A Sanna

Serum uric acid and multiple sclerosis.

Abstract. Several studies indicate that patients with multiple sclerosis (MS) have low serum levels of the endogenous antioxidant uric acid (UA), although it has not been established whether UA is primarily deficient or secondarily reduced due to its peroxynitrite scavenging activity. We measured serum urate levels in 124 MS patients and 124 age- and sex-matched controls with other neurological diseases. In addition, we compared UA levels when MS patients were stratified according to disease activity (by means of clinical examination and MRI), duration, disability and course. MS patients had significantly lower serum urate levels than controls (p= 0.001). However, UA levels did not significantly correlate with disease activity, duration, disability or course. Our study favors the view that reduced UA in MS is a primary, constitutive loss of protection against oxidative agents, which deserves further pathogenetic elucidation aimed at future therapeutic strategies.

Seasonal fluctuation of multiple sclerosis births in Sardinia

AbstractStudy results from different geographical areas provide some circumstantial evidence that, when compared with the general population, people who later in life develop multiple sclerosis (MS) have a pattern of birth excess numbers in spring and late summer, which may disclose an association with MS–predisposing environmental agents. To identify the presence of season–related cluster of MS birth in Sardinia we have designed a case–control study in the province of Sassari, Northern Sardinia, insular Italy, an area at veryhigh and increasing risk for MS. Mean birth incidence rate of people with MS (810 cases) on a threeand six–months basis were compared with that of two control populations: the MS unaffected siblings (1069), sharing genetic material with patients, and a representative number of births (247,612) of the general population of the study area. We found that the birth in months peaking in spring significantly represents one risk factor for future MS development. This seasonal deviation of MS births reveals an intriguing epidemiological overlap with common environmental agents, which may open a new scenario of hypothetical explanations for environmental factors perhaps affecting the CNS at the crucial time of myelination or shaping the newborn immune system.

Glatiramer acetate reduces lymphocyte proliferation and enhances IL-5 and IL-13 production through modulation of monocyte-derived dendritic cells in multiple sclerosis

Dendritic cells (DC), as the most effective antigen presenting cells, are protagonists of the complex immune network involved in multiple sclerosis (MS) lesion formation. Glatiramer acetate (GA), a synthetic random copolymer, is thought to exert its therapeutical effect in MS by favouring both Th2 cell development and IL‐10 production from peripheral lymphocytes as well as by systemically affecting the antigen presenting cells. In the present study we further analysed the mechanisms of action of GA by using an autologous DC‐lymphocytes (Ly) coculture system from 11 MS patients and 12 matched healthy controls (HC). We found that, in MS patients, pretreatment with GA significantly decreases the in vitro proliferative effect of DC on lymphocytes as compared to HC and to unpulsed or myelin basic protein (MBP)‐pulsed DC from MS patients (P < 0·05). In addition, GA‐treated DC from both MS patients and HC significantly increase the lymphocyte production of IL‐5 and IL‐13 as compared to MBP‐treated DC (P < 0·05). In conclusion our in vitro study may provide new therapeutical mechanisms of GA on lymphocytes, antiproliferative and Th2‐favouring effects, which are mediated by monocyte‐derived DC.

Multiple sclerosis complexity in selected populations: the challenge of Sardinia, insular Italy

Several lines of evidence indicate a genetic contribution to multiple sclerosis (MS) both in terms of predisposition to the disease and of immunological mechanisms which are known to play crucial roles in MS pathogenesis. The presence of high‐ and low‐risk areas for MS in neighbouring regions supports the theory that MS predisposition is influenced by a complex interaction of genetic and environmental factors. Therefore, the use of genetically homogeneous and geographically isolated populations becomes an increasing requirement to reduce biasing biological variables. Sardinians fulfil these conditions well because of their different phylogeny from Europeans and the unique selective pressures which shaped their genome. Sardinians display amongst the highest MS prevalence rates world‐wide and increasing MS incidence rates over time. Also, MS in Sardinia is linked to distinct human leucocyte antigen (HLA) alleles and associated to different patterns of cytokine production from lymphoid cells of different HLA subtypes. In this context, recent findings and future perspectives on the peculiarities of Sardinian MS concerning genetic, immunological and epidemiological aspects are presented. So far, our results indicate that variations at the level of territorial distribution and HLA‐association are present which render MS heterogeneous even in this ethnically homogeneous population.

Intrathecal chitotriosidase and the outcome of multiple sclerosis

Activated macrophages are major effectors at all stages of lesion formation in multiple sclerosis (MS) brain. Here, we report that the macrophage enzyme chitotriosidase (Chit) is significantly elevated both in plasma and cerebrospinal fluid (CSF) of patients with MS as compared to healthy controls and other neurological patients (P< 0.001). Furthermore, the Chit activity in blood significantly associates with the MS clinical course (higher in secondary progressive relative to relapsing remitting, P = 0.01) and the clinical severity as measured by Kurtkze’s Expanded Disability Status Scale (P<0.001). Also, we found that Chit activity is compartmentalized in the central nervous system of early MS patients and that its CSF/plasma quotient, in the presence of a preserved albumin quotient, correlates with the extent of future clinical deterioration (r = 0.91; P<0.001). These findings confirm that innate immunity, here represented by Chit, is clinically relevant in MS and allows, if confirmed, reconsidering novel MS therapeutic strategies specifically aimed at this branch of the immune response.

Multiple sclerosis: expression of C D1a and production of IL-12 p70 and IFN-γ by blood mononuclear cells in patients on combination therapy with IFN-β and glatiramer acetate compared to monotherapy with IFN-β

Yassir Hussien, Alessandra Sanna, Mats Söderström, Hans Link and Yu-Min Huang* Neurotec Department, Division of Neuroimmunology, Karolinska Institute, Alfred Nobels Allé 10, Stockholm, Sweden; Institute of Clinical Neurology, University of Sassari, Sassari, Italy; Division of Ophthalmology, Karolinska Institute, Alfred Nobels Allé 10, SE-141 83 Stockholm, Sweden; Department of Ophthalmology, Huddinge University Hospital, Stockholm, Sweden; Department of Neurology, Huddinge University Hospital, Stockholm, Sweden

Multiple sclerosis: reduced proportion of circulating plasmacytoid dendritic cells expressing BDCA-2 and BDCA-4 and reduced production of IL-6 and IL-10 in response to herpes simplex virus type 1

Objective We hypothesized that autoaggressive immune responses observed in multiple sclerosis (MS) could be associated with an imbalance in proportion of immune cell subsets and in cytokine production in response to infection, including viruses. Methods We collected blood mononuclear cells (MNC) from 23 patients with MS and 23 sex- and age-matched healthy controls (HC) from the island of Sardinia, Italy, where the prevalence of MS is extraordinarily high. Using flow cytometry, we studied MNC for expression of blood dendritic cell antigens (BDCA)-2 and BDCA-4 surface markers reflecting the proportion of plasmacytoid dendritic cells (pDC) that produce type I interferons (IFNs) after virus challenge and promote Th2/anti-inflammtory cytokine production. In parallel, pro-inflammatory (interleukin [IL]-2, IL-12, IFN-γ), anti-inflammatory (IL-4, IL-10), and immuno-regulatory/pleiotropic cytokines (type I IFNs including IFN-α and β, IL-6) were measured before and after an in vitro exposure to herpes simplex virus type 1 (HSV-1). Results The subset of lineage negative (lin−), BDCA-2+ cells was lower in patients with MS compared with HC (0.08 ± 0.02% vs 0.24 ± 0.02%; P < 0.001). A similar pattern was observed for lin−BDCA-4+ cells (0.08 ± 0.02% vs 0.17% ± 0.03; P < 0.01). Spontaneous productions of IL-6 (45 ± 10 pg/mL vs 140 ± 26 pg/mL; P < 0.01) and IL-10 (17 ± 0.4 pg/mL vs 21 ± 1 pg/mL; P < 0.05) by MNC were lower in patients with MS compared with HC. Spontaneous production of IL-6 (6.5 ± 0.15 pg/mL vs 21 ± 5 pg/mL; P < 0.01 and IL-10 (11 ± 1 pg/mL vs 14 ± 3 pg/mL; P < 0.05) by pDC was also lower in patients with MS compared with HC. Exposure of MNC to HSV-1 showed, in both patients with MS and HC, increased production of IFN-α, IL-6, and IL-10 but decreased production of IL-4. In response to HSV-1 exposure, productions of IL-6 (165 ± 28 pg/mL vs 325 ± 35 pg/mL; P < 0.01) and IL-10 (27 ± 3 vs 33 ± 3 P < 0.05) by MNC as well as by pDC (IL-6: 28 ± 7 vs 39 ± 12 P < 0.05; IL-10: 14 ± 1 vs 16 ± 3 P < 0.05) were lower in patients with MS compared with HC. Conclusion The results implicate a new evidence for altered immune cells and reduced immune responses in response to viral challenge in MS.

Anti-inflammatory nuclear receptor superfamily in multiple sclerosis patients from Sardinia and Sweden.

Several nuclear hormone receptors have been associated with inflammatory reactions. Particularly, liver X receptors (LXRs) have recently been identified as key transcriptional regulators of genes involved in lipid homeostasis and inflammation. LXRs are negative regulators of macrophage inflammatory gene expression. Multiple sclerosis (MS), a demyelinating disease of the central nervous system of unknown cause, is characterized by recurrent inflammation involving macrophages and their inflammatory mediators. Sweden belongs to the countries with a high MS incidence. In Italy, the MS incidence is lower, except on the island of Sardinia where the incidence is even higher than in Sweden. Subjects from Sardinia are ethnically more homogeneous, and differ from Swedes also regarding genetic background and environment. We studied mRNA expression of several nuclear hormone receptors in blood mononuclear cells (MNC) from female patients with untreated relapsing-remitting MS from Sassari, Sardinia, and Stockholm, Sweden. Sex- and age-matched healthy controls (HC) were from both areas. mRNA expression was evaluated by quantitative real-time PCR. We found altered mRNA expression of LXRs, estrogen receptors (ERs), and androgen receptor (AR) in MS. mRNA expression of both LXRalpha and LXRbeta is lower in MS from Stockholm but not from Sassari. In particular, LXRalpha mRNA expression was significantly lower in MS from Stockholm as compared with all groups in the study including MS from Sassari. Low levels of ERalpha mRNA are seen in MS from both Stockholm and Sassari. The splice variant ERbetacx showed significantly higher mRNA expression in MS from Sassari and Stockholm as compared with corresponding HC. In particular, ERbetacx mRNA in MS from Sassari was remarkably higher as compared with all other groups in the study. Higher levels of AR mRNA are present in HC from Sassari. The findings indicate that the expression levels of anti-inflammatory nuclear receptor superfamily genes in MS appear to reflect both ethnic and environmental influences.

Alpha B-crystallin is not a dominant peripheral T-cell autoantigen in multiple sclerosis amongst Sardinians

The heat shock protein alpha B‐crystallin appears to be the dominantly recognized autoantigen in the early demyelinative process of multiple sclerosis (MS) in brain of patients. In Sardinia, MS is linked to human leucocyte antigen (HLA)‐DR alleles that might influence the production of cytokines from peripheral lymphocytes. We tested the nature of peripheral anti‐alpha B‐crystallin‐specific T‐cell response in the context of predisposing HLA haplotypes both in MS patients and healthy controls. The alpha B‐crystallin specific T‐cell lines were generated by using the ‘split‐well’ technique. The results indicate that the presence of short‐term T‐cell lines towards alpha B‐crystallin is numerically comparable between the two groups and not restricted to MS‐predisposing HLA‐DR alleles. As for the T‐cell characterization, CD4+ anti‐alpha B‐crystallin T cells secreting high levels of interferon‐γ are similarly identified in MS and healthy donors. In conclusion, the peripheral response towards the myelin antigen alpha B‐crystallin is neither quantitatively nor qualitatively peculiar to MS, in contrast to the theoretical paradigm suggesting peripheral activation of myelin‐reactive T cells to be the prerequisite for MS induction.

Immunogenetic heterogeneity of multiple sclerosis in Sardinia.

Abstract. Multiple sclerosis (MS) predisposition is thought to be influenced by a complex, yet unclear interaction of genetic and environmental factors. Studying ethnically selected populations may reduce genetic and environmental heterogeneities and help clarify the underlying mechanisms of MS susceptibility. Sardinians kept a homogeneous genetic structure and have among the highest MS frequency rates worldwide. Interestingly, MS in Sardinia is linked to otherwise rare HLA alleles. In this light, recent findings from epidemiological and immunogenetic studies of Sardinian MS are presented. Results confirm that, likely due to significant genetic differences at a microgeographic level, even in this homogeneous population MS is immunogenetically heterogeneous and tends to preferentially cluster in some more archaic areas of the island.