Martin Krakauer

T helper cell type 1 (Th1), Th2 and Th17 responses to myelin basic protein and disease activity in multiple sclerosis.

Autoreactive T cells are thought to play an essential role in the pathogenesis of multiple sclerosis (MS). We examined the stimulatory effect of human myelin basic protein (MBP) on mononuclear cell (MNC) cultures from 22 patients with MS and 22 sex‐matched and age‐matched healthy individuals, and related the patient responses to disease activity, as indicated by magnetic resonance imaging. The MBP induced a dose‐dependent release of interferon‐γ (IFN‐γ), tumour necrosis factor‐α (TNF‐α) and interleukin‐10 (IL‐10) by patient‐derived MNCs. The patients’ cells produced higher amounts of IFN‐γ and TNF‐α, and lower amounts of IL‐10, than cells from healthy controls (P < 0·03 to P < 0·04). Five patients with MS and no controls, displayed MBP‐induced CD4+ T‐cell proliferation. These high‐responders exhibited enhanced production of IL‐17, IFN‐γ, IL‐5 and IL‐4 upon challenge with MBP, as compared with the remaining patients and the healthy controls (P < 0·002 to P < 0·01). A strong correlation was found between the MBP‐induced CD4+ T‐cell proliferation and production of IL‐17, IFN‐γ, IL‐5 and IL‐4 (P < 0·0001 to P < 0·01) within the patient group, and the production of IL‐17 and IL‐5 correlated with the number of active plaques on magnetic resonance images (P = 0·04 and P = 0·007). These data suggest that autoantigen‐driven CD4+ T‐cell proliferation and release of IL‐17 and IL‐5 may be associated with disease activity. Larger studies are needed to confirm this.

Increased IL-10 mRNA and IL-23 mRNA expression in multiple sclerosis: interferon-β treatment increases IL-10 mRNA expression while reducing IL-23 mRNA expression

Background Interferon (IFN)-β therapy in multiple sclerosis (MS) has been suggested to promote a deviation from T lymphocyte production of pathogenic Th1 cytokines to less detrimental Th2 cytokines, but this is still controversial. We studied patterns of in vivo blood mononuclear cell (MNC) and whole blood cytokine and transcription factor mRNA expression before and during IFN-β therapy in MS. Methods Twenty patients with relapsing–remitting MS were sampled before and after 3 months of treatment with IFN-β along with 15 healthy volunteers. An additional 39 patients and 50 healthy volunteers served to confirm initial findings. mRNA was analyzed by real-time reverse transcriptase polymerase chain reaction (PCR). Results We found elevated expression of interleukin (IL)-23 and IL-10 in untreated MS patients. IFN-β therapy increased IL-10 and decreased IL-23 expression independently of any Th1 or Th2 cytokines. The largest changes in cytokine mRNA levels occurred early (~9–12 h) after an IFN-β injection. Conclusion We found no evidence of a Th1- or Th2-mRNA-promoting effect of IFN-β therapy. The therapeutic effect of IFN-β is more likely attributable to the induction of the regulatory cytokine IL-10. The elevated IL-23 mRNA levels in MS patients are noteworthy in view of the newly discovered IL-23-driven Th17 T-cell subset, which is crucial in animal models of MS. Since IFN-β therapy resulted in decreased IL-23 mRNA levels, the Th17 axis could be another target of IFN-β therapy.

Differential microRNA expression in blood in multiple sclerosis

Background: microRNAs (miRNAs) regulate the expression of the genome at the post-transcriptional level. They play a role in autoimmunity and inflammation, and show potential for use as therapeutic targets in many diseases. With the recent detection of miRNAs in body fluids, the possibility for using miRNAs as diagnostic biomarkers has emerged. Objective: We assessed whether miRNAs contribute to the altered immune activation state in relapsing–remitting multiple sclerosis (RRMS) patients and investigated the possible use of miRNAs as diagnostic biomarkers in multiple sclerosis (MS). Methods: We performed global miRNA expression profiling analysis in peripheral blood mononuclear cells (PBMCs) and selected miRNAs were measured in plasma. We detected expression of miRNAs by real-time qPCR and compared results with cytokines related to inflammation and disease activity. Selected miRNAs were analyzed in PBMC subpopulations, after isolating them by magnetic bead separation. Results: We found that among validated miRNAs, let-7d correlated with the pro-inflammatory cytokine interleukin-1B. The miR-145 was 3-fold up-regulated in MS patients; its possible use as a diagnostic biomarker in PBMCs, plasma and serum was confirmed by ROC-curve analysis (Area under the curve (AUC) 0.785, p = 0.0004; 0.785, p = 0.004; 0.981, P < 0.0001, respectively). Conclusions: RRMS patients in remission had altered expression of miRNAs. We validated miR-145 as a potential diagnostic biomarker for the diagnosis of MS in blood, plasma and serum.

Identification of new sensitive biomarkers for the in vivo response to interferon-β treatment in multiple sclerosis using DNA-array evaluation

Objective:  Neutralizing antibodies (NAbs) occur in a proportion of multiple sclerosis (MS) patients treated with interferon (IFN)‐β. NAbs impair the effect of treatment. The biological effect of IFN‐β can be measured as the induction of the myxovirus resistance protein A (MxA) molecule. However, other markers could be more sensitive for evaluating the response to IFN‐β. We used DNA array analysis to identify genes that are strongly induced in blood cells by IFN‐β, and measured their expression in MS patients with different NAb levels.

Cellular sources of dysregulated cytokines in relapsing-remitting multiple sclerosis

BackgroundNumerous cytokines are implicated in the immunopathogenesis of multiple sclerosis (MS), but studies are often limited to whole blood (WB) or peripheral blood mononuclear cells (PBMCs), thereby omitting important information about the cellular origin of the cytokines. Knowledge about the relation between blood and cerebrospinal fluid (CSF) cell expression of cytokines and the cellular source of CSF cytokines is even more scarce.MethodsWe studied gene expression of a broad panel of cytokines in WB from relapsing-remitting multiple sclerosis (RRMS) patients in remission and healthy controls (HCs). Subsequently we determined the gene expression of the dysregulated cytokines in isolated PBMC subsets (CD4+, CD8+T-cells, NK-cells, B-cells, monocytes and dendritic cells) from RRMS patients and HCs and in CSF-cells from RRMS patients in clinical relapse and non-inflammatory neurological controls (NIND).ResultsRRMS patients had increased expression of IFN-gamma (IFNG), interleukin (IL) 1-beta (IL1B), IL7, IL10, IL12A, IL15, IL23, IL27, lymphotoxin-alpha (LTA) and lymphotoxin-beta (LTB) in WB. In PBMC subsets the main sources of pro-inflammatory cytokines were T- and B-cells, whereas monocytes were the most prominent source of immunoregulatory cytokines. In CSF-cells, RRMS patients had increased expression of IFNG and CD19 and decreased expression of IL10 and CD14 compared to NINDs. CD19 expression correlated with expression of IFNG, IL7, IL12A, IL15 and LTA whereas CD14 expression correlated with IL10 expression.ConclusionsUsing a systematic approach, we show that expression of pro-inflammatory cytokines in peripheral blood primarily originates from T- and B-cells, with an important exception of IFNG which is most strongly expressed by NK-cells. In CSF-cell studies, B-cells appear to be enriched in RRMS and associated with expression of pro-inflammatory cytokines; contrarily, monocytes are relatively scarce in CSF from RRMS patients and are associated with IL10 expression. Thus, our findings suggest a pathogenetic role of B-cells and an immunoregulatory role of monocytes in RRMS.

CD4+ memory T cells with high CD26 surface expression are enriched for Th1 markers and correlate with clinical severity of multiple sclerosis ☆

An aberrant immune activation is believed to be important in the pathogenesis of multiple sclerosis (MS). Expression of CD4(+) T lymphocyte surface molecules indicative of immune activation and effector functions has been correlated with disease severity and activity. CD4(+) CD45R0(+) CD26(high) memory T lymphocytes contained the high levels of markers of Th1, activation, and effector functions and cell counts of this subset correlated with MS disease severity. This subset had lower expression of PD-1, CCR4, and L-selectin in MS than in controls. These changes were only partially normalised by treatment with interferon-beta. We point to this subset as a putative target for immunological monitoring of MS disease activity and of treatment efficacy.

Disease protection and interleukin‐10 induction by endogenous interferon‐β in multiple sclerosis?

Objective:  An immune activation response resembling virus or type I interferon responses has been observed in untreated multiple sclerosis (MS), but its pathogenic significance is uncertain. We studied the relationship between a type I interferon‐like response in untreated patients with MS and disease activity.

Dynamic T‐lymphocyte Chemokine Receptor Expression Induced by Interferon‐beta Therapy in Multiple Sclerosis

Treatment with interferon (IFN)‐β reduces clinical disease activity in multiple sclerosis (MS). Using flow cytometry, an enzyme‐linked immunosorbent assay and a real‐time polymerase chain reaction, we studied in vivo IFN‐β‐induced effects on CD4+ T‐lymphocyte chemokine receptor expression as these influence central nervous system (CNS) transmigration and inflammation. At ‘steady state’ (≥1 day after the most recent IFN‐β injection), IFN‐β treatment increased CD4+ T‐cell surface expression of CC chemokine receptor (CCR)4, CCR5 and CCR7 after 3 months of treatment, whereas that of CXC chemokine receptor (CXCR)3 was unaltered. Conversely, at 9–12 h after the most recent IFN‐β injection, CCR4, CCR5 and CCR7 expressions were unaltered, while CXCR3 expression was reduced. CD4+ T‐cell surface expression of CCR4 was significantly lower in untreated MS patients compared with healthy volunteers. Of the plasma chemokines, only CXCL10 was increased by IFN‐β treatment; CCL3, CCL4, CCL5 and CXCL9 were unaltered. CCR5 mRNA expression in blood mononuclear cells correlated with the expression of T‐helper type 1 (Th1)‐associated genes whereas CCR4 and CCR7 mRNA expression correlated with Th2 and immunoregulatory genes. In conclusion, IFN‐β treatment caused ‘steady‐state’ increases of several chemokine receptors relevant for CD4+ T‐lymphocyte trafficking and function, possibly facilitating lymphocyte migration into the CNS. An important therapeutic effect of IFN‐β treatment may be the normalization of a decreased Th2‐related CD4+ T‐cell CCR4 expression in MS patients. Surface chemokine receptor expression and CXCL10 varied according to the timing of blood sampling in relation to the most recent IFN‐β injection. Thus, it is imperative to distinguish acute effects of IFN‐β from steady‐state effects.

FOXP3, CBLB and ITCH gene expression and cytotoxic T lymphocyte antigen 4 expression on CD4+CD25high T cells in multiple sclerosis

Expression of the forkhead box protein 3 (FoxP3) transcription factor is regulated by the E3 ubiquitin ligases Itch and Cbl‐b and induces regulatory activity CD4+CD25high T cells. Treatment with interferon (IFN)‐β enhances regulatory T cell activity in multiple sclerosis (MS). We studied the phenotype of CD4+CD25high T cells in MS by flow cytometry and its relationship with expression of the FOXP3, ITCH and CBLB genes. We found that untreated MS patients had lower cell surface expression of cytotoxic T lymphocyte antigen 4 (CTLA‐4) on CD4+CD25high T cells and higher intracellular CTLA‐4 expression than healthy controls. Cell surface expression of CTLA‐4 on CD4+CD25high T cells correlated with expression of FOXP3 mRNA in untreated patients and increased significantly with time from most recent injection in patients treated with IFN‐β. FOXP3 mRNA expression correlated with CBLB and ITCH and T helper type 2 cytokine mRNA expression in MS patients. These data link expression of FOXP3, CBLB and ITCH mRNA and CTLA‐4 expression on the surface of CD4+CD25high T cell in MS. We hypothesize that this may reflect alterations in the inhibitory effect of CTLA‐4 or in regulatory T cell function.

Blood-Brain Barrier Permeability of Normal Appearing White Matter in Relapsing-Remitting Multiple Sclerosis

Background Multiple sclerosis (MS) affects the integrity of the blood-brain barrier (BBB). Contrast-enhanced T1 weighted magnetic resonance imaging (MRI) is widely used to characterize location and extent of BBB disruptions in focal MS lesions. We employed quantitative T1 measurements before and after the intravenous injection of a paramagnetic contrast agent to assess BBB permeability in the normal appearing white matter (NAWM) in patients with relapsing-remitting MS (RR-MS). Methodology/Principal Findings Fifty-nine patients (38 females) with RR-MS undergoing immunomodulatory treatment and nine healthy controls (4 females) underwent quantitative T1 measurements at 3 tesla before and after injection of a paramagnetic contrast agent (0.2 mmol/kg Gd-DTPA). Mean T1 values were calculated for NAWM in patients and total cerebral white matter in healthy subjects for the T1 measurements before and after injection of Gd-DTPA. The pre-injection baseline T1 of NAWM (945±55 [SD] ms) was prolonged in RR-MS relative to healthy controls (903±23 ms, p = 0.028). Gd-DTPA injection shortened T1 to a similar extent in both groups. Mean T1 of NAWM was 866±47 ms in the NAWM of RR-MS patients and 824±13 ms in the white matter of healthy controls. The regional variability of T1 values expressed as the coefficient of variation (CV) was comparable between the two groups at baseline, but not after injection of the contrast agent. After intravenous Gd-DTPA injection, T1 values in NAWM were more variable in RR-MS patients (CV = 0.198±0.046) compared to cerebral white matter of healthy controls (CV = 0.166±0.018, p = 0.046). Conclusions/Significance We found no evidence of a global BBB disruption within the NAWM of RR-MS patients undergoing immunomodulatory treatment. However, the increased variation of T1 values in NAWM after intravenous Gd-DTPA injection points to an increased regional inhomogeneity of BBB function in NAWM in relapsing-remitting MS.