The interleukin-7 receptor α chain contributes to altered homeostasis of regulatory T cells in multiple sclerosis.

Treg homeostasis is disturbed in multiple sclerosis (MS). Frequencies of recent thymic emigrant (RTE)-Treg are reduced and the disparity between RTE-Treg and long-lived memory Treg coincides with the MS-associated Treg defect, as shown previously. Recent studies demonstrate that IL-7 and thymic stromal lymphopoietin (TSLP) are critical for Treg maturation. Therefore, altered signaling through their receptors (IL-7R, TSLP receptor (TSLPR)), sharing the IL-7Rα-chain (IL-7Rα), might contribute to impaired Treg development. Using blood samples from 56 patients with MS and 33 healthy controls, we assessed IL-7Rα-expression on conventional T cells; frequencies, phenotypes and suppressive activities of Treg, plasma levels of IL-7 and soluble IL-7Rα; and screened for MS-associated IL-7RA gene polymorphism rs6897932. Moreover, we determined Treg expressing two different TCR Vα-chains designating thymus-originated cells. As TSLP/TSLPR signaling in thymic myeloid dendritic cells (MDCs) promotes Treg differentiation, we measured TSLPR expression on peripheral MDCs to indirectly test whether altered TSLPR expression might add to compromised Treg neogenesis. We found reduced IL-7Rα expression on conventional T cells and upregulated IL-7 plasma levels together with reduction of RTE-Treg frequencies and Treg function in MS, without clear genetic influence. Decreased IL-7Rα expression in MS correlated with declined dual-receptor-Treg and reduced MDC TSLPR expression, indicating contracted thymic Treg output. We suggest that altered IL-7R/TSLPR signaling contributes to impaired Treg neogenesis in MS, which is compensated by expanded memory-Treg and finally results in dysfunctional Treg.

Accidental intoxication with 60 mg intrathecal baclofen: survived.

BACKGROUND: Intrathecal baclofen (ITB) is an effective and well-tolerated treatment for patients with severe spasticity. Intoxications are rare and usually iatrogenic, with reported intrathecal boluses varying between 0.050 and 30 mg. METHODS: We here report the case of a 47-year-old woman with severe spastic paraplegia due to multiple sclerosis who, during a routine filling procedure, accidentally received a bolus of 60 mg ITB because of injection into the side-port instead of the reservoir of her ITB pump (Archimedes(®), Codman, Germany). RESULTS: After a short period of dizziness, she lost consciousness and stopped breathing. She was immediately intubated, mechanically ventilated, and admitted to the intensive care unit. As specific treatment, she received cerebrospinal fluid drainage through a newly implanted lumbar catheter. A series of generalized and complex partial seizures were treated with levetiracetam and lacosamide. Acute autonomic dysfunction with episodic arterial hypo- and hypertensions was controlled by catecholamines and clonidine, respectively. Recurrent hyperthermia, however, responded neither to drugs nor to physical treatment. After 3 weeks, the patient was discharged without any relevant new neurologic signs or symptoms. CONCLUSIONS: This case demonstrates that even excessive doses of ITB can let the patients survive without sequelae if treated promptly and offensively. A pertinent problem during detoxification is the question of when to restart ITB to avoid drug withdrawal.

B cells undergo unique compartmentalized redistribution in multiple sclerosis.

Increasing evidence fosters the role of B cells (BC) in multiple sclerosis (MS). The compartmentalized distribution of BC in blood and cerebrospinal fluid (CSF) is incompletely understood. In this study, we analyzed BC-patterns and BC-immunoreactivity at these sites during active and during stable disease and the impact of disease modifying drugs (DMD) on peripheral BC-homeostasis. For this purpose we assessed BC-subsets in blood and CSF from patients with clinically isolated syndrome (CIS), relapsing remitting MS (RRMS), rheumatoid arthritis (RA), and healthy controls (HC) by flow cytometric detection of whole (W-BC), naïve, transitional (TN-BC), class-switched memory (CSM-BC), unswitched memory (USM-BC), double-negative memory (DNM-BC) BC-phenotypes, plasma blasts (PB), and plasma cells (PC). FACS-data were correlated with BC-specific chemotactic activities in CSF, intrathecal CXCL13-levels, and immunoreactivity of peripheral W-BC. Our study revealed that frequencies of systemic CSM-BC/USM-BC became contracted in active CIS/MS while proportions of naive BC, TN-BC and DNM-BC were reciprocally expanded. Moreover, the shifted BC-composition promoted reduced immunoreactivity of W-BC and resolved during remission. Cross-over changes in CSF included privileged accumulation of CSM-BC linked to intrathecal CXCL13-concentrations and expansion of PB/PC. Treatment with interferon-beta and natalizumab evoked distinct though differing redistribution of circulating BC-subsets. We conclude that symptomatic CIS and MS are accompanied by distinctive changes in peripheral and CSF BC-homeostasis. The privileged reciprocal distribution between naïve versus CSM-phenotypes in both compartments together with the marked chemotactic driving force towards BC prompted by CSF supernatants renders it likely that CSF BC are mainly recruited from peripheral blood during active CIS/MS, whereas constantly low percentages of circulating PB/PC and their failure to respond to migratory stimuli favors intrathecal generation of antibody secreting cells. Notably, BC-redistribution closely resembles alterations detectable in systemic autoimmunity associated with active RA and impacts BC-function Together with unique effects of DMDs on BC-homeostasis these findings underline the important role of BC in MS.

Exposure of NK cells to intravenous immunoglobulin induces IFN gamma release and degranulation but inhibits their cytotoxic activity.

The mechanisms underlying the modulation of Natural Killer (NK) cell functions by intravenous immunoglobulin (IVIg) are poorly understood. Using an ex vivo whole blood assay system we demonstrate that IVIg suppresses NK cell cytotoxicity. This was paralleled by IVIg-induced degranulation of CD56(bright), CD16(positive) NK cells, reduced expression of CD16 and elevated IFN gamma release. To assess whether these findings also occur in vivo we analyzed whole blood before and after IVIg therapy of patients. Following IVIg treatment the number of NK cells in peripheral blood dropped significantly. We observed reduced CD16 expression, elevated IFN gamma-amounts in plasma, reduced NK cell cytotoxicity, and granzyme B release into the plasma, confirming our in vitro data. These effects on the functions of NK cells describe a novel immunomodulatory effect of IVIg. The in vitro assays employed here could represent informative test systems to monitor effects of in vivo IVIg treatment at an individual level.

Similar sensitivity of regulatory T cells towards CD95L-mediated apoptosis in patients with multiple sclerosis and healthy individuals.

Impaired suppressive function of CD4(+)CD25(high) regulatory T cells (T(reg)) has been reported as a novel pathogenetic mechanism in Multiple sclerosis (MS). We addressed if high apoptosis sensitivity of MS-T(reg) could explain this functional T(reg) defect. T(reg) from treatment-naïve MS patients showed high sensitivity towards CD95Ligand-mediated apoptosis and exhibited enhanced cell death to IL-2 and TCR-signal deprivation. Since susceptibility of T(reg) to cell death was similar in MS patients and healthy controls, this cannot explain the inhibitory dysfunction of T(reg) associated with MS. Furthermore, as cell death is not enhanced, therapeutic expansion of MS-T(reg)in vitro should be a reasonable and novel therapeutic option.

Ocular outcome and frequency of neurological manifestations in patients with acute posterior multifocal placoid pigment epitheliopathy (APMPPE).

PURPOSE: The purpose of this study was to describe the visual prognosis as well as the frequency and clinical severity of central nervous system involvement in all acute posterior multifocal placoid pigment epitheliopathy (APMPPE) patients of one centre. METHODS: A retrospective database review of all patients and a prospective clinical, ophthalmological and neurological follow-up, if possible, were conducted. RESULTS: Eighteen patients with APMPPE were included with a mean follow-up of 17.1 months. Thirteen patients participated in a follow-up exam. Visual acuity improved in 9 of 18 patients to a mean of 0.17 log minimum angle of resolution (MAR) in the worse eye and remained stable in eight patients (mean, 0.03 logMAR). In the majority of patients, the 30° static perimetry improved at follow-up compared to the initial exams. Still, in up to 50 to 60 %, small visual field defects persisted. Overall, 11 patients (61 %) showed neurologic symptoms of varying severity. The most common neurological symptom was headache in nine (50 %) patients. Other symptoms included paraesthesias, psychosis, vertigo, and, as the most severe complication, stroke due to cerebral vasculitis. Fifteen patients were treated with systemic corticosteroids. CONCLUSIONS: Visual prognosis is good in patients with APMPPE, but visual field defects may remain. Neurological signs and symptoms, especially headaches, are frequent in APMPPE and should be taken seriously. Adequate investigations including MRI and CSF examination should be initiated in these patients.

Glatiramer acetate improves regulatory T-cell function by expansion of naive CD4(+)CD25(+)FOXP3(+)CD31(+) T-cells in patients with multiple sclerosis.

Naturally occurring regulatory T-cells (Treg) exhibit impaired function in patients with relapsing-remitting multiple sclerosis (RRMS) resulting from an age-inappropriate disproportion between prevalences of newly generated CD31-coexpressing naive Treg and long-lived memory Treg in the periphery. Recent evidence suggests that the immunomodulatory action of glatiramer acetate (GA) includes effects on Treg function and frequencies. We prospectively assessed suppressive activities and frequencies of Treg and Treg subsets in 15 patients with RRMS undergoing long-term therapy with GA. Treatment for up to six months reconstituted naive Treg and increased total Treg numbers with concomitant reversion of the Treg defect.

Interferon beta-induced restoration of regulatory T-cell function in multiple sclerosis is prompted by an increase in newly generated naive regulatory T cells.

BACKGROUND: Naturally occurring regulatory T (T(reg)) cells are functionally impaired in patients with relapsing-remitting multiple sclerosis. We recently showed that prevalences of newly generated CD31-coexpressing naive T(reg) cells (recent thymic emigrant-T(reg) cells) are critical for suppressive function of circulating T(reg) cells, and a shift in the homeostatic composition of T(reg)-cell subsets related to a reduced de novo generation of recent thymic emigrant-T(reg) cells may contribute to the multiple sclerosis (MS)-related T(reg)-cell dysfunction. Interferon beta, an immunomodulatory agent with established efficacy in MS, lowers relapse rates and slows disease progression. Emerging evidence suggests that T(reg)-cell suppressive capacity may increase in patients with MS undergoing treatment with interferon beta, although the mechanisms mediating this effect are uncertain. OBJECTIVE: To evaluate the effect of interferon beta treatment on the suppressive activity and the homeostasis of circulating T(reg) cells in patients with MS. PARTICIPANTS: Twenty patients with relapsing-remitting MS and 18 healthy control subjects. INTERVENTIONS: Administration of interferon beta. MAIN OUTCOME MEASURES: Effect of interferon beta on T(reg)-cell homeostasis and suppressive capacity. RESULTS: Suppressive capacities of T(reg) cells were consistently upregulated at 3 and 6 months after treatment with interferon beta. The restoration of T(reg)-cell function was paralleled by increased naive recent thymic emigrant-T(reg) cells and a coincidental reduction in memory T(reg) cells. CONCLUSION: The increase in T(reg)-cell inhibitory capacity mediated by interferon beta treatment can be explained by its effect on the homeostatic balance within the T(reg) cell compartment.

Prevalence of newly generated naive regulatory T cells (Treg) is critical for Treg suppressive function and determines Treg dysfunction in multiple sclerosis.

The suppressive function of regulatory T cells (T(reg)) is impaired in multiple sclerosis (MS) patients. The mechanism underlying the T(reg) functional defect is unknown. T(reg) mature in the thymus and the majority of cells circulating in the periphery rapidly adopt a memory phenotype. Because our own previous findings suggest that the thymic output of T cells is impaired in MS, we hypothesized that an altered T(reg) generation may contribute to the suppressive deficiency. We therefore determined the role of T(reg) that enter the circulation as recent thymic emigrants (RTE) and, unlike their CD45RO(+) memory counterparts, express CD31 as typical surface marker. We show that the numbers of CD31(+)-coexpressing CD4(+)CD25(+)CD45RA(+)CD45RO(-)FOXP3(+) T(reg) (RTE-T(reg)) within peripheral blood decline with age and are significantly reduced in MS patients. The reduced de novo generation of RTE-T(reg) is compensated by higher proportions of memory T(reg), resulting in a stable cell count of the total T(reg) population. Depletion of CD31(+) cells from T(reg) diminishes the suppressive capacity of donor but not patient T(reg) and neutralizes the difference in inhibitory potencies between the two groups. Overall, there was a clear correlation between T(reg)-mediated suppression and the prevalence of RTE-T(reg), indicating that CD31-expressing naive T(reg) contribute to the functional properties of the entire T(reg) population. Furthermore, patient-derived T(reg), but not healthy T(reg), exhibit a contracted TCR Vbeta repertoire. These observations suggest that a shift in the homeostatic composition of T(reg) subsets related to a reduced thymic-dependent de novo generation of RTE-T(reg) with a compensatory expansion of memory T(reg) may contribute to the T(reg) defect associated with MS.

Reduced suppressive effect of CD4+CD25high regulatory T cells on the T cell immune response against myelin oligodendrocyte glycoprotein in patients with multiple sclerosis.

Immunoregulatory T cells of (CD4+)CD25+ phenotype suppress T cell function and protect rodents from organ-specific autoimmune disease. The human counterpart of this subset of T cells expresses high levels of CD25 and its role in human autoimmune disorders is currently under intense investigation. In multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system (CNS), the activation of circulating self-reactive T cells with specificity for myelin components is considered to be an important disease initiating event. Here, we investigated whether MS is associated with an altered ability of (CD4+)CD25high regulatory T cells (Treg) to confer suppression of myelin-specific immune responses. Whereas Treg frequencies were equally distributed in blood and cerebrospinal fluid of MS patients and did not differ compared to healthy controls, the suppressive potency of patient-derived (CD4+)CD25high T lymphocytes was impaired. Their inhibitory effect on antigen-specific T cell proliferation induced by human recombinant myelin oligodendrocyte protein as well as on immune responses elicited by polyclonal and allogeneic stimuli was significantly reduced compared to healthy individuals. The effect was persistent and not due to responder cell resistance or altered survival of Treg, suggesting that a defective immunoregulation of peripheral T cells mediated by (CD4+)CD25high T lymphocytes promotes CNS autoimmunity in MS.

Thymic export function and T cell homeostasis in patients with relapsing remitting multiple sclerosis.

Multiple sclerosis (MS) is an inflammatory and possibly autoimmune mediated demyelinating disease of the CNS. Autoimmunity within the CNS may be triggered by dysfunction of peripheral immune tolerance mechanisms via changes in the homeostatic composition of peripheral T cells. We have assessed the release of naive T lymphocytes from the thymus in patients with relapsing remitting MS (RRMS) to identify alterations in the equilibrium of the peripheral T cell compartment. Thymic T cell production was estimated by measuring TCR excision circles (TRECs) as a traceable molecular marker in recent thymic emigrants. A total of 46 treatment-naive patients with active RRMS and 49 gender- and age-matched healthy persons were included in the study. The levels of TREC-expressing CD4(+) and CD8(+) T lymphocytes were significantly decreased in MS patients, and TREC quantities overall matched those of 30 years older healthy individuals. The average concentrations of TRECs/10(6) CD4(+) and CD8(+) T lymphocytes derived from MS patients and healthy donors were 26 x 10(3)/10(6) and 28 x 10(3)/10(6) vs 217 x 10(3)/10(6) and 169 x 10(3)/10(6), respectively. To account for any influence of T cell proliferation on TREC levels, we assayed T lymphocytes from additional patients with MS and normal individuals for telomere length (n = 20) and telomerase activity (8 MS patients, 16 controls), respectively. There were no significant differences between CD4(+) and CD8(+) T cells from MS patients and controls. Altogether, our findings suggest that an impaired thymic export function and, as a consequence, altered ability to maintain T cell homeostasis and immune tolerance may play an important pathogenic role in RRMS.