Induction of human IL-10-producing neutrophils by LPS-stimulated Treg cells and IL-10.

Recent evidence has revealed an unsuspected suppressive role played by neutrophils during microbial infections. An especially intriguing aspect of this role is the ability of neutrophils to produce interleukin (IL)-10 following interaction with lipopolysaccharide (LPS)-stimulated regulatory T (Treg) cells. The present study demonstrates that generation of IL-10 in neutrophils induced by LPS-stimulated Treg cells required direct cell-cell contact. This effect was dependent on the binding of CD11b and intercellular adhesion molecule 1. Neither stimulation of neutrophils with LPS nor their culture with unstimulated Treg cells, CD3/CD28 monoclonal antibodies-stimulated Treg cells, or T conventional cells affected intracellular IL-10 expression. IL-10-positive neutrophils were also induced by exogenous IL-10, providing an example of a positive feedback loop. Both LPS-stimulated Treg cells and exogenous IL-10 exclusively promoted posttranslational modifications of histones, H3K4me3 and H3Ac Lys4, that activate IL-10 genomic locus in neutrophils, while the promoter of IL-10 gene was inactive in resting, LPS-stimulated neutrophils, following blocking of direct interaction with LPS-stimulated Treg cells or in LPS-preactivated neutrophils incubated with LPS-stimulated Treg cells. We additionally confirmed the presence of IL-10-producing neutrophils in vivo in patients with periodontal abscess induced by Gram-negative bacteria, as opposed to neutrophils isolated from the site of aseptic inflammation in patients with neuromyelitis optica.

Development and selection of Valpha l4i NKT cells.

Valpha14 invariant natural killer T (Valpha14i NKT) cells are a unique lineage of mouse T cells that share properties with both NK cells and memory T cells. Valpha14i NKT cells recognize CDld-associated glycolipids via a semi-invariant T cell receptor (TCR) composed of an invariant Valpha14-Jalpha 18 chain paired preferentially with a restricted set of TCRbeta chains. During development in the thymus, rare CD4+ CD8+ (DP) cortical thymocytes that successfully rearrange the semi-invariant TCR are directed to the Valpha14i NKT cell lineage via interactions with CD d-associated endogenous glycolipids expressed by other DP thymocytes. As they mature, Valphal4i NKT lineage cells upregulate activation markers such as CD44 and subsequently express NK-related molecules such as NKI.1 and members of the Ly-49 inhibitory receptor family. The developmental program of Valpha l4i NKT cells is critically regulated by a number of signaling cues that have little or no effect on conventional T cell development, such as the Fyn/SAP/SLAM pathway, NFkappaB and T-bet transcription factors, and the cytokine IL-15. The unique developmental requirements of Valphal4i NKT cells may represent a paradigm for other unconventional T cell subsets that are positively selected by agonist ligands expressed on hematopoietic cells.

Multiple Sclerosis Severity Score: using disability and disease duration to rate disease severity.

BACKGROUND: There is no consensus method for determining progression of disability in patients with multiple sclerosis (MS) when each patient has had only a single assessment in the course of the disease. METHODS: Using data from two large longitudinal databases, the authors tested whether cross-sectional disability assessments are representative of disease severity as a whole. An algorithm, the Multiple Sclerosis Severity Score (MSSS), which relates scores on the Expanded Disability Status Scale (EDSS) to the distribution of disability in patients with comparable disease durations, was devised and then applied to a collection of 9,892 patients from 11 countries to create the Global MSSS. In order to compare different methods of detecting such effects the authors simulated the effects of a genetic factor on disability. RESULTS: Cross-sectional EDSS measurements made after the first year were representative of overall disease severity. The MSSS was more powerful than the other methods the authors tested for detecting different rates of disease progression. CONCLUSION: The Multiple Sclerosis Severity Score (MSSS) is a powerful method for comparing disease progression using single assessment data. The Global MSSS can be used as a reference table for future disability comparisons. While useful for comparing groups of patients, disease fluctuation precludes its use as a predictor of future disability in an individual.

Multiple sclerosis: the increased frequency of the ICAM-1 exon 6 gene point mutation genetic type K469.

Intracellular adhesion molecule-1 (ICAM-1) plays an important role in the cascade of adhesion events in the homing of inflammatory cells to the central nervous system (CNS) in experimental autoimmune encephalomyelitis (EAE) and in multiple sclerosis (MS). Two single-base ICAM-1 polymorphisms have been described, in exons 4 and 6, changing codons 241 and 469 in the ICAM-1 gene, respectively. Both polymorphisms result in amino acid changes and can potentially lead to different interactions of ICAM-1 with its ligands. To detect ICAM-1 gene polymorphisms in MS, we have developed a highly sensitive and site-specific, two-stage, nested polymerase chain reaction. Genomic DNA was extracted from blood cells of 79 MS patients and 68 control subjects. The results were confirmed by direct dideoxy chain termination sequencing. The frequency of exon 6 allele T was found to be significantly higher in MS patients than in controls (68% vs 49%). Most interesting, the frequency of exon 6 homozygote K469 was significantly higher in MS patients than in controls (53% vs 34%). Higher frequency of the K469 genotype was found to be independent of possible linkage with the previously described MS susceptibility factor, the HLA class II DR2 allele. In the present study, we have shown for the first time the ICAM-1 gene polymorphisms in MS. The results indicate increased frequency of ICAM-1 exon 6 allele T in MS patients, which may contribute to the MS genetics background.

Suppression of experimental autoimmune encephalomyelitis with a TNF binding protein (TNFbp) correlates with down-regulation of VCAM-1/VLA-4.

The effect of a novel TNF binding protein (TNFbp), a polyethylene glycol-linked form of the type I soluble receptor of TNF, on the expression of adhesion molecules has been investigated with a passive transfer model of experimental autoimmune encephalomyelitis (EAE) in SJL/J mice. The expression of L-selectin, VLA-4 and LFA-1 on spleen cells of EAE animals treated with TNFbp or saline was examined by FACS analysis. The expression of VCAM-1 and ICAM-1 was investigated by immunochemistry in spinal cord tissue of SJL/J mice with EAE. In animals sensitized for EAE and treated with TNFbp, the expression of VCAM-1 in the central nervous system as well as VLA-4 on spleen cells was clearly diminished. Reduction in VCAM-1 staining and VLA-4 expression corresponded to inhibition of inflammation in the spinal cord and to prevention of clinical signs of EAE. The results have also shown that myelin basic protein responses as well as non-antigen-specific responses were not diminished in animals treated with TNFbp. The findings suggest that TNFbp might prevent EAE development by modulating the expression of VCAM-1 and VLA-4.

Multiple sclerosis: the frequency of allelic forms of tumor necrosis factor and lymphotoxin-alpha.

The cytokines LTa and TNF have been implicated as major mediators of tissue injury in multiple sclerosis (MS). In this study we have assessed the frequency of specific polymorphisms for these genes in MS (n = 53) and controls (n = 81) using a highly sensitive, two stage nested polymerase chain reaction (PCR), with the second stage using mutation-specific primers. Genomic DNA was extracted from blood cells and the results confirmed by direct dideoxy chain termination sequencing. The frequency of the -308 G to A mutation in the TNF promoter region in normal controls was 15% and in MS was 24%. For LTa gene the exon 3 polymorphism allele A was detected in 36% of controls and 34% of the MS patients. In MS, the combined genotype TNF G + A and LTa C + C was present 6 times more frequently (12%) than in controls (2%), and patients with this genotype showed the highest EDSS scores. We found the TNF and LTa polymorphisms to occur independently from the HLA class II DR2 allele distribution in MS. Whilst the G - A polymorphism in TNF gene promoter has been studied previously in MS, with conflicting results, this is the first study that has addressed the exon 3 polymorphism in LTa in MS. The results indicate that this polymorphism is not linked with the higher genetic predisposition for MS, but that combined TNF G + A and LTa C + C genotype might contribute to development of the disease.