Jongkonnee Wongpiyabovorn

SHP-1 promoter 2 methylation in normal epithelial tissues and demethylation in psoriasis.

SHP-1 promoter hypermethylation has been studied in hematopoietic cells and observed only in various types of lymphoma and leukemia. This study reports a contrasting situation in normal epithelial tissues and an association with skin pathogenesis, particularly in psoriasis. We investigated several cell lines, five of them were epithelial and six were hematopoietic, white blood cells from normal, healthy donors, and normal microdissected epithelium of kidney, liver, breast, cervix, lung, prostate, bladder, and skin. Interestingly, promoter 2 hypermethylation was apparent in all epithelial cell lines and tissues. However, distinctive degrees of demethylation were noted in some skin samples. The methylation patterns of each cell line corresponded to their mRNA isoforms, in that isoforms I and II could not be detected with either promoter 1 or 2 hypermethylation, respectively. We further explored whether an enhanced degree of demethylation could be observed in various dermatopathology lesions. While the promoter 2 methylation levels of squamous cell cancers, eczemas, and normal skins were not different, a significant degree of demethylation can be observed in psoriasis (p<0.005). In addition, psoriasis displays a higher level of SHP-1 isoform II than normal skin (p<0.05). In conclusion, this study discovered an unprecedented role of SHP-1 methylation in tissue-specific expression and its alteration in a nonmalignant human disease besides the transcription inhibition in leukemia and lymphoma. Furthermore, the promoter demethylation may play an important role in skin pathogenesis by enhancing SHP-1 isoform II transcription in psoriatic skin lesions.

Association of IL-18 gene polymorphism (−137C) with arthritis manifestations in SLE: combined effect with IFN gamma gene polymorphism (+874A)

We analyzed the association between single nucleotide polymorphisms in IL-12 and IL-18 genes in disease susceptibility and severity of SLE in Thais. A weak association was observed between A allele of the IL-12 gene at the 3′ untranslated region in SLE patients with proteinuria (OR = 1.89, 95% CI = 1.05–3.40, P = 0.02, Pc = 0.06). In addition, we found a significant association between C allele of IL-18 (−137) with arthritis (OR = 6.88, 95% CI = 1.54–42.93, P = 0.003, Pc = 0.009). The presence of one C allele (C/C+C/G) was associated with significant OR of 8.72 (95% CI = 1.83–56.71, P = 0.001, Pc = 0.003). Interestingly, we found the combined effect between the G/C genotype of IL-18 (−137) and the A/A genotype of IFNG (+874) gene causing susceptibility of arthritis in SLE patients (OR = 13.22, 95% CI = 1.56–291.66, P = 0.004).

Association of interferon-gamma gene polymorphism (+874A) with arthritis manifestation in SLE

Systemic lupus erythematosus (SLE) is a complex autoimmune disease in which genetic factors strongly influence susceptibility. Cytokines such as the interferon-gamma (IFNG) gene play a key role in controlling the immunity and inflammation, and therefore their polymorphisms may affect these genes’ expression levels among individuals. We investigated the frequency of IFNG gene intron (+874) polymorphism, previously reported to be associated with IFNG production, in SLE patients compared to a control group. This population-based case–control study includes 154 SLE patients and 154 healthy control subjects with similar ethnic backgrounds. The genotyping was determined by polymerase chain reaction sequence-specific primer method and using the Chi-squared test for analyzing the association between this single-nucleotide polymorphism and SLE. The allele frequencies of the IFNG (+874) gene polymorphism were not significantly different between SLE patients and control subjects (72.7 vs 77%). However, there was a significant association between A dominance model of inheritance with arthritis (odds ratio = 7.64, 95% confidence interval = 1.56–41.64, P = 0.006, Pc = 0.03). The result suggested that the +874 intron polymorphism of IFNG can be used as the marker for SLE susceptibility with arthritis in the Thai population.

Effect of methotrexate on serum levels of IL-22 in patients with psoriasis

Interleukin-22 (IL-22) is the effector molecule of T-helper subset 22 (Th-22) lineage that promotes keratinocyte proliferation and dermal inflammation in psoriasis. Methotrexate is widely used as a first-line treatment in moderate to severe psoriasis. Methotrexate inhibits inflammatory and cytokinetic processes via various mechanisms, but the relevance of these to psoriasis is limited and whether methotrexate is specifically able to down-regulate Th22 cytokines is unknown. To determine if methotrexate reduces IL-22 in cases of psoriasis. Nineteen patients with moderate to severe psoriasis were given methotrexate 15 mg per week for up to 12 weeks. Serum levels of IL-22 were determined by enzyme-linked immunosorbent assay (ELISA) before and after treatment. Eleven of 19 patients (57.8%) achieved a 75% PASI score reduction. IL-22 levels were significantly higher in untreated psoriasis patients (56.63 ± 60.73 pg/mL) than in controls (12.58 ± 12.59 pg/mL). Methotrexate significantly reduced serum levels of IL-22 in psoriasis patients to 5.91 ± 7.97 pg/mL (p<0.001). Moreover, there was a significant positive correlation between IL-22 levels and PASI (r=0.63, p=0.004). Methotrexate significantly reduces serum IL-22 levels in cases of psoriasis. This is a novel mechanism by which methotrexate acts in the treatment of this disease.

Association of the CTG (−2578/−460/+405) haplotype within the vascular endothelial growth factor gene with early-onset psoriasis

Polymorphism of vascular endothelial growth factor (VEGF) influences the VEGF production and is subjected to genetic susceptibility of many diseases including psoriasis. Three single nucleotide polymorphisms (SNPs) within the promoter and exon 1 region [-2578(C/A), -460(C/T) and +405(C/G)] were analyzed in 154 patients with chronic plaque psoriasis and in 234 ethnically matched healthy controls from Thailand. The CTG (-2578/-460/+405) haplotype frequency was higher in patients with early-onset psoriasis (44.12%) compared with healthy controls (33.33%) (odds ratio = 1.54, 95% confidence interval = 1.08-2.18, P = 0.016, corrected P value: P(c) = 0.048). The results suggest that the CTG haplotype can be used as a genetic marker for psoriasis especially the early-onset group of Thais.

Component-resolved diagnostics for the evaluation of peanut allergy in a low-prevalence area.

Major allergenic components of peanut from distinct geographical regions are widely dispersed. Most of the diagnostic studies are from countries with a high prevalence. There have been only few reports of allergen component sensitizations from countries with a low prevalence of peanut allergy. We aimed to investigate roles of component‐resolved diagnostic (CRD) to differentiate peanut allergy and peanut tolerance in the Asian population from a country with low prevalence of peanut allergy.

Parakeratosis in skin is associated with loss of inhibitor of differentiation 4 via promoter methylation

Parakeratosis refers to incomplete maturation of epidermal keratinocytes, resulting in abnormal retention of nuclei in the stratum corneum. It occurs in many diseases of the skin, particularly in psoriasis. Down-regulation of inhibitor of differentiation 4 messenger RNA has been demonstrated in psoriatic skin, but the specificity and mechanism for this finding are unknown. In this study, we addressed specificity by immunohistochemical staining for inhibitor of differentiation 4 protein in skin disorders showing parakeratosis, including: psoriasis (n = 9), chronic eczema (n = 6), and squamous cell carcinoma (n = 7). In these conditions, parakeratotic keratinocytes in the upper layers of the skin lacked inhibitor of differentiation 4 protein expression, whereas keratinocytes in the lower layers were densely stained, in contrast to diffuse expression in normal skin. Because promoter hypermethylation of inhibitor of differentiation 4 has been described in several cancers, we determined the methylation pattern of the inhibitor of differentiation 4 promoter in psoriasis and compared this with squamous cell carcinoma. We found a novel methylation pattern of the inhibitor of differentiation 4 promoter in both conditions. Inhibitor of differentiation 4 promoter methylation was significantly increased in psoriasis (34.8%) and squamous cell carcinoma (21.8%), compared with normal skin (0%). Moreover, cells in the upper and lower parts of psoriatic epidermis were, respectively, hypermethylated and nonmethylated, at the inhibitor of differentiation 4 promoter. Comparable studies in several cell lines confirmed that hypermethylation of the promoter was associated with loss of inhibitor of differentiation 4 messenger RNA and protein expression. Our study demonstrates a previously unreported link between gene-specific promoter hypermethylation and abnormal cellular differentiation in several skin diseases. This mechanism might provide clues for novel therapies for skin disorders characterized by parakeratosis.

Increased interleukin-23 receptor+T cells in peripheral blood mononuclear cells of patients with systemic lupus erythematosus

IntroductionSystemic lupus erythematosus (SLE) is an autoimmune disorder characterized by production of autoantibodies and immune complex deposition in various organs. Aberrations in the T lymphocyte compartment and dysregulated cytokine production are key features of SLE pathogenesis and disease progression. Recently, the role of the interleukin (IL)-17/IL-23 axis in the pathogenesis of SLE has been reported. IL-23 and IL-23R are essential for expansion of pathogenic IL-17-producing T lymphocytes and have been shown to be important in the pathogenesis of lupus in animal models.MethodsIn this study, the expression of IL-23R and IL-17 in CD4+ and CD8+ T lymphocytes in peripheral blood mononuclear cells (PBMCs) of SLE patients and control subjects were examined by flow cytometry. Twenty-nine SLE patients and 10 control subjects were recruited in this study. Patients were divided into active and inactive groups based on the SLE disease activity index (SLEDAI). As another disease control population, five psoriatic patients were recruited in this study.ResultsPercentages of both IL23R+ CD4+ and IL-23R+ CD8+ T cell subsets were significantly higher in freshly isolated PBMCs from both groups of SLE patients compared to control subjects (P = 0.0021 and P = 0.0006, respectively). In addition, this difference was maintained after ex vivo stimulation with plate-bound anti-CD3/CD28 antibodies (P = 0.007 and P = 0.0019, respectively). When the fold increase in IL-17+ T cells after ex vivo stimulation for three days was compared between patients and controls, SLE patients exhibited significantly higher increases in CD4+ IL-17+ and CD8+ IL-17+ T cells, suggesting that PBMCs from SLE patients promoted the expansion of IL-17-producing T cells upon stimulation more vigorously than control PBMCs. These trends were not observed in psoriasis patients. The correlations between IL-23R+ T cells and IL-17+ T cells and IL-23R+ CD8+ T cells and SLEDAI scores in patients were also found to be statistically significant.ConclusionsThe results of our study confirmed the relevance of the IL-23/IL-17 axis in the pathogenesis of SLE and further highlighted the importance of IL-23R+ T cell subsets in this autoimmune disease.

Association of the interleukin‐10 distal promoter (‐2763A/C) polymorphism with late‐onset psoriasis

Polymorphisms of the IL‐10 promoter have been implicated in the genetic susceptibility to many autoimmune diseases, including psoriasis. Four putative functional single‐nucleotide polymorphisms (SNPs) within the interleukin‐10 promoter region (−3575T/A, −2763A/C, −1082G/A and −592C/A) were analysed in 139 patients with chronic plaque psoriasis and in 155 unrelated healthy controls from Thailand. There were no significant differences in the allele frequencies of any of the four SNPs between patients with psoriasis and controls. However, the frequency of the −2763A allele was increased in patients with late‐onset psoriasis compared with controls and patients with early‐onset psoriasis [OR = 2.94, 95% CI 1.16–7.39, corrected P value (Pc) = 0.04 and OR = 3.26, 95% CI 1.13–9.51, Pc = 0.048, respectively]. The AAGC (−3575/−2763/−1082/−592) haplotype frequency was higher in late‐onset compared with early onset psoriasis (OR = 4.37, 95% CI 1.24–15.97, Pc = 0.027). This study suggests that the −2763A allele and the extended AAGC haplotype can be used as a genetic marker for susceptibility to late‐onset psoriasis in a Thai population.

Genetic association of interferon-alpha subtypes 1, 2 and 5 in systemic lupus erythematosus.

In this study, the association between the systemic lupus erythematosus (SLE) susceptibility and the new candidate genes, IFNA1, IFNA2 and IFNA5 genes, major interferon-alpha subtypes, in responses to viral infection was investigated. Allele and genotype frequencies of each marker were compared between 150 SLE patients and 150 healthy control subjects. This study indicated that the A/A genotype of IFNA5 (-2529) and the G/G genotype of IFNA1 (-1823) were associated with the protection of SLE disease in a recessive model [P(c) = 0.03, P = 0.01, odds ratio (OR) = 0.4, 95% confidence interval (CI) = 0.2-0.8 and P(c) = 0.09, P = 0.03, OR = 0.5, 95% CI = 0.2-0.9, respectively). Multifactor dimensionality reduction analysis showed a marginal interaction between IFNA5 (-2529) and IFNA1 (-1823) gene, with a cross-validation consistency of 10 of 10 and a prediction error of 46% (permutation P-value = 0.05). This is the first report of positive association of IFNA gene in SLE, especially the role of specific subtypes IFNA1 and IFNA5.