Search

ObjectiveTo investigate whether vitamin D, smoking, and anti-Epstein-Barr virus (EBV) antibody concentrations predict long-term cognitive status and neuroaxonal injury in multiple sclerosis (MS).MethodsThis study was conducted among 278 patients with clinically isolated syndrome who participated in the clinical trial BENEFIT (Betaferon/Betaseron in Newly Emerging Multiple Sclerosis for Initial Treatment) and completed the 11-year assessment (BENEFIT-11). We measured serum 25-hydroxyvitamin-D (25(OH)D), cotinine (smoking biomarker), and anti-Epstein-Barr virus nuclear antigen 1 (EBNA-1) immunoglobulin G (IgG) at baseline and at months 6, 12, and 24 and examined whether these biomarkers contributed to predict Paced Auditory Serial Addition Test (PASAT)-3 scores and serum neurofilament light chain (NfL) concentrations at 11 years. Linear and logistic regression models were adjusted for sex, baseline age, treatment allocation, steroid treatment, multifocal symptoms, T2 lesions, and body mass index.ResultsHigher vitamin D predicted better, whereas smoking predicted worse cognitive performance. A 50-nmol/L higher mean 25(OH)D in the first 2 years was related to 65% lower odds of poorer PASAT performance at year 11 (95% confidence intervals [95% CIs]: 0.14–0.89). Standardized PASAT scores were lower in smokers and heavy smokers than nonsmokers (ptrend = 0.026). Baseline anti–EBNA-1 IgG levels did not predict cognitive performance (ptrend = 0.88). Associations with NfL concentrations at year 11 corroborated these findings—a 50-nmol/L higher mean 25(OH)D in the first 2 years was associated with 20% lower NfL (95% CI: −36% to 0%), whereas smokers had 20% higher NfL levels than nonsmokers (95% CI: 2%–40%). Anti–EBNA-1 antibodies were not associated with NfL.ConclusionsLower vitamin D and smoking after clinical onset predicted worse long-term cognitive function and neuronal integrity in patients with MS.

BACKGROUND AND PURPOSE: Cellular uptake of the manganese ion, when administered as a contrast agent for MR imaging, can noninvasively highlight cellular activity and disease processes in both animals and humans. The purpose of this study was to explore the enhancement profile of manganese in patients with multiple sclerosis. MATERIALS AND METHODS: Mangafodipir is a manganese chelate that was clinically approved for MR imaging of liver lesions. We present a case series of 6 adults with multiple sclerosis who were scanned at baseline with gadolinium, then injected with mangafodipir, and followed at variable time points thereafter. RESULTS: Fourteen new lesions formed during or shortly before the study, of which 10 demonstrated manganese enhancement of varying intensity, timing, and spatial pattern. One gadolinium-enhancing extra-axial mass, presumably a meningioma, also demonstrated enhancement with manganese. Most interesting, manganese enhancement was detected in lesions that formed in the days after mangafodipir injection, and this enhancement persisted for several weeks, consistent with contrast coming from intracellular uptake of manganese. Some lesions demonstrated a diffuse pattern of manganese enhancement in an area larger than that of both gadolinium enhancement and T2-FLAIR signal abnormality. CONCLUSIONS: This work demonstrates the first use of a manganese-based contrast agent to enhance MS lesions on MR imaging. Multiple sclerosis lesions were enhanced with a temporal and spatial profile distinct from that of gadolinium. Further experiments are necessary to uncover the mechanism of manganese contrast enhancement as well as cell-specific uptake.

BACKGROUND/PURPOSE Contrast-enhancing lesions (CEL) on magnetic resonance imaging (MRI) are believed to represent inflammatory disease activity in multiple sclerosis (MS), but their relationship to subsequent long-term disability and progression is unclear, particularly at longer time periods such as 8-10 years. METHODS Between 1989 and 1994, 111 MS patients were seen at the National Institutes of Health for clinical evaluations and 3 monthly contrast-enhanced MRI scans. Of these, 94 patients were re-evaluated a mean of 8 years later (range 6.1-10.5 years) with a single MRI scan and clinical evaluation. CEL number and volume were determined at baseline and follow-up. The number of relapses was ascertained over the follow-up period and annualized relapse rates were calculated. Other MRI parameters, such as T2 hyperintensity volume, T1 volume, and brain parenchymal fraction, were also calculated. RESULTS While there was no direct correlation between CEL number or volume at baseline and disability status at follow-up, CEL measures at baseline did correlate with number of relapses observed in the subsequent years, and the number of relapses in turn correlated with subsequent disability as well as transition to progressive MS. CONCLUSION While number and volume of CEL at baseline do not directly correlate with disability in the longer term in MS, our data suggest that 1 route to disability involves relapses as a mediator variable in the causal sequence of MS progression from CEL to disability. Further studies using relapse as a mediator variable in a larger data set may be warranted.

Therapies with both immunomodulatory and neuroprotective properties are thought to have the greatest promise in reducing the severity and progression of multiple sclerosis (MS). Several reactive oxygen (ROS) and reactive nitrogen species (RNS) are implicated in inflammatory-mediated damage to the central nervous system (CNS) in MS and its animal model, experimental autoimmune encephalomyelitis (EAE). TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl) is a stable nitroxide radical with potent antioxidant activity. The goal of our studies was to investigate the immunomodulatory effects and therapeutic potential of orally-delivered TEMPOL in the mouse EAE model. Mice receiving TEMPOL chow ad libitum for 2 weeks prior to induction of active EAE showed delayed onset and reduced incidence of disease compared to control-fed animals. Reduced disease severity was associated with limited microglial activation and fewer inflammatory infiltrates. TEMPOL’s effects were immunomodulatory, not immunosuppressive: T cells produced less interferon-γ and tumor necrosis factor-α, and TEMPOL-fed mice exhibited a shift towards TH2-type antibody responses. Both myeloid and myeloid-dendritic cells of TEMPOL-fed EAE animals had significantly lower levels of MHC class II expression than controls; CD40 was also significantly reduced. TEMPOL administration was associated with an enrichment of CD8+ T cell populations and CD4+FoxP3+regulatory populations. TEMPOL reduced the severity of clinical disease when administered after the induction of disease, and also after the onset of clinical symptoms. To exclude effects on T cell priming in vivo, TEMPOL was tested with the passive transfer of encephalitogenic T cells and was found to reduce the incidence and peak severity of disease. Protection was associated with reduced infiltrates and a relative sparing of neurofilaments and axons. The ability of oral TEMPOL to reduce inflammation and axonal damage and loss demonstrate both anti-inflammatory and protective properties, with significant promise for the treatment of MS and related neurological disorders.

The development of new regenerative therapies for multiple sclerosis is hindered by the lack of potential targets for enhancing remyelination. The study of naturally regenerative processes such as the innate immune response represents a powerful approach for target discovery to solve this problem. By ‘mining’ these processes using transcriptional profiling we can identify candidate factors that can then be tested individually in clinically-relevant models of demyelination and remyelination. Here, therefore, we have examined a previously described in vivo model of the innate immune response in which zymosan-induced macrophage activation in the retina promotes myelin sheath formation by oligodendrocytes generated from transplanted precursor cells. While this model is not itself clinically relevant, it does provide a logical starting point for this study as factors that promote myelination must be present. Microarray analysis of zymosan-treated retinae identified several cytokines (CXCL13, endothelin 2, CCL20 and CXCL2) to be significantly upregulated. When tested in a cerebellar slice culture model, CXCL13 and endothelin 2 promoted myelination and endothelin 2 also promoted remyelination. In studies to identify the receptor responsible for this regenerative effect of endothelin 2, analysis of both remyelination following experimental demyelination and of different stages of multiple sclerosis lesions in human post-mortem tissue revealed high levels of endothelin receptor type B in oligodendrocyte lineage cells. Confirming a role for this receptor in remyelination, small molecule agonists and antagonists of endothelin receptor type B administered in slice cultures promoted and inhibited remyelination, respectively. Antagonists of endothelin receptor type B also inhibited remyelination of experimentally-generated demyelination in vivo. Our work therefore identifies endothelin 2 and the endothelin receptor type B as a regenerative pathway and suggests that endothelin receptor type B agonists represent a promising therapeutic approach to promote myelin regeneration.

BACKGROUND AND PURPOSE Using high-field magnetic resonance imaging (MRI), we investigated the relationships between white matter (WM) lesion volume (LV), normal-appearing WM (NAWM) normalized volume, WM-lesion and NAWM magnetization transfer ratios (MTRs), brain parenchyma fraction (BPF), and cognitive impairment (CI) in multiple sclerosis (MS). METHODS Twenty-four patients and 24 healthy volunteers (age, sex, and years of education–matched) underwent a 3.0 Tesla (3T) scan and evaluation of depression, fatigue, and CI using the Minimal Assessment of Cognitive Function in MS (MACFIMS) battery. RESULTS In this clinically relatively well-preserved cohort of patients (median score on the Expanded Disability Status Scale = 1.5), CI was detected on Symbol Digit Modalities Test (SDMT), California Verbal Learning Test-II (CVLT-II), and Controlled Oral Word Association Test. MT data were available in 19 pairs on whom correlation analyses were performed. Associations were seen between SDMT and normalized NAWM volume (P= .034, r= .502), CVLT-II long delay and normalized NAWM volume (P= .012, r= .563), WM-LV (P= .024, r= .514), and BPF (P= .002, r= .666). CONCLUSIONS The use of 3T MRI in a sample of clinically stable MS patients shows the importance of WM disease in hampering processing speed and word retrieval.

Rolipram, a prototypic phosphodiesterase-4 inhibitor, is highly effective in suppressing Th1 autoimmunity in multiple animal models, including experimental autoimmune encephalomyelitis. In addition, rolipram has been extensively studied as a potential neuroprotective agent. Based on its anti-inflammatory activity, we tested the efficacy of rolipram in suppressing inflammatory disease activity in multiple sclerosis in a proof-of-principle phase I/II open-label clinical trial. Enrolled MS patients were evaluated by monthly MRI and clinical examinations during 3 months (four MRIs) of pretreatment baseline and 8 months of rolipram therapy. The primary outcome was a change in contrast-enhanced lesions between baseline and the last 4 months of rolipram therapy. Previously defined biomarkers of rolipram-mediated immunomodulation were evaluated during the study. The trial was stopped prematurely because the drug was poorly tolerated and because of safety concerns: we observed an increase, rather than decrease, in the brain inflammatory activity measured by contrast-enhanced lesions on brain MRI. At the administered doses rolipram was active in vivo as documented by immunological assays. We conclude that the reasons underlying the discrepancy between the therapeutic efficacy of rolipram in experimental autoimmune encephalomyelitis versus multiple sclerosis are at present not clear.

Magnetic Resonance Imaging (MRI) has brought in several benefits to the study of Multiple Sclerosis (MS). It provides accurate measurement of disease activity, facilitates precise diagnosis, and aid in the assessment of newer therapies. The imaging guidelines for MS are broadly divided in to approaches for imaging patients with suspected MS or clinically isolated syndromes (CIS) or for monitoring patients with established MS. In this review, the technical aspects of MR imaging for MS are briefly discussed. The imaging process need to capture the twin aspects of acute MS viz. the autoimmune acute inflammatory process and the neurodegenerative process. Gadolinium enhanced MRI can identify acute inflammatory lesions precisely. The commonly applied MRI marker of disease progression is brain atrophy. Whole brain magnetization Transfer Ratio (MTR) and Magnetic Resonance Spectroscopy (MRS) are two other techniques use to monitor disease progression. A variety of imaging techniques such as Double Inversion Recovery (DIR), Spoiled Gradient Recalled (SPGR) acquisition, and Fluid Attenuated Inversion Recovery (FLAIR) have been utilized to study the cortical changes in MS. MRI is now extensively used in the Phase I, II and III clinical trials of new therapies. As the technical aspects of MRI advance rapidly, and higher field strengths become available, it is hoped that the impact of MRI on our understanding of MS will be even more profound in the next decade.

The increasing number of established effective therapies for relapsing multiple sclerosis (MS) and emerging consensus for early treatment raise practical concerns and ethical dilemmas for placebo-controlled clinical trials in this disease. An international group of clinicians, ethicists, statisticians, regulators, and representatives from the pharmaceutical industry convened to reconsider prior recommendations regarding the ethics of placebo-controlled trials in MS. The group concluded that placebo-controlled trials can still be done ethically, with restrictions. For patients with relapsing MS for which established effective therapies exist, placebo-controlled trials should only be offered with rigorous informed consent if the subjects refuse to use these treatments, have not responded to them, or if these treatments are not available to them for other reasons (e.g., economics). Suggestions are provided to protect subject autonomy and improve informed consent procedures. Recommendations are tighter than previously suggested for placebo-controlled trials in "resource-restricted" environments where established therapies may not be available. Guidance is also provided on the ethics of alternative trial designs and the balance between study subject burden and risk, scientific rationale and interpretability of trial outcomes.

Over the past few years, MRI has become an indispensable tool for diagnosing multiple sclerosis (MS). However, the current MRI criteria for MS diagnosis have imperfect sensitivity and specificity. The central vein sign (CVS) has recently been proposed as a novel MRI biomarker to improve the accuracy and speed of MS diagnosis. Evidence indicates that the presence of the CVS in individual lesions can accurately differentiate MS from other diseases that mimic this condition. However, the predictive value of the CVS for the development of clinical MS in patients with suspected demyelinating disease is still unknown. Moreover, the lack of standardization for the definition and imaging of the CVS currently limits its clinical implementation and validation. On the basis of a thorough review of the existing literature on the CVS and the consensus opinion of the members of the North American Imaging in Multiple Sclerosis (NAIMS) Cooperative, this article provides statements and recommendations aimed at helping radiologists and neurologists to better understand, refine, standardize and evaluate the CVS in the diagnosis of MS.

Summary Interferon beta (IFN-β) is among the first-line treatment options for patients with multiple sclerosis (MS). A potential caveat of therapy, however, is the development of neutralizing antibodies (NAb) and/or neutralizing activity (NA) non-antibody mediated, although debate is still ongoing as to whether NAb significantly hampers the efficacy of the drug or rather represents an immunologically irrelevant epiphenomenon. In the present study, we describe the effect of NAb on IFN-β-1b through clinical and magnetic resonance imaging (MRI) outcome measures of five relapsing–remitting multiple sclerosis (RRMS) patients who were treated with 250 μg of subcutaneously administered IFN-β-1b every other day and developed NAb at varying titres and times during the course of therapy. Despite the small number of NAb+ patients, heterogeneity in MRI/clinical response to IFN-β-1b was identified. Response to IFN-β-1b therapy was observed in the absence or presence of NAb. Also observed was failure to IFN-β-1b coincident with high and sustained NAb titres, but also before NAb development or in the presence of low NAb titres. Multiple MRI and NAb measurements performed within the same individual allow for a better description of the complex heterogeneous response to IFN-β-1b with respect to NAb occurrence.

Administration of daclizumab, a humanized mAb directed against the IL-2Rα chain, strongly reduces brain inflammation in multiple sclerosis patients. Here we show that daclizumab treatment leads to only a mild functional blockade of CD4+T cells, the major candidate in multiple sclerosis pathogenesis. Instead, daclizumab therapy was associated with a gradual decline in circulating CD4+and CD8+T cells and significant expansion of CD56brightnatural killer (NK) cellsin vivo, and this effect correlated highly with the treatment response.In vitrostudies showed that NK cells inhibited T cell survival in activated peripheral blood mononuclear cell cultures by a contact-dependent mechanism. Positive correlations between expansion of CD56brightNK cells and contraction of CD4+and CD8+T cell numbers in individual patientsin vivoprovides supporting evidence for NK cell-mediated negative immunoregulation of activated T cells during daclizumab therapy. Our data support the existence of an immunoregulatory pathway wherein activated CD56brightNK cells inhibit T cell survival. This immunoregulation has potential importance for the treatment of autoimmune diseases and transplant rejection and toward modification of tumor immunity.

Interferon-beta (IFNbeta) reduces the number and load of new contrast-enhancing lesions (CELs) in patients with multiple sclerosis (MS). However, the ability of IFNbeta to reduce lesion sizes and re-enhancements of pre-existing CELs has not been examined extensively. Activity of contrast re-enhancing lesions (Re-CELs) and contrast single-enhancing lesions (S-CELs) were monitored in ten patients with relapsing-remitting (RR) MS. These patients underwent monthly post-contrast magnetic resonance imaging (MRIs) for an 18-month natural history phase and an 18-month therapy phase with subcutaneous IFNbeta-1b, totaling 37 images per patient. The activity was analysed using the first image as a baseline and registering subsequent active monthly images to the baseline. There was a 76.4% reduction in the number of CELs with IFNbeta therapy. The decrease was greater (P = 0.003) for S-CELs (82.3%) than for Re-CELs (57.4%). S-CELs showed no changes in durations of enhancement and maximal lesion sizes with treatment. Exclusively for Re-CELs, IFNbeta-1b significantly decreased maximal lesion sizes, total number of enhancement periods and total months of enhancement. Thus, IFNbeta appears to be effective in reducing the degree of severity of inflammation among Re-CELs, as reflected by their reduced maximal lesion sizes and durations of enhancement.

Due to past success in testing and gaining regulatory approval for a variety of therapies in multiple sclerosis (MS), the conduct of future clinical trials has become increasingly problematic. An international workshop has met to discuss the issues facing the MS clinical trial community and to examine possible new strategies for the design of trials. Particular focus has been placed on trials that either avoid the use of a placebo because of ethical considerations or on designs that allow new therapies to be studied more rapidly or with fewer patients than needed in a conventional placebo-controlled trial. The discussions resulting from the workshop should provide a basis for the examination and implementation of innovative clinical trial designs in MS.

Conventional brain and spinal cord magnetic resonance images were performed in 21 patients with human T-cell lymphotropic virus (HTLV)-1 associated myelopathy/tropical spastic paraparesis, to assess the role of conventional magnetic resonance imaging (MRI) in the disease diagnosis. These patients had no other central nervous system conditions or related risk factors at the time of tropical spastic paraparesis diagnosis. Eleven (52.4%) patients showed nonspecific brain abnormalities on T2-weighted images. The majority (77.2%) of brain abnormalities were located in the deep white matter. A transient contrast-enhancing lesion was identified in the brain of only one patient. In the brain of another patient, 9.0% of the T2-hyperintense lesion load was hypointense on the correspondent T1-weighted images. No differences in terms of demographic, biological, or clinical variables were present between patients with abnormal brain images and those with normal brain magnetic resonance images. Spinal cord T2-weighted images were abnormal in three (14.3%) patients. In one of these three patients, a diffuse but transient edema was found along the entire tract of the spinal cord. White matter lesions were present in the central nervous system of 60% of the cases in this study. However, no correlations between magnetic resonance imaging and clinical findings, and no specificity of lesions were observed. Hence, conventional magnetic resonance imaging is a sensitive but not highly specific tool for diagnosis of tropical spastic paraparesis.

New diagnostic criteria for multiple sclerosis integrating magnetic resonance image assessment with clinical and other paraclinical methods were introduced in 2001. The "McDonald Criteria" have been extensively assessed and used since 2001. New evidence and consensus now strengthen the role of these criteria in the multiple sclerosis diagnostic workup to demonstrate dissemination of lesions in time, to clarify the use of spinal cord lesions, and to simplify diagnosis of primary progressive disease. The 2005 Revisions to the McDonald Diagnostic Criteria for MS should simplify and speed diagnosis, whereas maintaining adequate sensitivity and specificity.

Cortical reorganization has been demonstrated in the motor network that mediates performance of a motor task in patients with multiple sclerosis. How this network responds to motor training is not known. This study examined functional MRI (fMRI) activation patterns associated with performance of a motor task, consisting of repetition of directionally specific voluntary thumb movements, before and after motor training in a group of multiple sclerosis patients with mild motor impairment of the right upper extremity. Patients and healthy subjects were scanned in one session before, during and after a 30 min training period. fMRI data obtained during rest, thumb flexion (trained movement) and thumb extension (untrained movement) were analysed using random effects analysis (SPM99). Motor kinematics of training motions and EMG from the resting hand were monitored with an accelerometer and surface EMG electrodes. Kinematics of thumb movements before, during and after training were comparable in the absence of mirror EMG activity in the resting hand. Before training, thumb movements elicited more prominent activation of the contralateral dorsal premotor cortex [PMd, Brodmann area (BA) 6] in multiple sclerosis patients than in controls. After training, unlike the control group, multiple sclerosis patients did not exhibit task-specific reductions in activation in the contralateral primary somatosensory (S1), motor (M1) and adjacent parietal association (BA 40) cortices. These results indicate that patients engage the contralateral PMd more than controls in order to perform directionally specific movements before training. The absence of training-dependent reductions in activation in S1, M1 and BA 40 is consistent with a decreased capacity to optimize recruitment of the motor network with practice.

Amino acid residues 111–129 represent an immunodominant epitope of myelin basic protein (MBP) in humans with human leukocyte antigen (HLA)-DRB1*0401 allele(s). The MBP 111–129–specific T cell clone MS2-3C8 was repeatedly isolated from a patient with multiple sclerosis (MS), suggesting an involvement of MS2-3C8 T cells in the pathogenesis. To address the pathogenic potential of the MS2-3C8 T cell clone, we generated transgenic (Tg) mice expressing its T cell receptor and restriction element, HLA-DRB1*0401, to examine the pathogenic characteristics of MS2-3C8 Tg T cells by adoptive transfer into HLA-DRB1*0401 Tg mice. In addition to the ascending paralysis typical of experimental autoimmune encephalomyelitis, mice displayed dysphagia due to restriction in jaw and tongue movements and abnormal gait. In accordance with the clinical phenotype, infiltrates of MS2-3C8 Tg T cells and inflammatory lesions were predominantly located in the brainstem and the cranial nerve roots in addition to the spinal cord and spinal nerve roots. Together, these data suggest a pathogenic role of MBP-specific T cells in inflammatory demyelination within the brainstem and cranial nerve roots during the progression of MS. This notion may help to explain the clinical and pathological heterogeneity of MS.

Since myelin basic protein (MBP)111-129 is an immunodominant epitope in humans carrying HLA-DRB1*0401, we investigated the encephalitogenic potential of HLA-DRB1*0401-restricted MBP111-129-specific T cells using HLA-DRB1*0401/DRA*0101 transgenic (Tg) mice. Although we could not detect the primary recall response to MBP111-129 peptide after immunization of HLA-DRB1*0401/DRA*0101 Tg mice with human MBP, V beta 10(+) and V beta 2(+) HLA-DRB1*0401-restricted MBP111-129-specific T cells proliferated after restimulation of the lymph node cells with human MBP111-129 in vitro. The V beta 2(+) T cell line recognized only human MBP111-129 in the context of HLA-DRB1*0401, while the V beta 10(+) T cell line recognized both the human and murine MBP111-129 epitopes. Therefore, we examined the encephalitogenic potential of the V beta 10(+) T cell line in HLA-DRB1*0401/DRA*0101 Tg mice by adoptive transfer experiments. The V beta 10(+) T cell line induced mild EAE and inflammatory lesions were observed in the spinal cord and the brainstem. In the spinal cord, the inflammation was observed in the peripheral nerve roots as well as in the CNS. These data suggest the pathogenic potential of HLA-DRB1*0401-restricted MBP111-129-specific T cells in humans.

To determine the effect of interferon-beta-1b (IFNbeta-1b) treatment on total contrast-enhancing lesions (CEL), white matter lesion load (WMLL), and cerebral atrophy (CA) in patients with relapsing-remitting multiple sclerosis (RRMS) using serial monthly MRI.An open-label baseline-vs-treatment crossover trial was conducted with 30 RRMS patients monitored during a 6-month baseline and up to 36 months on treatment with IFNbeta-1b. Monthly MRI exams and neurologic exams using the Expanded Disability Status Scale (EDSS) were performed.The percentage changes from baseline for years 1, 2, and 3 on IFNbeta-1b were as follows: brain volume (BV) = -1.35, -1.48, and -1.68%; CEL = -76.5, -60.1, and -54.7%; WMLL = -12.2, -9.8, and -10.4%. There was no difference in the BV, CEL, or WMLL for between-year comparisons, and the decrease in BV from year 1 to years 2 and 3 was less than the change from baseline to year 1. EDSS did increase (p0.001) when comparing the last 3 months of baseline (2.8 +/- 2.1) and the last 3 months on IFNbeta-1b (3.6 +/- 2.1). Eleven patients developed neutralizing antibody (NAb) during the study. The effect of IFNbeta-1b on CEL and WMLL was significantly reduced in NAb+ patients compared with NAb- patients (p0.003).IFNbeta-1b decreases contrast-enhancing lesions and white matter lesion load over 3 years on therapy and slows the progression in cerebral atrophy during years 2 and 3.

Multiple sclerosis is the principal demyelinating disease of the central nervous system. Although the prevalence of the disease is moderately low, averaging about 40 cases per 100,000 people in high risk areas, it is a particularly devastating disease. It primarily affects young adults, is chronic, and has an unpredictable course. Most discouraging, the cause of the disease is not known and an effective treatment has not been identified. Recently, however, research has yielded some important findings concerning the etiology of MS. Much evidence now points to an immunological process as one of the major elements in the disease. It is also likely that an environmental influence, possibly an infectious process, may contribute to the disease. Finally, it is now certain that genetic makeup influences susceptibility to the disease. At present, the strongest evidence is for a polygenic effect, not the effect of a single gene or gene locus. This review will examine some of the possible immunologically mediated disease processes that could be involved in MS, especially those that could account for a role for infectious and genetic factors in the disease.

New MRI techniques such as the analysis of magnetization transfer or diffusion have provided evidence for subtle progressive alterations in tissue integrity prior to focal leakage of the blood-brain barrier (BBB) as part of plaque formation in multiple sclerosis. Since inflammation is capable of modulating the microcirculation, we investigated the hypothesis that changes in the local perfusion might be one of the earliest signs of lesion development. 20 patients with definite relapsing-remitting multiple sclerosis were analysed with regard to cerebral blood volume, cerebral blood flow, mean transit time and apparent diffusion coefficient (ADC), as well as conventional MRI parameters, on monthly follow-up scans. Among 89 gadolinium-enhancing lesions, we selected 18 that developed during the study and met strict inclusion criteria. In these, changes of perfusion parameters were detectable not only prior to the BBB breakdown, but also prior to increases in the ADC. Our data indicate that inflammation is accompanied by altered local perfusion, which can be detected prior to permeability of the BBB.

Multiple sclerosis (MS) is a T cell-mediated autoimmune disease with early lesions characterized by mononuclear cellular infiltrate, edema, demyelination, and axonal loss that contribute to the clinical course of the disease. Experimental autoimmune encephalomyelitis (EAE) in the mouse is a valuable model with a similar disease course to relapsing-remitting MS. The ability to detect the migration of encephalitogenic T cells into the central nervous system in EAE and MS would provide key information on these cells role in the development of lesions observed on magnetic resonance imaging (MRI). T cells were labeled for detection by magnetic resonance imaging using Food and Drug Administration-approved, superparamagnetic iron oxide nanoparticles (Ferumoxides) complexed to poly-L-Lysine (FE-PLL). EAE was induced by adoptive transfer of either labeled or unlabeled T cells. After disease onset, FE-PLL-labeled T cells were detected in the mouse spinal cord using in vivo and ex vivo cellular MRI. Excellent correlation was seen between MRI-visible lesions in the spinal cord and histopathology. The results demonstrate that T cells labeled with FE-PLL can induce EAE disease and can be detected in vivo in the mouse model. The magnetic labeling of cells opens the possibility of monitoring specific cellular phenotypes or pharmacologically or genetically engineered cells by MRI.

T1 black holes (BHs) on MRIs may represent either areas of oedema or axonal loss in patients with multiple sclerosis. BHs begin as contrast enhancing lesions (CELs) and evolve differently from patient to patient, and within the same patient over time. We analysed BHs formation over a 4-year period. Forty-eight monthly MRIs of nine non-treated multiple sclerosis patients were evaluated for numbers of CELs and BHs. A BH was defined as a hypointense lesion on a T1 pre-contrast image that coincided with a region of high signal intensity on the T2-weighted images. A BH was considered as acute (ABH) when it occurred coincidently with the presence of enhancement and as persisting (PBH) when present after the cessation of enhancement. The present study aimed to analyse: (i) the incidence of CELs and new PBHs, and the accumulation of PBHs; (ii) the relationship between the quantity of the CELs in a given month and the likelihood of accumulating PBHs in the subsequent month; and (iii) the relationship between the duration of CELs and PBHs. Pitman's correlation test evaluated the effect of time on either the increase of CELs and new PBHs or the accumulation of PBHs, while a multiple logistic regression analysis evaluated the relationship between progression of time and CELs, and the increase of PBHs in a multivariate model. The relationship between the enhancing lesions duration and the PBHs duration, or the time to revert back to an isointense lesion was analysed using Kaplan-Meier survival models. PBHs accumulated (P0.001) in all patients, but the formation of new PBHs increased in four patients (Por = 0.007) in conjunction with an increase in either the quantity of CELs (P0.001, for two patients) or the proportion of CELs turning into PBHs (Por = 0.02, for two patients). Logistic regression analysis showed that neither progression of time nor the number of CELs in a given month were able to predict the probability of increasing the number of PBHs in the subsequent month in any patient. Out of 397 ABHs, 55.7% evolved to a PBH. The duration of PBHs correlated with the duration of enhancement. PBHs preceded by CELs observable on a single MRI persisted for a shorter time (P0.002) than those preceded by CELs visible onor =2 monthly MRIs. The formation of a new PBH was found to be related to CELs activity; however, duration of PBHs is most likely a consequence of the duration of the enhancement.

Autoimmune diseases such as multiple sclerosis are characterized by complex genetic traits and pathomechanisms that translate into clinical heterogeneity. This wide heterogeneity of multiple sclerosis as well as different biological responses to immunomodulatory drugs can be expected to contribute to differential treatment responses. Strategies that dissect the relationship between the treatment response and the biological characteristics in individual patients are valuable not only as a clinical tool, but also in leading to a better understanding of the disease. Here we address the in vitro and ex vivo RNA expression profile under one approved therapy of multiple sclerosis, interferon-beta (IFN-beta, Betaseron), by cDNA microarrays and demonstrate that non-responder and responder phenotypes to IFN-beta as assessed by longitudinal gadolinium-enhanced MRI scans and clinical disease activity differ in their ex vivo gene expression profile. These findings will help to better elucidate the mechanism of action of IFN-beta in relation to different disease patterns and eventually lead to optimized therapy.

T cells recognizing self or microbial antigens may trigger or reactivate immune-mediated diseases. Monitoring the frequency of specific T cell clonotypes to assess a possible link with the course of disease has been a difficult task with currently available technology. Our goal was to track individual candidate pathogenic T cell clones, selected on the basis of previous extensive studies from patients with immune-mediated disorders of the CNS, including multiple sclerosis, HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) and chronic Lyme neuroborreliosis. We developed and applied a highly specific and sensitive technique to track single CD4(+) and CD8(+) T cell clones through the detection and quantification of T cell receptor (TCR) alpha or beta chain complementarity-determining region 3 transcripts by real-time reverse transcriptase (RT)-PCR. We examined the frequency of the candidate pathogenic T cell clones in the peripheral blood and CSF during the course of neurological disease. Using this approach, we detected variations of clonal frequencies that appeared to be related to clinical course, significant enrichment in the CSF, or both. By integrating clonotype tracking with direct visualization of antigen-specific staining, we showed that a single T cell clone contributed substantially to the overall recognition of the viral peptide/MHC complex in a patient with HAM/TSP. T cell clonotype tracking is a powerful new technology enabling further elucidation of the dynamics of expansion of autoreactive or pathogen-specific T cells that mediate pathological or protective immune responses in neurological disorders.

The discovery of T lymphocytes reactive to the peptide encoded by exon 2 of the myelin basic protein (MBP) gene in multiple sclerosis (MS) patients has drawn attention to MBP isoforms harboring that peptide as candidate autoantigens. Previously, immunological studies in MS had almost exclusively used the more abundant 18.5 kDa isoform of MBP, which does not does not contain the exon 2 peptide. Investigations of experimental allergic encephalomyelitis (EAE) have also focussed on the 18.5 kDa MBP isoform and its peptides. Since EAE is an animal model widely used widly used to study MS, we examined the encephalitogenic potential of exon 2 peptide in the SJL/J mouse. Evidence for increased expression of exon 2-containing isoforms during remyelination in mouse CNS suggested that exon 2-sensitized T cels, with encephalitogenic capacity, might be important in the pertuation of relapsing EAE (rEAE). Our experiments have demonstrated that exon 2 peptide is inherently immunogenic in SJL mice and that EAE could be induced by the adoptive transfer of exon 2-sensitized lymphocytes. Furthermore, the disease could be accentuated by the transfer of short-term exon 2-reactive lines or by a combination of adoptive transfer and antigenic challenge with exon 2 peptide. The immunodominant epitope(s) appeared to localize to the segment bordered by amino acids 59–85.

The major isoform of myelin basic protein (MBP) in the healthy adult central nervous system is the 18.5-kDa protein which is produced by mRNA derived from exons 1, 3, 4, 5, 6 and 7 of the MBP gene. Since isoforms containing exon 2-encoded protein (X2MBP) are expressed during myelin formation, we examined T cell ractivity specific for X2MBP in a disease characterized by remyelination subsequent to demyelination, multiple sclerosis (MS). T cell lines specific for X2MBP were derived from three MS patients as well as one healthy control. This suggests that candidate autoantigens in demyelinating/remyelinating diseases should include not only the major isoforms of myelin proteins, but also isoforms expressed aberrantly during a disease process since they too may be the target of a T cell-mediated autoimmune process.

To determine the effect of IV methylprednisolone (IVMP) on brain fraction volume (BFV), contrast-enhancing (CE) lesions, and white matter lesion load (WMLL) in patients with relapsing-remitting MS treated for acute exacerbations.MRI metrics of MS disease activity are being used as outcome measures in early phase treatment trials, however the short-term effects of IVMP treatment on cerebral atrophy are unknown.Serial monthly MRI were performed in 26 patients enrolled in a baseline vs treatment trial with interferon beta-1b (IFNbeta-1b) who were followed for 3 months before and after IVMP. All 26 patients were evaluated while receiving IFNbeta-1b, and 12 patients were also studied during the baseline stage of the trial (NHx). Acute exacerbations were treated with IVMP (1 g/d) for 3 to 5 days. Precontrast and postcontrast T1-weighted and proton density T2-weighted fast spin-echo images were analyzed.Fifty-six acute exacerbations were evaluated. For the 3 months before IVMP, there was no difference in WMLL or BFV compared to month IVMP was administered. There was a significant decrease in BFV at month 1 after IVMP in the IFNbeta-1b and NHx groups. Compared to the month IVMP was administered, there was a difference in the CE lesions for months -3 and -1 prior (p0.039) in NHx patients. Following IVMP, CE lesions decreased (p0.0004) for months 1, 2, and 3 in both groups, but there was no effect on WMLL.BFV and CE lesions were significantly decreased for 1 month (BFV) and 3 months (CE lesions) following IVMP. Therefore, MRI studies should be delayed by probably at least 2 months following IVMP to avoid a possible confounding steroid effect in a clinical trial.

The need for more specific and more sensitive outcome measures for use in testing new therapies in multiple sclerosis (MS) is generally accepted. This need has been accentuated by the realization that the ability to conduct large placebo-controlled trials will be limited in the future. From the first use of magnetic resonance imaging (MRI) to study MS, the ability of this imaging technique to identify areas of the central nervous system damage by the disease process in MS has been impressive. Thus, the possibility that MRI could serve as a surrogate outcome measure in clinical trials in MS has been attractive. The use of MRI as a surrogate outcome measure has been examined by an international group of investigators with expertise in clinical aspects of MS, the use of MRI in MS, and in experimental therapeutics. The group agreed that MRI does not represent a validated surrogate in any clinical form of MS. It was also agreed, however, that MRI does provide a reflection of the underlying pathology in the disease, but no single MRI measurement in isolation was seen as sufficient to monitor disease. The use for multiple imaging techniques, especially new, emerging techniques that may better reflect the underlying pathology, was seen as particularly important in monitoring studies of patients with either secondary or primary progressive MS. The choice of MRI techniques used to monitor new therapies needs to be consistent with the proposed mechanisms of the new therapy and phase of the disease. It was also noted, however, that additional validation is required for nonconventional imaging techniques. Finally, the participants noted that clinical trials using MRI as a primary outcome measure may fail to fully identify the effects of the therapy on clinical measures and that the risk and cost-benefit ratio of the treatment might be unresolved. Thus, before MRI is used as a primary outcome measure, new approaches to trial design must be given careful consideration. Multiple Sclerosis (2002)8, 40-51

T cell responses targeting myelin antigens are possibly involved in the pathogenesis of demyelinating diseases, such as multiple sclerosis (MS). Little is known about human T cell responses to 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase), the third most abundant myelin protein. We examined the primary peripheral T cell response to CNPase and characterized CNPase-specific CD4+ long-term T cell lines (TCL) from MS patients and healthy donors. The strongest primary responses were found in two MS patients with very active disease and were directed against CNP(343–373). We identified immunodominant epitope clusters in the regions CNP(343–373) and (356–388) that were recognized in the context of MS-associated HLA-DR2 and DR4 molecules. These data provide the immunological basis for further investigation of CNPase as a potential target self-antigen in MS.

On June 24-26, 2001, the first meeting of the White Matter Study Group (WMSG) of the International Society for Magnetic Resonance in Medicine (ISMRM) was held in Bordeaux, France. This paper is the report of the consensus reached among the delegates of the meeting on how to use magnetic resonance imaging (MRI) to make an early diagnosis of multiple sclerosis (MS), to measure MS activity accurately and reliably, and to monitor the effect of treatment on disease evolution.

In recent years, human herpesvirus 6 (HHV-6) has been investigated as a possible causative agent for MS. To determine if the detection of HHV-6 DNA in the serum of MS patients correlates with clinical parameters of MS disease progression, a total of 215 serum samples was obtained from 59 MS patients followed prospectively for a 5-month period. These samples were analyzed for the presence of HHV-6 DNA by nested PCR and compared in parallel to MS disease activity. HHV-6 DNA was amplified in 22% (4/18) of samples obtained during a period of clinical exacerbation. Significantly fewer (P = 0.008) sera, 5.6% (11/197), obtained from MS patients during clinical remission tested positive for the presence of HHV-6 DNA. This work demonstrates that the detection of serum HHV-6 DNA is significantly correlated with clinical exacerbations in MS. Moreover, the findings presented in this study have confirmed previous reports supporting an association between MS and HHV-6 and suggest a role for this human herpesvirus in the pathogenesis of MS.

We studied 24 patients with multiple sclerosis (MS) by proton magnetic resonance spectroscopic imaging (1H-MRSI) to assess the neurochemical pathology of the white-matter lesions (WML) and normal-appearing white matter (NAWM). Our 1H-MRSI technique allowed simultaneous measurement of N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine plus phosphocreatine (Cr) signal intensities from four 15-mm slices divided into 0.84 ml single-volume elements. In WML we found significantly lower NAA/Cr and NAA/Cho ratios and a significantly higher Cho/Cr ratio than in NAWM or control white matter. In NAWM, NAA/Cr and Cho/Cr were significantly lower than in control white matter. 1H-MRSI was compatible with damage to myelin in WML, and with axonal damage and/or dysfunction in WML and NAWM. These findings extend data on involvement of NAWM in MS beyond the abnormalities visible on MRI.

Differences in multiple sclerosis patient's disease and their responses to standard drugs indicate that today's therapies need to be more individualized. It is proposed that gene expression profiling in conjunction with magnetic resonance imaging be used to optimize future treatment approaches.

Multiple sclerosis (MS) is thought to be an autoimmune disease with a chronic inflammatory response directed against central nervous system (CNS) myelin antigens. Immunologic studies indicate that autoreactive CD4+ lymphocytes migrate into the CNS causing blood brain barrier (BBB) disruption, an initial event in the evolution of the MS lesion. Subsequent antigen recognition within the CNS initiates inflammatory responses that, through the multiple effector mechanisms, lead to demyelination. Magnetic resonance imaging (MRI) studies provide new insights into the evolution of the MS lesion, revealing an active and continuous pathologic process that is not only localized to focal lesions, but also diffusely affects normal appearing white matter (NAWM). Standard T2-weighted images are exquisitely sensitive, showing changes due to inflammation, edema, demyelination, and axonal loss, but because of the lack of pathologic specificity, they only moderately correlate with the clinical parameters. New MRI techniques, including magnetic resonance spectroscopy, magnetization transfer, and diffusion imaging, provide a better measure of axonal loss and demyelination, the most clinically relevant components of MS lesions. Hopefully, they will enable us to more accurately monitor disease activity and evaluate the effects of new therapies on the progression of the disease.

The concept of molecular mimicry provides and elegant framework as to how cross-reactivity between antigens from a foreign agent with self proteins may trigger autoimmune diseases. While it was previously thought that sequence and structural homology between foreign and self proteins or the sharing of T cell receptor (TCR) and MHC-binding motifs are required for molecular mimicry to occur, we have shown that even completely unrelated peptide sequences may lead to cross-recognition by T cells. The use of synthetic combinatorial peptide libraries in the positional scanning format (PS-SCL) together with novel biometric prediction approaches has allowed us to describe the recognition profiles of individual autoreactive T cell clones (TCC) with unprecedented accuracy. Through studies of myelin-specific TCC as well as clones from the nervous system of patients suffering from chronic central nervous (CNS) Lyme disease it has become clear that at least some T cells are more degenerate than previously anticipated. These data will not only help us to redefine what constitutes specific T cell recognition, but also allow us to study in more detail the biological role of molecular mimicry. A recent clinical trial with an altered peptide ligand (APL) of one of the candidate myelin basic protein (MBP) epitopes in MS (amino acids 83-99) has shown that such a modified MBP peptide may not only have therapeutic efficacy, but also bears the potential to exacerbate disease. Thus, we provide firm evidence that the basic principles of cross-recognition and their pathogenetic significance are relevant in MS.

Membrane cofactor protein (CD46) is a member of a family of glycoproteins that are regulators of complement and prevent activation of complement on autologous cells. Recently, CD46 has been identified as the cellular receptor for human herpesvirus Type 6 (HHV-6). Elevated levels of soluble CD46 have been described in several autoimmune disorders, and may be implicated in the pathogenesis of these diseases. As several reports have supported an association of HHV-6 and multiple sclerosis, it was of interest to compare levels of soluble CD46 in the sera of multiple sclerosis patients to that of healthy controls, other neurological disease controls, and other inflammatory disease controls. Using an immunoaffinity column comprised of immobilized monoclonal antibodies to CD46, serum levels of soluble CD46 were found to be significantly elevated in multiple sclerosis patients compared with healthy and other neurological disease controls. Moreover, multiple sclerosis patients who tested positive for HHV-6 DNA in serum had significantly elevated levels of soluble CD46 in their serum compared with those who were negative for HHV-6 DNA. A significant increase in soluble CD46 was also found in the serum of other inflammatory disease controls tested compared to healthy controls. Additionally, a significant correlation was demonstrated between levels of soluble CD46 in the serum and cerebrospinal fluid of multiple sclerosis patients. Collectively, these data suggest that elevated levels of soluble CD46 may contribute to the pathogenesis of inflammatory diseases, including multiple sclerosis.

The International Panel on MS Diagnosis presents revised diagnostic criteria for multiple sclerosis (MS). The focus remains on the objective demonstration of dissemination of lesions in both time and space. Magnetic resonance imaging is integrated with dinical and other paraclinical diagnostic methods. The revised criteria facilitate the diagnosis of MS in patients with a variety of presentations, including "monosymptomatic" disease suggestive of MS, disease with a typical relapsing-remitting course, and disease with insidious progression, without clear attacks and remissions. Previously used terms such as "clinically definite" and "probable MS" are no longer recommended. The outcome of a diagnostic evaluation is either MS, "possible MS" (for those at risk for MS, but for whom diagnostic evaluation is equivocal), or "not MS."

T cells with specificity for self-Ags are normally present in the peripheral blood, and, upon activation, may target tissue Ags and become involved in the pathogenesis of autoimmune processes. In multiple sclerosis, a demyelinating disease of the CNS, it is postulated that inflammatory damage is initiated by CD4+ T cells reactive to myelin Ags. To investigate the potential naive vs memory origin of circulating myelin-reactive cells, we have generated myelin basic protein (MBP)- and tetanus toxoid-specific T cell clones from CD45RA+/RO− and CD45RO+/RA− CD4+ T cell subsets from the peripheral blood of multiple sclerosis patients and controls. Our results show that 1) the response to MBP, different from that to TT, predominantly emerges from the CD45RA+ subset; 2) the reactivity to immunodominant MBP epitopes mostly resides in the CD45RA+ subset; 3) in each individual, the recognition of single MBP epitopes is skewed to either subset, with no overlap in the Ag fine specificity; and 4) in spite of a lower expression of costimulatory and adhesion molecules, CD45RA+ subset-derived clones recognize epitopes with higher functional Ag avidity. These findings point to a central role of the naive CD45RA+ T cell subset as the source for immunodominant, potentially pathogenic effector CD4+ T cell responses in humans.

Monthly MRI activity and clinical disability were evaluated in two relapsing-remitting multiple sclerosis (RRMS) patient for 4 years during a cross-over treatment trial with IFNβ-Ib, and for a mean of 21 months after terminating treatment with IFNβ-Ib. Post-treatment MRI activity was compared to baseline activity in these patient. Although contrast enhancing lesions (CEL) and the bulk white matter lesion load (BWMLL) on T2-weighted images eventually returned to baseline values, there was a refractory period of 6-10 months after terminating treatment before baseline MRI activity was restored. Although the mechanism for a sustained effect of IFNβ- Ib is unclear at this time, these result have important implications for enrollment of such patients into new treatment protocols that rely on contrast enhancing lesion frequency as an outcome measure.

CD4(+) T lymphocytes usually recognize peptides of 12-16 amino acids in the context of HLA class II molecules. We have recently used synthetic peptide combinatorial libraries to dissect in detail antigen recognition by autoreactive CD4(+) T cell clones (TCC). The results of these studies demonstrated that antigen recognition by T cells is highly degenerate and that many cross-reactive ligands can be defined, some of which much more potent than the selecting autoantigen. Based on these observations, we examined the response of a myelin basic protein-specific HLA class II-restricted CD4(+) TCC to truncation variants of optimal ligands. Surprisingly, pentapeptides, tetrapeptides and even tripeptides derived from different segments of the optimal ligands were recognized by the TCC, and some were even more potent than the selecting autoantigen. In addition, these peptides enhanced the survival of the TCC at low concentration. The relevance of this finding was supported by the generation of pentapeptide-specific CD4(+) TCC from peripheral blood lymphocytes. These observations not only change existing views on the length requirements for activation of CD4(+) HLA class II-restricted T cells, but also extend our knowledge about the flexibility of TCR recognition and the potential for cross-reactivity in the immune system.

Several reports have suggested an association of human herpesvirus 6 (HHV-6) and multiple sclerosis (MS) based on immunohistochemical demonstration of HHV-6 antigens in inflammatory lesions, detection of increased HHV-6 specific serum antibody titers, and amplification of HHV-6 DNA from sera and cerebrospinal fluid of MS patients but not in controls. Characterization of the cellular immune response of MS patients to HHV-6 may further clarify the role of HHV-6 in MS and provide insight into the pathogenesis of this immune-mediated disease. We have compared lymphoproliferative responses to HHV-6A (U1102)-, HHV-6B (Z29)-, and HHV-7 (H7SB)-infected cell lysates in healthy controls and patients with MS. Most healthy controls (71%) proliferated to HHV-6B lysate, and fewer (33%) responded to the HHV-6A lysate. In contrast, 67% of MS patients had a lymphoproliferative response to HHV-6A, which is a significant increase in comparison with healthy controls. A similar frequency of lymphoproliferative response (78%) to HHV-6B was demonstrated in MS patients. Lymphoproliferation to HHV-7 lysate was demonstrated in 23% of healthy controls and 28% of MS patients. These results indicate that the lymphoproliferative response to the HHV-6A variant, which was recently reported to have greater neurotropism, is increased in MS patients.

Experimental autoimmune encephalomyelitis (EAE) is a prototypic model of organ specific autoimmunity. MHC class II restricted T-cells directed against myelin basic protein (MBP) have been shown to cause EAE in susceptible strains of mice. We have asked whether the introduction of a gene encoding an autoantigen (MBP) into the hematopoetic stem cells of mice would result in tolerance to that protein. We have introduced cDNA encoding the 21.5 kDa isoform of MBP into the hematopoetic stem cells of B10.PL (73NS), SJL, and B10 mice by retrovirus-mediated gene transfer. Our experiments show expression of proviral MBP in peripheral blood and thymus following transplantation of genetically modified stem cells. Such expression does not result in deletion of MBP-specific T cells or tolerance to MBP, nor does it alter susceptibility to MBP-induced EAE in susceptible strains B10.PL and SJL. However, retrovirus-mediated gene transfer resulted in resistant B10 mice developing mild EAE. This report demonstrates that autoreactive MBP-specific T cells can be selected in the presence of endogenous antigen or an MBP-encoding retrovirus.

Phosphodiesterase-4 (PDE4) inhibitors have the potential to modulate immune responses from the Th1 toward the Th2 phenotype and are considered candidate therapies for Th1-mediated autoimmune disorders. However, depending on the model and cell types employed, studies of atopic individuals have come to the opposite conclusion, i.e., that PDE inhibitors may be beneficial in asthma. Using in vitro immunopharmacologic techniques we analyzed the effects of PDE4 and PDE3 inhibitors on human immune cells to address these discrepancies and broaden our understanding of their mechanism of action. Our results indicate that PDE inhibitors have complex inhibitory effects within in vivo achievable concentration ranges on Th1-mediated immunity, whereas Th2-mediated responses are mostly unaffected or enhanced. The Th2 skewing of the developing immune response is explained by the effects of PDE inhibitors on several factors contributing to T cell priming: the cytokine milieu; the type of costimulatory signal, i.e., up-regulation of CD86 and down-regulation of CD80; and the Ag avidity. The combination of PDE4 and PDE3 inhibitors expresses synergistic effects and may broaden the therapeutic window. Finally, we observed a differential sensitivity to PDE inhibition in autoreactive vs foreign Ag-specific T cells and cells derived from multiple sclerosis patients vs those derived from healthy donors. This suggests that PDE inhibition weakens the strength of the T cell stimulus and corrects the underlying disease-associated cytokine skew in T cell-mediated autoimmune disorders. These new findings broaden the understanding of the immunomodulatory actions of PDE inhibitors and underscore their promising drug profile for the treatment of autoimmune disorders.

In phase I (safety) trials, we have demonstrated the feasibility of autologous hematopoietic stem cell transplantation (HSCT) for patients with autoimmune diseases. Although this review comments on results of our phase I trials, the focus is on phase II (efficacy) trials using gene-marked autologous stem cells.