Interferon Alpha mRNA level and subtypes in lesion and non-lesion from discoid lupus erythematosus patients without systemic lupus erythematosus.

Background: Up-regulation of interferon alpha (IFN-?) in cutaneous lesions of lupus erythematosus (LE) has been proposed to play a role in the pathogenesis of cutaneous LE lesions of LE patients. IFN- ? is composed of 13 subtypes of immunoregulatory cytokines that promote innate and adaptive immune responses. However, the precise biological properties may differ among subtypes. Objective: To investigate the mRNA level of IFN-? and subtypes in cutaneous LE patients Methods: We analyzed the mRNA level of IFN-? and subtypes in normal skin from 12 healthy female controls and compared it to normal skin and discoid lupus erythematosus (DLE) lesions from 16 DLE patients without systemic involvement (14 females and 2 males) by real-time PCR, cloning, and sequencing. Results: Significant up-regulation of mRNA level of IFN-? was found in both lesional and non-lesional skin from DLE patients without SLE when compared to normal skin from healthy donors (P=0.05 and P=0.04, respectively). An analysis of the IFN-? subtypes from skin biopsies detected a reduction of IFN-? subtype 5 in DLE lesion compared to healthy control skin. Conclusions: Our results indicate that IFN- ? is upregulated in both lesional and non-lesional DLE in cutaneous LE patients. IFN-? subtype 5 is the main subtype of IFN- ? expression in normal skin but declines in DLE.

Association between CTLA-4 polymorphisms and the susceptibility to systemic lupus erythematosus and Graves’disease in Thai population.

Background: Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is a cell surface molecule involved in the regulation of T cells. Single nucleotide polymorphisms (SNPs) of CTLA-4 gene are known to be associated with susceptibility to several autoimmune diseases, including systemic lupus erythematosus (SLE) and Graves’ disease (GD). Objective: The aim of this study was to determine whether the common SNPs +49A/G on exon1 and CT60A/G in 3’UTR of the CTLA-4 gene are associated with susceptibility to SLE and GD in Thai population. Methods: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze these two SNPs in 151 patients with SLE, 132 patients with GD and 153 healthy controls. Results: Our study showed that there were no statistically significant differences in the allele and genotype frequencies of +49A/G and CT60A/G SNPs between patients with SLE and healthy controls as well as patients with GD vs. healthy controls (P >0.05). However, the GG genotypes of +49A/G and CT60A/G were likely to be risk factors (OR >1) for GD but not in SLE. The effect of the +49G allele was similar to that of an autosomal recessive gene in the presence of the GG genotype, when compared to AA and AG, with an OR of 1.58 (95% CI =0.95-2.61, p =0.061) in GD. We also observed a dose response effect of the CT60G allele on GD susceptibility with an OR of 1.43 for GG homozygous and 1.17 for AG heterozygous subjects, when compared to the AA genotype, although these were not statistically significant (P >0.05). Conclusion: We found no association between two functional polymorphisms (+49A/G and CT60A/G) of the CTLA-4 gene and susceptibility to SLE and GD. However, the association study utilizing a larger sample size should be performed to confirm this.

Association of TNF-alpha, TNF-beta, IFN-gamma and IL-1Ra gene polymorphisms with Graves' disease in the Thai population.

Cytokines play a key role in the regulation of immune and inflammatory responses. Therefore, cytokine genes are potentially related to susceptibility to Graves' disease (GD). The aim of this study was to investigate the putative functional polymorphisms within tumor necrosis factor-alpha (TNF-alpha), tumor necrosis factor-beta (TNF-beta), interferon-gamma (IFN-gamma), and interleukin-1 receptor antagonist (IL-1Ra) genes, in patients with GD (n = 137) compared to a healthy Thai control group (n = 137). The results showed no statistically significant difference between the study groups for TNF-beta (Ncol site in intron 1), IFN-gamma (+874 in intron 1), and IL-1Ra (variable numbers of tandem repeats in intron 2) gene polymorphisms. Only the -863A allele within the promoter region of the TNF-alpha gene, which may affect the affinity of the promoter nuclear factor (NF)-kappab interaction, was found to be increased in GD patients compared to the controls (p = 0.009, OR = 1.8, 95% CI = 1.15 to 2.84). The effect of the -863A allele of the TNF-alpha gene was similar to the autosomal dominance mode of inheritance (p = 0.01, OR = 2, 95% CI = 1.16 to 3.44). This polymorphism may be involved in the susceptibility to GD in part through its higher promoter activity of TNF-alpha production.

The distribution of IL-10 promoter polymorphism in Thais.

IL-10 is a regulatory cytokine, which plays important roles in the pathogenesis of many diseases polymorphism of IL-10 promoter influences the phenotypic expressions such as the variation of IL-10 production among individuals and is subjected to the genetic susceptibility study of many diseases. However, there is no information about the frequencies of IL-10 promoter polymorphism in a Thai population. To determine the distribution of IL-10 promoter polymorphism in unrelated healthy Thais, genomic-DNA from 160 unrelated healthy volunteers were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The functional single-nucleotide polymorphisms (SNPs) in IL-10 promoter (positions -1082 (G/A), -819 (C/T), -592 (C/A) were included. The allele frequencies of -1082*A (93.4%), -819*T (71.9%), and -592*A (71.9%) were significantly higher than the allele frequencies of -1082*G (6.6%), -819*C (28.1%), and -592*C (28.1%) respectively in a Thai population similar to other Asian populations (Korean, Japanese, Chinese). As for the haplotype analysis, the ATA haplotype (72%) was significantly higher in Thais and other Asian populations compared to non-Asian populations; whereas, GCC haplotype (6.6%) was significantly lower in Thais. Additionally, two rare haplotypes of IL-10 promoter (ATC and ACA) which were previously reported only in the Chinese Han people, were found with similar frequencies (0.6%) in the present study. In conclusion, the distribution of IL-10 promoter polymorphisms in Thais was comparable to other Asian populations but distinct from Non-Asian populations. At least five haplotypes existed in an unrelated healthy Thai population as ACC, GCC, ATA, ATC, and ACA haplotypes.

No association between an interleukin 4 gene promoter (-589) polymorphism and Graves' disease in Thai patients.

Cytokines play a key role in the regulation of immune and inflammatory responses and therefore are potential candidate genes for autoimmune thyroid disease. Polymorphisms in cytokine genes may effect gene transcription, causing individual variations in cytokine production. Several investigators have linked the interleukin-4 (IL-4) gene and autoimmune disease. The present population-based study was to investigate the polymorphisms of IL-4 gene promoter (-589C/T) in GD patients compared with a control group and determine the association with GD in a Thai population. The subjects included 137 GD patients and 137 healthy control subjects with similar ethnic and geographic backgrounds. The IL-4 gene polymorphism at position -589 in the promoter was analyzed using the PCR-RFLP. The protective effect of the -589T allele as suggested by Hunt et al in a Caucasian population was not observed in the present study. The -589T allele frequencies were similar between patients and control subjects (69% vs 69.3%) suggesting that this polymorphism can not be used as a genetic marker for GD susceptibility in Thais.