Metabolic patterns in prion diseases: an FDG PET voxel-based analysis.

PURPOSE: Clinical diagnosis of human prion diseases can be challenging since symptoms are common to other disorders associated with rapidly progressive dementia. In this context, (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) might be a useful complementary tool. The aim of this study was to determine the metabolic pattern in human prion diseases, particularly sporadic Creutzfeldt-Jakob disease (sCJD), the new variant of Creutzfeldt-Jakob disease (vCJD) and fatal familial insomnia (FFI). METHODS: We retrospectively studied 17 patients with a definitive, probable or possible prion disease who underwent FDG PET in our institution. Of these patients, 12 were diagnosed as sCJD (9 definitive, 2 probable and 1 possible), 1 was diagnosed as definitive vCJD and 4 were diagnosed as definitive FFI. The hypometabolic pattern of each individual and comparisons across the groups of subjects (control subjects, sCJD and FFI) were evaluated using a voxel-based analysis. RESULTS: The sCJD group exhibited a pattern of hypometabolism that affected both subcortical (bilateral caudate, thalamus) and cortical (frontal cortex) structures, while the FFI group only presented a slight hypometabolism in the thalamus. Individual analysis demonstrated a considerable variability of metabolic patterns among patients, with the thalamus and basal ganglia the most frequently affected areas, combined in some cases with frontal and temporal hypometabolism. CONCLUSION: Patients with a prion disease exhibit a characteristic pattern of brain metabolism presentation in FDG PET imaging. Consequently, in patients with rapidly progressive cognitive impairment, the detection of these patterns in the FDG PET study could orient the diagnosis to a prion disease.

Total remission of thymus carcinoma after treatment with intravenous immunoglobulin.

We report the case of a 42 year-old woman with myasthenia gravis associated with a malignant thymoma. Despite surgery, chemotherapy and radiotherapy, the thymoma showed soft tissues, pleural and mediastinic progression. Unexpectedly, a complete remission of the thymoma was confirmed by FDG-PET after four cycles of immunoglobulins, administered as treatment for a myasthenic crisis. To our knowledge this is the first case report of complete remission of a malignant thymoma with immunoglobulin therapy.

Association between peripheral IFN-gamma producing CD8+ T-cells and disability score in relapsing-remitting multiple sclerosis.

A large body of evidence supports the involvement of the immune system in the pathogenesis of multiple sclerosis (MS). Nevertheless, how the peripheral T-cells phenotypes are associated with factors such as the disability score, the effects of immunomodulatory treatments, or the activation period is poorly understood. In this study, we have centered our attention on the presence of IFN-gamma and IL-4 producing CD4+ and CD8+ T-cells in the peripheral blood of 58 relapsing-remitting MS (RRMS) patients, 48 that were stable and 10 who were in relapse period, and 30 healthy controls (HC). Our results support the existence of an independent association between the percentage of IFN-gamma producing CD8+ lymphocytes and the increased levels of disability score. Furthermore, the number of IFN-gamma producing CD8+ lymphocytes and the disability score were not correlated in patients treated with interferon-beta, evidence of its possible benefits in combating a pro-inflammatory profile. Finally, we compared the T-cell populations in RRMS patients in the stable or active period, and we found a significant decrease of IFN-gamma producing CD4+ lymphocytes in active patients. In conclusion our study supports the hypothesis that different peripheral blood T-cell phenotypes are associated with disability score or active period of the disease.