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-gamma), anti-inflammatory (IL-4, IL-10), and immuno-regulatory/pleiotropic cytokines (type I IFNs including IFN-alpha and beta, 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 + or - 0.02% vs 0.24 + or - 0.02%; P < 0.001). A similar pattern was observed for lin(-)BDCA-4(+) cells (0.08 + or - 0.02% vs 0.17% + or - 0.03; P < 0.01). Spontaneous productions of IL-6 (45 + or - 10 pg/mL vs 140 + or - 26 pg/mL; P < 0.01) and IL-10 (17 + or - 0.4 pg/mL vs 21 + or - 1 pg/mL; P < 0.05) by MNC were lower in patients with MS compared with HC. Spontaneous production of IL-6 (6.5 + or - 0.15 pg/mL vs 21 + or - 5 pg/mL; P < 0.01 and IL-10 (11 + or - 1 pg/mL vs 14 + or - 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-alpha, IL-6, and IL-10 but decreased production of IL-4. In response to HSV-1 exposure, productions of IL-6 (165 +or - 28 pg/mL vs 325 + or - 35 pg/mL; P < 0.01) and IL-10 (27 +or - 3 vs 33 + or - 3 P < 0.05) by MNC as well as by pDC (IL-6: 28 + or - 7 vs 39 + or - 12 P < 0.05; IL-10: 14 + or - 1 vs 16 + or - 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.

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.

Inflammatory biomarkers in blood of patients with acute brain ischemia.

Although many failed surrogate markers are provided in the literature, inflammation may contribute to the outcome of ischemic stroke. In 50 consecutive patients with acute ischemic stroke, in the absence of symptoms and signs of concomitant infection, we evaluated a panel of biomarkers reported to be variably associated with brain ischemia, and correlate their serum level with the brain lesion volume and clinical outcome. Infarct size was calculated on computed tomography (CT) scans by means of the Cavalieri's method. Neurological impairment was scored by using the Glasgow Coma Scale, Glasgow Outcome Scale and National Institutes of Health (NIH) scales at stroke onset and 3-month follow-up. Some markers showed a direct significant correlation with both initial and final NIH scale and with infarct size, particularly tumor necrosis factor alpha (TNF-alpha) (P=0.002), intercellular adhesion molecule-1 (P<0.01) and matrix metalloproteinase-2/9 (P=0.001). In contrast to previous reports, interleukin-6 (IL-6) serum level showed a significant inverse correlation with both final neurological impairment and infarct size (P<0.001). This novel finding allows us suggesting that IL-6, in the context of a complex pro-inflammatory network occurring during stroke, is associated with neuroprotection rather than neurotoxicity in patients with ischemic brain injury.

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.

Immunomodulation of fucosyl-lactose and lacto-N-fucopentaose on mononuclear cells from multiple sclerosis and healthy subjects.

The 1,2-fucosyl-oligosaccharides, and among these the 2'-fucosyl-lactose (2'-FL) and lacto-N-fucopentaose (LNFP)-I, are quantitatively the most represented oligosaccharides of human milk. They are also seen to represent an important immune device to prevent nursing infants from severe infectious diarrhoea. Recent evidences show that the appearance of 2'-FL and LNFP-I in human colostrums is synchronised with the macrophage inhibition and that LNFP-III induces a Th2 response from the mouse peripheral immune system. Since mannosyl-fucosyl receptors are described on the macrophage surface, all these evidences allow us to investigate on the possible immune function of human 2'-FL and LNFP-I in vitro on LPS-activated mononuclear cells (MNC) from 12 patients with multiple sclerosis (MS) and 20 matched health controls (HC). We found that 2'-FL and LNFP-I significantly decrease, to a different extent, the MNC proliferation from both HC and MS patients, in a linear and dose-dependent manner. 2'-FL and LNFP-I also reduce the production of IL-12 and IFN-γ, particularly in MS patients as compared to HC (p=0.01 and p<0.001, respectively), while increasing that of IL-10. The overall immunomodulatory effect of 2'-FL and LNFP I here presented may represent a future therapeutic option for the abnormal immune response found in some monocyte-mediated diseases.

Serum uric acid and multiple sclerosis.

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.