Luisa M. Villar

Cerebrospinal fluid chitinase 3-like 1 levels are associated with conversion to multiple sclerosis

In most patients with multiple sclerosis, the disease initiates with a first attack or clinically isolated syndrome. At this phase, magnetic resonance imaging is an important predictor of conversion to multiple sclerosis. With the exception of oligoclonal bands, the role of other biomarkers in patients with clinically isolated syndrome is controversial. In the present study, we aimed to identify proteins associated with conversion to multiple sclerosis in patients with clinically isolated syndrome. We applied a mass spectrometry-based proteomic approach (isobaric labelling) to previously collected pooled cerebrospinal fluid samples from patients with clinically isolated syndrome, who subsequently converted to clinically definite multiple sclerosis (n=30) and patients who remained as having clinically isolated syndrome (n=30). Next, three of the most represented differentially expressed proteins, i.e. ceruloplasmin, vitamin D-binding protein and chitinase 3-like 1 were selected for validation in individual cerebrospinal fluid samples by enzyme-linked immunosorbent assay. Only chitinase 3-like 1 was validated and cerebrospinal fluid levels were increased in patients who converted to clinically definite multiple sclerosis compared with patients who continued as clinically isolated syndrome (P=0.00002) and controls (P=0.012). High cerebrospinal fluid levels of chitinase 3-like 1 significantly correlated with the number of gadolinium enhancing lesions and the number of T2 lesions observed in brain magnetic resonance imaging scans performed at baseline, and were associated with disability progression during follow-up and shorter time to clinically definite multiple sclerosis (log-rank P-value=0.003). Cerebrospinal fluid chitinase 3-like 1 levels were also measured in a second validation clinically isolated syndrome cohort and found to be increased in patients who converted to multiple sclerosis compared with patients who remained as having clinically isolated syndrome (P=0.018). Our results indicate that patients who will convert to clinically definite multiple sclerosis could be distinguished from those patients who will remain as clinically isolated syndrome by proteomic analysis of cerebrospinal fluid samples. Although protein levels are also increased in other disorders characterized by chronic inflammation, chitinase 3-like 1 may serve as a prognostic biomarker for conversion to multiple sclerosis and development of disability which may help to improve the understanding of the aetiopathogenesis in the early stages of multiple sclerosis.

Intrathecal IgM synthesis predicts the onset of new relapses and a worse disease course in MS.

BackgroundThe authors have recently described that intrathecal IgM synthesis (ITMS) correlates with a higher disability in patients with clinically definite MS (CDMS). ObjectiveTo follow-up a group of patients with MS in the initial stages of the disease to evaluate if the presence of ITMS correlates with a worse evolution. Methods Oligoclonal IgM bands were performed in 22 patients with MS with a mean of 1.14 months of evolution. Patients were followed for a period ranging from 6 to 36 months (mean, 21.4 months). During follow-up, time to conversion to CDMS, number of relapses, and changes in Expanded Disability Status Scale (EDSS) score were evaluated. ResultsPatients were divided into two groups according to the presence (Group 1, 10 patients) or absence (Group 2, 12 patients) of ITMS. No clinical differences were observed between the groups at inclusion in the study. During the follow-up, the probability of conversion to CDMS was greater in Group 1 (90% of the patients had converted to CDMS after 8 months of follow-up) than in Group 2 (51% of patients had converted to CDMS after 36 months of follow-up) (p = 0.0001). Patients from Group 1 had more relapses (mean, 2.0) than those from Group 2 (mean, 0.58) (p = 0.02). At the end of the study, patients from Group 1 had higher EDSS scores (mean, 1.70) than those from Group 2 (mean, 0.79) (p = 0.02). ConclusionThe presence of oligoclonal IgM bands in CSF can be a prognostic marker in the early phases of MS.

Consensus definitions and application guidelines for control groups in cerebrospinal fluid biomarker studies in multiple sclerosis.

The choice of appropriate control group(s) is critical in cerebrospinal fluid (CSF) biomarker research in multiple sclerosis (MS). There is a lack of definitions and nomenclature of different control groups and a rationalized application of different control groups. We here propose consensus definitions and nomenclature for the following groups: healthy controls (HCs), spinal anesthesia subjects (SASs), inflammatory neurological disease controls (INDCs), peripheral inflammatory neurological disease controls (PINDCs), non-inflammatory neurological controls (NINDCs), symptomatic controls (SCs). Furthermore, we discuss the application of these control groups in specific study designs, such as for diagnostic biomarker studies, prognostic biomarker studies and therapeutic response studies. Application of these uniform definitions will lead to better comparability of biomarker studies and optimal use of available resources. This will lead to improved quality of CSF biomarker research in MS and related disorders.

Intrathecal IgM synthesis in neurologic diseases: Relationship with disability in MS

Abstract—The authors studied the intrathecal IgM synthesis (ITMS) in paired sera and CSF samples from 65 patients with MS, 28 with CNS infection, 40 with other neurologic diseases and eight control subjects. ITMS was found in 30 patients with MS and in 20 with CNS infection, but not in patients with other neurologic diseases or in control subjects. In infectious samples, the ITMS is likely a primary response. In MS group, it was associated with higher Expanded Disability Status Scale index (p = 0.017).

Chitinase 3-like 1: prognostic biomarker in clinically isolated syndromes.

Chitinase 3-like 1 (CHI3L1) has been proposed as a biomarker associated with the conversion to clinically definite multiple sclerosis in patients with clinically isolated syndromes, based on the finding of increased cerebrospinal fluid CHI3L1 levels in clinically isolated syndrome patients who later converted to multiple sclerosis compared to those who remained as clinically isolated syndrome. Here, we aimed to validate CHI3L1 as a prognostic biomarker in a large cohort of patients with clinically isolated syndrome. This is a longitudinal cohort study of clinically isolated syndrome patients with clinical, magnetic resonance imaging, and cerebrospinal fluid data prospectively acquired. A total of 813 cerebrospinal fluid samples from patients with clinically isolated syndrome were recruited from 15 European multiple sclerosis centres. Cerebrospinal fluid CHI3L1 levels were measured by enzyme-linked immunosorbent assay. Multivariable Cox regression models were used to investigate the association between cerebrospinal fluid CHI3L1 levels and time to conversion to multiple sclerosis and time to reach Expanded Disability Status Scale 3.0. CHI3L1 levels were higher in patients who converted to clinically definite multiple sclerosis compared to patients who continued as clinically isolated syndrome (P = 8.1 × 10(-11)). In the Cox regression analysis, CHI3L1 levels were a risk factor for conversion to multiple sclerosis (hazard ratio = 1.7; P = 1.1 × 10(-5) using Poser criteria; hazard ratio = 1.6; P = 3.7 × 10(-6) for McDonald criteria) independent of other covariates such as brain magnetic resonance imaging abnormalities and presence of cerebrospinal fluid oligoclonal bands, and were the only significant independent risk factor associated with the development of disability (hazard ratio = 3.8; P = 2.5 × 10(-8)). High CHI3L1 levels were associated with shorter time to multiple sclerosis (P = 3.2 × 10(-9) using Poser criteria; P = 5.6 × 10(-11) for McDonald criteria) and more rapid development of disability (P = 1.8 × 10(-10)). These findings validate cerebrospinal fluid CHI3L1 as a biomarker associated with the conversion to multiple sclerosis and development of disability and reinforce the prognostic role of CHI3L1 in patients with clinically isolated syndrome. We propose that determining cerebrospinal fluid chitinase 3-like 1 levels at the time of a clinically isolated syndrome event will help identify those patients with worse disease prognosis.

Neurofilament ELISA validation

BACKGROUNDnNeurofilament proteins (Nf) are highly specific biomarkers for neuronal death and axonal degeneration. As these markers become more widely used, an inter-laboratory validation study is required to identify assay criteria for high quality performance.nnnMETHODSnThe UmanDiagnostics NF-light (R)enzyme-linked immunoabsorbent assays (ELISA) for the neurofilament light chain (NfL, 68kDa) was used to test the intra-assay and inter-laboratory coefficient of variation (CV) between 35 laboratories worldwide on 15 cerebrospinal fluid (CSF) samples. Critical factors, such as sample transport and storage, analytical delays, reaction temperature and time, the laboratories accuracy and preparation of standards were documented and used for the statistical analyses.nnnRESULTSnThe intra-laboratory CV averaged 3.3% and the inter-laboratory CV 59%. The results from the test laboratories correlated with those from the reference laboratory (R=0.60, p<0.0001). Correcting for critical factors improved the strength of the correlation. Differences in the accuracy of standard preparation were identified as the most critical factor. Correcting for the error introduced by variation in the protein standards improved the correlation to R=0.98, p<0.0001 with an averaged inter-laboratory CV of 14%. The corrected overall inter-rater agreement was subtantial (0.6) according to Fleiss multi-rater kappa and Gwets AC1 statistics.nnnCONCLUSIONnThis multi-center validation study identified the lack of preparation of accurate and consistent protein standards as the main reason for a poor inter-laboratory CV. This issue is also relevant to other protein biomarkers based on this type of assay and will need to be solved in order to achieve an acceptable level of analytical accuracy. The raw data of this study is available online.

A sensitive and reproducible method for the detection of oligoclonal IgM bands

We have developed a sensitive and specific isoelectrofocusing (IEF) method for the detection of oligoclonal (OGC) IgM in the cerebrospinal fluid (CSF) and sera. In this procedure, ampholytes, in the range pH 5-8, were used to improve the resolution, and serum was diluted in saline to avoid IgM precipitation. Samples were treated with 50 mM dithiothreitol (DTT) at pH 9.5 to reduce IgM and improve the migration of the protein. Using an anti-IgM labelled with alkaline phosphatase, the limit of detection was found to be 0.1 ng in 5 microl of sample.

Lipid-specific immunoglobulin M in CSF predicts adverse long-term outcome in multiple sclerosis.

Background and Objective The presence of lipid-specific immunoglobulin M bands in the cerebrospinal fluid (CSF) predicts an aggressive course in patients with relapsing–remitting multiple sclerosis (MS) during early stages of the disease. This study examined whether it is also a predictor of long-term prognosis in MS. Methods Eighty-one patients with MS and 22 headache controls were analyzed for anti-lipid IgM reactivity in CSF samples. The correlation between the presence of lipid-specific immunoglobulin M bands in CSF and disease progression was assessed in patients with MS who had been followed longitudinally for, on average, more than 11 years. Results Lipid-specific immunoglobulin M bands were detected in the CSF of 24 of 81 patients with MS and were absent in the CSF of all headache controls. Median time to conversion to a secondary progressive course was 11 years in patients with bands and 22 years in patients without bands. Median time to an Expanded Disability Status Scale score of 4 was 14 years in patients with bands and 24 years in patients without bands. Conclusion The presence of lipid-specific immunoglobulin M bands in CSF predicts a more adverse long-term outcome in patients with MS; it may thus define a subset of patients who might benefit from aggressive treatment during the early phase of the disease.

Influence of oligoclonal IgM specificity in multiple sclerosis disease course

Oligoclonal IgM bands (OCMB) against myelin lipids predict an aggressive multiple sclerosis (MS) course. However, the clinical significance of OCMB without lipid specificity, present in other MS patients, remains unknown. We describe here a characterization of these antibodies and study their role in MS progression. Fifty-four MS patients showing CSF-restricted OCMB were included in this study at disease onset and followed-up during 61.1 ± 2.7 months. The specificity of OCMB and the CSF B-cell profile were investigated. A second CSF IgM study was performed in a group of eight patients. Thirty-eight patients showed OCMB against myelin lipids (M+L+) and other sixteen had OCMB lacking this specificity (M+L-). The CD5+ B cell subpopulation, responsible for most persistent IgM responses, was considerably higher in M+L+ than in M+L- patients (3.3 ± 0.6% versus 0.8 ± 0.2, P = 0.009). In addition, M+L+ bands persisted during disease course, while M+L- disappeared during follow-up. M+L+ patients suffered more relapses (4.2 ± 0.6 versus 1.6 ± 0.3, P = 0.002) and reached higher disability (EDSS score of 2.2 ± 0.2 versus 1.2 ± 0.2, P = 0.02) than M+L- group. These data corroborate that anti-lipid OCMB associate with an aggressive MS course and show that OCMB that do not recognize myelin lipids represent a transient immune response related to a more benign disease course. Multiple Sclerosis 2008; 14: 183—187. http://msj.sagepub.com

Lipid‐specific immunoglobulin M bands in cerebrospinal fluid are associated with a reduced risk of developing progressive multifocal leukoencephalopathy during treatment with natalizumab

Progressive multifocal leukoencephalopathy (PML) is a serious side effect associated with natalizumab treatment in multiple sclerosis (MS). PML risk increases in individuals seropositive for anti–John Cunningham virus (JC) antibodies, with prolonged duration of natalizumab treatment, and with prior exposure to immunosuppressants. We explored whether the presence of lipid‐specific immunoglobulin M oligoclonal bands in cerebrospinal fluid (CSF; IgM bands), a recognized marker of highly inflammatory MS, may identify individuals better able to counteract the potential immunosuppressive effect of natalizumab and hence be associated with a reduced risk of developing PML.