Increased circulating Th17 cell populations and elevated CSF osteopontin and IL-17 concentrations in patients with Guillain-Barré syndrome.

PURPOSE: Guillain-Barré syndrome (GBS) is an acute post-infectious immune-mediated demyelinating disease of the peripheral nervous system. Th17 cells and osteopontin (OPN) have been implicated in the development of autoimmune diseases, but little is known about their relationship and roles in the pathogenesis of GBS. METHODS: In this study, we used flow cytometry to evaluate peripheral numbers of Th17, real-time polymerase chain reaction to assay mRNA expression of RORγt, and enzyme-linked immunosorbent assay to determined OPN and IL-17 concentrations. RESULTS: The frequency of Th17 cells was significantly higher in the peripheral blood of acute-stage GBS patients comparison with other non-inflammatory neurological diseases (OND). In line with these observations, the levels of mRNA expression of RORγt in peripheral blood mononuclear cells and the concentrations IL-17 in both plasma and cerebrospinal fluid (CSF) were significantly higher in the acute-stage GBS than stable-stage GBS. OPN concentrations were significantly increased in the CSF of acute-stage GBS patients compared to OND. Circulating Th17 cell populations and CSF OPN levels, respectively, are correlated with GBS disability scale scores (GDSs), and there was a positive correlation between them. CONCLUSION: In summary, our preliminary findings suggest that both Th17 and OPN may be associated with the pathogenesis of GBS.

Elevated osteopontin levels in mild cognitive impairment and Alzheimer's disease.

Inflammatory mediators are closely associated with the pathogenesis of neurodegenerative changes in Alzheimer's disease (AD) and mild cognitive impairment (MCI). Osteopontin (OPN) is a proinflammatory cytokine that has been shown to play an important role in various neuroinflammatory diseases. However, the function of OPN in AD and MCI progression is not well defined. Cerebrospinal fluid (CSF) and plasma samples were obtained from 35 AD patients, 31 MCI patients, and 20 other noninflammatory neurologic diseases (OND). Concentrations of OPN in the CSF and plasma were determined by enzyme-linked immunosorbent assay. During a 3-year clinical followup, 13 MCI patients converted to AD (MCI converters), and 18 were clinically stable (MCI nonconverters). CSF OPN concentrations were significantly increased in AD and MCI converters compared to OND, and increased levels of OPN in AD were associated with MMSE score; OPN protein levels both in the CSF and plasma of newly diagnosed AD patients were higher than that of chronical patients. In MCI converters individuals tested longitudinally, both plasma and CSF OPN concentrations were significantly elevated when they received a diagnosis of AD during followup. Further wide-scale studies are necessary to confirm these results and to shed light on the etiopathogenic role of osteopontin in AD.

Distribution of Th17 cells and Th1 cells in peripheral blood and cerebrospinal fluid in chronic inflammatory demyelinating polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated demyelinating disease of the peripheral nervous system. Th17 and Th1 cells contribute to the pathogenesis of most autoimmune diseases, but little is known about their distribution and reciprocal relationship in CIDP. In this study, we analyzed the distribution of Th17, Th1, and Th17/Th1 cells in the peripheral blood and cerebrospinal fluid (CSF). The results showed that the frequency of Th17 cells was significantly higher in the peripheral blood mononuclear cell (PBMCs) and CSF of active CIDP in comparison with remitting CIDP or to other non-inflammatory neurological diseases (ONDs), accompanied by similar findings for Th17/Th1 cells. Both active and remitting CIDP have higher percentage of Th1 cells in the CSF than OND. CSF protein levels positively correlated with the frequencies of Th17 cells either in the PBMCs or CSF of active CIDP, while there was no significant correlation with Th1 cells. In line with these observations, the levels of interleukin-17 (IL-17) in plasma and transcript factors retinoic acid receptor-related orphan receptor (ROR)γt expressed by PBMCs were significantly higher in the active CIDP than remitting CIDP or OND. In summary, our preliminary findings suggest that elevated numbers of inflammatory T cells, especially for Th17 cells, might be an important determinant in the evolution of CIDP.

Impairment of circulating CD4+CD25+ regulatory T cells in patients with chronic inflammatory demyelinating polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated peripheral nervous system disease. CD4+CD25+ T regulatory cells (Tregs) have been unequivocally shown to be critical in maintaining immune tolerance and preventing auto-immune diseases by suppressing self-reactive T cells. Thus, we hypothesized that the numbers and/or the function of Tregs would be deranged during the progressive or relapse phases of CIDP. The number of Tregs was determined by flow cytometry according to their characteristic CD4+CD25(high) membrane phenotype. Functional characterization of Tregs was analyzed by suppression of proliferation and secretion of cytokines by co-cultured effector CD4+CD25- T cells. FOXP3 message expression level was assessed by quantitative real-time polymerase chain reaction. The results showed significant reduction in both the number and the suppressive function of Tregs in the patients with CIDP compared with healthy controls. Also, Tregs isolated from CIDP patients expressed lower levels of FoxP3 mRNA. During the progressive or the relapsing phases of CIDP, the number of Tregs was reduced, and the suppressive function of them decreased. These findings may be helpful to our understanding of the possible role of Tregs in the pathogenesis of CIDP.

Abnormality of circulating CD4(+)CD25(+) regulatory T cell in patients with Guillain-Barré syndrome.

CD4(+)CD25(+) T regulatory cells (Tregs), a subset of CD4(+) T cells expressing high levels of CD25 and the transcription factor Foxp3, are critical in maintaining immunologic homeostasis and preventing autoimmunity by suppressing self-reactive T cells. Guillain-Barré syndrome (GBS) is thought to be a self-limiting, autoimmune disease of the peripheral nervous system. We hypothesized that altered frequency and/or function of Tregs play a role in the breakdown of immunologic self-tolerance in GBS patients. To characterize Tregs in GBS patients, we used flow cytometry to evaluate peripheral numbers of Tregs, real-time polymerase chain reaction to assay mRNA expression of FOXP3, and coculture to analyze functional suppressive properties of Tregs. The results showed that acute-stage patients with AMAN and AIDP exhibited significantly reduced numbers of peripheral Tregs as compared with healthy donors, but marked improvement was observed in stable-stage patients with GBS after treatment with intravenous immunoglobulin (IVIG), concomitantly with improvement of neuropathic symptoms. On the other hand, GBS-derived Tregs and Tregs from healthy individuals exhibited equal FOXP3-expression of mRNA and their ability of suppressing the proliferation and cytokine secretion of CD4 (+) effector T cells was unimpaired in GBS patients. These results suggest that short-term reduced circulating Tregs may be associated with the pathogenesis of two subtypes of GBS. Reversible number and intact function of Tregs presumably contribute to monophasic self-limiting course in GBS.

The role of FoxP3+CD4+CD25hi Tregs in the pathogenesis of myasthenia gravis.

CD4(+)CD25(+) regulatory T cells (CD4(+)CD25(+) Tregs) play a critical role in the maintenance of peripheral self-tolerance and the regulation of immune responses. Genetic defects that primarily affect the development and/or function of CD4(+)CD25(+) Tregs result in severe autoimmune diseases and inflammatory disorders. In this study, we investigated whether the peripheral pool and the function of CD4(+)CD25(+) Tregs are altered in patients of myasthenia gravis (MG), a chronic autoimmune disorder that results in progressive skeletal muscle weakness. Here we showed that both mRNA and protein expression level of FoxP3 in CD4(+)CD25(+) Tregs are dramatically down-regulated, accompanied by an severe functional defect in CD4(+)CD25(+) Tregs regulatory activity when cocultured with autologous CD4(+)CD25(-) T cells, although the reservoir of CD4(+)CD25(+) Tregs is not changed in peripheral blood from MG patients. Since FoxP3 is a pivotal transcription factor that indispensable for the generation and the regulatory function of CD4(+)CD25(+) Tregs, our data suggested that the functional activity of CD4(+)CD25(+) Tregs is inhibited in MG patients and that MG might originate from the dysfunction of CD4(+)CD25(+) Tregs. Although the underlying molecular basis for the reduced expression of FoxP3 in CD4(+)CD25(+) Tregs from MG patients remains unknown, this study provided a potential target for MG therapy.