Manuel Comabella

A consensus protocol for the standardization of cerebrospinal fluid collection and biobanking

There is a long history of research into body fluid biomarkers in neurodegenerative and neuroinflammatory diseases. However, only a few biomarkers in CSF are being used in clinical practice. One of the most critical factors in CSF biomarker research is the inadequate powering of studies because of the lack of sufficient samples that can be obtained in single-center studies. Therefore, collaboration between investigators is needed to establish large biobanks of well-defined samples. Standardized protocols for biobanking are a prerequisite to ensure that the statistical power gained by increasing the numbers of CSF samples is not compromised by preanalytical factors. Here, a consensus report on recommendations for CSF collection and biobanking is presented, formed by the BioMS-eu network for CSF biomarker research in multiple sclerosis. We focus on CSF collection procedures, preanalytical factors, and high-quality clinical and paraclinical information. The biobanking protocols are applicable for CSF biobanks for research targeting any neurologic disease.

Do oligoclonal bands add information to MRI in first attacks of multiple sclerosis

Background: To evaluate whether oligoclonal bands (OB) add information to MRI in predicting both a second attack and development of disability in patients with clinically isolated syndromes (CIS). Methods: From 1995 to 2006, 572 patients with CIS were included in a prospective study. Patients underwent brain MRI and determination of OB within 3 months of first attack. The number and location of lesions and presence of OB were studied. We analyzed time to second attack and to Expanded Disability Status Scale 3.0 according to number of Barkhof criteria (BC) and the presence or absence of OB. Results: We studied 415 (73%) patients with CIS with both baseline MRI and determination of OB. Patients were followed for a mean of 50 months (SD 31). Compared to the reference group with 0 BC at baseline MRI, patients with one to two BC showed a hazard ratio (HR) for conversion to CDMS of 3.8 (2.0 to 7.2) and patients with three to four BC of 8.9 (4.8 to 16.4). Of the total cohort, OB were positive in 61% of the patients. However, broken down by MRI group, OB were positive in 31% of those with no BC; 69% of those with one to two BC; and 85% of those with three or four BC. The presence of OB increased the risk of a second relapse (HR 1.7; 1.1 to −2.7) independently of baseline MRI but did not modify the development of disability. Conclusions: Presence of oligoclonal bands doubles the risk for having a second attack, independently of MRI, but does not seem to influence the development of disability. GLOSSARY: BC = Barkhof criteria; CDMS = clinically definite multiple sclerosis; CIS = clinically isolated syndromes; EDSS = Expanded Disability Status Scale; HR = hazard ratio; MS = multiple sclerosis; OB = oligoclonal bands.

Defining the response to interferon-β in relapsing-remitting multiple sclerosis patients

Many patients with multiple sclerosis (MS) are currently receiving treatment with interferon (IFN)–β. Early identification of nonresponder patients is crucial to try different therapeutic approaches. We investigated various criteria of treatment response to assess which criterion better identifies patients with a poor response.

Baseline MRI predicts future attacks and disability in clinically isolated syndromes

Objective: To determine the relation between baseline MRI and both conversion to multiple sclerosis (MS) and development of disability in a cohort of patients with clinically isolated syndromes (CIS). Methods: From 1995 to 1998, 175 consecutive patients with CIS underwent brain MRI within 3 months of their first attack and again 12 months and 5 years later. We studied the number and location of lesions at baseline and development of new T2 lesions. We also analyzed conversion to MS and development of disability (Expanded Disability Status Scale [EDSS] ≥ 3.0). Results: We included 156 patients with CIS followed for a median of 7 years. Compared to the reference group with 0 Barkhof criteria at baseline MRI, patients with one or two Barkhof criteria showed an adjusted hazard ratio (HR) of 6.1 (2.2 to 16.6) and patients with three to four Barkhof criteria of 17.0 (6.7 to 43) for conversion to MS and differentiated patients with low, medium, and high conversion risk. EDSS at year 5 correlated with baseline number of Barkhof criteria (r = 0.46, p < 0.0001). When categorizing by number of baseline lesions, similar results were seen. Patients with a baseline MRI with three to four Barkhof criteria had an adjusted HR of 3.9 (1.1 to 13.6) for reaching EDSS ≥ 3.0. Only 10% of the latter had disability at year 5, but 40% reached this at 8 years. Conclusions: Baseline MRI determines the risk for converting to clinically definite multiple sclerosis and correlates with disability at 5 years. The proportion of patients developing disability is low during the first 5 years but rapidly increases shortly after.

New diagnostic criteria for multiple sclerosis Application in first demyelinating episode

Background: Recently developed diagnostic criteria for MS (McDonald criteria) indicate that in patients with a single demyelinating episode (clinically isolated syndromes [CIS]), evidence for dissemination in space and time, essential for diagnosis, may be provided by MRI. Objective: To assess the usefulness of these new criteria in patients with CIS suggestive of MS. Methods: A total of 139 patients with CIS followed for a median of 3 years underwent brain MRI within 3 months of their first attack and again 12 months later. The number and location of lesions at baseline, the development of new lesions at follow-up, and the results of CSF examination (which, if positive, requires fewer MR abnormalities for diagnosis) were analyzed. The new McDonald criteria (incorporating MRI) were compared to the existing Poser diagnostic criteria and their accuracy was evaluated. Results: At 12 months, 11% had clinically definite MS according to the Poser criteria compared to 37% with the McDonald criteria. Eighty percent of patients fulfilling these new criteria developed a second clinical episode within a mean follow-up of 49 months. The new criteria showed a sensitivity of 74%, specificity of 86%, and accuracy of 80% in predicting conversion to clinically definite MS. Conclusion: One year after symptom onset, more than three times as many patients with CIS were diagnosed with MS using new diagnostic criteria incorporating MRI results compared to older criteria. However, the proposed MRI criteria require further prospective studies to optimize sensitivity and specificity.

Elevated interleukin-12 in progressive multiple sclerosis correlates with disease activity and is normalized by pulse cyclophosphamide therapy.

Multiple sclerosis is postulated to be a Th1-type cell-mediated autoimmune disease. We investigated cytokine profiles in patients with progressive multiple sclerosis by using intracytoplasmic staining. We found increased IL-12 production by monocytes and increased IFN-gamma production by T cells in untreated patients as compared with controls. In patients treated with methotrexate, methylprednisolone, or cyclophosphamide/methylprednisolone (CY/MP), only CY/MP treatment normalized the elevated IL-12 production. Furthermore, CY/MP-treated patients had decreased IFN-gamma and increased IL-4, IL-5, and TGF-beta expression. Patients followed prospectively before and after starting CY/MP treatment showed a gradual decrease in IL-12 and IFN-gamma production and an increase in IL-4 and IL-5. In vitro, addition of 4-hydroperoxycyclophosphamide, a metabolite of cyclophosphamide decreased IL-12 production in mononuclear cell cultures. When patients were classified as having active or stable disease, IL-12 production correlated with disease activity. In summary, our results demonstrate a Th1-type cytokine bias in peripheral blood mononuclear cells of untreated progressive MS patients that is reversed by CY/MP treatment and is associated with Th2 and TGF-beta (Th3) type responses. These findings provide a basis for immune monitoring of patients with MS and suggest that treatments that downregulate IL-12 may prove to be beneficial in progressive MS.

A type I interferon signature in monocytes is associated with poor response to interferon-β in multiple sclerosis

The effect of interferon-beta in multiple sclerosis is modest and many patients do not respond to treatment. To date, no single biomarker reliably correlates with responsiveness to interferon-beta in multiple sclerosis. In the present study, genome-wide expression profiling was performed in peripheral blood mononuclear cells from 47 multiple sclerosis patients treated with interferon-beta for a minimum of 2 years and classified as responders and non-responders based on clinical criteria. A validation cohort of 30 multiple sclerosis patients was included in the study to replicate gene-expression findings. Before treatment, interferon-beta responders and non-responders were characterized by differential expression of type I interferon-induced genes with overexpression of the type interferon-induced genes in non-responders. Upon treatment the expression of these genes remained unaltered in non-responders, but was strongly upregulated in responders. Functional experiments showed a selective increase in phosphorylated STAT1 levels and interferon receptor 1 expression in monocytes of non-responders at baseline. When dissecting this type I interferon signature further, interferon-beta non-responders were characterized by increased monocyte type I interferon secretion upon innate immune stimuli via toll-like receptor 4, by increased endogenous production of type I interferon, and by an elevated activation status of myeloid dendritic cells. These findings indicate that perturbations of the type I interferon signalling pathway in monocytes are related to lack of response to interferon-beta, and type I interferon-regulated genes may be used as response markers in interferon-beta treatment.

Transcription-Based Prediction of Response to IFNβ Using Supervised Computational Methods

Changes in cellular functions in response to drug therapy are mediated by specific transcriptional profiles resulting from the induction or repression in the activity of a number of genes, thereby modifying the preexisting gene activity pattern of the drug-targeted cell(s). Recombinant human interferon beta (rIFNβ) is routinely used to control exacerbations in multiple sclerosis patients with only partial success, mainly because of adverse effects and a relatively large proportion of nonresponders. We applied advanced data-mining and predictive modeling tools to a longitudinal 70-gene expression dataset generated by kinetic reverse-transcription PCR from 52 multiple sclerosis patients treated with rIFNβ to discover higher-order predictive patterns associated with treatment outcome and to define the molecular footprint that rIFNβ engraves on peripheral blood mononuclear cells. We identified nine sets of gene triplets whose expression, when tested before the initiation of therapy, can predict the response to interferon beta with up to 86% accuracy. In addition, time-series analysis revealed potential key players involved in a good or poor response to interferon beta. Statistical testing of a random outcome class and tolerance to noise was carried out to establish the robustness of the predictive models. Large-scale kinetic reverse-transcription PCR, coupled with advanced data-mining efforts, can effectively reveal preexisting and drug-induced gene expression signatures associated with therapeutic effects.

Genome-Wide Pharmacogenomic Analysis of the Response to Interferon Beta Therapy in Multiple Sclerosis

OBJECTIVE To identify promising candidate genes linked to interindividual differences in the efficacy of interferon beta therapy. Recombinant interferon beta therapy is widely used to reduce disease activity in multiple sclerosis (MS). However, up to 50% of patients continue to have relapses and worsening disability despite therapy. DESIGN We used a genome-wide pharmacogenomic approach to identify single-nucleotide polymorphism (SNP) allelic differences associated with interferon beta therapy response. SETTING Four collaborating centers in the Mediterranean Basin. Data Coordination Center at the University of California, San Francisco. PATIENTS A cohort of 206 patients with relapsing-remitting MS followed up prospectively for 2 years after initiation of treatment. INTERVENTION DNA was pooled and hybridized to Affymetrix 100K GeneChips. Pooling schemes were designed to minimize confounding batch effects and increase confidence by technical replication. MAIN OUTCOME MEASURES Single-nucleotide polymorphism detection. Comparison of allelic frequencies between good responders and nonresponders to interferon beta therapy. RESULTS A multianalytical approach detected significant associations between several SNPs and treatment response, which were validated by individual DNA genotyping on an independent platform. After the validation stage was complete, 81 additional individuals were added to the analysis to increase power. We found that responders and nonresponders had significantly different genotype frequencies for SNPs located in many genes, including glypican 5, collagen type XXV alpha1, hyaluronan proteoglycan link protein, calpastatin, and neuronal PAS domain protein 3. CONCLUSIONS The reported results address the question of genetic heterogeneity in MS and the response to immunotherapy by analysis of the correlation between different genotypes and clinical response to interferon beta therapy. Many of the detected differences between responders and nonresponders were genes associated with ion channels and signal transduction pathways. The study also suggests that genetic variants in heparan sulfate proteoglycan genes may be of clinical interest in MS as predictors of the response to therapy. In addition to new insights into the mechanistic biology of interferon beta, these results help define the molecular basis of interferon beta therapy response heterogeneity.

Measures in the first year of therapy predict the response to interferon β in MS

Background and objective Several criteria for treatment response to interferon beta (IFNβ) have been proposed, although there is no consensus among different investigators. Hence, the aim of this study was to investigate magnetic resonance imaging (MRI) and clinical predictors of response during the first 12 months of therapy. Methods This is a prospective and longitudinal study of relapsing-remitting multiple sclerosis (RRMS) patients treated with IFNβ. Patients were classified based on the presence of new lesions on MRI, relapses, confirmed disability increase, or combinations of all these variables after 1 year of therapy. Regression analysis was performed in order to identify variables of response after a follow-up of 3 years. Results We included 222 RRMS patients. The logistic model demonstrated that only the combination of new active lesions on MRI with the presence of relapses (OR 4.4; 95% CI 1.6–12.5) or disability progression (Odds Ratio (OR) 7.1; 95% Confidence Interval (CI) 1.6–33.9), or both (OR 6.5; 95% CI 1.9–23.4) achieved significant values to identify those patients with a poor outcome. Conclusions In RRMS patients treated with IFNβ, the combination of measures of disease activity and the presence of new active lesions on MRI may have a prognostic value for identifying patients with disease activity in the second and third year of therapy.