·kg·h, t = 2.53, P = 0.02).</p><p><b>Conclusions</b>Chinese boys with severe HA have similar PK values to other ethnic groups and large differences in FVIII PK between individual patients. Age, blood group, and VWF:Ag levels are important determining factors for FVIII CL.</p>

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.

Immunoregulatory function of interleukin-6 on human Th17 cells / 中国实验血液学杂志

The aim of this study was to explore the regulatory function of interleukin-6(IL-6) on human Th17 cells. Human peripheral blood CD4(+) T cells were purified from healthy donors by anti-CD4 monoclonal antibody (mAb) conjugated microbeads. The experiment was divided into 2 groups. Test group in which CD4(+) T cells (1 × 10(6)/ml) were stimulated by human recombined IL-6 (20 ng/ml) for 4 days; control group in which CD4(+) T cells did not stimulated by IL-6. The concentrations of IL-17 protein in the supernatants were assayed by enzyme-linked immunosorbent assay (ELISA), and quantity of Th17 cells were detected by flow cytometry. The results showed that as compared to control group, IL-17 protein level in the supernatants of CD4(+) T cells significantly increased in IL-6 stimulated group: (337.05 ± 189.09 pg/ml; vs 15.07 ± 12.70 pg/ml) (p < 0.05). Furthermore, the percentage of Th17 cells in cultures of CD4(+) T cells stimulated by IL-6 was significantly higher than that in control group (4.05% ± 0.30% vs. 2.81% ± 0.44%)(p < 0.01). It is concluded that IL-6 promotes the expansion of Th17 cells in vitro.

Adenovirus-delivered BMI-1 shRNA / 中国实验血液学杂志

Recently, some plasmid vectors that direct transcription of small hairpin RNAs have been developed, which are processed into functional siRNAs by cellular enzymes. Although these vectors possess certain advantages over synthesized siRNA, many disadvantages exist, including low and variable transfection efficiency. This study was aimed to establish an adenoviral siRNA delivery system without above-mentioned disadvantages on the basis of commercially available vectors. A vector was designed to target the human polycomb gene BMI-1. The pAd-BMI-1shRNA-CMV-GFP vector was produced by cloning a 300 bp U6-BMI-1 cassette from the pGE1BMI-1shRNA plasmid and a CMV-GFP cassette from pAdTrack CMV in pShutter vector. The adenovirus was produced from the 293A packaging cell line and then infected K562 cells. The mRNA and protein levels of Bmi-1 were detected by real time-PCR and Western blot respectively. The results showed that the adenovirus carrying the BMI-1shRNA was successfully produced. After being transfected with the adenovirus, the K562 cells dramatically down-regulated BMI-1 expression, whereas the adenoviruses carrying control shRNA had no effect on BMI-1 expression. It is concluded that the adenoviruses are efficient vectors for delivery of siRNA into mammalian cells and may become a candidate vector carrying siRNA drugs for gene therapy.

Expression of human factor IX in retrovirus-transfected human umbilical cord tissue derived mesenchymal stem cells / 中国实验血液学杂志

The purpose of this study was to investigate the expression of human Factor IX (hFIX) in retrovirus-transfected human umbilical cord tissue derived mesenchymal stem cells (hUCT-MSCs). The pLEGFP-N1-hFIX vector was generated by cloning a 3.0 kb Bgl II-BamH I fragment from the pIRES2-EGFP-hFIX plasmid containing the hFIX cDNA and part of intron 1 of hFIX in pLEGFP-N1 vector. The retroviral supernatants were produced from the Phoenix packaging cell line and then infected the hUCT-MSCs. After selection with G418 for 10 day, the expression of FIX was detected by ELISA and Western blot. The biological activity of FIX was determined by the clotting assay employing human Factor IX-deficient plasma. The results showed that compared with the activity of pooled human normal plasma (100%), transduced cells produced biologically active hFIX with 100-130% activity in two-day culture supernatant and expressed hFIX at levels of 2.68 +/- 0.36 microg/10(6) cells/24 hours after G418 selection for 10 days. The secretion of hFIX into culture supernatant was also confirmed by Western blot analysis. It is concluded that genetically modified hUCT-MSCs can express biologically active hFIX and thus serve as an efficient drug delivery vehicle carrying hFIX used as a way of somatic gene therapy for hemophilia B.

Effect of silencing bmi-1 by RNA interference on function of K562 cell line / 中国实验血液学杂志

Bmi-1 is a transcriptional repressor, which belongs to the polycomb group family. It has been demon- started that over-expression of Bmi-1 occurs in a variety of cancers, including several types of leukemia. Bmi-1 gene plays a key role in regulation of self-renewal in normal and leukemic stem cells. Acute myeloid leukemic cells lacking Bmi-1 undergo proliferation arrest and show signs of differentiation and apoptosis, which leads to the proposal of Bmi-1 as a potential target for therapeutic intervention in leukemia. The purpose of this study was to investigate the effect of short hairpin RNA (shRNA) targeting Bmi-1 on functions of K562 cell line. The shRNA eukaryotic expression vector targeting Bmi-1 was constructed and transfected into K562 cells through lipofectamine 2000. The mRNA and protein levels of Bmi-1 were detected by PCR and Western blot respectively. The proliferation of K562 after Bmi-1 silencing was measured by using MTT assay and clone formation assay. The cell cycle was detected by flow cytometry. The results indicated that among the four shRNA designed, there was a shRNA which efficiently interfered with the expression of Bmi-1. The results of PCR and Western blot validated that the Bmi-1 gene of K562 cells transfected with such a Bmi-1 shRNA was suppressed successfully. Although levels of Bmi-1 mRNA and protein were significantly reduced, delivery of this siRNAs had no effect on cell viability or growth. Flow cytometry analysis suggested that Bmi-1 inhibition did not affect the cell cycle. It is concluded that the suppression of Bmi-1 expression is not able to reduce proliferation of K562 cells, suggesting existence of some other parallel signaling pathways, which are fundamental for leukemic transformation and are independent of Bmi-1 over-expression. Bmi-1 over-expression may play a secondary role in chronic myeloid leukemia transformation.

Mesenchymal stem cells derived from human umbilical cord tissue modulate the secretion of antiplatelet antibody from splenocytes of ITP patients in vitro / 中国实验血液学杂志

The study was aimed to investigate the potential immunotherapeutical values of umbilical cord tissue-derived mesenchymal stem cells (UC-MSC) on patients with chronic idiopathic thrombocytopenic purpura (ITP). UC-MSC was cocultured in vitro with splenocytes isolated from ITP patients who experienced splenectomy. The level of IgG antiplatelet antibody (PAIgG) was determined by a competitive micro-enzyme-linked immunosorbent assay (ELISA) method. The proliferation of platelet-reactive CD4+ T lymphocytes was also measured in the presence of UC-MSCs. The results showed that UC-MSCs could stimulate the spontaneous secretion of PAIgG in supernatants; In the platelet-inducing condition, UC-MSC inhibited the production of PAIgG at a low ratio of 1 UC-MSC to 100 splenocytes, but promoted at a high proportion of 1 UC-MSC to 10 splenocytes. Moreover, UC-MSC exerted a suppressive effect on proliferation of platelet-reactive T helper cells in a dose-dependent manner. It is concluded that the UC-MSCs can regulate secretion of antiplatelet antibodies in vitro. Its concrete regulation mechanism and potential immunotherapeutical value are need to further study.