Neonatal seizures associated with white-matter changes on neuroimaging suggest an etiology of hypoxic-ischemic encephalopathy. Metabolic and idiopathic etiologies are also considerations but are less ...likely. Despite the fact that two disorders associated with neonatal seizures are diagnosed by cerebrospinal fluid neurotransmitter analysis, such an analysis is not standard in the work-up for idiopathic neonatal seizures. We describe an infant who had a prolonged delivery, seizures on the first day of life, and white-matter changes on neuroimaging. A progressive seizure disorder that was refractory to standard antiepilepsy medications developed at 2 months of age. Analysis of cerebrospinal fluid neurotransmitters at that time demonstrated a pattern consistent with folinic acid—responsive seizures. Seizures ceased 24 hours after starting folinic acid. Serial neuroimaging, electroencephalograms, and metabolic changes from this patient are presented. This case illustrates the importance of cerebrospinal fluid neurotransmitter analysis as part of the work-up for idiopathic neonatal seizures. (J Child Neurol 2003;18:562—569).
The ability of alcohols to regulate InsP3-receptor activity was examined in permeabilized hepatocytes. Incubation with 30-300 mM ethanol decreased the sensitivity to InsP3 for Ca2+ release, with ...little effect on the size of the Ca2+ store that could be released with maximal concentrations of InsP3. Ethanol (300 mM) increased the EC50 for InsP3 from a control value of 134.0 +/- 13.5 nM to 220.0 +/- 25.9 nM. Although ethanol also caused a partial depletion of the total pool of stored Ca2+, the ethanol-induced shift in InsP3 sensitivity was not secondary to this alteration in Ca2+ loading. Partial depletion of the Ca2+ stores with low doses of ionomycin and thapsigargin did not cause a shift in InsP3 sensitivity. Furthermore, measurements of InsP3 receptor channel activity using retrograde flux of Mn2+ to quench the fluorescence of Fura-2 within the Ca2+ stores demonstrated that ethanol inhibited InsP3-activated channel activity in the absence of stored Ca2+. Other short chain alcohols (methanol, 1-propanol and 1-butanol) also decreased the efficacy of InsP3 to release Ca2+. Measurements of 3H-InsP3 binding demonstrated that ethanol decreased the total number of InsP3 binding sites without changing the KD. The effect of ethanol on InsP3 binding was apparent in the presence or absence of Ca2+ and was observed when the cells were pre-incubated with ethanol at either 37 degrees C or 4 degrees C. The initial rate of InsP3-induced Mn2+ quenching of compartmentalized Fura-2 was reduced by ethanol at all doses of InsP3. These data suggest that ethanol decreases the sensitivity of the intracellular Ca2+ store to release by InsP3, by reducing the number of channels that can be activated by InsP3.
Reactivation of EBV (Epstein-Barr virus) after bone marrow transplantation can result in EBV-associated lymphoproliferative disease (EBV-LPD). We have administered donor-derived EBV-specific ...cytotoxic T lymphocytes (CTL) to patients who are at high risk of this complication after receiving a T-cell-depleted allograft from a matched unrelated or mismatched related donor. The cells were marked with the neo gene before infusion so that we could evaluate their persistence and efficacy. CTL infusion produced a virus-specific immune response to EBV that persisted for up to 2 years. None of the 36 patients who received prophylactic CTLs have developed EBV-LPD, compared with a cumulative risk of 14% in patients who did not receive this treatment. Strong evidence of clinically valuable immune activity comes from 6 of these 36 patients whose pre-CTL levels of EBV DNA were elevated to a degree strongly predictive of the onset of lymphoma. In each of these cases, the levels returned to baseline after CTL infusion. 2 patients who were treated for clinically evident EBV-LPD attained prolonged remission after CTL infusion and in situ hybridization and semiquantitative PCR showed that the gene-marked CTL had selectively accumulated at disease sites. The prophylactic CTL treatment lacked acute adverse effects, whereas 1 patient who received CTLs for bulky established disease developed initial tumor swelling and respiratory obstruction. We conclude that EBV-specific CTLs are a safe and effective prophylaxis for EBV lymphoma and can also eradicate established disease. This approach is now being extended to other viruses that produce post-transplant morbidity and to other EBV-associated malignancies.
Epstein-Barr virus nuclear antigen type 1 (EBNA1), the only viral protein that is unequivocally expressed in all Epstein-Barr virus (EBV)-associated malignant diseases, is essential for viral DNA ...replication and maintenance of the viral episome in infected cells. A glycine-alanine repeat domain inhibits antigen processing through the ubiquitin-proteasome pathway for presentation on human leukocyte antigen (HLA) class I molecules. EBNA1 is not protected from the HLA class II processing pathway, and CD4+ HLA class II-restricted T cells recognize the antigen. CD4+ T-helper (Th) cells play critical roles in initiating, regulating, and maintaining immune responses against viral infections and tumors, so that inclusion of EBNA1 as a target antigen may improve immunotherapy for EBV-associated cancers. In this study, the authors used the TEPITOPE software program to predict promiscuous class II epitope candidates. After several HLA-DR-restricted peptides were identified by in vitro analysis of the T-cell response to synthetic peptides, a T-cell clone was established that was specific for one of the peptides. Functional studies were performed with this clone. The CD4+ T helper cells specific for the HLA-DR15-restricted peptide EBNA1(482) (AEGLRALLARSHVER) recognized naturally processed EBNA1 protein. This epitope was presented by several HLA-DR alleles, including DR4, DR7, and DR11. The inclusion of the promiscuous, naturally processed EBNA1(482) epitope in vaccine constructs could enhance immune responses against EBV-positive cancers.
Wegener's granulomatosis (WG) is classically associated with the presence of cytoplasmic antineutrophil cytoplasmic autoantibodies (c-ANCA). Proteinase 3 (PR3), the target antigen for c-ANCA, is ...inhibited by the antiprotease alpha1-antitrypsin (A1AT), and recent studies have demonstrated that WG patients who are A1AT-deficient have a worse clinical course, suggesting that a protease-antiprotease imbalance may play a role in WG. We evaluated the effect of A1AT on anti-PR3 antibody-induced activation of neutrophils. The neutrophil was chosen because of its central role in the pathogenesis of WG. Isolated neutrophils from healthy controls were incubated with tumor necrosis factor (TNF)-alpha to induce surface expression of PR3. Subsequently, they were stimulated with a monoclonal antibody to PR3, resulting in a significant increase in respiratory burst. Addition of A1AT (1 mg/ml) to the TNF-alpha- primed cells before the addition of the anti-PR3 antibody resulted in a 47% reduction in anti-PR3 antibody-induced activation. A1AT mediated this inhibitory action by preventing anti-PR3 antibody binding to PR3 on the cell, thereby preventing the PR3-FcgammaR11a cross-linkage required for cell activation. Further, anti-PR3 antibody-induced activation of neutrophils from WG patients can be reduced by 56% with A1AT. These data suggest that protease-antiprotease interactions may play a pivotal role in neutrophil activation in WG.
Epstein-Barr virus (EBV) is a latent herpesvirus that is associated with a number of tumors. EBV-infected cells show three patterns of latency ranging from type 1, where only one EBV-encoded antigen ...is expressed, to type 3, where all nine latent cycle proteins encoded by EBV are expressed. Malignancies exhibiting the type 3 latency pattern are highly immunogenic and occur only in immunocompromised patients. It has recently been shown that adoptive immunotherapy with EBV-specific cytotoxic T lymphocytes is an effective therapy for such tumors. Immunotherapy strategies and approaches to increase tumor immunogenicity are now being evaluated in tumors expressing type 2 latency.
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