Structural insights reveal interplay between LAG-3 homodimerization, ligand binding, and function

Lymphocyte activation gene-3 (LAG-3) is an inhibitory receptor expressed on activated T cells and an emerging immunotherapy target. Domain 1 (D1) of LAG-3, which has been purported to directly interact with major histocompatibility complex class II (MHCII) and fibrinogen-like protein 1 (FGL1), has been the major focus for the development of therapeutic antibodies that inhibit LAG-3 receptor-ligand interactions and restore T cell function. Here, we present a high-resolution structure of glycosylated mouse LAG-3 ectodomain, identifying that cis-homodimerization, mediated through a network of hydrophobic residues within domain 2 (D2), is critically required for LAG-3 function. Additionally, we found a previously unidentified key protein-glycan interaction in the dimer interface that affects the spatial orientation of the neighboring D1 domain. Mutation of LAG-3 D2 residues reduced dimer formation, dramatically abolished LAG-3 binding to both MHCII and FGL1 ligands, and consequentially inhibited the role of LAG-3 in suppressing T cell responses. Intriguingly, we showed that antibodies directed against D1, D2, and D3 domains are all capable of blocking LAG-3 dimer formation and MHCII and FGL-1 ligand binding, suggesting a potential allosteric model of LAG-3 function tightly regulated by dimerization. Furthermore, our work reveals unique epitopes, in addition to D1, that can be targeted for immunotherapy of cancer and other human diseases.

A pilot study of recombinant insulin-like growth factor-I in seven multiple sclerosis patients

The purpose of this open-label, crossover study was to determine the safety and efficacy of recombinant insulin-like growth factor-I (rhIGF-I) using magnetic resonance imaging (MRI) and clinical measures of disease activity in seven multiple sclerosis (MS) patients. Monthly clinical and MRI examinations were performed during a 24-week baseline and a 24-week treatment period with rhIGF-I. The primary outcome measure was contrast enhancing lesion (CEL) frequency on treatment compared to baseline. Secondary outcome measures included clinical and MRI measures of disease activity including. white matter lesion load (WMLL), magnetization transfer ratio (MTR), TI-Hypointensity volume, cervical spine cross-sectional area and proton magnetic resonance spectroscopic (MRS) imaging for determining regional metabolite ratios. rhIGF-I (Cephalon) was administered at a dose of 50 mg subcutaneously twice a day for 6 months. rhIGF-I was safe and well tolerated with no severe adverse reactions. There was no significant difference between baseline and treatment periods for any MRI or clinical measures of disease activity. Although rhIGF-I did not alter the course of disease in this small cohort of MS patients, the drug was well tolerated. Further studies using rhIGF-I alone or in combination with other therapies may be of value because of the proposed mechanism of action of this growth factor on the oligodendrocyte and remyelination. Multiple Sclerosis (2002)8,24-29

Contrast-enhanced MRI lesions during treatment with interferonβ-1b predict increase in T1 black hole volume in patients with relapsing-remitting multiple sclerosis

T1 black holes (BH) have been found to represent focal areas of substantial central nervous system tissue damage in multiple sclerosis (MS) patients. We examined the development of T1 BH over a three-year period of treatment with interferon (IFN)β-1b in a group of 20 patients with relapsing-remitting MS. The number of contrast-enhancing lesions (CEL) after one year of treatment predicted a change in the T1 BH volume in the following two years. In patients without CEL, the T1 BH volume remained stable, whereas it increased in patients with CEL. The occurrence of CEL in patients treated with IFNβ may indicate a heightened risk of accumulating T1 BH.

Improved metagenome assemblies and taxonomic binning using long-read circular consensus sequence data

DNA assembly is a core methodological step in metagenomic pipelines used to study the structure and function within microbial communities. Here we investigate the utility of Pacific Biosciences long and high accuracy circular consensus sequencing (CCS) reads for metagenomic projects. We compared the application and performance of both PacBio CCS and Illumina HiSeq data with assembly and taxonomic binning algorithms using metagenomic samples representing a complex microbial community. Eight SMRT cells produced approximately 94 Mb of CCS reads from a biogas reactor microbiome sample that averaged 1319 nt in length and 99.7% accuracy. CCS data assembly generated a comparative number of large contigs greater than 1 kb, to those assembled from a ~190x larger HiSeq dataset (~18 Gb) produced from the same sample (i.e approximately 62% of total contigs). Hybrid assemblies using PacBio CCS and HiSeq contigs produced improvements in assembly statistics, including an increase in the average contig length and number of large contigs. The incorporation of CCS data produced significant enhancements in taxonomic binning and genome reconstruction of two dominant phylotypes, which assembled and binned poorly using HiSeq data alone. Collectively these results illustrate the value of PacBio CCS reads in certain metagenomics applications.

A red-shifted photochromic sulfonylurea for the remote control of pancreatic beta cell function

Azobenzene photoresponsive elements can be installed on sulfonylureas, yielding optical control over pancreatic beta cell function and insulin release. An obstacle to such photopharmacological approaches remains the use of ultraviolet-blue illumination. Herein, we synthesize and test a novel yellow light-activated sulfonylurea based on a heterocyclic azobenzene bearing a push-pull system.

Characterizing contrast-enhancing and re-enhancing lesions in multiple sclerosis

OBJECTIVES

In multiple sclerosis (MS), contrast-enhancing lesions (CELs) in T1-weighted postcontrast MRI are considered markers of blood-brain barrier breakdown. It remains unknown if re-enhancement can be considered a radiologic indicator of different pathology in CELs. We investigated 1) the incidence of re-enhancing lesions (re-CELs) from chronic lesions; 2) differences in size, magnetization transfer ratio (MTR), and likelihood to appear as acute black holes (aBHs) between new lesions (n-CELs) and re-CELs; and 3) associations between re-CELs and features indicating more advanced disease.

METHODS

In this retrospective natural history study, we examined 264 monthly MRI scans performed at month 1 (M1), month 2 (M2), and month 3 (M3) for 88 patients with MS. CELs were defined as n-CELs if not present in the M1 T2W MRI and re-CELs if present in the M1 T2W MRI.

RESULTS

A total of 311 (82.7%) n-CELs and 65 (17.3%) re-CELs were identified. Of the 88 patients, 54 presented only n-CELs, 8 presented only re-CELs, and 26 presented both CEL types. Patients with both lesion types presented more CELs than those presenting only one type (p = 0.01). Re-CELs were larger (z = 2.72, p = 0.007) and had lower MTR (z = -2.80, p = 0.005) than n-CELs but the estimated proportion of aBHs from n-CELs was similar (z = -0.09, p = 0.1) from the proportion of aBHs from re-CELs.

CONCLUSIONS

Nearly 20% of CELs represent the reoccurrence of enhancement in chronic plaques. Re-CELs represent larger areas of inflammation, not necessarily associated with larger areas of edema.

Quantification of SPIO nanoparticles in vivo using the finite perturber method

The susceptibility gradients generated by super-paramagnetic iron oxide (SPIO) nanoparticles make them an ideal contrast agent in magnetic resonance imaging. Traditional quantification methods for SPIO nanoparticle-based contrast agents rely on either mapping T₂* values within a region or by modeling the magnetic field inhomogeneities generated by the contrast agent. In this study, a new model-based SPIO quantification method is introduced. The proposed method models magnetic field inhomogeneities by approximating regions containing SPIOs as ensembles of magnetic dipoles, referred to as the finite perturber method. The proposed method was verified using data acquired from a phantom and in vivo mouse models. The phantom consisted of an agar solution with four embedded vials, each vial containing known but different concentrations of SPIO nanoparticles. Gaussian noise was also added to the phantom data to test performance of the proposed method. The in vivo dataset was acquired using five mice, each of which was subcutaneously implanted in the flanks with 1 × 10(5) labeled and 1 × 10(6) unlabeled C6 glioma cells. For the phantom data set, the proposed algorithm was generate accurate estimations of the concentration of SPIOs. For the in vivo dataset, the method was able to give estimations of the concentration within SPIO-labeled tumors that are reasonably close to the known concentration.

The role of the peck-food contingency on fixed-interval schedules

Pigeons were trained to peck on a fixed-interval schedule of food reinforcement and then exposed to three schedules in which there was either no, or an indirect, relation between pecking and food delivery: (a) a conjunctive schedule in which food was delivered at fixed intervals, providing at least one peck was emitted in the interval; (b) a recycling version of the conjunctive schedule that essentially eliminated occasional peck-food contiguities (recycling conjunctive); (c) delivery of food at fixed intervals independently of the birds' behavior (fixed time). The rates and patterns of pecking sustained by these procedures depended on interfood interval and relative proximity of pecks to food.

Reproducibility of human 3D fMRI brain maps acquired during a motor task

This study is an investigation into the reproducibility of brain activation in the sensorimotor cortex obtained with 3D "PRESTO" fMRI on eleven normal subjects. During one session, two series of functional scans were acquired while the subjects performed a finger opposition task (2 Hz). Nine subjects were tested once more on a different day. Each individual motor trial was analyzed separately, with a conservative zt-based method. Using these results, the agreement between repeated series was examined in a number of ways, comparing the two series within one session, and the two series across sessions. In 28 of the 31 series (90%) significant signal change was found in the contralateral primary sensorimotor cortex (PSM). Overall, 0.20% of all voxels (total about 11,000) in the scanned volume reached significance, and approximately 60% of the significant positive signal changes were located in the PSM (P<5x10(-7) for a chance occurrence). Comparisons within and across sessions yielded similar results: there was a 20-30% overlap of the clusters of activated voxels in the PSM (chance overlap within the PSM: P<0.01). The mean distance between zt-weighted centers of mass was 4.0-4.4 mm (chance distance within the PSM: P=0.033 and 0.058, respectively). No significant difference was found between series in the magnitude of significant signal change. Whereas the number of activated voxels in the PSM was not consistently correlated between series, the ratio of this number over the total number of activated voxels in the scanned volume was significantly correlated (rho=0.75-0.79, P<0.05). These results indicate that activation in sensorimotor cortex associated with oppositional finger movement is reliably mapped with 3D PRESTO fMRI.

Ring and nodular multiple sclerosis lesions: a retrospective natural history study

BACKGROUND

In patients with multiple sclerosis (MS), contrast-enhancing lesions (CELs) on postcontrast MRI are considered markers of the inflammatory responses associated with blood-brain barrier breakdown. Based upon shape, CELs may be defined as nodular (nCEL) or ring (rCEL) lesions. Several short-term studies pointed towards the assumption that rCELs represent areas of a more aggressive inflammatory process.

METHODS

In the present long-term (i.e., 2 years) retrospective natural history study, we used monthly imaging to follow rCEL and nCELs evolution in 16 patients with MS during the natural history. New CELs were identified monthly on month 4-9 MRIs, using month 1-3 MRIs to ensure that all CELs were not previously enhancing. Chronic black holes (cBHs) were counted monthly upon CEL disappearance up to the 24th MRI. Generalized estimating equation methods investigated within-patient differences between rCELs and nCELs in volume and likelihood to convert into cBHs. Kaplan-Meier survival curves estimated differences in the length of persistence between cBHs originating from nCELs and cBHs deriving from rCELs.

RESULTS

Fifty-two new rCELs and 281 nCELs were identified. rCELs had larger mean (z = 5.06, p < or = 0.0001) volumes than nCELs. The proportion of cBHs from rCELs was similar (z = 1.81, p = 0.0710) to the proportion of cBHs from nCELs. Likewise, the length of persistence of cBHs deriving from rCELs was similar (chi(1)(2) = 2.339, p = 0.1262) to the duration of cBHs from nCELs.

CONCLUSIONS

Our data suggest that worse radiologic characteristics associated with the acute phase of ring contrast-enhancing lesions and nodular contrast-enhancing lesions do not necessarily reflect a poorer lesion outcome over time.

Focal and diffuse cortical degenerative changes in a marmoset model of multiple sclerosis

BACKGROUND

Degenerative features, such as neuronal, glial, synaptic and axonal loss, have been identified in neocortical and other grey matter structures in patients with multiple sclerosis, but mechanisms for neurodegeneration are unclear. Cortical demyelinating lesions are a potential cause of this degeneration, but the pathological and clinical significance of these lesions is uncertain as they remain difficult to identify and study in vivo. In this study we aimed to describe and quantify cellular and subcellular pathology in the cortex of myelin oligodendrocyte glycoprotein-induced marmoset experimental autoimmune encephalomyelitis using quantitative immunohistochemical methods.

RESULTS

We found evidence of diffuse axonal damage occurring throughout cortical grey matter with evidence for synaptic loss and gliosis and a 13.6% decrease in neuronal size and occurring in deep cortical layers. Evidence of additional axonal damage and a 29.6-36.5% loss of oligodendrocytes was found in demyelinated cortical lesions. Leucocortical lesions also showed neuronal loss of 22.2% and a 15.8% increase in oligodendrocyte size.

CONCLUSIONS

The marmoset experimental autoimmune encephalomyelitis model, therefore, shows both focal and generalized neurodegeneration. The generalized changes cannot be directly related to focal lesions, suggesting that they are either a consequence of diffusible inflammatory factors or secondary to remote lesions acting through trans-synaptic or retrograde degeneration.

Protection from experimental ventilator-induced acute lung injury by IL-1 receptor blockade

Background: Clinical studies have shown that injurious mechanical ventilation is associated with elevated airspace and plasma levels of interleukin-1β (IL-1β); however, the potential therapeutic value of IL-1 inhibition in acute lung injury has not been thoroughly investigated.

A study was undertaken to determine if IL-1 signaling is a necessary early event in the pathogenesis of experimental ventilator-induced lung injury (VILI).

Methods: Mice deficient in IL-1 receptor type 1 (IL1R1) and rats treated with IL-1 receptor antagonist (IL-1Ra) were mechanically ventilated with high tidal volume (30 ml/kg) and the effect of IL-1 signaling blockade on lung injury severity was determined.

Results: Permeability as measured by radiolabeled albumin flux was significantly lower in IL1R1 null mice compared with wild type mice during injurious ventilation (P<0.05). IL-1Ra significantly decreased protein permeability and pulmonary oedema in rats during injurious ventilation. IL-1Ra also decreased airspace and plasma levels of the chemokine CXCL1 and airspace neutrophils. IL-1Ra decreased expression of NOS2 and ICAM-1 mRNA in whole lung. Bronchoalveolar lavage fluid levels of RTI40, a marker of type I cell injury, were 2.5 times lower in following IL-1Ra treatment (P < 0.05). In isolated type II pneumocytes, IL-1β reduced electrical resistance and increased transepithelial permeability.

Conclusions: IL-1 contributes to alveolar barrier dysfunction in VILI by promoting lung neutrophil recruitment, and by increasing epithelial injury and permeability. Because preserved alveolar barrier function is associated with better outcomes in patients with acute lung injury, these data support further testing of IL-1Ra for the treatment of acute lung injury.

A case study on the effect of neutralizing antibodies to interferon beta 1b in multiple sclerosis patients followed for 3 years with monthly imaging

Interferon beta (IFN-beta) 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-beta-1b through clinical and magnetic resonance imaging (MRI) outcome measures of five relapsing-remitting multiple sclerosis (RRMS) patients who were treated with 250 mug of subcutaneously administered IFN-beta-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-beta-1b was identified. Response to IFN-beta-1b therapy was observed in the absence or presence of NAb. Also observed was failure to IFN-beta-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-beta-1b with respect to NAb occurrence.

[From gene to disease; cutaneous leiomyomatosis]

Multiple cutaneous and uterine leiomyomatosis (MCUL; OMIM 150800) is an autosomal dominantly inherited disease characterized by leiomyomas of the skin and uterine leiomyomas. MCUL can be associated with various types of renal cancer. This syndrome is known as hereditary leiomyomatosis and renal cell cancer (HLRCC; OMIM 605839). Both disorders result from heterozygous germline mutations in the fumarate hydratase (FH) gene.

Occupational peri-ocular contact dermatitis due to sensitization against black rubber components of a microscope

A 24-year-old female working in the Department of Pathology of a University Hospital developed an acute peri-ocular eczema clearly being related to her daily work at the microscope. Patch testing revealed delayed type hypersensitivity against the black rubber mix, N-isopropyl-N'-phenyl paraphenylenediamine, N-cyclohexyl-N'-phenyl paraphenylenediamine and the rubber ring situated on the ocular of the respective microscope. This is the first report, to our knowledge, on peri-orbital allergic contact eczema because of sensitization with rubber components of a microscope.

Activation of the stress protein response prevents the development of pulmonary edema by inhibiting VEGF cell signaling in a model of lung ischemia-reperfusion injury in rats

Lung endothelial damage is a characteristic morphological feature of ischemia-reperfusion (I/R) injury, although the molecular steps involved in the loss of endothelial integrity are still poorly understood. We tested the hypothesis that the activation of vascular endothelial growth factor (VEGF) cell signaling would be responsible for the increase in lung vascular permeability seen early after the onset of I/R in rats. Furthermore, we hypothesized that the I/R-induced pulmonary edema would be significantly attenuated in rats by the activation of the stress protein response. Pretreatment with Ad Flk-1, an adenovirus encoding for the soluble VEGF receptor type II, prevented I/R-mediated increase in lung vascular permeability in rats. Furthermore, the I/R-induced lung injury was significantly decreased by prior activation of the stress protein response with geldanamycin or pyrrolidine dithiocarbamate. In vitro studies demonstrated that VEGF caused an increase in protein permeability across primary cultures of bovine macro- and microvascular lung endothelial cell monolayers that were associated with a phosphorylation of VE- and E-cadherin and the formation of actin stress fibers. Activation of the stress protein response prevented the VEGF-mediated changes in protein permeability across these cell monolayers and reduced the phosphorylation of VE-and E-cadherins, as well as the formation of actin stress fibers in these cells.

MRI T2 lesion burden in multiple sclerosis: a plateauing relationship with clinical disability

BACKGROUND

Previous studies have shown only modest correlation between multiple sclerosis (MS) lesions on MRI and clinical disability.

OBJECTIVE

To investigate the relationship between proton density/T2-weighted (T2) burden of disease (BOD) quantitatively measured on MRI scans and clinical determinants including disability.

METHODS

Using the Sylvia Lawry Centre for Multiple Sclerosis Research (SLCMSR) database, the authors studied baseline T2 BOD data from a pooled subsample of 1,312 placebo MS patients from 11 randomized controlled trials. Univariate comparisons guided development of multiple regression models incorporating the most important clinical predictors.

RESULTS

Significant, although weak to moderate, correlations were found between T2 BOD and age at disease onset, disease duration, disease course, disability (as measured by the Expanded Disability Status Scale [EDSS]), relapse rate, certain presenting symptoms, and gadolinium enhancement. An unexpected but key finding that persisted in the multiple regression analyses was a plateauing relationship between T2 BOD and disability for EDSS values above 4.5.

CONCLUSIONS

This study confirmed the limited correlation between clinical manifestations and T2 burden of disease (BOD) but revealed an important plateauing relationship between T2 BOD and disability.

Predicting gadolinium enhancement status in MS patients eligible for randomized clinical trials

BACKGROUND

Gadolinium enhancement is often used in randomized clinical trials to evaluate the efficacy of new drugs in multiple sclerosis (MS). Knowledge about predictors of enhancement status is important for the selection of patients for MRI monitored trials.

METHODS

Data from 17 trials were available in anonymized format through the Sylvia Lawry Centre for MS Research. In an open part containing 1,328 (non primary progressive) patients, two logistic regression analyses were explored, including demographic, clinical, and MRI predictors. The authors examined the area under the curve (AUC) and the increase in positive predictive value (PPV). The final selection of models was validated in a closed part of 848 comparable patients.

RESULTS

Age at onset, disease duration, and disease course (CIS/RR/SP) were important predictors from the multivariate models. Further, a multivariate model including T2 burden of disease was more predictive than one with only clinical predictors (AUC 0.719 vs 0.625, p < 0.001). For the model with T2 burden of disease, the PPV was 66.8%, compared to 58.5% for the model without (a priori chance 46.4%). These findings were unequivocally confirmed in the closed part of the database.

CONCLUSION

Gadolinium status can be predicted by a set of baseline variables, certainly when T2 burden of disease is included. These findings may benefit the design and statistical power of future randomized clinical trials.

Relationship between inflammatory lesions and cerebral atrophy in multiple sclerosis

OBJECTIVE

To investigate the temporal relationship between inflammation and cerebral atrophy in a longitudinal study of 19 patients with relapsing-remitting multiple sclerosis (RRMS) using serial monthly contrast enhanced MRI examinations and monthly measurements of brain fractional volume (BFV) for an average of 4 (range 2.4 to 10) years.

METHODS

In this retrospective study, all patients had an active MRI scan at entry with a minimum of two new contrast enhancing lesions (CEL) on baseline MRI examinations. Patients were followed for a minimum of 3 months during a baseline (pretreatment) phase and subsequently followed during treatment with recombinant interferon beta (IFN) and various other immunomodulatory agents. Pre- and post contrast axial images were obtained using 3-mm slice thickness and a gadolinium contrast dose of 0.1 mmol/kg. Monthly CEL were sequentially numbered on hardcopy films and monthly BFV was determined on precontrast T1W images using a semiautomated program. For BFV measurements, all T1W scans were registered to the entry examination, which served as a mask image. Cerebral atrophy was measured as percent brain fractional volume change (PBVC) compared to the entry baseline scan.

RESULTS

The results demonstrate that cerebral atrophy paralleled that of contrast enhancing lesion accumulation. The correlation between cumulative CEL and PBVC ranged from R2 = 0.47 to 0.81. Immunomodulatory agents that effectively reduced CEL accumulation also slowed the rate of atrophy.

CONCLUSIONS

The correlation between contrast enhancing lesions (CEL) and atrophy suggests that patients who are not responding to therapy with a decrease in CEL may also be at risk for developing increased atrophy.

MRI as a marker for disease heterogeneity in multiple sclerosis

BACKGROUND

Whereas recent data from imaging studies challenge the prevailing notion that multiple sclerosis (MS) is purely an inflammatory disease, pathologic studies suggest differences in the disease processes between individual patients with MS. The ability to dissect the pathophysiologic disease heterogeneity, if it indeed exists, by methodologies that can be applied in vivo is important both for the development of new therapeutics and for the ability to identify the optimal therapy for an individual patient.

OBJECTIVE

To design a stratification algorithm for patients with MS based on accepted MRI measurements reflective of inflammation and axonal damage/tissue loss and to assess if such MS subgroups retain their intergroup differences long term.

METHODS

Mathematical modeling was used to select three discriminatory MRI measures for clinical outcome based on the cross-sectional analysis of 71 patients with untreated MS and tested general applicability of the stratification scheme on the independent longitudinal cohort of 71 MS patients.

RESULTS

By consecutive employment of MRI measures reflective of inflammation and tissue loss, the authors were able to separate MS patients into four clinically meaningful subgroups. The analysis of the longitudinal confirmatory cohort demonstrated persistence of the intergroup differences in selected MRI measures for 8 years.

CONCLUSIONS

The inflammatory activity and destructiveness of the multiple sclerosis process are to some degree independent of each other, and the successive evaluation of both of these variables can strengthen prediction of clinical outcome in individual patients.

Imaging and nanomedicine for diagnosis and therapy in the central nervous system: report of the eleventh annual Blood-Brain Barrier Disruption Consortium meeting

The blood-brain barrier (BBB) presents a major obstacle to the treatment of malignant brain tumors and other central nervous system (CNS) diseases. The Eleventh Annual Blood-Brain Barrier Disruption Consortium Meeting was convened to discuss recent advances and future directions in imaging and nanomedicine. Two sessions, one on Cell and Molecular Imaging in the CNS and another on Nanotechnology, Nanobiology, and Nanomedicine, were held March 17-18, 2005, in Portland, Ore. CNS imaging presentations targeted differentiating tumor, neural lesions, and necrosis from healthy brain tissue; methods of delivery of imaging agents across the BBB; and new iron oxide-based nanoparticle contrast agents for MR imaging. Nanobiology presentations covered the development of new nanotechnology and its use in imaging, diagnosis, and therapy in the CNS. Discussions at this meeting stressed the role of biotechnology in the convergence of CNS imaging and nanomedicine and are summarized in this article.

Interferon-beta-1b effects on re-enhancing lesions in patients with multiple sclerosis

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.

Noise reduction in multi-slice arterial spin tagging imaging

Attenuating the static signal in arterial spin tagging (ASSIST) was initially developed for 3D imaging of cerebral blood flow. To enable the simultaneous collection of cerebral blood flow and BOLD data, a multi-slice version of ASSIST is proposed. As with the 3D version, this sequence uses multiple inversion pulses during the tagging period to suppress the static signal. To maintain background suppression in all slices, the multi-slice sequence applies additional inversion pulses between slice acquisitions. The utility of the sequence was demonstrated by simultaneously acquiring ASSIST and BOLD data during a functional task and by collecting resting-state ASSIST data over a large number of slices. In addition, the temporal stability of the perfusion signal was found to be 60% greater at 3 T compared to 1.5 T, which was attributed to the insensitivity of ASSIST to physiologic noise.

Methods for magnetically labeling stem and other cells for detection by in vivo magnetic resonance imaging

Superparamagnetic iron oxide (SPIO) nanoparticles are being used for intracellular magnetic labeling of stem cells and other cells in order to monitor cell trafficking by magnetic resonance imaging (MRI) as part of cellular-based repair, replacement and treatment strategies. This review focuses on the various methods for magnetic labeling of stem cells and other mammalian cells and on how to translate experimental results from bench to bedside.

Interferon- -1b slows progression of atrophy in RRMS: Three-year follow-up in NAb- and NAb+ patients

OBJECTIVE

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.

METHODS

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.

RESULTS

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 (p < 0.001) 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 (p < 0.003).

CONCLUSION

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.

The utility of MRI in suspected MS: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

Advancements in imaging technologies and newly evolving treatments offer the promise of more effective management strategies for MS. Until recently, confirmation of the diagnosis of MS has generally required the demonstration of clinical activity that is disseminated in both time and space. Nevertheless, with the advent of MRI techniques, occult disease activity can be demonstrated in 50 to 80% of patients at the time of the first clinical presentation. Prospective studies have shown that the presence of such lesions predicts future conversion to clinically definite (CD) MS. Indeed, in a young to middle-aged adult with a clinically isolated syndrome (CIS), once alternative diagnoses are excluded at baseline, the finding of three or more white matter lesions on a T2-weighted MRI scan (especially if one of these lesions is located in the periventricular region) is a very sensitive predictor (>80%) of the subsequent development of CDMS within the next 7 to 10 years. Moreover, the presence of two or more gadolinium (Gd)-enhancing lesions at baseline and the appearance of either new T2 lesions or new Gd enhancement on follow-up scans are also highly predictive of the subsequent development of CDMS in the near term. By contrast, normal results on MRI at the time of clinical presentation makes the future development of CDMS considerably less likely.

Combination of transfection agents and magnetic resonance contrast agents for cellular imaging: relationship between relaxivities, electrostatic forces, and chemical composition

The purpose of this study was to investigate the changes in electrostatic and magnetic resonance (MR) properties observed when MR contrast agents (CAs) (Feridex, MION-46L, or G5-dendrimer-DOTA-Gd) are combined with transfection agents (TAs) under various conditions for use as a CA-TA complex basis for cellular labeling and MRI. CAs were incubated with various classes of TAs for 0-48 hr in solutions of varying concentrations and pH values. NMR relaxation rates (1/T(1), 1/T(2)), MRI and zeta potential (ZP) of CA-TA solutions were measured. TAs decreased the 1/T(1) and 1/T(2) of G5-DOTA-Gd, Feridex, and MION-46L by 0-95%. Altering the pH of G5-DOTA-Gd-TA decreased the T(1)-weighted signal intensity (SI) on MRI from 0 to 78%. Measured ZP values for G5-DOTA-Gd, Feridex, and MION-46L were -51, -41, and -2.0 mV, respectively. The TA LV had a negative ZP, while the other TAs had ZPs ranging from +20 to +65 mV. The alteration of the ZP and NMR relaxivities of the MR CAs, Feridex, MION-46L, and G5-DOTA-Gd by TAs has been demonstrated. These results enhance our understanding of the relationship between electrostatic and MR properties.

Measuring the effects of indomethacin on changes in cerebral oxidative metabolism and cerebral blood flow during sensorimotor activation

The work presented here uses combined blood oxygenation level-dependent (BOLD) and arterial spin tagging (AST) approaches to study the effect of indomethacin on cerebral blood flow (CBF) and oxygen consumption (CMRO(2)) increases during motor activation. While indomethacin reduced the CBF increase during activation, it did not significantly affect the CMRO(2) increase during activation. The ratio of the activation-induced CBF increase in the presence and absence of indomethacin was 0.54 +/- 0.08 (+/-SEM, n = 8, P < 0.001), while the ratio of the CMRO(2) increase in the presence and absence of the drug was 1.02 +/- 0.08 (+/-SEM, N = 8, ns). Potential difficulties in estimating CMRO(2) changes from combined BOLD/AST data are discussed.

Longitudinal MRI study: the effects of azathioprine in MS patients refractory to interferon beta-1b

An open-label study was performed to assess the effectiveness of oral azathioprine (AZA) on augmenting the response to interferon beta-1b (IFNbeta-1b) in patients with treatment-refractory relapsing-remitting MS. Six IFNbeta-1b-treated MS patients with continued disease activity were studied on IFNbeta-1b and AZA therapy for a median period of 15 months. A 69% reduction in the number of contrast-enhancing lesions was observed during the combination therapy (p = 0.002).

Expression profiling identifies responder and non-responder phenotypes to interferon-beta in multiple sclerosis

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.

Estimating cerebral atrophy in multiple sclerosis patients from various MR pulse sequences

PURPOSE

The purpose of this study was to determine how measures reflecting cerebral atrophy (CA) are influenced by pulse sequence (PS) and segmentation algorithm (SA) used in multiple sclerosis (MS) patients and healthy control (HC)s.

METHODS

Magnetic resonance imaging (MRI) scans from 10 relapsing-remitting MS (RRMS) patients and five HCs were used to determine the change in brain fractional volume (BFV) over a two-year period. T1-weighted, fluid-attenuated inversion recovery (FLAIR), and proton density (PD)/T2-weighted sequences were analysed Image segmentation to determine brain volume was performed using the following a histogram SA, an adaptive fuzzy c-means algorithm (AFCM), and an adaptive Bayesian segmentation with a K-means clustering.

RESULTS

Combinations of the SA and PS in MS patents demonstrated significant differences in the per cent change in BFV from baseline. For the combination of PS and SA the per cent change in BFV for year one and year two varied from +2.05% to - 1.6% and +0.79% to -3.11%, respectively. Analysis of the HCs data revealed fluctuations in BFV varying from +0.26% to -0.29%.

CONCLUSIONS

MRI estimates of CA are dependent on both the type of PS and SA; therefore, the choice of SA technique and PS should be consistent during an MS treatment trial. The progression of CA in MS should only be used as a secondary or tertiary outcome measure in treatment trials until a better understanding of how this measurement is affected by the disease, the image acquisition and analysis techniques.

Methylprednisolone effect on brain volume and enhancing lesions in MS before and during IFNbeta-1b

OBJECTIVE

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.

BACKGROUND

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.

METHODS

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.

RESULTS

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 (p < 0.039) in NHx patients. Following IVMP, CE lesions decreased (p < 0.0004) for months 1, 2, and 3 in both groups, but there was no effect on WMLL.

CONCLUSIONS

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.

A pilot study of recombinant insulin-like growth factor-1 in seven multiple sderosis patients

The purpose of this open-label, crossover study was to determine the safety and efficacy of recombinant insulin-like growth factor-1 (rhIGF-1) using magnetic resonance imaging (MRI) and clinical measures of disease activity in seven multiple sderosis (MS) patients. Monthly clinical and MPI examinations were performed during a 24-week baseline and a 24-week treatment period with rhIGF-1. The primary outcome measure was contrast enhancing lesion (CEL) frequency on treatment compared to baseline. Secondary outcome measures included dinical and MRI measures of disease activity including: white matter lesion load (WMLL), magnetization transfer ratio (MTR), T1-Hypointensity volume, cervical spine cross-sectional area and proton magnetic resonance spectroscopic (MRS) imaging for determining regional metabolite ratios. rhIGF-1 (Cephalon) was administered at a dose of 50 mg subcutaneously twice a day for 6 months. rhIGF-1 was safe and well tolerated with no severe adverse reactions. There was no significant difference between baseline and treatment periods for any MRI or clinical measures of disease activity. Although rhIGF-1 did not alter the course of disease in this small cohort of MS patients, the drug was well tolerated. Further studies using rhIGF-1 alone or in combination with other therapies may be of value because of the proposed mechanism of action of this growth factor on the oligodendrocyte and remyelination.

Proton MR spectroscopic imaging in multiple sclerosis

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.

Magnetodendrimers allow endosomal magnetic labeling and in vivo tracking of stem cells

Magnetic resonance (MR) tracking of magnetically labeled stem and progenitor cells is an emerging technology, leading to an urgent need for magnetic probes that can make cells highly magnetic during their normal expansion in culture. We have developed magnetodendrimers as a versatile class of magnetic tags that can efficiently label mammalian cells, including human neural stem cells (NSCs) and mesenchymal stem cells (MSCs), through a nonspecific membrane adsorption process with subsequent intracellular (non-nuclear) localization in endosomes. The superparamagnetic iron oxide nanocomposites have been optimized to exhibit superior magnetic properties and to induce sufficient MR cell contrast at incubated doses as low as 1 microg iron/ml culture medium. When containing between 9 and 14 pg iron/cell, labeled cells exhibit an ex vivo nuclear magnetic resonance (NMR) relaxation rate (1/T2) as high as 24-39 s-1/mM iron. Labeled cells are unaffected in their viability and proliferating capacity, and labeled human NSCs differentiate normally into neurons. Furthermore, we show here that NSC-derived (and LacZ-transfected), magnetically labeled oligodendroglial progenitors can be readily detected in vivo at least as long as six weeks after transplantation, with an excellent correlation between the obtained MR contrast and staining for beta-galactosidase expression. The availability of magnetodendrimers opens up the possibility of MR tracking of a wide variety of (stem) cell transplants.

Simultaneous BOLD/perfusion measurement using dual-echo FAIR and UNFAIR: sequence comparison at 1.5T and 3.0T

Functional MRI (fMRI) studies designed for simultaneously measuring Blood Oxygenation Level Dependent (BOLD) and Cerebral Blood Flow (CBF) signal often employ the standard Flow Alternating Inversion Recovery (FAIR) technique. However, some sensitivity is lost in the BOLD data due to inherent T1 relaxation. We sought to minimize the preceding problem by employing a modified UN-inverted FAIR (UNFAIR) technique, which (in theory) should provide identical CBF signal as FAIR with minimal degradation of the BOLD signal. UNFAIR BOLD maps acquired from human subjects (n = 8) showed significantly higher mean z-score of approximately 17% (p < 0.001), and number of activated voxels at 1.5T. On the other hand, the corresponding FAIR perfusion maps were superior to the UNFAIR perfusion maps as reflected in a higher mean z-score of approximately 8% (p = 0.013), and number of activated voxels. The reduction in UNFAIR sensitivity for perfusion is attributed to increased motion sensitivity related to its higher background signal, and, T2 related losses from the use of an extra inversion pulse. Data acquired at 3.0T demonstrating similar trends are also presented.

Ring-enchancement in multiple sclerosis: marker of disease severity

Correlations between conventional MRI measures of disease activity and clinical disability in multiple sclerosis (MS) have been disappointing. Because ring-enhancing lesions may reflect a more destructive pathology, we tested their potential association with disease severity. We evaluated active lesions with regard to their enhancement pattern on serial magnetic resonance images in a cohort of 28 patients with relapsing-remitting MS. The percentage of ring-enhancing lesions correlated with EDSS, T2 lesion load and duration of disease and predicted the occurrence of relapses during the baseline period of observation as well as after 3 years of follow-up in multiple logistic regression analysis. The findings suggest that the pathological process reflected by ring-enhancing lesions may contribute to more severe clinical disease.

Structural analysis reflects the evolutionary relationship between the human desmocollin gene family members

Desmocollins, members of the desmosomal cadherin family, are known to play an important role in desmosomal intercellular adhesion. The human desmosomal cadherin cluster is located on chromosome 18q12, and consists of three desmoglein and three desmocollin genes. The cDNAs of all six of these genes have been cloned and sequenced, however, the exon-intron organization was reported for only one human desmocollin gene, DSC2. We elucidated the exon-intron structures of the DSC1 and DSC3 genes using PCR amplification of genomic DNA and direct sequencing of BAC clones. The results suggest a strong evolutionary conservation between the genomic organization of the desmocollin genes.

Effective antigen-specific immunotherapy in the marmoset model of multiple sclerosis

Mature T cells initially respond to Ag by activation and expansion, but high and repeated doses of Ag cause programmed cell death and can suppress T cell-mediated diseases in rodents. We evaluated repeated systemic Ag administration in a marmoset model of experimental allergic encephalomyelitis that closely resembles the human disease multiple sclerosis. We found that treatment with MP4, a chimeric, recombinant polypeptide containing human myelin basic protein and human proteolipid protein epitopes, prevented clinical symptoms and did not exacerbate disease. CNS lesions were also reduced as assessed in vivo by magnetic resonance imaging. Thus, specific Ag-directed therapy can be effective and nontoxic in primates.

Interferon beta-1b and intravenous methylprednisolone promote lesion recovery in multiple sclerosis

OBJECTIVE

To determine whether lesion evolution in relapsing-remitting multiple sclerosis (RRMS) patients is altered by treatment with interferonbeta1b (IFNbeta-1b) or by intravenous methylprednisolone (IVMP) as measured by magnetization transfer imaging.

METHODS

Magnetization transfer ratios (MTR) of 225 contrast enhancing lesions (CEL), in four RRMS patients were serially determined for 12 months before and 12-18 months after contrast enhancement in a baseline vs treatment trial with IFNbeta-1b. During the baseline period, 185 new CEL were identified: 76 were treated with IVMP (1 g/day x 5 days) and designated steroid CEL (S-CEL); the remaining 109 were considered baseline lesions (BCEL). During IFNbeta-1b treatment, 40 CEL (IFN-CEL) were identified. After image co-registration, regions of interest (ROIs) defining new CEL were transferred to the MTR image set to determine the mean lesion MTR on each monthly exam. The lesion MTR was compared to MTR of normal appearing white matter (NAWM) on the same exam.

RESULTS

As early as 12 months prior to enhancement, the MTR of CEL was reduced compared to NAWM (mean 9.43 +/- 3.2%; P<0.001). The further reduction in MTR (28% +/- 4.0) at the time of contrast enhancement was not significantly different for BCEL, S-CEL or IFN-CEL Following enhancement, lesion recovery for IFN-CEL (P=0.02) and S-CEL (P=0.002) was significantly higher than BCEL CONCLUSION: IFNbeta-1b and IVMP reduce tissue damage and promote lesion recovery in RRMS patients. The additional benefit of IVMP compared to IFNbeta-1b may be related to its inhibitory effect on demyelination.

Enhancing magnetic resonance imaging lesions and cerebral atrophy in patients with relapsing multiple sclerosis

OBJECTIVE

To examine the relation between the frequency of enhancing magnetic resonance imaging lesions and their characteristics of enhancement and atrophy in patients with early relapsing multiple sclerosis.

DESIGN

Analysis of number of enhancing lesions, ventricular volumes and diameters, and lesion characteristics on monthly magnetic resonance imaging scans during natural history follow-up.

SETTING

A clinical research institution.

PATIENTS

Sixteen patients with confirmed early relapsing multiple sclerosis.

MAIN OUTCOME MEASURE

Cerebral atrophy as measured by ventricular enlargement.

RESULTS

Numbers of enhancing lesions correlated well with an increase of ventricular size. This correlation was strongest for patients with a high proportion of concentric ring-enhancing lesions with central contrast pallor.

CONCLUSIONS

Inflammatory events, especially those within lesions with associated blood-brain barrier breakdown, affect the ensuing loss of brain parenchyma. Patients with a high proportion of lesions with central contrast pallor, which is likely associated with more extensive tissue damage, have a higher rate of atrophic changes.

Overview of imaging in multiple sclerosis and white matter disease

MR imaging is the dominant paraclinical test for evaluating multiple sclerosis (MS) because of its exquisite sensitivity to white matter pathology. Knowledge of the signal characteristics of MS lesions, anatomic distribution of lesions, differential diagnosis, and most important, the clinical context, markedly improve the specificity of the MR examination. MR imaging findings can be used to predict future conversion to clinically definite MS before a second clinical exacerbation.

How to participate in a multiple sclerosis clinical trial

MR imaging has made a significant contribution to the understanding of the natural history of multiple sclerosis (MS). MR imaging is an important technique for investigating the pathologic process in the MS patient's brain and spinal cord, and it is now considered an essential part of all clinical trials being performed on new agents in the treatment of MS. This article provides an overview for those wishing to become involved in MS clinical research. Discussion includes the use of conventional and newer MR imaging techniques in clinical trials, current thoughts regarding the role of MR imaging as a surrogate outcome measure, and various types of trial designs.

Beta-adrenergic agonist therapy accelerates the resolution of hydrostatic pulmonary edema in sheep and rats

To determine whether beta-adrenergic agonist therapy increases alveolar liquid clearance during the resolution phase of hydrostatic pulmonary edema, we studied alveolar and lung liquid clearance in two animal models of hydrostatic pulmonary edema. Hydrostatic pulmonary edema was induced in sheep by acutely elevating left atrial pressure to 25 cmH(2)O and instilling 6 ml/kg body wt isotonic 5% albumin (prepared from bovine albumin) in normal saline into the distal air spaces of each lung. After 1 h, sheep were treated with a nebulized beta-agonist (salmeterol) or nebulized saline (controls), and left atrial pressure was then returned to normal. beta-Agonist therapy resulted in a 60% increase in alveolar liquid clearance over 3 h (P < 0.001). Because the rate of alveolar fluid clearance in rats is closer to human rates, we studied beta-agonist therapy in rats, with hydrostatic pulmonary edema induced by volume overload (40% body wt infusion of Ringer lactate). beta-Agonist therapy resulted in a significant decrease in excess lung water (P < 0.01) and significant improvement in arterial blood gases by 2 h (P < 0.03). These preclinical experimental studies support the need for controlled clinical trials to determine whether beta-adrenergic agonist therapy would be of value in accelerating the resolution of hydrostatic pulmonary edema in patients.

Proton MR spectroscopic imaging without water suppression

To improve reproducibility in proton magnetic resonance (MR) spectroscopic imaging in human brain, simultaneous acquisition of the internal water reference and metabolite signals was evaluated. Measurements in healthy volunteers showed that the increase in dynamic range from signal oversampling was sufficient to avoid digitization errors. In addition, use of singular value decomposition techniques and finite impulse response filters proved effective in separating water and metabolite signals and providing estimates of the metabolite concentrations.

Encephalitogenic potential of the myelin basic protein peptide (amino acids 83-99) in multiple sclerosis: results of a phase II clinical trial with an altered peptide ligand

Myelin-specific T lymphocytes are considered essential in the pathogenesis of multiple sclerosis. The myelin basic protein peptide (a.a. 83-99) represents one candidate antigen; therefore, it was chosen to design an altered peptide ligand, CGP77116, for specific immunotherapy of multiple sclerosis. A magnetic resonance imaging-controlled phase II clinical trial with this altered peptide ligand documented that it was poorly tolerated at the dose tested, and the trial had therefore to be halted. Improvement or worsening of clinical or magnetic resonance imaging parameters could not be demonstrated in this small group of individuals because of the short treatment duration. Three patients developed exacerbations of multiple sclerosis, and in two this could be linked to altered peptide ligand treatment by immunological studies demonstrating the encephalitogenic potential of the myelin basic protein peptide (a.a. 83-99) in a subgroup of patients. These data raise important considerations for the use of specific immunotherapies in general.