Modest Expansion of Vβ2+CD4+ T Cells and No Expansion of Vβ7+CD4+ T Cells in a Subgroup of Kawasaki Disease Patients with Erythematic BCG Inoculation Site Lesions

Background: The similarities between Kawasaki disease (KD) and superantigen (SA) diseases indicate that a microbial SA might cause KD. Viral diseases can trigger an endogenous SA.Methods: We evaluated expression of Vβ2 (responding to staphylococcal TSST-1) and Vβ7 (responding to the endogenous SA induced by type-1 interferon or Epstein-Barr virus infection) on T cells from 70 KD patients along with the following control subjects: 18 non-vasculitic patients (NVs), 7 patients with anaphylactoid purpura (AP), and two with neonatal TSS-like exanthematous disease (NTED), a typical SA disease. We examined the correlation of clinical features of KD with Vβ2+ or Vβ7+CD4+T cell populations.Results: The Vβ2+CD4+T cell rates were comparable between KD patients (9.9±2.9%) and NVs (9.0±1.8%), but were lower in AP patients (6.6±1.8%). However, the Vβ2+CD4+T cell rate was significantly higher in KD patients with erythematic BCG inoculation site lesions (10.8±3.2%) than in those without (8.8±2.1%) and NVs (9.0±1.8%), but much lower than in NTED patients (25.2%, 16.9%). Multivariate linear regression analysis with elevation of Vβ2 expression as a dependent variable revealed significant correlations with BCG. In contrast, Vβ7+CD4+T cell rates were not significantly different between KD patients and other study subjects.Conclusion: While we were unable to find evidence supporting the involvement of the endogenous SA in the pathogenesis of KD in this study, modest expansion of the Vβ2+CD4+T cell population in a subgroup of KD with erythematic BCG inoculation site lesions implies the involvement of a microbial agent(s) different from TSST-1 as well as immunopathological heterogeneity of KD. (249 words

Postmortem Quantitative Analysis of Prion Seeding Activity in the Digestive System

Human prion diseases are neurodegenerative disorders caused by prion protein. Although infectivity was historically detected only in the central nervous system and lymphoreticular tissues of patients with sporadic Creutzfeldt-Jakob disease, recent reports suggest that the seeding activity of Creutzfeldt-Jakob disease prions accumulates in various non-neuronal organs including the liver, kidney, and skin. Therefore, we reanalyzed autopsy samples collected from patients with sporadic and genetic human prion diseases and found that seeding activity exists in almost all digestive organs. Unexpectedly, activity in the esophagus reached a level of prion seeding activity close to that in the central nervous system in some CJD patients, indicating that the safety of endoscopic examinations should be reconsidered

Rapid and Quantitative Assay of Amyloid-Seeding Activity in Human Brains Affected with Prion Diseases

The infectious agents of the transmissible spongiform encephalopathies are composed of amyloidogenic prion protein, PrPSc. Real-time quaking-induced conversion can amplify very small amounts of PrPSc seeds in tissues/body fluids of patients or animals. Using this in vitro PrP-amyloid amplification assay, we quantitated the seeding activity of affected human brains. End-point assay using serially diluted brain homogenates of sporadic Creutzfeldt-Jakob disease patients demonstrated that 50% seeding dose (SD50) is reached approximately 1010/g brain (values varies 108.79-10.63/g). A genetic case (GSS-P102L) yielded a similar level of seeding activity in an autopsy brain sample. The range of PrPSc concentrations in the samples, determined by dot-blot assay, was 0.6-5.4 μg/g brain; therefore, we estimated that 1 SD50 unit was equivalent to 0.06-0.27 fg of PrPSc. The SD50 values of the affected brains dropped more than three orders of magnitude after autoclaving at 121°C. This new method for quantitation of human prion activity provides a new way to reduce the risk of iatrogenic prion transmission

Synthesis and Characterization of Hydroxyethylamino- and Pyridyl-Substituted 2-Vinyl Chromone Derivatives for Detection of Cerebral Abnormal Prion Protein Deposits

Prion diseases are fatal neurodegenerative diseases characterized by the deposition of abnormal prion protein aggregates (PrPSc) in the brain. In this study, we developed hydroxyethylamino-substituted styrylchromone (SC) and 2-(2-(pyridin-3-yl)vinyl)-4H-chromen-4-one (VPC) derivatives for single-photon emission computed tomography (SPECT) imaging of PrPSc deposits in the brain. The binding affinity of these compounds was evaluated using recombinant mouse prion protein (rMoPrP) aggregates, which resulted in the inhibition constant (Ki) value of 61.5 and 88.0 nM for hydroxyethyl derivative, (E)-2-(4-((2-hydroxyethyl)amino)styryl)-6-iodo-4H-chromen-4-one (SC-NHEtOH) and (E)-2-(4-((2-hydroxyethyl)(methyl)amino)styryl)-6-iodo-4H-chromen-4-one (SC-NMeEtOH), respectively. However, none of the VPC derivatives showed binding affinity for the rMoPrP aggregates. Fluorescent imaging demonstrated that the accumulation pattern of SC-NHEtOH matched with the presence of PrPSc in the brain slices from mouse-adapted bovine spongiform encephalopathy-infected mice. A biodistribution study of normal mice indicated low initial brain uptake of [125I]SC-NHEtOH (0.88% injected dose/g (% ID/g) at 2 min) despite favorable washout from the brain (0.26% ID/g, at 180 min) was displayed. [125I]SC-NHEtOH exhibited binding affinities to both artificial prion aggregates as well as prion deposits in the brain. However, significant improvement in the binding affinity for PrPSc and blood–brain barrier permeability is necessary for the development of successful in vivo imaging probes for the detection of cerebral PrPSc in the brain

Synthesis and Biological Evaluation of Novel 2-(Benzofuran-2-yl)-chromone Derivatives for In Vivo Imaging of Prion Deposits in the Brain

Prion diseases are fatal neurodegenerative disorders caused by deposition of scrapie prion protein aggregates (PrPSc) in the brain. We previously reported that styrylchromone (SC) and benzofuran (BF) derivatives have potential as imaging probes for PrPSc. To further improve their properties, we designed and synthesized 2-(benzofuran-2-yl)-chromone (BFC) derivatives hybridized with SC and BF backbones as novel single-photon emission computed tomography probes for the detection of cerebral PrPSc deposits. Recombinant mouse prion protein (rMoPrP) aggregates and mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice were used to evaluate the binding properties of BFC derivatives to PrPSc. The BFC derivatives exhibited high binding affinities (equilibrium dissociation constant [Kd] = 22.6–47.7 nM) for rMoPrP aggregates. All BFC derivatives showed remarkable selectivity against amyloid beta aggregates. Fluorescence microscopy confirmed that the fluorescence signals of the BFC derivatives corresponded to the antibody-positive deposits of PrPSc in mBSE-infected mouse brains. Among the BFC derivatives, [125I]BFC-OMe and [125I]BFC-NH2 exhibited high brain uptake and favorable washout from the mouse brain. In vitro autoradiography demonstrated that the distribution of [125I]BFC-OMe in the brain tissues of mBSE-infected mice was co-localized with PrPSc deposits. Taken together, BFC derivatives appear to be promising prion imaging probes