Genetic susceptibility to multiple sclerosis in Sardinians: an immunological study

GWAS-identified multiple sclerosis risk loci involved in immune response: validation in Russians

Multiple sclerosis (MS) is a chronic neuro-inflammatory disease of complex etiology. The results of GWAS, a high-throughput method to discover genetic architecture of MS, require replication in independent ethnic groups. We performed a replication study of nine GWAS-identified SNPs in immune response in Russians. Associations of CLEC16A and IL2RA with MS were validated. Besides, we observed the associations of CLEC16A and IRF8 in women, and IL7RA and CD58 in men. With multi-locus association analysis two protective biallelic combinations: (TNFRSF1A*T+CLEC16A*A) and (TNFRSF1A*T+IRF8*A) were identified in women. Associations of CLEC16A*G/G and both biallelic combinations in women with MS survived the permutation test.

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-gamma 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.

No association of serum levels of interleukin-6 and its soluble receptor components with a genetic variation in the 3'flanking region of the interleukin-6 gene in patients with multiple sclerosis

Interleukin-6 (IL-6) plays an important role in the regulation of the inflammatory response in multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Previous reports indicated that a variable number tandem repeat (vntr) polymorphism in the 3'flanking region of the IL-6 gene (C allele) is associated with altered activity of IL-6 in vivo. Therefore, we analyzed the frequency distribution of IL-6 gene C allele vntr poymorphism in 96 MS patients and 106 ethnically matched healthy controls. Moreover, possible correlations between genotypic differences of IL-6 gene and serum levels of IL-6, soluble IL-6 receptor (sIL6-R), soluble gp130 (sgp130), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were investigated. There were no differences in the allelic distribution of the IL-6 gene C allele between MS patients and healthy controls, and no association of the IL-6 gene C allele with serum levels of IL-6, sIL-6R, spg130, sICAM and sVCAM-1 was found.

Cytokine secretion is impaired in women with diabetes mellitus

BACKGROUND

As women with diabetes mellitus (DM) have an increased prevalence of asymptomatic bacteriuria (ASB) and it is known that a correlation exists between the increased prevalence of genitourinary tract infection and impaired cytokine production in women infected with Human Immunodeficiency Virus (HIV), we studied urinary cytokine excretion in diabetic women and compared it with that of nondiabetic controls.

MATERIALS AND METHODS

To evaluate the cytokine secretion capacity of women with DM, both whole blood and isolated monocytes of women with and without DM were stimulated in vitro with lipopolysaccharide (LPS).

RESULTS

Lower urinary interleukin-8 (IL-8) and interleukin-6 (IL-6) concentrations (P = 0.1 and P < 0.001, respectively) were found in diabetic women than in nondiabetic controls. A lower urinary leukocyte cell count correlated with lower urinary IL-8 and IL-6 concentrations (P < 0.05). Lower tumour necrosis factor-alpha (TNF-alpha) and IL-6, but comparable interleukin-10 (IL-10) concentrations were found in whole blood (P < 0.04) and isolated monocytes (P = 0.03) of women with DM type 1 compared to women without DM.

CONCLUSIONS

Diabetic women with ASB have lower urinary IL-6 concentrations than nondiabetic bacteriuric controls. In addition, monocytes of women with DM type 1 secrete lower pro-inflammatory cytokines after stimulation with LPS than monocytes of women without DM. This is not due to an inhibitory effect of the anti-inflammatory cytokine IL-10. This can have important consequences for both host defense, endothelial cell functioning and atherogenesis.