Background: Despite an increase in the number of therapies available to treat patients with immune thrombocytopenia (ITP), there are minimal data from randomized trials to assist physicians with the management of patients. Objective: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the management of ITP. Methods: In 2015, ASH formed a multidisciplinary guideline panel that included 8 adult clinical experts, 5 pediatric clinical experts, 2 methodologists with expertise in ITP, and 2 patient representatives. The panel was balanced to minimize potential bias from conflicts of interest. The panel reviewed the ASH 2011 guideline recommendations and prioritized questions. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including evidence-to-decision frameworks, to appraise evidence (up to May 2017) and formulate recommendations. Results: The panel agreed on 21 recommendations covering management of ITP in adults and children with newly diagnosed, persistent, and chronic disease refractory to first-line therapy who have non–life-threatening bleeding. Management approaches included: observation, corticosteroids, IV immunoglobulin, anti-D immunoglobulin, rituximab, splenectomy, and thrombopoietin receptor agonists. Conclusions: There was a lack of evidence to support strong recommendations for various management approaches. In general, strategies that avoided medication side effects were favored. A large focus was placed on shared decision-making, especially with regard to second-line therapy. Future research should apply standard corticosteroid-dosing regimens, report patient-reported outcomes, and include cost-analysis evaluations.

BACKGROUND-We conducted a trial of prophylactic platelet transfusions to evaluate the effect of platelet dose on bleeding in patients with hypoproliferative thrombocytopenia.

Patients with antiphospholipid antibodies (APLAs) are at increased risk for arterial and venous thrombosis. Many APLAs associated with these events react with ␤ 2 glycoprotein I (␤ 2 GPI), and endothelial cell reactive antibodies that activate endothelial cells in a ␤ 2 GPI-dependent manner occur commonly in these patients. We previously reported that ␤ 2 GPI binds with high affinity to annexin A2 on the endothelial surface, though the relevance of this interaction to APLA/anti-␤ 2 GPI antibodyinduced endothelial activation has not been determined. In this report, we confirm that anti-␤ 2 GPI antibodies activate endothelial cells in the presence of ␤ 2 GPI, and demonstrate that anti-annexin A2 antibodies directly cause endothelial cell activation of a similar magnitude and with a similar time course. Moreover, bivalent anti-annexin A2 F(ab) 2 fragments also caused endothelial cell activation, whereas monomeric Fab fragments not only did not cause activation, but blocked activation induced by anti-annexin A2 antibodies and F(ab) 2 fragments, as well as that caused by anti-␤ 2 GPI antibodies in the presence of ␤ 2 GPI. These observations suggest a novel pathway for endothelial activation induced by APLA/anti-␤ 2 GPI antibodies that is initiated by crosslinking or clustering of annexin A2 on the endothelial surface. (Blood. 2005;105: 1964-1969

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We examined the localization of transforming growth factor (TGF)-beta in first-trimester and term human decidua and chorionic villi and explored the role of this factor on the proliferation and differentiation of cultured trophoblast cells. Two antibodies, 1D11.16.8, a mouse monoclonal neutralizing antibody capable of recognizing both TGF-beta 1 and TGF-beta 2 and CL-B1/29, a rabbit polyclonal antibody capable of recognizing TGF-beta 2, were used to immunolocalize TGF-beta in fixed, paraffin-embedded, or fixed, frozen sections of placenta and decidua, providing similar results. Intense labeling was observed in the extracellular matrix (ECM) of the first-trimester decidua and cytoplasm of term decidual cells. Syncytiotrophoblast cell cytoplasm as well as the ECM in the core of the chorionic villi of both first-trimester and term placentas exhibited a moderate degree of labeling. Strong cytoplasmic labeling was observed in the cytotrophoblastic shell of the term placenta. To examine the role of TGF-beta on trophoblast proliferation and differentiation, early passage cultures of first-trimester and primary cultures of term trophoblast cells were established and characterized on the basis of numerous immunocytochemical and functional markers. These cells expressed cytokeratin, placental alkaline phosphatase, urokinase-type plasminogen activator, and pregnancy-specific beta glycoprotein, but not factor VIII or 63D3; they also produced hCG and collagenase type IV. Exposure of first-trimester trophoblast cultures to TGF-beta 1 significantly inhibited proliferation in a dose-dependent manner. An antiproliferative effect was also noted in the presence of TGF-beta 2. These effects were abrogated in the presence of the neutralizing anti-TGF-beta antibody (1D11.16.8) in a concentration-dependent manner. In a 3-day culture, exogenous TGF-beta 1 stimulated formation of multinucleated cells by the first trimester as well as term trophoblast cells. Addition of neutralizing anti-TGF-beta antibody to first-trimester trophoblast cells stimulated proliferation beyond control levels in a 24-h culture and reduced formation of multinucleated cells in a 3-day culture, indicating the presence of endogenous TGF-beta activity. These results indicate that TGF-beta produced at the human fetal-maternal interface plays a major regulatory role in the proliferation and differentiation of the trophoblast.

Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease. Most KS tumor cells are latently infected with KSHV and are of endothelial origin. While PEL-derived cell lines maintain KSHV indefinitely, all KS tumor-derived cells to date have lost viral genomes upon ex vivo cultivation. To study KSHV latency and tumorigenesis in endothelial cells, we generated telomerase-immortalized human umbilical vein endothelial (TIVE) cells. TIVE cells express all KSHV latent genes 48 h postinfection, and productive lytic replication could be induced by RTA/Orf50. Similar to prior models, infected cultures gradually lost viral episomes. However, we also obtained, for the first time, two endothelial cell lines in which KSHV episomes were maintained indefinitely in the absence of selection. Long-term KSHV maintenance correlated with loss of reactivation in response to RTA/Orf50 and complete oncogenic transformation. Long-term-infected TIVE cells (LTC) grew in soft agar and proliferated under reduced-serum conditions. LTC, but not parental TIVE cells, formed tumors in nude mice. These tumors expressed high levels of the latency-associated nuclear antigen (LANA) and expressed lymphatic endothelial specific antigens as found in KS (LYVE-1). Furthermore, host genes, like those encoding interleukin 6, vascular endothelial growth factor, and basic fibroblast growth factor, known to be highly expressed in KS lesions were also induced in LTC-derived tumors. KSHV-infected LTCs represent the first xenograft model for KS and should be of use to study KS pathogenesis and for the validation of anti-KS drug candidates.Kaposi's sarcoma-associated herpesvirus (KSHV), also called human herpesvirus 8 (HHV-8), is believed to be the causative agent for Kaposi's sarcoma (KS) (for a review, see references 1 and 27). Within KS tumor lesions, the majority of cells express endothelial markers and are latently infected with KSHV, as defined by the presence of the circular viral genome and limited viral-gene expression. Studying KSHV's role in KS is complicated by the fact that cells explanted from KS lesions lose the KSHV genome after several cell divisions in culture (2, 43). In addition to KS, KSHV is associated with two lymphoproliferative diseases: primary effusion lymphomas (PEL) and multicentric Castleman's disease (MCD) (11, 59). In contrast to KS lesions, PEL-derived cell lines that are latently infected with KSHV are readily established in culture. These cells maintain viral episomes indefinitely and remain dependent on KSHV for survival (31,33). Therefore, many aspects of KSHV biology have been studied in PEL-derived cell lines rather than in endothelial cells (56; for a review, see reference 1).Several endothelial-cell-derived tissue culture models have been described. Common to these models, which are based on dermal microvascular endothelial cells (DMVEC), are their susceptibility to cell-free infection with PEL-derived KSHV and their capabili...

We previously reported that the binding of two-chain high molecular weight kininogen (HKa) to endothelial cells may occur through interactions with endothelial urokinase receptors. Since the binding of urokinase to urokinase receptors activates signaling responses and may stimulate mitogenesis, we assessed the effect of HKa binding on endothelial cell proliferation. Unexpectedly, HKa inhibited proliferation in response to several growth factors, with 50% inhibition caused by approximately 10 nM HKa. This activity was Zn(2+) dependent and not shared by either single-chain high molecular weight kininogen (HK) or low molecular weight kininogen. HKa selectively inhibited the proliferation of human umbilical vein and dermal microvascular endothelial cells, but did not affect that of umbilical vein or human aortic smooth muscle cells, trophoblasts, fibroblasts, or carcinoma cells. Inhibition of endothelial proliferation by HKa was associated with endothelial cell apoptosis and unaffected by antibodies that block the binding of HK or HKa to any of their known endothelial receptors. Recombinant HK domain 5 displayed activity similar to that of HKa. In vivo, HKa inhibited neovascularization of subcutaneously implanted Matrigel plugs, as well as rat corneal angiogenesis. These results demonstrate that HKa is a novel inhibitor of angiogenesis, whose activity is dependent on the unique conformation of the two-chain molecule.

The urokinase receptor (uPAR) binds urokinase-type plasminogen activator (u-PA) through specific interactions with uPAR domain 1, and vitronectin through interactions with a site within uPAR domains 2 and 3. These interactions promote the expression of cell surface plasminogen activator activity and cellular adhesion to vitronectin, respectively. High molecular weight kininogen (HK) also stimulates the expression of cell surface plasminogen activator activity through its ability to serve as an acquired receptor for prekallikrein, which, after its activation, may directly activate prourokinase. Here, we report that binding of the cleaved form of HK (HKa) to human umbilical vein endothelial cells (HUVEC) is mediated through zinc-dependent interactions with uPAR. These occur through a site within uPAR domains 2 and 3, since the binding of 125 I-HKa to HUVEC is inhibited by vitronectin, anti-uPAR domain 2 and 3 antibodies and soluble, recombinant uPAR (suPAR), but not by antibody 7E3, which recognizes the ␤ chain of the endothelial cell vitronectin receptor (integrin ␣ v ␤ 3 ), or fibrinogen, another ␣ v ␤ 3 ligand. We also demonstrate the formation of a zinc-dependent complex between suPAR and HKa. Interactions of HKa with endothelial cell uPAR may underlie its ability to promote kallikrein-dependent cell surface plasmin generation, and also explain, in part, its antiadhesive properties. (