Longitudinal analysis of immune cell phenotypes in early stage multiple sclerosis: distinctive patterns characterize MRI-active patients

Relapsing-remitting multiple sclerosis patients exhibit differential natural killer functional subpopulations

BACKGROUND

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) and has been known as T-cell mediated. However, the contribution of multiple cell types, notably natural killer (NK) cells, has also been reported.

AIM

To quantify circulating total NK cells and its subpopulations, CD56 dim and bright, and to characterize the functional phenotype and IFN-γ and TNF-α production in relapsing-remitting patients treated with IFN-β and in apparently healthy controls.

RESULTS

CD56bright NK cells were found to be the least represented subpopulation. In relapse patients, the frequencies of IFN-γ-producing NK cells and their subpopulations were significantly decreased. In remission patients, CD56dim NK cells expressed high levels of HLA-DR and CD54.

CONCLUSION

These results suggest that remission RRMS patients, although in an inactive stage of MS, present circulating NK cells with an activation phenotype, supporting the idea that NK cells may be relevant mediators in the MS pathophysiology.

The immunology of multiple sclerosis

Our incomplete understanding of the causes and pathways involved in the onset and progression of multiple sclerosis (MS) limits our ability to effectively treat this complex neurological disease. Recent studies explore the role of immune cells at different stages of MS and how they interact with cells of the central nervous system (CNS). The findings presented here begin to question the exclusivity of an antigen-specific cause and highlight how seemingly distinct immune cell types can share common functions that drive disease. Innovative techniques further expose new disease-associated immune cell populations and reinforce how environmental context is critical to their phenotype and subsequent role in disease. Importantly, the differentiation of immune cells into a pathogenic state is potentially reversible through therapeutic manipulation. As such, understanding the mechanisms that provide plasticity to causal cell types is likely key to uncoupling these disease processes and may identify novel therapeutic targets that replace the need for cell ablation.

HLA-DR-expressing NK cells: Effective killers suspected for antigen presentation

HLA-DR-expressing cells comprise an intriguing group of NK cells, which combine phenotypic characteristics of both NK cells and dendritic cells. These cells can be found in humans and mice; they are present in blood and tissues in healthy conditions and can expand in a spectrum of pathologies. HLA-DR⁺ NK cells are functionally active: they produce proinflammatory cytokines, degranulate, and easily proliferate in response to stimuli. Additionally, HLA-DR⁺ NK cells seem able to take in and then present certain antigens to CD4⁺ and CD8⁺ T cells, inducing their activation and proliferation, which puts them closer to professional antigen-presenting cells. It appears that these NK cells should be considerable players of the innate immune system, both due to their functional activity and regulation of the innate and adaptive immune responses. In this review, for the first time, we provide a detailed description and analysis of the available data characterizing phenotypic, developmental, and functional features of the HLA-DR⁺ NK cells in a healthy condition and a disease.

Peripheral blood lymphocytes immunophenotyping predicts disease activity in clinically isolated syndrome patients

Background

Clinically isolated syndrome (CIS) represents first neurological symptoms suggestive of demyelinating lesion in the central nervous system (CNS). Currently, there are no sufficient immunological or genetic markers predicting relapse and disability progression, nor there is evidence of the efficacy of registered disease modifying treatments (DMTs), such as intramuscular interferon beta1a. The aim of the study is to evaluate immunological predictors of a relapse or disability progression.

Methods

One hundred and eighty one patients with CIS were treated with interferon beta1a and followed over the period of 4 years. Lymphocyte subsets were analyzed by flow cytometry. A Kaplan-Meier estimator of survival probability was used to analyze prognosis. For statistical assessment only individual differences between baseline values and values at the time of relapse or confirmed disability progression were analysed.

Results

Higher levels of B lymphocytes predicted relapse-free status. On the other hand, a decrease of the naïve subset of cells (CD45RA+ in CD4+) after 12, 24, and 36 months of follow-up were associated with an increased risk of confirmed disability progression. Conclusion: Our data suggest that the quantification of lymphocyte subsets in patients after the first demyelinating event suggestive of MS may be an important biomarker.

Prolonged immunomodulation in inflammatory arthritis using the selective Kv1.3 channel blocker HsTX1[R14A] and its PEGylated analog

Effector memory T lymphocytes (TEM cells) that lack expression of CCR7 are major drivers of inflammation in a number of autoimmune diseases, including multiple sclerosis and rheumatoid arthritis. The Kv1.3 potassium channel is a key regulator of CCR7- TEM cell activation. Blocking Kv1.3 inhibits TEM cell activation and attenuates inflammation in autoimmunity, and as such, Kv1.3 has emerged as a promising target for the treatment of TEM cell-mediated autoimmune diseases. The scorpion venom-derived peptide HsTX1 and its analog HsTX1[R14A] are potent Kv1.3 blockers and HsTX1[R14A] is selective for Kv1.3 over closely-related Kv1 channels. PEGylation of HsTX1[R14A] to create a Kv1.3 blocker with a long circulating half-life reduced its affinity but not its selectivity for Kv1.3, dramatically reduced its adsorption to inert surfaces, and enhanced its circulating half-life in rats. PEG-HsTX1[R14A] is equipotent to HsTX1[R14A] in preferential inhibition of human and rat CCR7- TEM cell proliferation, leaving CCR7+ naïve and central memory T cells able to proliferate. It reduced inflammation in an active delayed-type hypersensitivity model and in the pristane-induced arthritis (PIA) model of rheumatoid arthritis (RA). Importantly, a single subcutaneous dose of PEG-HsTX1[R14A] reduced inflammation in PIA for a longer period of time than the non-PEGylated HsTX1[R14A]. Together, these data indicate that HsTX1[R14A] and PEG-HsTX1[R14A] are effective in a model of RA and are therefore potential therapeutics for TEM cell-mediated autoimmune diseases. PEG-HsTX1[R14A] has the additional advantages of reduced non-specific adsorption to inert surfaces and enhanced circulating half-life.

Quantification of γδ T cells and HLA-DR+ NK cells does not predict emergence of new contrast enhancing lesions in MS patients suspending natalizumab treatment

Background

Natalizumab (NTZ) is a drug that has been widely used in the treatment of multiple sclerosis (MS). NTZ is very effective in suppressing inflammation, but if treatment is suspended many patients will experience relapses.

Objective

To investigate if quantification of γδ T cells and HLA-DR⁺ NK cells could predict early disease reactivation after NTZ suspension.

Methods

Absolute counts of γδ T cells and HLA-DR⁺ NK cells in whole blood were determined with flow cytometry in fifteen patients treated with NTZ. NTZ treatment was then withdrawn and patients were followed with clinical visits and MR investigations.

Results

Patients with recurrent disease had higher absolute counts of γδ T cells 129 (±156) cells/μl in comparison to patients with stable disease 50.0 (±51.0) cells/μl but the difference was not statistically significant and largely driven by outliers. Patients with recurrent and stable disease had similar absolute counts of HLA-DR⁺ NK cells.

Conclusion

Quantification of γδ T cells and HLA-DR⁺ NK cells could not predict active disease after NTZ suspension.

Innate lymphoid cell-derived cytokines in autoimmune diseases

The most recently recognized types of immune cells, the innate lymphoid cells (ILCs), have been sub-divided according to respective distinct expression profiles of regulatory factors or/and cytokines. ILCs have also been shown to participate in a variety of beneficial immune responses, including participation in attack against pathogens and mediation of the pre-inflammatory and inflammatory responses through their production of pro-inflammatory cytokines. As such, while the ILCs exert protective effects they may also become detrimental upon dysregulation. Indeed, recent studies of the ILCs have revealed a strong association with the advent and pathogenesis of several common autoimmune diseases, including psoriasis, inflammatory bowel disease (IBD) and multiple sclerosis (MS). Though the ILCs belong to lineage negative cells that are distinctive from the Th cells, the profiles of secreted cytokines from the ILCs overlap with those of the corresponding Th subsets. Nevertheless, considering that the ILCs belong to the innate immune system and the Th cells belong to the adaptive immune system, it is expected that the ILCs should function at the early stage of diseases and the Th cells should exert predominant effects at the late stage of diseases. Therefore, it is intriguing to consider targeting of ILCs for therapy by targeting the corresponding cytokines at the early stage of diseases, with the late stage cytokine targeting mainly influencing the Th cells' function. Here, we review the knowledge to date on the roles of ILCs in various autoimmune diseases and discuss their potential as new therapeutic targets.

Serum lipid antibodies are associated with cerebral tissue damage in multiple sclerosis

Objective:

To determine whether peripheral immune responses as measured by serum antigen arrays are linked to cerebral MRI measures of disease severity in multiple sclerosis (MS).

Methods:

In this cross-sectional study, serum samples were obtained from patients with relapsing-remitting MS (n = 21) and assayed using antigen arrays that contained 420 antigens including CNS-related autoantigens, lipids, and heat shock proteins. Normalized compartment-specific global brain volumes were obtained from 3-tesla MRI as surrogates of atrophy, including gray matter fraction (GMF), white matter fraction (WMF), and total brain parenchymal fraction (BPF). Total brain T2 hyperintense lesion volume (T2LV) was quantified from fluid-attenuated inversion recovery images.

Results:

We found serum antibody patterns uniquely correlated with BPF, GMF, WMF, and T2LV. Furthermore, we identified immune signatures linked to MRI markers of neurodegeneration (BPF, GMF, WMF) that differentiated those linked to T2LV. Each MRI measure was correlated with a specific set of antibodies. Strikingly, immunoglobulin G (IgG) antibodies to lipids were linked to brain MRI measures. Based on the association between IgG antibody reactivity and each unique MRI measure, we developed a lipid index. This comprised the reactivity directed against all of the lipids associated with each specific MRI measure. We validated these findings in an additional independent set of patients with MS (n = 14) and detected a similar trend for the correlations between BPF, GMF, and T2LV vs their respective lipid indexes.

Conclusions:

We propose serum antibody repertoires that are associated with MRI measures of cerebral MS involvement. Such antibodies may serve as biomarkers for monitoring disease pathology and progression.

Quantitative peripheral blood perturbations of γδ T cells in human disease and their clinical implications

Human γδ T cells, which play innate and adaptive, protective as well as destructive, roles in the immune response, were discovered in 1986, but the clinical significance of alterations of the levels of these cells in the peripheral blood in human diseases has not been comprehensively reviewed. Here, we review patterns of easily measurable changes of this subset of T cells in peripheral blood from relevant publications in PubMed and their correlations with specific disease categories, specific diagnoses within disease categories, and prognostic outcomes. These collective data suggest that enumeration of γδ T cells and their subsets in the peripheral blood of patients could be a useful tool to evaluate diagnosis and prognosis in the clinical setting.

Invariant natural killer T cells and their ligands: focus on multiple sclerosis

Invariant natural killer T (iNKT) cells are an innate population of T cells identified by the expression of an invariant T-cell receptor and reactivity to lipid-based antigens complexed with CD1d. They account for a small percentage of lymphocytes, but are extremely potent and play central roles in immunity to infection, in some cancers, and in autoimmunity. The list of relevant stimulatory lipids and glycolipid antigens now includes a range of endogenous self-antigens including the myelin-derived acetylated galactosylceramides. Recent progress in studies to identify the nature of lipid recognition for iNKT cells in autoimmune diseases like multiple sclerosis is likely to foster the development of therapeutic strategies aimed at harnessing iNKT cell activity.

Long-term proper name anomia after removal of the uncinate fasciculus

A previous study reporting on 44 patients who underwent awake surgery for a left frontal or temporal glioma resection demonstrated the removal of the uncinate fasciculus to have consequences on language 3 months post-surgery. At this time-point, patients with a temporal glioma who had undergone uncinate removal showed the worst overall performance with a significant impairment in naming of famous faces and objects compared to patients without removal. Also, verbal fluency was mildly impaired. We report a longer-term follow-up (9-12 months) in a selected group of 17 patients (six female, age range 27-64) who did not suffer any tumour recurrence in this timeframe. MRI and DTI were performed before and after surgery. While verbal fluency on categorical cue and object naming recovered to the same level as before surgery, proper naming remained significantly impaired even after 12 months (P = 0.032) in patients with uncinate removal, demonstrating this structure to be crucial for that function and supporting the hypothesis that subcortical connectivity is relevant to allow plasticity. We thus argued that the left frontal and temporal poles connected by means of the uncinate fasciculus constitute a dedicated circuit for naming of unique entities.

MRI phenotypes based on cerebral lesions and atrophy in patients with multiple sclerosis

BACKGROUND

While disease categories (i.e. clinical phenotypes) of multiple sclerosis (MS) are established, there remains MRI heterogeneity among patients within those definitions. MRI-defined lesions and atrophy show only moderate inter-correlations, suggesting that they represent partly different processes in MS. We assessed the ability of MRI-based categorization of cerebral lesions and atrophy in individual patients to identify distinct phenotypes.

METHODS

We studied 175 patients with MS [age (mean ± SD) 42.7 ± 9.1 years, 124 (71%) women, Expanded Disability Status (EDSS) score 2.5 ± 2.3, n = 18 (10%) clinically isolated demyelinating syndrome (CIS), n=115 (66%) relapsing-remitting (RR), and n = 42 (24%) secondary progressive (SP)]. Brain MRI measures included T2 hyperintense lesion volume (T2LV) and brain parenchymal fraction (to assess whole brain atrophy). Medians were used to create bins for each parameter, with patients assigned a low or high severity score.

RESULTS

Four MRI phenotype categories emerged: Type I = low T2LV/mild atrophy [n = 67 (38%); CIS = 14, RR = 47, SP = 6]; Type II = high T2LV/mild atrophy [n = 21 (12%); RR = 19, SP = 2]; Type III = low T2LV/high atrophy [n = 21 (12%); CIS = 4, RR = 16, SP = 1]; and Type IV = high T2LV/high atrophy [n = 66 (38%); RR = 33, S P = 33]. Type IV was the most disabled and was the only group showing a correlation between T2LV vs. BPF and MRI vs. EDSS score (all p < 0.05).

CONCLUSIONS

We described MRI-categorization based on the relationship between lesions and atrophy in individual patients to identify four phenotypes in MS. Most patients have congruent extremes related to the degree of lesions and atrophy. However, many have a dissociation. Longitudinal studies will help define the stability of these patterns and their role in risk stratification.

Fair play doesn't matter: MEP modulation as a neurophysiological signature of status quo bias in economic interactions

Transcranial magnetic stimulation (TMS) studies show that watching others' movements enhances motor evoked potential (MEPs) amplitude of the muscles involved in the observed action (motor facilitation, MF). MF has been attributed to a mirror neuron system mediated mechanism, causing an excitability increment of primary motor cortex. It is still unclear whether the meaning an action assumes when performed in an interpersonal exchange context could affect MF. This study aims at exploring this issue by measuring MF induced by the observation of the same action coupled with opposite reward values (gain vs loss) in an economic game. Moreover, the interaction frame was manipulated by showing the same actions within different economic games, the Dictator Game (DG) and the Theft Game (TG). Both games involved two players: a Dictator/Thief and a receiver. Experimental participants played the game always as receivers whereas the Dictator/Thief roles were played by our confederates. In each game Dictator/Thief's choices were expressed by showing a grasping action of one of two cylinders, previously associated with fair/unfair choices. In the DG the dictator decides whether to share (gain condition) or not (no-gain condition) a sum of money with the receiver, while in TGs the thief decides whether to steal (loss condition) or not to steal (no-loss condition) it from the participants. While the experimental subjects watched the videos showing these movements, a single TMS pulse was delivered to their motor hand area and a MEP was recorded from the right FDI muscle. Results show that, in the DG, MF was enhanced by the status quo modification, i.e. MEP amplitude increased when the dictator decided to change the receivers' status quo and share his/her money, and this was true when the status quo was more salient. The same was true for the TG, where the reverse happened: MF was higher for trials in which the thief decided to steal the participants' money, thus changing the status quo, in the block in which the status quo maintenance occurred more often. Data support the hypothesis that the economic meaning of the observed actions differently modulates MEP amplitude, pointing at an influence on MF exerted by a peculiar interaction between economic outcomes and variation of the subjects' initial status quo.

Gamma delta T cells in non-immune patients during primary schistosomal infection

The mevalonate pathway is critical for the survival of Schistosoma. γδ T cells, a small subset of peripheral blood (PB) T cells, recognize low molecular weight phosphorylated antigens in the mevalonate pathway, which drive their expansion to exert protective and immunoregulatory effects. To evaluate their role in schistosomiasis, we measured γδ T cells in the PB of non-immune travelers who contracted Schistosoma hematobium or Schistosoma mansoni in Africa. The maximal level of γδ T-cells following infection was 5.78 ± 2.19% of the total T cells, versus 3.72 ± 3.15% in 16 healthy controls [P = 0.09] with no difference between S. hematobium and S. mansoni in this regard. However, among the nine patients in the cohort who presented with acute schistosomiasis syndrome (AS), the level (3.5 ± 1.9%) was significantly lower than in those who did not (8.6 ± 6.4%, P < 0.05), both before and after therapy. Furthermore, γδ T cells increased significantly in response to praziquantel therapy. In a patient with marked expansion of γδ T cells, most expressed the Vδ2 gene segment, a hallmark of cells responding to cognate antigens in the mevalonate pathways of the parasite or the human host. These results suggest an immunoregulatory role of antigen responsive γδ T cells in the clinical manifestations of early schistosomal infection.

The effects of teriflunomide on lymphocyte subpopulations in human peripheral blood mononuclear cells in vitro

Teriflunomide is an inhibitor of dihydro-orotate dehydrogenase (DHODH), and is hypothesized to ameliorate multiple sclerosis by reducing proliferation of stimulated lymphocytes. We investigated teriflunomide's effects on proliferation, activation, survival, and function of stimulated human peripheral blood mononuclear cell subsets in vitro. Teriflunomide had little/no impact on lymphocyte activation but exerted significant dose-dependent inhibition of T- and B-cell proliferation, which was uridine-reversible (DHODH-dependent). Viability analyses showed no teriflunomide-associated cytotoxicity. Teriflunomide significantly decreased release of several pro-inflammatory cytokines from activated monocytes in a DHODH-independent fashion. In conclusion, teriflunomide acts on multiple immune cell types and processes via DHODH-dependent and independent mechanisms.

The innate immune system in demyelinating disease

Demyelinating diseases such as multiple sclerosis are chronic inflammatory autoimmune diseases with a heterogeneous clinical presentation and course. Both the adaptive and the innate immune systems have been suggested to contribute to their pathogenesis and recovery. In this review, we discuss the role of the innate immune system in mediating demyelinating diseases. In particular, we provide an overview of the anti-inflammatory or pro-inflammatory functions of dendritic cells, mast cells, natural killer (NK) cells, NK-T cells, γδ T cells, microglial cells, and astrocytes. We emphasize the interaction of astroctyes with the immune system and how this interaction relates to the demyelinating pathologies. Given the pivotal role of the innate immune system, it is possible that targeting these cells may provide an effective therapeutic approach for demyelinating diseases.

Identifying patient subtypes in multiple sclerosis and tailoring immunotherapy: challenges for the future

The accelerating pace of technological and analytical development in the fields of genetic and phenotypic profiling has ushered in an era of great promise for multiple sclerosis (MS) research. As we continue to identify modest but meaningful associations to MS susceptibility, disease course, treatment response, and other clinical or paraclinical phenotypes, we must begin to (1) embark on the challenging set of studies that will integrate disparate observations into clinical algorithms, and (2) validate their clinical utility. Genetic data are receiving muchofthe attention today, but they are unlikelytobesufficienttooffer a personalized approach to disease management in MS. Rather, the genetic architecture of the disease, once uncovered, will offer a fixed platform upon which more dynamic molecular profiles can be assembled to deconstruct the structure of the patient population that we label with a diagnosis of MS. The tools and methods to gain insight into the heterogeneity of MS patients are available today; we must now realize their potential in enhancing the care of MS patients.

γδ T cells enhance autoimmunity by restraining regulatory T cell responses via an interleukin-23-dependent mechanism

Mice that lack interleukin-23 (IL-23) are resistant to T cell-mediated autoimmunity. Although IL-23 is a maturation factor for T helper 17 (Th17) cells, a subset of γδ T cells expresses the IL-23 receptor (IL-23R) constitutively. Using IL-23R reporter mice, we showed that γδ T cells were the first cells to respond to IL-23 during experimental autoimmune encephalomyelitis (EAE). Although γδ T cells produced Th17 cell-associated cytokines in response to IL-23, their major function was to prevent the development of regulatory T (Treg) cell responses. IL-23-activated γδ T cells rendered αβ effector T cells refractory to the suppressive activity of Treg cells and also prevented the conversion of conventional T cells into Foxp3(+) Treg cells in vivo. Thus, IL-23, which by itself has no direct effect on Treg cells, is able to disarm Treg cell responses and promote antigen-specific effector T cell responses via activating γδ T cells.

Contribution of CD8 T lymphocytes to the immuno-pathogenesis of multiple sclerosis and its animal models

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) characterized by multi-focal demyelination, axonal loss, and immune cell infiltration. Numerous immune mediators are detected within MS lesions, including CD4(+) and CD8(+) T lymphocytes suggesting that they participate in the related pathogenesis. Although CD4(+) T lymphocytes are traditionally considered the main actors in MS immunopathology, multiple lines of evidence suggest that CD8(+) T lymphocytes are also implicated in the pathogenesis. In this review, we outline the recent literature pertaining to the potential roles of CD8(+) T lymphocytes both in MS and its animal models. The CD8(+) T lymphocytes detected in MS lesions demonstrate characteristics of activated and clonally expanded cells supporting the notion that these cells actively contribute to the observed injury. Moreover, several experimental in vivo models mediated by CD8(+) T lymphocytes recapitulate important features of the human disease. Whether the CD8(+) T cells can induce or aggravate tissue destruction in the CNS needs to be fully explored. Strengthening our understanding of the pathogenic potential of CD8(+) T cells in MS should provide promising new avenues for the treatment of this disabling inflammatory disease.

Soluble CD30: a biomarker for evaluating the clinical risk versus benefit of IFNbeta1A treatment in multiple sclerosis patients

Aberrant redox regulation occurs in immune and neurological pathologies, hence targeting the pathways involved in the regulation of the redox system could provide further insights into these diseases and open up new avenues for therapy. Soluble (s) CD30 is of key clinical importance in this respect, as its levels reflect the functionality of the CD30 receptor (CD30R), the specific lymphocyte receptor for thiol disulfide/oxidoreductase thioredoxin 1 (Trx1) which is known to regulate important immune and neurological processes. Increased levels of sCD30 appear to be a common element of oxidative stress, immunological alterations and neurological deficit, therefore these increases could be used as a clinical biomarker and target for therapy. We targeted sCD30 in our study of dendritic cell (DC) regulation of the T helper (Th) cell network in multiple sclerosis (MS) patients, as abnormalities in T regulatory (Treg)/Th1/Th17 pathways contribute to the pathogenesis of this immunological/neurological disease. DC profiles in Treg/Th1/Th2/Th17-types of cytokine production in culture supernatants were used as they determine the type of Th differentiation. Our results show that sCD30 levels increase significantly in MS patients, reflecting the disruption in the regulation of the Treg/Th1/Th17 cell network. A fall in the level of soluble CD30, induced by IFNbeta1a therapy, opposed the increase of neurological deficit through increasing IL10 and TGFbeta levels, thus re-establishing network homeostasis but only when this was accompanied by an increase in IL12p70 levels. Since IL12p70 cytokine production is regulated by Trx1, our results indicate that redox system alterations may be the cause of IFNbeta1a therapeutic inefficacy. We conclude that an increase in the level of IL10, TGFbeta and IL12p70 and a fall in the level of sCD30 represent a means of evaluating the clinical risk/benefit of IFNbeta1a treatment.

Role of the innate immune system in the pathogenesis of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease with heterogeneous clinical presentations and course. MS is considered to be a T cell mediated disease but in recent years contribution of innate immune cells in mediating MS pathogenesis is being appreciated. In this review, we have discussed the role of various innate immune cells in mediating MS. In particular, we have provided an overview of potential anti-inflammatory or pro-inflammatory function of DCs, microglial Cells, NK cells, NK-T cells and gamma delta T cells along with their interaction among themselves and with myelin. Given the understanding of the role of the innate immune cells in MS, it is possible that immunotherapeutic intervention targeting these cells may provide a better and effective treatment.

HIV Coreceptors and Their Roles in Leukocyte Trafficking During Neuroinflammatory Diseases

Due to the increasing resistance of HIV-1 to antiretroviral therapies, there has been much emphasis on the discovery and development of alternative therapeutics for HIV-1-infected individuals. The chemokine receptors CXCR4 (Bleul et al. 1996a; Feng et al. 1996; Nagasawa et al. 1996; Oberlin et al. 1996) and CCR5 (Alkhatib et al. 1996; Deng et al. 1996; Dragic et al. 1996) were identified as target molecules from the time their role as coreceptors for HIV-1 entry into leukocytes was first discovered 10 years ago. Initial studies focused on the use of the chemokine ligands, or altered derivatives, of CXCR4 and CCR5 to prevent the entrance of HIV-1 into immune cells (Schols 2006). While these studies showed some initial promise, there was evidence of significant caveats to their use, including selection of alternative coreceptor utilizing strains (Marechal et al. 1999; Mosier et al. 1999) and the potential to cause inflammatory side effects. These data prompted the development and study of small molecule inhibitors of CXCR4 and CCR5, which have also been used to examine the roles of these molecules in a variety of inflammatory and infectious diseases.

Update on inflammation, neurodegeneration, and immunoregulation in multiple sclerosis: therapeutic implications

Multiple sclerosis (MS) is an inflammatory, demyelinating, and neurodegenerative disease of the central nervous system of uncertain etiology. There is consensus that a dysregulated immune system plays a critical role in the pathogenesis of MS; therefore, we aim to summarize current hypotheses concerning the complex cellular and molecular interactions involved in the immunopathology of MS. Although CD4+ T lymphocytes have long been implicated in the immunopathology of MS, the role of other T-cell subtypes has been recognized. CD4+ and CD8+ cells have been isolated from different locations within MS lesions and gamma/delta T cells have been isolated from early MS lesions. The prevalent dogma has been that CD4+ TH1 cells release cytokines and mediators of inflammation that may cause tissue damage, although CD4+ TH2 cells may be involved in modulation of these effects. Recent evidence, however, suggests that additional T-cell subsets play a prominent role in MS immunopathology: TH17 cells, CD8+ effector T cells, and CD4+CD25+ regulatory T cells. In addition, laboratory and clinical data are accumulating on the prominent role of B lymphocytes and antigen-presenting cells in MS pathogenesis. On the basis of these observations, new therapeutic approaches for MS will need to focus on resetting multiple components of the immune system.

Increased numbers of IL-7 receptor molecules on CD4+CD25-CD107a+ T-cells in patients with autoimmune diseases affecting the central nervous system

Background

High content immune profiling in peripheral blood may reflect immune aberrations associated with inflammation in multiple sclerosis (MS) and other autoimmune diseases affecting the central nervous system.

Methods and Findings

Peripheral blood mononuclear cells from 46 patients with multiple sclerosis (MS), 9 patients diagnosed with relapsing remitting MS (RRMS), 13 with secondary progressive multiple sclerosis (SPMS), 9 with other neurological diseases (OND) and well as 15 healthy donors (HD) were analyzed by 12 color flow cytometry (TCRαβ, TCRγδ, CD4, CD8α, CD8β, CD45RA, CCR7, CD27, CD28, CD107a, CD127, CD14) in a cross-sectional study to identify variables significantly different between controls (HD) and patients (OND, RRMS, SPMS). We analyzed 187 individual immune cell subsets (percentages) and the density of the IL-7 receptor alpha chain (CD127) on 59 individual immune phenotypes using a monoclonal anti-IL-7R antibody (clone R34.34) coupled to a single APC molecule in combination with an APC-bead array. A non-parametric analysis of variance (Kruskal-Wallis test) was conducted in order to test for differences among the groups in each of the variables. To correct for the multiplicity problem, the FDR correction was applied on the p-values. We identified 19 variables for immune cell subsets (percentages) which allowed to segregate healthy individuals and individuals with CNS disorders. We did not observe differences in the relative percentage of IL-7R-positive immune cells in PBMCs. In contrast, we identified significant differences in IL-7 density, measured on a single cell level, in 2/59 variables: increased numbers of CD127 molecules on TCRαβ+CD4+CD25 (intermed) T-cells and on TCRαβ+CD4+CD25−CD107a+ T-cells (mean: 28376 Il-7R binding sites on cells from HD, 48515 in patients with RRMS, 38195 in patients with SPMS and 33692 IL-7 receptor binding sites on cells from patients with OND).

Conclusion

These data show that immunophenotyping represents a powerful tool to differentiate healthy individuals from individuals suffering from neurological diseases and that the number of IL-7 receptor molecules on differentiated TCRαβ+CD4+CD25−CD107a+ T-cells, but not the percentage of IL-7R-positive cells, segregates healthy individuals from patients with neurological disorders.

T-cells expressing natural killer (NK) receptors are altered in multiple sclerosis and responses to alpha-galactosylceramide are impaired

Multiple sclerosis (MS) is an autoimmune disorder characterised by clinical relapse and remission and pathological demyelination with varying inflammation. Because it is suggested that T-cells expressing natural killer cell receptors (NKR) play important roles in regulating human autoimmune diseases, we have quantified populations of T-cells expressing the NKR CD56, CD161 and CD94 in the peripheral blood of MS patients, in healthy control subjects (HS) and in patients with other neurological diseases (OND). CD161(+) T-cells and CD94(+) T-cells were significantly decreased in MS patients with primary progressive disease and secondary progressive disease respectively whereas CD56(+) T-cell numbers were unchanged. In contrast NKT-cells that express the invariant Valpha24-Jalpha18(+) T-cell receptor identified here by specific receptor antibody and CD1d-tetrameric PBS57-loaded complexes, were increased in MS patients compared with HS. Reductions in CD161(+) T-cells and CD94(+) T-cells relative to HS were also observed in the OND group and this was particularly prominent in Parkinsonian patients. A striking functional finding was that while NKT-cells in unfractionated peripheral blood from healthy subjects expanded in number and produced IFN-gamma upon stimulation with alpha-galactosylceramide, NKT-cells from MS patients did not. Thus we have identified alterations in a number of potentially important lymphocyte sub-populations warranting further investigation in the immune response in MS.

Cytometric profiling in multiple sclerosis uncovers patient population structure and a reduction of CD8low cells

As part of a biomarker discovery effort in peripheral blood, we acquired an immunological profile of cell-surface markers from healthy control and untreated subjects with relapsing-remitting MS (RRMS). Fresh blood from each subject was screened ex vivo using a panel of 50 fluorescently labelled monoclonal antibodies distributed amongst 56 pools of four antibodies each. From these 56 pools, we derived an immunological profile consisting of 1018 'features' for each subject in our analysis using a systematic gating strategy. These profiles were interrogated in an analysis with a screening phase (23 patients) and an extension phase (15 patients) to identify cell populations in peripheral blood whose frequency is altered in untreated RRMS subjects. A population of CD8(low)CD4(-) cells was identified as being reduced in frequency in untreated RRMS subjects (P = 0.0002), and this observation was confirmed in an independent sample of subjects from the Comprehensive Longitudinal Investigation of MS at the Brigham & Women's Hospital (P = 0.002). This reduction in the frequency of CD8(low)CD4(-) cells is also observed in 38 untreated subjects with a clinically isolated demyelination syndrome (CIS) (P = 0.0006). We also show that these differences may be due to a reduction in the CD8(low)CD56(+)CD3(-)CD4(-) subset of CD8(low) cells, which have a natural killer cell profile. Similarities between untreated CIS and RRMS subjects extend to broader immunological profiles: consensus clustering of our data suggests that there are three distinct populations of untreated RRMS subjects and that these distinct phenotypic categories are already present in our sample of untreated CIS subjects. Thus, our large-scale immunophenotyping approach has yielded robust evidence for a reduction of CD8(low)CD4(-) cells in both CIS and RRMS in the absence of treatment as well as suggestive evidence for the existence of immunologically distinct subsets of subjects with a demyelinating disease.

Expression of the inhibitor of apoptosis protein family in multiple sclerosis reveals a potential immunomodulatory role during autoimmune mediated demyelination

A failure of autoreactive T cells to undergo apoptosis may contribute to the pathogenesis of multiple sclerosis (MS). The role of the inhibitor of apoptosis (IAP) family of anti-apoptotic proteins such as X-linked IAP (XIAP), human inhibitor of apoptosis-1 (HIAP-1), human inhibitor of apoptosis-2 (HIAP-2), neuronal apoptosis inhibitory protein (NAIP) and Survivin in relapsing–remitting, secondary-progressive, primary-progressive or benign forms of MS is unclear. We report here that expression of the IAP family of genes in peripheral blood samples and brain tissues from MS cases support a role for differential regulation of these potent anti-apoptotic proteins in the pathology of MS. XIAP mRNA and protein levels were elevated in peripheral blood mononuclear cells from patients with active disease relative to normal subjects. In patients with active MS, HIAP-1 and HIAP-2 mRNA levels were elevated in resting T cells while NAIP mRNA was increased in whole blood. In post-mortem MS brain tissue, XIAP and HIAP-1 in myelin lesions were co-localized with microglia and T cells, respectively. Only in primary-progressive patients was Survivin expression elevated suggestive of a distinct pathological basis for this subtype of MS. Taken together, these results suggest that patterns of inhibitor of apoptosis expression in immune cells may have value in distinguishing between MS subtypes and offer insight into the mechanisms responsible for their distinct clinical courses.

High-content T-cell and B-cell analysis

Immune responses are orchestrated by B- and T-cells endowed with a diverse repertoire of antigen receptors. Comprehensive profiling of the humoral and cellular immune responses, including molecular composition, the specificity of the response, the cellular activation, differentiation, and homing status, will aid to improve diagnosis, classification, monitoring, and prognostication of immune disorders driven by antigen-specific B- and T-lymphocytes.

Andrews B, Sankaranarayanan A, Homerick D, Roeck WW, Tehranzadeh J, Stanhope KL, Zimin P, Havel PJ, Griffey S, Knaus HG, Nepom GT, Gutman GA, Calabresi PA, Chandy KG. Kv1.3 channels are a therapeutic target for T cell-mediated autoimmune diseases

Autoreactive memory T lymphocytes are implicated in the pathogenesis of autoimmune diseases. Here we demonstrate that disease-associated autoreactive T cells from patients with type-1 diabetes mellitus or rheumatoid arthritis (RA) are mainly CD4+ CCR7- CD45RA- effector memory T cells (T(EM) cells) with elevated Kv1.3 potassium channel expression. In contrast, T cells with other antigen specificities from these patients, or autoreactive T cells from healthy individuals and disease controls, express low levels of Kv1.3 and are predominantly naïve or central-memory (T(CM)) cells. In T(EM) cells, Kv1.3 traffics to the immunological synapse during antigen presentation where it colocalizes with Kvbeta2, SAP97, ZIP, p56(lck), and CD4. Although Kv1.3 inhibitors [ShK(L5)-amide (SL5) and PAP1] do not prevent immunological synapse formation, they suppress Ca2+-signaling, cytokine production, and proliferation of autoantigen-specific T(EM) cells at pharmacologically relevant concentrations while sparing other classes of T cells. Kv1.3 inhibitors ameliorate pristane-induced arthritis in rats and reduce the incidence of experimental autoimmune diabetes in diabetes-prone (DP-BB/W) rats. Repeated dosing with Kv1.3 inhibitors in rats has not revealed systemic toxicity. Further development of Kv1.3 blockers for autoimmune disease therapy is warranted.