Clinical Spectrum and Prognostic Factors of Acute Necrotizing Encephalopathy in Children

This study was conducted to investigate the etiology, the clinical characteristics and prognosis of acute necrotizing encephalopathy (ANE) in Korean children. Six children (1 yr to 7 yr) patients with ANE were enrolled. They were diagnosed by clinical and radiological characteristics and their clinical data were retrospectively analyzed. In a search of clinically plausible causes, brain MRI in all patients, mitochondrial DNA studies for mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) and myoclonus epilepsy and ragged red fibers (MERRF) in four patients, and genomic typing on HLA DRB/HLA DQB genes in three patients were performed. All had precedent illnesses and the main initial symptoms included mental change (83%), seizures (50%), and focal deficits (50%). MRI revealed increased T2 signal density in the bilateral thalami and/or the brainstem in all patients. Mitochodrial DNA studies for MELAS and MERRF were negative in those children and HLA-DRB1*1401, HLA-DRB3*0202, and HLA-DQB1*0502 seemed to be significant. A high dose steroid was given to all patients, which seemed to be partly effective except for 2 patients. In conclusion, ANE is relatively rare, but can result in serious neurological complication in children. Early detection and appropriate treatment may lead to a better neurological outcome.

Ketotifen inhibits allergen-specific T lymphocytes' responses by suppressing antigen presentation with concomitant decrease of HLA-DQ antigen on macrophages.

Allergen activates T lymphocytes responsive to interleukin 2 (IL-2) in allergic patients but not in normal individuals. This response was suppressed by anti-allergic agent, Ketotifen (4-(1-methyl-4-piperidylidene)-4H-benzo [4, 5] cyclohepta [1, 2-b] thiophen-10 (9H)-one hydrogen (fumarate). Prolonged culture of antigen-presenting adherent cells impaired the ability to present Dermatophagoides farinae (Df) antigen to T cells, whereas stimulation of adherent cells with recombinant interferon-gamma (IFN-gamma) restored the antigen-presenting capability. The maintained antigen presenting ability of adherent cells treated with IFN-gamma was also suppressed by Ketotifen. Fluorescence activated cell sorter (FACS) analysis disclosed that Ketotifen selectively reduced the expression of HLA-DQ antigen, crucial restriction elements in Df antigen-related responses, on macrophages but not on B cells, even in the presence of IFN-gamma. Collectively, Ketotifen prevented macrophages from inducing allergen-activated T lymphocytes' responsiveness to IL-2 at least in part by decreasing the expression of HLA-DQ antigen.