Reduced toxicity, myeloablative HLA-haploidentical hematopoietic stem cell transplantation with post-transplantation cyclophosphamide for sickle cell disease.

Allogeneic hematopoietic stem cell transplantation (HSCT) offers the possibility of cure for sickle cell disease (SCD) patients. Unfortunately, the probability of finding an HLA-matched donor for SCD patients is low. HSCT from HLA-haploidentical donors using reduced intensity conditioning, unmanipulated bone marrow and post-transplantation cyclophosphamide (ptCy) has resulted in negligible toxicity but high rates of graft rejection. We hypothesized that combining ptCy with a myeloablative reduced toxicity conditioning including serotherapy to increase immune ablation would allow for better engraftment. In a pilot approach, we treated three patients with SCD (5, 8, and 20 years old) lacking a matched donor. All patients had severe disease-related complications despite standard treatment. They received unmanipulated bone marrow from parental HLA-haploidentical donors. Conditioning consisted of alemtuzumab 0.2 mg/kg/day on days -9 and -8, fludarabine 30 mg/m2/day on days -7 to -3, treosulfan 14 g/m2/day on days -7 to -5, thiotepa 2 × 5 mg/kg/day on day -4, and cyclophosphamide 14.5 mg/kg/day on days -3 and -2. GVHD prophylaxis was performed using cyclophosphamide 2 × 50 mg/kg on days +3 and +4 and mycophenolate mofetil, tacrolimus from day +5. After a follow-up of 11, 14, and 30 months, all three patients are alive and well, off immunosuppression, and without symptoms of SCD. One patient experienced mild skin GVHD grade I, none showed chronic GVHD. Asymptomatic CMV reactivation was seen in two patients. HLA-haploidentical HSCT can extend the donor pool for patients with SCD. Whether intensification of the conditioning regimen and intensive immunosuppression leads to improvement in engraftment rates while still allowing a favorable toxicity profile deserves further investigation.

Perioperative management of hemostasis in children and adolescents.

Invasive procedures in children are in most cases elective and are carried out in otherwise healthy children. While many surgeries are still performed in a hospital, more and more procedures are defined as "outpatient procedures," leading to increased discussion about safety and risks. This review will examine common practices, review the sparse literature and provide recommendations regarding the identification of children with increased bleeding risk, planning for children with known bleeding disorders and strategies for perioperative management. In conclusion, after careful planning, surgeries can be performed safely even in children with known bleeding disorders.

[Haemostatic disorders in children]. / Hämostaseologie in der Pädiatrie.

Haemorrhagic and thrombotic events occur in both children and adults. The underlying causes are congenital or acquired disorders. In contrast to haemorrhagic disorders, inherited thrombotic disorders nearly exclusively in association with additional external risk factors lead to thrombotic events predominantly during the newborn period and adolescence. It is necessary to be aware of age-specific properties of coagulation in order to correctly interpret clinical and laboratory findings and to provide optimal care for children with haemorrhagic and thrombotic complications.

NFkappaB-mediated upregulation of bcl-xl restrains TRAIL-mediated apoptosis in murine viral hepatitis.

Inhibition of NFkappaB enhances the susceptibility of cancer to TRAIL-mediated apoptosis and is suggested as a strategy for cancer therapy. Because the role of NFkappaB in TRAIL-mediated apoptosis of hepatocytes is unknown, we investigated the influence of NFkappaB-inhibition in death ligand-mediated apoptosis in hepatitis. Adenoviral hepatitis resulted in upregulation of NFkappaB-activity, which could be inhibited by expression of IkappaBalpha-superrepressor. We treated mice after the onset of adenoviral hepatitis with adenoviruses expressing FasL (AdFasL), TRAIL (AdTRAIL), or GFP (AdGFP). In contrast to apoptosis induced by AdFasL, NFkappaB inhibition strongly enhanced AdTRAIL-mediated apoptosis of hepatocytes. Expression of IkappaBalpha inhibits adenoviral infection-mediated overexpression of bcl-xl, providing a molecular mechanism for TRAIL sensitization. In agreement with this hypothesis, downregulation of bcl-xl by siRNA enhanced susceptibility of hepatocytes to TRAIL, but not to FasL-mediated apoptosis, resulting in TRAIL-mediated severe liver damage after AdTRAIL application. Our data demonstrate that inhibition of NFkappaB in adenoviral hepatitis strongly sensitizes hepatocytes to TRAIL-mediated apoptosis. Bcl-xl, in contrast to bcl-2 and c-FLIP, is strongly upregulated after viral infection and represents an essential NFkappaB-dependent survival factor against TRAIL-mediated apoptosis. In conclusion, inhibition of NFkappaB or bcl-xl during TRAIL therapy may harbor a risk of liver damage in patients with viral hepatitis.

Caspase 8 small interfering RNA prevents acute liver failure in mice.

A major concern in therapy of acute liver failure is protection of hepatocytes to prevent apoptosis and maintain liver function. Small interfering RNA (siRNA) is a powerful tool to silence gene expression in mammalian cells. To evaluate the therapeutic efficacy of siRNA in vivo we used different mouse models of acute liver failure. We directed 21-nt siRNAs against caspase 8, which is a key enzyme in death receptor-mediated apoptosis. Systemic application of caspase 8 siRNA results in inhibition of caspase 8 gene expression in the liver, thereby preventing Fas (CD95)-mediated apoptosis. Protection of hepatocytes by caspase 8 siRNA significantly attenuated acute liver damage induced by agonistic Fas (CD95) antibody (Jo2) or by adenovirus expressing Fas ligand (AdFasL). However, in a clinical situation the siRNAs most likely would be applied after the onset of acute liver failure. Therefore we injected caspase 8 siRNA at a time point during AdFasL- and adenovirus wild type (Adwt)-mediated liver failure with already elevated liver transaminases. Improvement of survival due to RNA interference was significant even when caspase 8 siRNA was applied during ongoing acute liver failure. In addition, it is of particular interest that caspase 8 siRNA treatment was successful not only in acute liver failure mediated by specific Fas agonistic agents (Jo2 and AdFasL) but also in acute liver failure mediated by Adwt, which is an animal model reflecting multiple molecular mechanisms involved in human acute viral hepatitis. Consequently, our data raise hope for future successful application of siRNA in patients with acute liver failure.