Antibodies to PF4/heparin can be demonstrated in almost all patients with heparin-induced thrombocytopenia/thrombosis (HIT/HITT) and in some persons exposed to heparin who do not have clinical manifestations. The role of anti-PF4/heparin antibodies in the pathogenesis of HIT/HITT has been difficult to establish because the antibodies found in serum are generally polyclonal and polyspecific. To circumvent this problem, we developed a murine monoclonal antibody (mAb) to human (h) PF4/heparin complexes. A monoclonal IgG2bκ antibody (designated KKO) was identified that bound specifically to hPF4/heparin complexes. Maximal binding of KKO to hPF4/heparin complexes occurred at similar molar ratios of PF4:heparin observed for HIT/HITT antibodies. KKO also bound to hPF4 in association with other glycosaminoglycans. Platelet activation by KKO required heparin and was abrogated by blockade of FcγRIIA. In the presence of PF4, KKO bound to endothelial cells, but not to CHO cells lacking heparan sulfate proteoglycans. Variants of PF4 complexed to heparin were recognized equally well by KKO and HIT/HITT sera. KKO competes for binding with a subset of HIT/HITT antibodies that are relatively spared by mutations in the 3rd domain of PF4. The nucleotide and predicted amino acid sequences of KKO and RTO, a murine anti-hPF4 mAb that does not require heparin for binding, revealed no obvious relationship in either the heavy- or the light-chain immunoglobulin variable regions. These studies suggest that KKO recapitulates the antigenic and functional specificity of a subset of HIT/HITT antibodies and may, therefore, provide insight into the pathogenesis of thrombocytopenia and thrombosis in affected persons.

Objective: Herpes simplex virus encephalitis (HSVE) is associated with significant morbidity and mortality, even with appropriate antiviral therapy. In the present investigation, the first to assess efficacy of corticosteroid treatment with aciclovir therapy in HSVE, multiple logistic regression analysis was performed of predictors of outcome in adult patients with HSVE. Methods: A non-randomised retrospective study of 45 patients with HSVE treated with aciclovir was conducted. The patients were divided into poor and good groups based on outcome at three months after completion of aciclovir treatment. The variables evaluated were: clinical variables (sex, age, days after onset at initiation of aciclovir, Glasgow Coma Scale (GCS) at initiation of aciclovir, initial and maximum values for the cell numbers and protein concentration in the cerebrospinal fluid, and corticosteroid administration); neuroradiological variables (detection of lesions by initial cranial computed tomography and by initial magnetic resonance imaging); and one neurophysiological variable (detection of periodic lateralised epileptiform discharges on the initial electroencephalogram). Single variable logistic regression analysis was performed followed by multiple logistic regression analysis. The best set of predictors for the outcome of HSVE was estimated by stepwise logistic regression analysis. Results: A poor outcome was evident with older age, lower GCS score at initiation of aciclovir, and no administration of corticosteroid. Patient age, GCS at initiation of aciclovir, and corticosteroid administration were found to be significant independent predictors of outcome on multiple logistic regression analysis, and these three variables also formed the best set of predictors (R 2 = 0.594, p,0.0001). Conclusion: Combination therapy using both aciclovir and corticosteroid represents one of the predictors of outcome in HSVE.

Recent basic experiments have strongly suggested that cell transplantation therapy may promote functional recovery in patients with spinal cord injury (SCI). However, a safe and efficient transplantation technique still remains undetermined. This study, therefore, was aimed to clarify whether fibrin matrix could be a useful scaffold in bone marrow stromal cell (BMSC) transplantation for the injured spinal cord. To clarify the issue, three-dimensional structure of fibrin matrix was assessed and the green fluorescent protein (GFP)-expressing BMSC were cultured in fibrin matrix. The rats were subjected to spinal cord hemisection at T8 level, and the vehicle, BMSC or BMSC-fibrin matrix construct was implanted into the cavity. Neurologic function was serially evaluated. Using immunohistochemistry, we evaluated the survival, migration and differentiation of the transplanted cells at 4 weeks after transplantation. In the initial in vitro study, the BMSC could survive in fibrin matrix for 2 weeks. The animals treated with the BMSC-fibrin matrix construct showed significantly more pronounced recovery of neurologic function than vehicle- or BMSC-treated animals. Fibrin scaffold markedly improved the survival and migration of the transplanted cells. There was no significant difference in the percentage of cells doubly positive for GFP and microtubule-associated protein 2 between the animals treated with BMSC-fibrin matrix construct and those treated with BMSC, but a certain subpopulation of GFP-positive cells morphologically simulated the neurons in the animals treated with BMSC-fibrin matrix construct. These findings strongly suggest that fibrin matrix may be one of the promising candidates for a potential, minimally invasive scaffold for injured spinal cord, and that such strategy of tissue engineering could be a hopeful option in regeneration therapy for patients with SCI.