The -431C>T polymorphism of thymus and activation-regulated chemokine increases the promoter activity but is not associated with susceptibility to atopic dermatitis in Japanese patients.

BACKGROUND: Thymus and activation-regulated chemokine (TARC) plays an important role in the pathogenesis of atopic dermatitis (AD). We recently detected the single nucleotide polymorphism (SNP) (-431C>T) in the 5'-flanking region of TARC gene. OBJECTIVES: To examine whether the -431C>T SNP of the TARC gene is associated with susceptibility to AD and whether it affects the promoter activity of the TARC gene. METHODS: We investigated the genotype and allele frequencies of the SNP in 193 AD patients and 158 healthy controls by polymerase chain reaction-restriction fragment length polymorphism method. We compared the promoter activities between TARC promoter carrying 431C and that carrying -431T by transient-transfection assay in DJM-1 cell line. RESULTS: There were no significant differences in genotype or allele frequencies between AD patients and controls (genotype: P = 0.38, allele: P = 0.22). Luciferase activity was higher in -431T constructs than in -431C constructs (2.3-fold, P = 9.5 x 10(-6)). CONCLUSION: These results suggest that the -431C>T SNP of the TARC gene enhances the promoter activity of TARC gene but is not associated with susceptibility to AD in Japanese population.

Lack of association of CCR4 single nucleotide polymorphism with atopic dermatitis in Japanese patients.

CCR4, a member of the CC chemokine receptor family, is believed to play an important role in the pathogenesis of atopic dermatitis. To examine whether CCR4 single nucleotide polymorphism (SNP) is associated with susceptibility to atopic dermatitis, we investigated the allele and genotype frequencies of C1014T SNP of CCR4 in 198 Japanese patients with atopic dermatitis and controls by a PCR-restriction fragment length polymorphism method. There was no significant difference in allele or genotype frequencies between patients with atopic dermatitis and controls. Serum IgE levels and peripheral blood eosinophil counts were not significantly different among genotypes. There was also no significant difference in allele or genotype frequencies between the patient subgroup with and without asthma, with mild or moderate disease, with and without family history of atopic dermatitis, or with and without family history of atopic disorders. C1014T SNP of CCR4 does not appear to be associated with susceptibility to atopic dermatitis in Japanese patients.

Increased serum cutaneous T cell-attracting chemokine (CCL27) levels in patients with atopic dermatitis and psoriasis vulgaris.

BACKGROUND: Both atopic dermatitis (AD) and psoriasis vulgaris (PsV) are characterized as chronic and relapsing inflammatory skin diseases associated with various immunologic abnormalities. Cutaneous T cell-attracting chemokine (CTACK; CCL27) is a member of the CC chemokine family and a functional ligand for CC chemokine receptor 10. It is selectively expressed in skin and attracts CC chemokine receptor 10-expressing skin-homing memory T cells. The epidermal keratinocyte is a main source of CTACK, suggesting the involvement of various inflammatory skin diseases. OBJECTIVE: The purpose of this investigation was to clarify whether CTACK produced by keratinocytes is detected in the sera of patients with AD and PsV and to examine the correlation between the serum CTACK levels and disease activity of patients with AD and PsV. METHODS: We measured the serum CTACK levels in 50 patients with AD, 30 patients with PsV, and 22 healthy control subjects. We also divided 50 patients with AD into 3 groups (ie, those with mild, moderate, and severe disease) and compared them among 3 categories. Moreover, we compared the serum CTACK levels of patients with AD and PsV with clinical or laboratory data. Immunohistochemical staining of CTACK and IFN-induced protein of 10 kd (IP-10; CXCL10) was performed on the lesional skin of patients with AD and PsV. RESULTS: The serum CTACK levels in patients with AD and PsV were significantly higher than those in healthy control subjects. The serum CTACK levels in patients with AD significantly correlated with scoring atopic dermatitis (SCORAD) scores, serum soluble IL-2 receptor levels, serum soluble E-selectin levels, serum thymus and activation-regulated chemokine levels, and serum macrophage-derived chemokine levels. Serum CTACK levels in patients with PsV significantly correlated with the serum IP-10 levels but not with the Psoriasis Area and Severity Index score. Immunohistochemical staining showed CTACK was strongly expressed in lesional ke-ratinocytes of patients with AD and PsV, whereas IP-10 was strongly expressed in lesional keratinocytes of patients with PsV and focally in those with AD. CONCLUSION: These results suggest that CTACK might be one of the important chemokines for the pathogenesis of AD and PsV.

Thymus and activation-regulated chemokine (TARC/CCL17) in mycosis fungoides: serum TARC levels reflect the disease activity of mycosis fungoides.

BACKGROUND: Mycosis fungoides (MF) belongs to cutaneous T-cell lymphoma and is clinically divided into 3 stages: patch, plaque, and tumor stage. Thymus and activation-regulated chemokine (TARC/CCL17) is a member of the CC chemokines and is a chemoattractant for CC chemokine receptor 4 (CCR4)- and CC chemokine receptor 8 (CCR8)-expressing cells. OBJECTIVE: In this study, we examined the involvement of TARC among patients with each stage of MF. METHODS: We investigated the expression of TARC, CCR4, and CXC chemokine receptor 3 in patients with each stage of MF by immunohistochemistry. We measured serum TARC levels in 20 patients with MF in varying degrees and compared them with 10 patients with psoriasis vulgaris and 10 healthy controls. In addition, we compared serum TARC levels in patients with MF with other laboratory data. RESULTS: Immunohistochemical staining revealed that TARC was expressed in the lesional keratinocytes in the patch, plaque, and tumor stages. CCR4 was expressed on the epidermotropic cells in both patch and plaque stages and on the large cell-transformed cells in the tumor stage, whereas CXC chemokine receptor 3 was constantly expressed on the small cells in the lesional dermis. Serum TARC levels in patients with MF were significantly higher than those in patients with psoriasis vulgaris or healthy controls. Moreover, serum TARC levels in patients with the tumor stage of MF (n = 5) were remarkably higher than those with patch stage (n = 8) or plaque stage (n = 7). Serum TARC levels significantly correlated with serum lactate dehydrogenase levels (r = 0.62), serum immunoglobulin E levels (r = 0.60), serum soluble interleukin 2 receptor levels (r = 0.72), and serum macrophage-derived chemokine levels (r = 0.70). CONCLUSION: These data strongly indicate that serum TARC levels are useful for assessing the disease activity of patients with MF and that TARC and CCR4 may be involved in the pathogenesis of MF.

Interleukin-13 gene polymorphism G4257A is associated with atopic dermatitis in Japanese patients.

Interleukin (IL)-13 plays an important role in the induction of immunoglobulin E (IgE) and in the pathogenesis of atopic dermatitis (AD). We investigated the allele and genotype frequencies of three IL-13 single nucleotide polymorphisms (SNPs) (A704C and C1103T in the promoter region and G4257A in exon 4) in Japanese patients with AD. For A704C and C1103T SNPs, there were no significant differences in allele or genotype frequencies between AD patients and controls. For G4257A SNP, A allele was significantly increased in AD patients (39.5%) compared with controls (29.4%) (P = 0.016). The same proportion of each genotype and allele was observed in the patient subgroup with and without asthma. Serum IgE levels and peripheral eosinophil counts were not significantly different among genotypes in G4257A SNP. There was also no significant difference in allele or genotype frequencies between AD patients with mild disease and those with severe disease, between those with family history of AD and those without it, or between those with family history of atopic disorders and those without it. This result suggests that 4257A allele is associated with susceptibility to AD and that it may function in the pathogenesis of AD itself, presumably by other mechanisms than inducing IgE production.

TGF-beta1-mediated regulation of thymus and activation-regulated chemokine (TARC/CCL17) synthesis and secretion by HaCaT cells co-stimulated with TNF-alpha and IFN-gamma.

Thymus and activation-regulated chemokine (TARC/CCL17) contributes not only to the recruitment of leukocytes, but is also involved in immune disorders, such as atopic dermatitis (AD) and bronchial asthma. We have previously reported that the levels of TARC were high in patients with AD and that lesional epidermis were strongly immunoreactive for TARC. In this paper, the effects of transforming growth factor (TGF)-beta(1) on the expression of TARC/CCL17 were examined in HaCaT cells, a human keratinocytes (KCs) cell line, co-stimulated with TNF-alpha and IFN-gamma. We found that TGF-beta(1) down-regulated the TARC synthesis and secretion of HaCaT cells co-stimulated with TNF-alpha and IFN-gamma in a dose-dependent manner. TGF-beta(1) at a concentration of 10ng/ml maximally inhibited this secretion. Northern blot analysis showed a similar inhibitory effect of TGF-beta(1) on TARC mRNA expression by HaCaT cells. The TGF-beta(1)-induced down-regulation of TARC/CCL17 in HaCaT cells suggests that TGF-beta(1) might regulate the TARC-related inflammatory processes, which may be important for understanding the pathogenesis of allergic diseases.

Interleukin-12 p40 gene (IL12B) 3'-untranslated region polymorphism is associated with susceptibility to atopic dermatitis and psoriasis vulgaris.

Interleukin-12 (IL-12) is believed to play an important role in inducing Th1-type cytokine profiles. Atopic dermatitis (AD) and psoriasis vulgaris (PsV) are considered to be Th2 and Th1 type disease, respectively. The IL-12 p40 subunit gene (IL12B) is located at chromosome 5q31-33 and linkage findings of AD on 5q31 were reported. Recently single nucleotide polymorphism (SNP) (1188A/C) of IL12B has been reported. In function, it has been reported that this SNP is associated with IL12B mRNA expression levels. To learn whether this SNP is associated with susceptibility to AD or PsV, we investigated the genotype and allele frequencies of the SNP in AD patients, in PsV patients and in controls, examining 164 AD patients, 143 PsV patients and 100 healthy individuals in Japanese population. Genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism method. The A allele was decreased in AD patients (40.9%, p = 0.031) and increased in PsV patients (60.1%, p = 0.035) compared with controls (50.5%). This suggests that IL12B SNP is associated with susceptibility to AD and PsV, presumably by affecting the Th1/Th2 balance.

IL-4, but not IL-13, modulates TARC (thymus and activation-regulated chemokine)/CCL17 and IP-10 (interferon-induced protein of 10kDA)/CXCL10 release by TNF-alpha and IFN-gamma in HaCaT cell line.

It is known that both interleukin-4 (IL-4) and IL-13 are produced by Th2-type cells and share similar biological functions with each other. However, recently accumulated evidences have revealed that IL-4 may be involved in the Th1-type response. Both thymus and activation-regulated chemokine (TARC/CCL17), a ligand for CC chemokine receptor 4 that is mainly expressed on Th2-type cells, and interferon-induced protein of 10kDa (IP-10/CXCL10), a ligand for CXC chemokine receptor 3 that is mainly expressed on Th1-type cells, are produced by keratinocytes after the stimulation with the primary cytokines such as tumor necrotic factor-alpha (TNF-alpha) and/or interferon-gamma (IFN-gamma). In this study, we investigated the regulation of TARC or IP-10 production from HaCaT cells, an immortalized human keratinocyte cell line, after stimulation with TNF-alpha, IFN-gamma, IL-4 and/or IL-13. Without stimulation, HaCaT cells did not produce TARC. When both TNF-alpha and IFN-gamma were added, they increased synergistically (P<0.003). In addition, when HaCaT cells were stimulated with IL-4, but not IL-13, in combination with TNF-alpha and IFN-gamma, the supernatant TARC levels significantly decreased compared to those with both TNF-alpha and IFN-gamma (P<0.009). This inhibition was completely abolished with the addition of neutralizing anti-IL-4 antibody. The supernatant IP-10 levels also increased synergistically by stimulation with TNF-alpha and IFN-gamma for 24h (P<0.001). When IL-4, but not IL-13, was added to the medium and the cells were co-cultured with these cytokines, the IP-10 levels significantly increased compared to those with both TNF-alpha and IFN-gamma (P<0.04). Furthermore, the effects of IL-4 on TARC and IP-10 production in these cells were detected in a dose-dependent manner. These data strongly suggest that IL-4 may act not only as a mediator of Th1-type response but also as a down-regulator of Th2-type response in terms of the regulation of chemokine production by HaCaT cells.

Eotaxin gene single nucleotide polymorphisms in the promoter and exon regions are not associated with susceptibility to atopic dermatitis, but two of them in the promoter region are associated with serum IgE levels in patients with atopic dermatitis.

Eotaxin is believed to play an important role in atopic dermatitis (AD) as a potent chemoattractant and activator of eosinophils and Th2 lymphocytes. The eotaxin gene is located at chromosome 17q21.1-q21.2, and linkage findings of AD on chromosome 17 were reported. Recently we have identified single nucleotide polymorphisms (SNPs) of eotaxin gene (-426C > T, -384A > G, 67G > A). To learn whether eotaxin gene SNPs are associated with susceptibility to AD or phenotypes of AD, we investigated the genotype frequencies at each SNP of the gene in AD patients and in controls. We examined 140 Japanese AD patients and 140 healthy Japanese individuals. Genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism method. No significant difference was observed in allele or genotype frequencies of any SNP between AD patients and controls. Serum immunoglobulin E (IgE) levels were significantly lower in CT and TT genotype than in CC (P = 0.038) in -426C > T SNP, and lower in GG than in AA and AG with borderline significance (P = 0.053) in -384A > G SNP in AD patients. Eotaxin gene SNPs in the promoter and exon regions are not associated with susceptibility to AD, but two of them in the promoter region are associated with phenotype of AD.

CC Chemokine Receptor 4 as a Possible Target for Therapy of Atopic Dermatitis.

The CC chemokine receptor CCR4 is selectively expressed on Th2-type CD4(+) T cells. Therefore, its ligands, thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine, can facilitate the recruitment, activation and development of Th2 polarized cells. The allergic inflammation of atopic dermatitis is characterized by a predominance of Th2-type cells. Some reports suggest that CCR4 and TARC are important for the pathogenesis of atopic dermatitis. The future aspects of atopic dermatitis therapy that specifically targets CCR4 are discussed. (c) 2002 Prous Science. All rights reserved.