Attenuation of Peripheral Regulatory T-Cell Suppression of Skin-Homing CD8+T Cells in Atopic Dermatitis

PURPOSE: Cutaneous lymphocyte-associated antigen (CLA)-expressing CD8+T cells have been known to play an important role in the pathogenesis of atopic dermatitis (AD). However, the mechanisms underlying the loss of self-tolerance remain unclear. Regulatory T cells (Tregs) play a key role in the development of homeostasis in the immune system. We, therefore, hypothesized that a reduced ability of Tregs to inhibit autologous CD8+CLA+T cells might be underlying mechanism in AD. MATERIALS AND METHODS: CD8+CLA+T cells and Tregs were obtained from the peripheral blood of AD patients and control volunteers. The frequencies of CD8+CLA+T cells were evaluated. The proliferative responses of CD8+CLA+T cells were assessed by flow cytometry, and the levels of transforming growth factor-beta1 (TGF-beta1) and interleukin-10 (IL-10) in culture supernatants were detected by enzyme-linked immunosorbent assay. RESULTS: Our results revealed higher frequency and increased expression of perforin and granzyme-B in peripheral CD8+CLA+T cells in AD, and lower inhibitory ability of Tregs on proliferation of CD8+CLA+T cells in AD. Meanwhile, the levels of TGF-beta1 produced by Tregs were significantly lower in AD, and anti-TGF-beta1 abolished such suppression. CONCLUSION: The attenuated inhibitory ability of Tregs on hyper-activated autologous CD8+CLA+T cells, mediated by TGF-beta1, plays an important role in the pathogenesis of AD.

Peripheral blood skin-homing CD8+ T cells in patients with atopic dermatitis / 中华皮肤科杂志

Objective To quantify the percentage of CD8+ T cells and their expressions of cytotoxic molecules and homing-related chemokine receptors in peripheral blood from patients with atopic dermatitis (AD).Methods Peripheral blood was obtained from 15 patients with AD and 14 healthy controls.Flow cytometric analysis was performed to determine the percentages of CD8+ T cells and CD8+CLA+ T cells in the peripheral blood samples,as well as the expression levels of cytotoxic molecules and homing-related chemokine receptors on these cells.Differences in these parameters were analyzed using t test,and relationship between these parameters was evaluated using Pearson correlation coefficient.Results No significant difference was observed between the patients with AD and healthy controls in the percentage of CD8+ T cells,the expressions of perforin,granzyme B,CCR10,CCR6 or FasL on CD8+ T cells,or the expressions of CCR4,CCR10,CXCR6 or FasL on CLA+CD8+ T cells (all P ＞ 0.05).A significant increase was noted in the percentage of CLA+CD8+ T cells (3.80％ ± 1.46％ vs.2.18％ ± 0.85％,t =3.636,P ＜ 0.01) and expression rates of CCR4 on CD8+ T cells (13.86％ ± 4.42％ vs.9.50％ ± 2.14％,t =3.738,P ＜ 0.01) as well as perforin and granzyme B on CLA+CD8+ T cells (74.27％ ± 15.94％ vs.57.20％ ± 14.64％,t =2.998,P ＜ 0.01; 70.90％ ± 13.85％ vs.56.41％ ± 11.00％,t =3.104,P ＜ 0.01) in the patients with AD compared with the healthy controls.Conclusions The proportion of CLA+CD8+ T cells is increased with enhanced expressions of cytotoxic molecules such as perforin and granzyme B in peripheral blood of patients with AD,which may contribute to the pathogenesis of AD.

Effect of PNCG on the Expression of CLA+T Cell Derived Cytokines in Atopic Dermatitis / 中国医科大学学报

Objective To investigate the influence of polysaccharide and nucleoside extract from bacille Calmett-Gueiin (PNCG) on the frequency of peripheral cutaneous lymphocyte-associated antigen positive (CLA~+) T lymphocyte derived lymphokines in atopic dermatitis (AD) and to explore their associations with the disease severity. Methods A randomized,double blind and placebo cross-over control method was used to treat the AD patients. Before and after the treatment,flow cytometry was used to measure the frequencies of IL-4,IL-5, IFN-γ,TNFα positive CLA~+T cells. Disease severity was evaluated by atopic dermatitis area and severity index score (ADASIS). Results After the PNCG treatment,the frequency of IL-5~+ CLA~+T cell decreased significantly,while IFN-γ increased,compared with the placebo con-trol group. PNCG could improve the ADASIS. Conclusion PNCG may treat AD through restoring the immune balance of CLA~+T cells.

Effects of Cyclosporine on the Cutaneous Lymphocyte-associated Antigen (CLA) Expression of the Lymphocytes in Psoriatic Skin / 대한피부과학회지

The cutaneous lymphocyte-associated antigen(CLA) has been proposed as a homing receptor for the selective migration of memory T cells into the skin. To investigate the effect of cyclosporine on the expression of CLA of the lymphocytes infiltrated in psoriatic lesions, CLA expression was assessed by the immunohistochemistry(HECA-452 epitope) with skin samples from 9 patients at time sequential(before treatment, 3 weeks, 6 weeks, and 12 weeks after initiation of treatment). CD3+ or CD4+ cells were also analyzed by immunohistochemistry on the same skin samples. Mean CLA expression on the infiltrated lymphocytes was decreased continuously during 12 weeks treatment with a further decrease during 3-6 weeks. CD3+ or CD4+ cells were decreased rapidly during the first 3 weeks of treatment. Although most CLA+ lymphocytes overlap with CD3 or CD4+ cells, cyclosporine could have therapeutic effects by differential decrease of CD3, CD4, or CLA+ cells during treatment period. In conclusion, reflecting the importance of CLA expression on the lymphocytes infiltrated in psoriatic lesion, one of the mechanisms to treat psoriasis may result from selective decrease of CLA+ T cells by cyclosporine in psoriatic lesions.

Expression of Cutaneous Lymphocyte-Associated Antigen in Psoriasis / 대한피부과학회지

BACKGROUND: The evidence that T lymphocytes play a key role in the pathogenesis of psoriasis is compelling. Memory T cells that infiltrate the skin express a unique skin-homing receptor called cutaneous lymphocyte-associated antigen (CLA). CLA is thought to target skin-associated T cells to inflammatory skin sites by interacting with endothelial cell ligand E-selectin. OBJECTIVE: The purpose of this study was to investigate the expression and pathogenetic roles of CLA in psoriasis. METHODS: We performed an immunohistochemical staining on the lesional and nonlesional skin specimens of 13 cases of chronic plaque type psoriasis and 5 skin specimens of normal persons as control group using seven monoclonal antibodies for CLA, CD3, CD4, CD8, CD20, CD45RO, and HLA- DR. Standard streptavidin-biotin peroxidase method using the monoclonal antibodies with AEC was used. RESULTS: CLA was expressed over 75% of mononuclear cells in the psoriatic epidermis and about 50% in the psoriatic dermis. CD3 was expressed in 50-90% of mononuclear cells in psoriatic epidermis and dermis. CD4 was expressed less than 10% in the psoriatic epidermis and 10-50% in the psoriatic dermis. In contrast, CD8 showed the strong reactivity in psoriatic epidermis (50-75%) and dermis (25-75%). CD20, the marker of B cell, was not expressed in the psoriatic epidermis and expressed in less than 25% in the psoriatic dermis. CD45RO, expressed on the memory T cells, was observed in less than 10% in the psoriatic epidermis but more than 75% in the psoriatic dermis. HLA-DR, the marker of activated lymphocytes, was expressed in less than 10% in the psoriatic epidermis and 25-50% in the psoriatic dermis. CONCLUSION: These results suggest that CLA may play a key role in the pathogenesis of psoriasis. In susceptible individuals, inciting factors, such as infection with streptococci, may activate the expression of CLA on T lymphocytes. CLA+ CD4+ T lymphocytes may be extravasated via CLA/E-selecin interaction and activated T lymphocytes could get together in the papillary dermis. Activated skin-homing CD4+ T lymphocytes arouse dormant intraepidermal CD8+ T lymphocytes. These CD8+ T lymphocytes may proliferate and produce cytokines and growth factors that trigger the chain reaction of cellular and molecular events to produce psoriatic plaques.

The Expression of CLA(Cutaneous Lymphocyte-Associated Antigen) in the Cutaneous Lymphoma / 대한피부과학회지

BACKGROUND: A pathogenesis of skin-homing lymphoid cells in primary cutaneous T-eell lymphoma(CTCL) has not been elucidated, CLA(cutaneous lymphocyte-associated antigen) defined by HECA-452 monoclonal anfibody has been proposed as the novel skin-homing receptors of infiltrative lymphocytes in atopic dermatitis and graft-versus-host disease. Accordingly, CLA may be a determinant explaining about the skin-homing properties of lymphoid tumor cells in CTCL. OBJECTIVE: This study was conducted to investigate the immunohistochemical expression of CLA in the lesional tissue specimens of cutaneous lymphomas. METHODS: Immunohistochemicslly, we examined the expression of CLA, E-selectin, ICAM-1 and LFA-1 antigens in the tissue specimens taken from the skin lesions and lymph nodes of the 22 patients with cutaneous lymphomas and the 20 control subjects with non-cutaneous lymphomas. Results : 1. The expression rate of CLA was 40.9% in the skin specimens of cutaneous lymphomas. We could not fad any expression of CLA in non-cutaneous lymphomas. 2. CTCL showed a more frequent expression of CLA(80%) than cutaneous B-cell lymphomas (CBCL)(8.3%). We found more frequently CLA+ high endothelial venules in non-cutaneous lymphomas(40%) than in cutaneous lymphomas(9.1%). 3. CLA and E-selectin were more frequently expressed in primary CTCL(100%, 83.3%) than in secondary CTCL(50%, 0%). 4. The positivity to ICAM-1 and LFA-1 antigens was higher in primary cutaneous lymphomas (72.7%, 81.8%) than in secondary forms(9.1%, 9.1%). Conclusion : CLA and E-selectin may represent the pivotal skin-homing receptor of infiltrative tumor cells and vascular counter-receptor in primary CTCL, respectively. Also, ICAM-1 and LFA-1 may have a role in the primary cutaneous infiltration of lymphoma cells as the additional cofactors.