Efficacy and safety of eculizumab in childhood atypical hemolytic uremic syndrome in Japan.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a severe life-threatening disease with frequent progression to end-stage renal disease (ESRD). Eculizumab, a humanized anti-C5 monoclonal antibody targeting the activated complement pathway, has recently been introduced as a novel therapy against aHUS. We, therefore, investigated the efficacy and safety of eculizumab in Japanese pediatric patients. METHODS: We retrospectively analyzed clinical course and laboratory data of the first ten children with aHUS treated with eculizumab nationwide. RESULTS: Seven patients were resistant to plasma therapy and three were dependent on it. Causative gene mutations were found in five patients. Two patients had anti-complement factor H autoantibody. Three patients had a family history of thrombotic microangiopathy (TMA). After initiation of eculizumab, all patients immediately achieved hematological remission and could successfully discontinue plasma therapy. The median periods to normalization of platelet count, lactate dehydrogenase levels and disappearance of schistocytes were 5.5, 17 and 12 days, respectively. Nine patients recovered their renal function and the median period to terminate renal replacement therapy (RRT) was 3 days. However, two patients progressed to ESRD and required chronic RRT at the last observation. No patients had a relapse of TMA under regular eculizumab therapy. No serious adverse events occurred during the follow-up period. CONCLUSIONS: Eculizumab is efficacious and well-tolerated therapy for children with aHUS. Although pathogenic mutations could not be detected in five patients, all patients showed immediate normalization of hematological abnormalities, strongly suggesting complement-related aHUS. This prompt hematological amelioration can become an indicator for therapeutic efficacy of eculizumab. However, appropriate indications and optimal duration of the treatment remain unclear.

10-year-old girl with life-threatening idiopathic systemic capillary leak syndrome: a case report.

BACKGROUND: Idiopathic systemic capillary leak syndrome (ISCLS) is a rare disorder, characterized by episodic life-threatening hypotension, hypoalbuminemia, and hemoconcentration. CASE PRESENTATION: A 10-year-old girl presented with abdominal pain, vomiting, diarrhea, fever and developed generalized edema a day after admission. Clinical and laboratory findings were consistent with ISCLS. She received aggressive fluid replacement, methylprednisolone pulse (30 mg/kg/day), high-dose intravenous immunoglobulin (IVIG, 2 g/kg/day) and plasma exchange in acute phase. She received fasciotomy of bilateral lower extremities as she developed complications of compartment syndrome. Since there were two episodes of ISCLS attacks, theophylline and terbutaline were initiated for prevention of attacks and then the remission is currently maintained. Because of high fatality rate in ISCLS, prompt diagnosis and intervention are very important. CONCLUSION: We describe here, a rare case of pediatric ISCLS. ISCLS should be considered as a differential diagnosis, when the patient presents with unexplained or sudden hypovolemic shock. Reports on pediatrics ISCLS are very few, and accumulation of similar case reports is needed.

Acute cerebellitis following hemolytic streptococcal infection.

BACKGROUND: Acute cerebellitis is a rare inflammatory syndrome in children, with either infectious or autoimmune etiologies. PATIENT: We describe a 7-year-old girl with a presentation of cerebellitis following group A streptococcal infection. RESULTS: Magnetic resonance imaging showed diffuse symmetrical swelling and edema of the cerebellum resulting in compression of the fourth ventricle and hydrocephalus. Autoantibodies against glutamate receptor δ2 were detected in the cerebrospinal fluid, suggesting that the cerebellum might be injured by postinfectious immunologic reaction. The most common causes of cerebellitis are acute viral infection, postinfection, and following vaccination. No examples of acute cerebellitis following group A streptococcal infection have been documented. CONCLUSION: Our report demonstrates that group A streptococcal can lead to acute cerebellitis.

Heterogeneity of neuroblastoma cell lines in insulin-like growth factor 1 receptor/Akt pathway-mediated cell proliferative responses.

Insulin-like growth factor 1 receptor (IGF-1R) is critical for cancer cell proliferation; however, recent clinical anti-IGF-1R trials did not show clear clinical benefit in cancer therapy. We hypothesized that IGF-1R signaling-mediated proliferative response is heterogeneous in neuroblastoma (NB) cells, and analyzed the cell growth of 31 NB cell lines cultured in three different media, including Hybridoma-SFM medium (with insulin) and RPMI1640 with/without 10% FBS. Three growth patterns were found. In response to IGF and insulin, cell proliferation and Akt phosphorylation were upregulated in 13 cell lines, and suppressed by MK2206 (Akt inhibitor) and picropodophyllin (IGF-1R inhibitor). Interestingly, 3 of these 13 cell lines showed Akt self-phosphorylation and cell proliferation in RPMI1640; their proliferation was downregulated by anti-IGF-1 or anti-IGF-2 neutralizing antibody, suggesting the existence of an autocrine loop in the IGF-1R/Akt pathway. Eighteen NB cell lines did not proliferate in RPMI1640, even though Akt phosphorylation was upregulated by IGF and insulin. Based on the heterogeneous response of the IGF-1R/Akt pathway, the 31 NB cell lines could be classified into group 1 (autocrine IGF-mediated), group 2 (exogenous IGF-mediated) and group 3 (partially exogenous IGF-mediated) NB cell lines. In addition, group 3 NB cell lines were different from group 1 and 2, in terms of serum starvation-induced caspase 3 cleavage and picropodophyllin-induced G2/M arrest. These results indicate that the response of the IGF-1R/Akt pathway is an important determinant of the sensitivity to IGF-1R antagonists in NB. To our knowledge, this is the first report describing heterogeneity in the IGF-1R/Akt-mediated proliferation of NB cells.

A novel Wiskott-Aldrich syndrome protein mutation in an infant with thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura (TTP) has not yet been reported to be associated with mutations in the Wiskott-Aldrich syndrome (WAS) gene. WAS is an X-linked recessive disorder characterized by thrombocytopenia, small platelet size, eczema, recurrent infections, and increased risk of autoimmune disorders and malignancies. A broad spectrum of mutations in the WAS protein (WASP) gene have been identified as causing the disease. In this study, we report on a 2-month-old Japanese boy who presented with cytomegalovirus (CMV) infection and TTP. The activity of von Willebrand factor cleaving metalloproteinase, ADAMTS13 was low and the antibody against ADAMTS13 was positive (3.6 Bethesda U/mL). Although TTP was improved by plasma exchange and steroid pulse therapy, thrombocytopenia persisted and regular transfusions of irradiated platelets were needed. Tiny platelets were found on a peripheral blood smear. CMV genome was positive in peripheral blood by polymerase chain reaction and the CMV viremia continued to persist despite intravenous gancyclovir therapy. Through direct sequencing of genomic DNA of the WASP gene in the patient, we identified a novel mutation of WASP gene: the seventh nucleotide in exon 11 (G) had been deleted (1345delG). This mutation causes a frameshift and a stop codon at amino acid 470. Western blotting demonstrated a truncated WAS protein. To our knowledge, this is the first report describing TTP in WAS patients with novel mutation in the WASP gene.

Apoptosis of human peripheral blood mononuclear cells by wild-type measles virus infection is induced by interaction of hemagglutinin protein and cellular receptor, SLAM via caspase-dependent pathway.

Although MV infection causes lymphopenia and degradation of cell-mediated immunity, the mechanisms are poorly known. MV interacts with cellular receptors which mediate virus binding and uptake and are on the surface of PBMC. In this study, apoptosis of MV-infected PBMC in vitro was analyzed. Both PBMC treated with UV-inactivated viruses and those infected with live MV underwent apoptosis. Apoptosis of wild-type MV-infected PBMC was blocked by anti-SLAM and anti-MV hemagglutinin antibodies, respectively. Furthermore, addition of soluble MV hemagglutinin recombinant protein induced apoptosis in PBMC. These data suggest that induction of apoptosis in MV-infected PBMC is triggered by interaction between hemagglutinin protein of MV and receptor, without other viral components. To further determine the mechanisms of apoptosis, caspase activity was analyzed by Western blotting. Wild-type virus Yonekawa strain-induced apoptosis was blocked by pretreatment with pan-caspase inhibitor (Z-VAD-fmk). Intriguingly, the laboratory-adapted Nagahata strain-induced apoptosis was not blocked by Z-VAD-fmk, indicating that there may be different apoptosis pathways which depend on the viral receptors, SLAM and CD46. Both extrinsic and intrinsic apoptotic pathways, including activation of caspase-3, -8 and -9, are involved in Yonekawa strain-induced apoptosis. Taken together, the findings of this study could open up a new avenue for understanding the molecular mechanisms of MV-induced PBMC apoptosis and immunosuppression.

Protein-loosing enteropathy associated with rotavirus infection in an infant.

Rotavirus is an acute enteric pathogen in infants and children. We reported a rare case of a 6-mo-old infant with protein-loosing enteropathy (PLE) caused by rotavirus gastroenteritis, and evaluated the immunological profile in peripheral blood lymphocytes. Laboratory examinations showed lymphopenia, hypoproteinemia, hypoalbuminemia, hypogammaglobulinemia, and elevation of alpha-1-antitrypsin (alpha1-AT) clearance. Lymphocytes subpopulation study revealed the reversal of CD4+/CD8+ ratio with the selective decrease of CD4-positive lymphocytes. Moreover, the excessive increase of T cells producing IFN-gamma (IFN-gamma) was found, which plays an important role in the protection against viral infection. The primary or secondary activation of immune system by rotavirus may influence structural integrity and vascular permeability, which may play a triggering role in protein-loosing enteropathy.