Miriam Mattoscio

Hematopoietic mobilization Potential biomarker of response to natalizumab in multiple sclerosis

Objective: To ascertain the mobilization from the bone marrow and the functional relevance of the increased number of circulating hematopoietic stem and progenitor cells (HSPC) induced by the anti-α-4 integrin antibody natalizumab in patients with multiple sclerosis (MS). Methods: We evaluated CD45lowCD34+ HSPC frequency by flow cytometry in blood from 45 natalizumab-treated patients (12 of whom were prospectively followed during the first year of treatment as part of a pilot cohort and 16 prospectively followed for validation), 10 untreated patients with MS, and 24 healthy donors. In the natalizumab-treated group, we also assessed sorted HSPC cell cycle status, T- and B-lymphocyte subpopulation frequencies (n = 29), and HSPC differentiation potential (n = 10). Results: Natalizumab-induced circulating HSPC were predominantly quiescent, suggesting recent mobilization from the bone marrow, and were capable of differentiating ex vivo. Circulating HSPC numbers were significantly increased during natalizumab, but heterogeneously, allowing the stratification of mobilizer and nonmobilizer subgroups. Nonmobilizer status was associated with persistence of disease activity during treatment. The frequency of B cells and CD103+CD8+ regulatory T cells persistently increased, more significantly in mobilizer patients, who also showed a specific naive/memory B-cell profile. Conclusions: The data suggest that natalizumab-induced circulating HSPC increase is the result of true mobilization from the bone marrow and has clinical and immunologic relevance. HSPC mobilization, associated with clinical remission and increased proportion of circulating B and regulatory T cells, may contribute to the treatments mode of action; thus, HSPC blood counts could represent an early biomarker of responsiveness to natalizumab.

A Comparison of Magnetization Transfer Methods to Assess Brain and Cervical Cord Microstructure in Multiple Sclerosis.

Demyelination is a core pathological feature of multiple sclerosis (MS) and spontaneous remyelination appears to be an important mechanism for repair in the disease. Magnetization transfer ratio imaging (MTR) has been used extensively to evaluate demyelination, although limitations to its specificity are recognized. MT saturation imaging (MTsat) removes some of the T1 dependence of MTR. We have performed a comparative evaluation of MTR and MTsat imaging in a mixed group of subjects with active MS, to explore their relative sensitivity to pathology relevant to explaining clinical outcomes.

Age independently affects myelin integrity as detected by magnetization transfer magnetic resonance imaging in multiple sclerosis.

Background Multiple sclerosis (MS) is a heterogeneous disorder with a progressive course that is difficult to predict on a case-by-case basis. Natural history studies of MS have demonstrated that age influences clinical progression independent of disease duration. Objective To determine whether age would be associated with greater CNS injury as detected by magnetization transfer MRI. Materials and methods Forty MS patients were recruited from out-patient clinics into two groups stratified by age but with similar clinical disease duration as well as thirteen controls age-matched to the older MS group. Images were segmented by automated programs and blinded readers into normal appearing white matter (NAWM), normal appearing gray matter (NAGM), and white matter lesions (WMLs) and gray matter lesions (GMLs) in the MS groups. WML and GML were delineated on T2-weighted 3D fluid-attenuated inversion recovery (FLAIR) and T1 weighted MRI volumes. Mean magnetization transfer ratio (MTR), region volume, as well as MTR histogram skew and kurtosis were calculated for each region. Results All MTR measures in NAGM and MTR histogram metrics in NAWM differed between MS subjects and controls, as expected and previously reported by several studies, but not between MS groups. However, MTR measures in the WML did significantly differ between the MS groups, in spite of no significant differences in lesion counts and volumes. Conclusions Despite matching for clinical disease duration and recording no significant WML volume difference, we demonstrated strong MTR differences in WMLs between younger and older MS patients. These data suggest that aging-related processes modify the tissue response to inflammatory injury and its clinical outcome correlates in MS.

Analysis of ageing-associated grey matter volume in patients with multiple sclerosis shows excess atrophy in subcortical regions

Age of onset in multiple sclerosis (MS) exerts an influence on the course of disease. This study examined whether global and regional brain volumes differed between “younger” and “older” onset MS subjects who were matched for short disease duration, mean 1.9 years and burden as measured by the MS Severity Score and relapses. 21 younger-onset MS subjects (age 30.4 ± 3.2 years) were compared with 17 older-onset (age 48.7 ± 3.3 years) as well as age-matched controls (n = 31, 31.9 ± 3.5 years and n = 21, 47.3 ± 4.0 years). All subjects underwent 3D volumetric T1 and T2-FLAIR imaging. White matter (WM) and grey matter (GM) lesions were outlined manually. Lesions were filled prior to tissue and structural segmentation to reduce classification errors. Volume loss versus control was predominantly in the subcortical GM, at > 13% loss. Younger and older-onset MS subjects had similar, strong excess loss in the putamen, thalamus, and nucleus accumbens. No excess loss was detected in the amygdala or pallidum. The hippocampus and caudate showed significant excess loss in the younger group (p < 0.001) and a strong trend in the older-onset group. These results provide a potential imaging correlate of published neuropsychological studies that reported the association of younger age at disease onset with impaired cognitive performance, including decreased working memory.

Multiple sclerosis therapy and Epstein–Barr virus antibody titres

BACKGROUND Anti-Epstein-Barr virus (EBV) nuclear antigen-1 (anti-EBNA-1) IgG antibody titres have been found to correlate with MRI and clinical measures of disease activity in MS. Despite being a putative biomarker of disease activity, the effect of disease modifying drugs on anti-EBNA-1 IgG titre has not yet been determined. METHODS In this study, we investigated the effect of interferon-beta and natalizumab therapy on prospective sera anti-EBNA-1 IgG titres, using a quantitative ELISA, in patients with relapsing-remitting MS. RESULTS For both the interferon-beta and natalizumab group, there was no significant difference between pre-therapy and post-therapy anti-EBNA-1 IgG titre. There was also no significant difference between the groups with regard to mean percentage change in anti-EBNA-1 IgG titre over 12 months of treatment. CONCLUSIONS This study suggests that anti-EBNA-1 IgG titre is unlikely to be a good surrogate marker for disease activity in patients on disease modifying drugs.

The cortical damage, early relapses, and onset of the progressive phase in multiple sclerosis

Objective To investigate the relationship among cortical radiologic changes, the number of early relapses (ERs), and the long-term course of multiple sclerosis (MS). Methods In this cohort study, we assessed the number of cortical lesions (CLs) and white matter (WM) lesions and the cortical thickness (Cth) at clinical onset and after 7.9 mean years among 219 patients with relapsing remitting (RR) MS with 1 (Low-ER), 2 (Mid-ER), and ≥3 (High-ER) ERs during the first 2 years. Kaplan-Meier and Cox regression analyses investigated early factors influencing the risk of secondary progressive (SP) MS. Results Fifty-nine patients (27%) converted to SPMS in 6.1 mean years. A larger number of CLs at onset predicted a higher risk of SPMS (hazard ratio [HR] 2.16, 4.79, and 12.3 for 2, 5, and 7 CLs, respectively, p < 0.001) and shorter latency to progression. The High-ER compared to the Low-ER and Mid-ER groups had a larger volume of WM lesions and CLs at onset, accrued more CLs, experienced more severe cortical atrophy over time, and entered the SP phase more rapidly. In the multivariate model, older age at onset (HR 1.97, p < 0.001), a larger baseline CL (HR 2.21, p = 0.005) and WM lesion (HR 1.32, p = 0.03) volume, early changes of global Cth (HR 1.36, p = 0.03), and ≥3 ERs (HR 6.08, p < 0.001) independently predicted a higher probability of SP. Conclusions Extensive cortical damage at onset is associated with florid inflammatory clinical activity and predisposes to a rapid occurrence of the progressive phase. Age at onset, the number of early attacks, and the extent of baseline focal cortical damage can identify groups at high risk of progression who may benefit from more active therapy.

Haematopoietic Stem Cells for the Treatment of MS

The last decade of research has achieved incredible advances in our understanding of stem cell biology. Amongst the best characterised types of stem cells are haematopoietic stem cells (HSC). Starting from the morphological description of bone marrow (BM)-resident cells in the early 1900s, studies on the physiological function of haematopoietic precursor cells have caught momentum in the 1960s and 1970s and have expanded exponentially following the increased availability of reagents and molecular methodologies in the 1980s and 1990s. In parallel, the clinical application of BM—and peripherally mobilised HSC—transplantation for haematological indications has been studied intensively in trials and applied in clinical practice. Since the mid-1990s, treatment of autoimmune disorders, including multiple sclerosis (MS), with autologous haematopoietic transplantation has been explored in clinical trials. More recently, an integrin-blocking antibody approved for treatment of MS has been shown to exert an effect on HSC recirculation as well as the expected effects on leucocyte trafficking.