Regulatory role of vitamin D in T-cell reactivity against myelin peptides in relapsing-remitting multiple sclerosis patients.

BACKGROUND: Low levels of plasma 25-hydroxyvitaminD (25(OH)D) are associated with a higher incidence of multiple sclerosis (MS) due to the immune suppressive properties of vitamin D.The aim of this study was to determine the correlation between plasma 25(OH)D concentrations and clinical and immunological variables in a cohort of multiple sclerosis patients. METHODS: Plasma 25(OH)D concentrations were evaluated in summer and winter in 15 primary progressive MS (PPMS) patients, 40 relapsing- remitting MS (RRMS) patients and 40 controls (HC). Protocol variables included demographic and clinical data, radiological findings and immunological variables (oligoclonal bands, HLADR15 and T-lymphocyte proliferation to a definite mix of 7 myelin peptides). RESULTS: During the winter, plasma concentrations were significantly lower in RRMS patients compared to HC, whereas no differences were found in summer. No relationships were found between plasma 25(OH)D concentrations and clinical or radiological variables. RRMS patients with a positive T-cell proliferation to a mix of myelin peptides (n = 31) had lower 25(OH)D concentrations. CONCLUSIONS: 25(OH)D is an immunomodulatory molecule that might have a regulatory role in T-cell proliferation to myelin peptides in RRMS patients.

Analysis of the cumulative changes in Graves' disease thyroid glands points to IFN signature, plasmacytoid DCs and alternatively activated macrophages as chronicity determining factors.

Graves' disease (GD) is a chronic autoimmune process in the thyroid gland and involves IFN and IFN driven immune activation. Assuming the thyroid gland is the main site stimulating the autoimmune response, we investigated the role of IFNs and other factors in the chronic evolution of GD by comparing the transcriptomic profiles of thyroid glands from short clinical course (SC), long clinical course (LC) cases, and control glands (C). Over 200 differentially expressed genes of the immune system were identified. Results were extensively analyzed bioinformatically and validated by qPCR in 31 glands. The analysis indicated that GD involved a progressive accumulation of changes with clearly distinct profiles in the SC and LC glands. Humoral response, antigen presentation and chemokines & cytokines were overall the most represented gene ontology categories in LC cases. Ingenuity Pathway Analysis pointed to a few inflammatory pathways in SC cases whereas LC cases involved numerous complex pathways, such us "communication between innate and adaptive immune cells" and "autoimmune thyroid signaling". A broad IFN signature consisted of the over-expression of 74 and 84 type I and type II IFN responsive genes respectively (overall 96 out of 211, 45%), but many of these genes can also be directly activated through cytoplasmic viral receptors. For the first time, plasmocytoid dendritic cells were identified in GD thyroid, but surprisingly, the main producers of IFN-alpha were cells with a myeloid cell phenotype. In addition, cells with the phenotype of alternatively activated macrophages were detected in abundance in GD thyroids, confirming data from the transcriptomic analysis. Collectively, these results confirmed the role of IFNs, suggested other natural immunity triggers, identified new cell types in the local disease process, and expanded our knowledge of the processes that may determine the chronicity of GD.