Peripheral blood lymphocytes from psoriatic patients are hyporesponsive to β-streptococcal superantigens

The strong association of acute guttate psoriasis and streptococcal throat infection, together with the preferential use of T cells expressing a particular T-cell receptor, has suggested a role for bacterial superantigens in the pathogenesis of psoriasis. We examined the proliferative responses of peripheral blood lymphocytes (PBLs), obtained from patients with psoriasis and from healthy controls, to streptococcal superantigens, cytoplasmic membrane-associated protein (CAP) and secretion-type CAP (SCAP), isolated from group A, β-haemolytic streptococci. PBLs from patients with psoriasis showed significantly less response to SCAP and CAP than those from healthy controls. Because there was no difference between psoriatic patients and controls in the proliferative response of PBLs to staphylococcal enterotoxin A or E (SEA, SEE) or the mitogen phytohaemagglutinin (PHA), these findings strongly suggest that the reduced reactivity to the streptococcal superantigens seems to reflect anergy of a population of PBLs to the superantigens. As the CAP used in the present study stimulates Vβ8 T cells selectively, we further examined the proliferation of Vβ8 T cells after such stimulation using flow cytometry. Vβ8 T cells obtained from three of four psoriatic patients failed to proliferate in the presence of CAP, whereas they proliferated vigorously in the presence of SEE, which activates Vβ8 T cells, confirming the specific hyporesponsiveness of PBLs from psoriatic patients to streptococcal superantigens. We then determined the effects of serum factors on the suppressed response of PBLs to the streptococcal superantigens with SCAP or CAP. It was partially restored when PBLs were cultured with sera obtained from healthy subjects, although the responses were still significantly lower than those of the healthy controls. In contrast, psoriatic sera markedly suppressed the proliferative response of PBLs from healthy controls to CAP or SCAP, but showed no suppression of the proliferative response of PBLs to SEA. Because these findings suggest the presence of specific inhibitory factors in psoriatic sera, we examined whether the inhibitory effect was caused by antisuperantigen antibody. However, no significant increase was detected in antibody titre to CAP in psoriatic sera, as has been noted in sera from patients with poststreptococcal glomerulonephritis. The present results show for the first time the hyporesponsiveness of PBLs to streptococcal superantigens and the presence of serum inhibitors that specifically inhibit T-cell response to the superantigens in psoriatic patients. These findings suggest a pathological role for streptococcal infections in the pathogenesis of psoriasis.     

Characterization of a T cell line bearing natural killer receptors and capable of creating psoriasis in a SCID mouse model system

T cells bearing natural killer receptors (NKRs) such as CD94 and CD161 are present in psoriasis. These immunocytes express several receptors for both classical and non-classical class I MHC molecules. Whether T cells bearing NKRs in psoriatic lesions represent immunoregulatory versus pathogenic immunocytes or are just bystander cells is unclear. To address this issue, a CD94+/CD161+ T cell line was established from a psoriatic patient using IL-2/superantigens, and the interaction between NK-T cells and keratinocytes was characterized using in-vitro and in-vivo assays. Upon incubation between NK-T cells and CD1d positive keratinocytes, high levels of IFN-gamma and IL-13 were produced. Cytokine production was inhibited by a mAb against CD1d, implicating recognition of this surface molecule in the T cell response. Furthermore when this line was injected into pre-psoriatic skin engrafted onto a SCID mouse, a psoriatic plaque was created. The hyperplastic epidermal keratinocytes diffusely expressed CD1d, and were infiltrated by CD161+ T cells. RNase protection assay revealed predominantly IFN-gamma and IL-15 mRNAs, with barely detectable IL-13 mRNA in the acute lesion. These in-vivo findings demonstrated that this T cell line was pathogenic by creating a psoriatic plaque. The in-vitro results support a pathophysiologic role for interaction between T cells expressing NKRs and CD1d positive keratinocytes, with subsequent production of IFN-gamma. Upon injection in-vivo, the cytokine network produced was characterized by an immunological response polarized towards Th1 rather than Th2 cytokines. Thus, this pathogenic cell line provides evidence that T cells bearing NKRs can directly provoke a Th1 disease such as psoriasis.     

Functional characterization of CD4+CD25+ regulatory T cells differentiated in vitro from bone marrow-derived haematopoietic cells of psoriasis patients with a family history of the disorder

BACKGROUND: In psoriasis CD4+CD25+ regulatory T cells are functionally deficient. The imbalance between regulatory and effector T-cell functions is important for inducing psoriasis. It is reasonable to speculate that the dysfunctional activity of CD4+CD25+ regulatory cells may originate partly from the abnormal haematopoietic cells determined mainly by genetic background. OBJECTIVES: To test the hypothesis that haematopoietic stem cells are responsible for dysfunctional CD4+CD25+ regulatory cells in psoriasis. METHODS: Bone marrow-derived CD34+ haematopoietic cells from patients with psoriasis (with a family history of psoriasis) and from normal controls were differentiated into T cells in vitro. CD4+CD25+ T cells were isolated by an immunomagnetic bead method, and proliferation activity and capacity for cytokine secretion were determined. Furthermore, the ability of CD4+CD25+ T cells to suppress the proliferative responses of allogeneous peripheral blood CD4+CD25- effector T cells was assessed in vitro. RESULTS: The differentiated CD4+CD25+ T cells of psoriatic origin showed similar characteristics to those of normal volunteers, including proliferation activity and secretion profile of the cytokines interleukin (IL)-2, IL-4, IL-8, IL-10 and interferon (IFN)-gamma. However, proliferation and secretion levels of the cytokines IL-2 and IL-10 for CD4+CD25+ cells of psoriatic CD34+ cell origin were significantly lower than those of normal controls in response to streptococcal superantigen (Strep-A). In particular, CD4+CD25+ T cells differentiated from psoriatic CD34+ cells were functionally insufficient to restrain effector T-cell proliferation. CONCLUSIONS: CD4+CD25+ T cells differentiated in vitro from haematopoietic cells of patients with psoriasis are impaired in regulatory function. The dysfunction of psoriatic CD4+CD25+ T cells may be due to inherent genetic programming passed down from bone marrow-derived haematopoietic cells.     

寻常性银屑病患者外周血单一核细胞IFN-γ受体和TNF-α受体mRNA表达的研究

目的 探讨寻常性银屑病患者外周血单一核细胞IFN-γ受体mRNA和TNF-α仅受体mRNA的表达及其在银屑病发病机制中的作用.方法 采集50例寻常性银屑病患者外周静脉血,分离单一核细胞后,以RT-PCR法检测其IFN-γ受体mRNA和TNF-α受体mRNA的表达,PASI评分法评估银屑病的严重程度.以24例正常人作对照.结果 50例银屑病患者外周血单一核细胞IFN-γ受体mRNA的表达均值为1.11±0.55,其中37例进行期患者为1.13±0.57,13例静止期患者为1.03±0.52,正常人对照组为0.72±0.17,银屑病患者显著高于正常人对照组(P=0.0034),进行期显著高于正常人对照组(P=0.008),而静止期与正常人对照组差异无统计学意义.正常人对照组和银屑病患者外周血单一核细胞TNF-α受体mRNA的表达水平差异无统计学意义.银屑病患者外周血单一核细胞IFN-γ受体mRNA表达水平与TNF-α受体mRNA表达水平及PASI值均无相关性.结论 IFN-γ受体mRNA在寻常性银屑病患者外周血单一核细胞中异常高表达,但与疾病的活动性无关.     

Effects of two novel cationic staphylococcal proteins (NP-tase and p70)and enterotoxin B on IgE synthesis and interleukin-4 and interferon-gamma production in patients with atopic dermatitis

We have characterized the cell-mediated and humoral immune response of patients with atopic dermatitis (AD) and healthy controls in response to two novel staphylococcal antigens (NP-tase, p70) and the superantigen staphylococcal enterotoxin B (SEB). The parameters studied were IgE, interleukin (IL)-4 and interferon (IFN)-gamma synthesis by peripheral blood mononuclear cells (PBMC) after stimulation with NP-tase, p70 and SEB in vitro. Both antigens, as well as SEB, induced IL-4 and IFN-gamma secretion in patients and controls. However, patients with AD showed a significantly diminished IFN-gamma production in response to NP-tase or SEB. Furthermore, we demonstrated a good correlation between antigen-stimulated IgE production and the IL-4/IFN-gamma ratio in vitro. A distinct subgroup of PBMC showed impaired IFN-gamma synthesis and enhanced IL-4 secretion after incubation with p70 or NP-tase. These data support evidence that a subgroup of patients with AD, synthesizing low levels of IFN-gamma after stimulation with staphylococcal antigens, may have impaired abilities to clear Staphylococcus aureus colonization. Persistent staphylococcal antigens could then be responsible for inflammatory and allergic skin reactions in patients with AD. We therefore conclude that, besides superantigens, staphylococcal antigens may also play a part in the pathogenesis of AD.     

Differential expression of interferon gamma by mitogen-stimulated peripheral blood mononuclear cells among Kuwaiti psoriasis patients

Most diseases exhibit characteristic profiles of cytokine expression, broadly subdivided into Th1, involving primarily cell-mediated responses, of which Interferon-gamma (INF-gamma), Interleukin-2 (IL-2) and Tumor Necrosis Factor-alpha (TNF-alpha) are hallmarks, and Th2 processes, which often involve activation of the humoral arm of the immune system, resulting in elevated levels of IL-4, IL-5 and IL-10. Psoriasis, a disorder characterized by disfiguring skin lesions and elevated levels of activated CD4+ T helper lymphocytes in both peripheral blood and lesional tissue, exhibits a profile of cytokine expression that includes high levels of TNF-alpha and IFN-gamma, with low IL-5 and IL-10, indicating that immunologically, the pathogenesis of the disease is Th1. In this study, we report the results of an investigation of peripheral blood mononuclear cell cytokine expression among Kuwaiti psoriasis patients; we demonstrated two patterns of IFN-gamma production which may suggest differing pathogeneses. Whole, haparinized blood was donated by 17 patients with active psoriasis and 11 healthy control subject. Mononuclear cells were isolated by density centrifugation and cultured for 3 days in the presence or absence of a mitogen (PHA). Supernatants were assayed for IFN-gamma (a Th1 marker) and IL-10 (a Th2 marker) by enzyme-linked immunoabsorption assay (ELISA). IFN-gamma expression by both PHA-stimulated and unstimulated cultures from psoriatics significantly exceeded that of controls (p < 0.001), whereas no significant differences in IL-10 expression were noted between psoriatic and control subjects. Stimulation indices (cytokine concentration in PHA-stimulated/unstimulated cultures, SI) for psoriatic subjects were significantly higher than those of controls for IFN-gamma (p = 0.000), but not for IL-10. Ratios of SI (SI IFN-gamma/SL IL-10) for the psoriatic subjects also were significantly greater for the psoriatic subjects than for the controls (p = 0.003). However, within the psoriatic group, eight patients failed to show the expected elevation of IFN-gamma/IL-10 ratio as a result of high unstimulated levels of IFN-gamma production. The divergence of IFN-gamma expression within the psoriatic group may indicate two different modes of T lymphocyte activation contributing to the pathogenesis of psoriasis in this study.     

Antagonistic effects of the staphylococcal enterotoxin a mutant, SEA(F47A/D227A), on psoriasis in the SCID-hu xenogeneic transplantation model

Psoriasis is a T-cell-mediated immune dermatosis probably triggered by bacterial superantigens. This pathomechanism has been experimentally reproduced in a SCID-hu xenogeneic transplantation model. We analyzed the effects of different bacterial superantigens on the induction of psoriasis in this model. Staphylococcal enterotoxin B and exfoliative toxin triggered the onset of psoriasis when administered repetitively intracutaneously over a period of 2 wk, whereas staphylococcal enterotoxin A representing a distinct subfamily of staphylococcal enterotoxins only mimicked certain aspects of psoriasis. The biologic effects of staphylococcal enterotoxin A were more pronounced when a mutated form, SEA(H187A), of this superantigen with reduced affinity to major histocompatibility complex class II was coinjected. Another mutated variant, SEA(F47A/D227A), exhibiting no measurable major histocompatibility complex class II affinity blocked the effects triggered by wild-type staphylococcal enterotoxin A when injected in a 10-fold higher dose. Inhibition was specific as induction of psoriasiform epidermal changes by staphylococcal enterotoxin B could not be blocked. As staphylococcal enterotoxin A, in contrast to the other superantigens tested, is capable of inducing epidermal thickening but not the typical appearance of psoriasis, we conclude that bacterial superantigens may differ with regard to their effects on human nonlesional psoriatic skin. Staphylococcal-enterotoxin-A-mediated effects were blocked by a genetically engineered superantigen highlighting the potential therapeutic use of mutated superantigens.     

Narrowband–UVB irradiation decreases the production of pro-inflammatory cytokines by stimulated T cells

Narrow-band ultraviolet B (UVB) phototherapy is an effective treatment for psoriasis. Owing to its limited penetration, the direct effects of UVB are mostly restricted to cells residing in the epidermis and papillary dermis, and are associated with epidermal depletion of Langerhans’ cells (LC) and T cells. It has been argued that the depletion of the skin-resident T-cell population may be due to a combination of UVB-induced apoptosis and decreased recruitment from the blood due to lower expression of the required adhesion and homing molecules. We have previously demonstrated that UVB treatment can alter the expression of adhesion molecules by blood lymphocytes, and as these can be influenced by cytokines, the aim of this study was to investigate whether UVB irradiation can also influence the cytokine production of circulating T cells. Four patients with active chronic plaque psoriasis were treated daily with narrow-band 312 nm UVB irradiation and blood samples obtained before treatment and weekly thereafter for 2 weeks. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with a streptococcal superantigen or a conventional streptococcal antigen preparation, and cell culture supernatants were assayed for various cytokines. When stimulated with the superantigen, PBMCs from UVB-treated psoriasis patients secreted greater amounts of the anti-inflammatory cytokine IL-10, and showed markedly decreased production of IL-1β, IL-2, IL-5 and IL-6 compared to the pre-treatment values; the production of IFN-γ, IL-8 and IL-12p70 were also decreased but did not reach statistical significance. Thus, the combination of UVB-induced apoptosis, increased secretion of anti-inflammatory cytokines and decreased trafficking to the skin may help to explain the beneficial effects of UVB treatment on psoriasis and why disease remission can sometimes be sustained for a prolonged period.     

Mast cells in psoriatic skin are strongly positive for interferon-gamma

The increased number and early activation of cutaneous mast cells is a typical feature of psoriatic inflammation. Interferon-gamma (IFN-gamma) is believed to be one of the important mediators in the cytokine cascade of psoriasis. Human mast cells have been previously reported to release various cytokines upon stimulation including interleukin (IL) -4, IL-5, IL-6, IL-8, IL-13 and tumour necrosis factor-alpha. Here we report that human mast cells synthesize also IFN-gamma at mRNA and protein level and that the number of IFN-gamma producing mast cells is significantly increased in the psoriatic skin. IFN-gamma immunoreactivity in mast cells was demonstrated by staining non-lesional and lesional skin sections from 21 patients with psoriasis. Ten patients with atopic dermatitis (AD) and five healthy persons served as control groups. The percentage (mean +/- SD) of IFN-gamma + mast cells in lesional compared with non-lesional psoriatic skin was 67 +/- 18% vs. 44 +/- 17% (P < 0.0001, paired t-test), respectively, but only 9 +/- 6% vs. 10 +/- 7% in corresponding skin samples of AD. In the skin of healthy controls, only 12 +/- 12% of the mast cells were IFN-gamma +. Using immunoelectron microscopy, we confirmed the ultrastructural localization of IFN-gamma within the granules of mast cells in psoriatic skin. In addition, stimulation of a human mast cell line HMC-1 with phorbol myristate acetate (PMA) (100 nmol/L) for periods of 2-24 h induced expression of IFN-gamma mRNA, which peaked at 24 h. When HMC-1 cells were stimulated with PMA (100 nmol/L) for periods of 0-3 days, the cells released IFN-gamma protein, peaking on day 1. These results provide further evidence for the important role of mast cells in the pathogenesis of psoriasis.     

链球菌抗原刺激的银屑病外周血单个核细胞培养上清液对角质形成细胞的作用

目的 了解链球菌抗原刺激的银屑病外周血单个核细胞(PBMCs)培养上清液对角质形成细胞的作用以探讨链球菌感染后的银屑病的发病机制。方法 ^3H—TdR掺入法检测PBMCs培养上清液对角质形成细胞DNA合成的影响；免疫组织化学方法检测细胞间教附因子1(ICAM—1)和人类白细胞抗原DR分子(HLA—DR)表达。结果 银屑病患者链球菌抗原刺激的PBMCs培养上清液对角质形成细胞的促增殖作用较对照组显著增强，并能诱导角质形成细胞表达HLIA—DR和ICAM—1分子。结论 受链球菌抗原刺激的银屑病PBMCs培养上清液可促进角质形成细胞增殖和活化，可能是链球菌感染之后银屑病发病的重要原因。     

CD8+ cell changes in psoriasis associated with roxithromycin-induced clinical improvement

We have shown that T cell receptor BV2- and BV8-bearing CD8+ cells are decreased in the peripheral blood of psoriatic patients, while T cells possessing these BVs accumulate in psoriatic lesions. T cells homing to skin express cutaneous lymphocyte-associated antigen (CLA), and bacterial superantigens that trigger psoriasis promote this expression. Roxithromycin has immunomodulatory potency and its effectiveness for psoriasis has been proposed. Therefore, we monitored BV usage and alteration of superantigen-promoted CLA expression in circulating CD8+ cells of psoriatics before and after roxithromycin therapy. After roxithromycin treatment, circulating BV2- and BV8-bearing CD8+ cells were increased and CD8+ cells exhibited reduced expression of CLA when stimulated in vitro with bacterial superantigens. It is suggested that roxithromycin downregulates augmented expression of CLA by CD8+ cells, thereby suppressing their skin-homing and elevating the numbers of circulating BV2- and BV8-positive CD8+ cells. Such events may be included in part in the improvement of psoriasis with roxithromycin.     

Influence of psoriatic peripheral blood CD4+ T and CD8+ T lymphocytes on C-myc, Bcl-xL and Ki67 gene expression in keratinocytes

T cells play a role in the hyperproliferation of keratinocytes, however, direct evidence on what is the main mechanism and which T-cell subset is central is still lacking. Our aim was to elucidate the role and mechanism of CD4+T and CD8+ T lymphocytes in the immunopathogenesis of lesion hyper-proliferation in psoriasis. T cell and CD4+T and CD8+ T cell subpopulations were isolated by immunomagnetic methods from peripheral blood of psoriatic patients and healthy volunteers. Keratinocytes from foreskins were incubated in the absence or presence of T cells and T cell subpopulations for 72 h. The expression of c-Myc, Bcl-xL and Ki67 proteins in keratinocytes were detected by immunohistochemical staining, and then IL-4, IL-8 and IFNgamma level in the supernatant was determined by respective ELISA. T cells of psoriatic origin induced keratinocytes to overexpress C-myc and Ki67 proteins with high amounts of IL-8 and IFN-gamma in the supernatant, while the T cells of normal origin did not. Furthermore, there was a difference in keratinocyte response to CD4+ T cells and CD8+ T cells from psoriatic patients. CD4+ T cells can secrete much higher levels of IL-8 and IFN-gamma and induced much stronger C-myc and Ki67 expression in keratinocytes, compared with CD8+ T cells. We concluded that psoriatic peripheral blood T cells and the T cell subpopulation could induce keratinocytes to over-express pro-proliferation proteins probably by secreting Th1 cytokines. T cells, especially the CD4+ T cell subpopulation, play an important role in the immunopathogenesis of lesion hyper-proliferation in psoriasis.     

Immunomodulation induced by Avène spring water on Th1- and Th2-dependent cytokine production in healthy subjects and atopic dermatitis patients.

Avène spring water (ASW) is commonly used in France for treating atopic dermatitis and psoriasis. Previous works demonstrated modulation of cell membrane fluidity by ASW. The aims of the present study were (a) to investigate a possible in vitro effect of ASW on Th1- and Th2-dependent cytokine production using peripheral blood mononuclear cells from healthy individuals and (b) to investigate both the in vitro effect of ASW on AD patients' cells and the in vivo cellular and clinical modifications induced by a 3-week Avène Medical Spa water cure (AMSWC). The effect of ASW was tested on lymphocyte cultures, which were stimulated in vitro by various mitogens and a superantigen of staphylococcal origin. The lymphocyte proliferation and the production of the cytokines IL-2, IL-4 and IFN-gamma were tested. The results showed that ASW-containing medium enhanced the lymphoproliferative response to some mitogens. IL-2 and IFN-gamma production were also increased in stimulated culture supernatants. Conversely, ASW-containing medium induced a decrease in IL-4 production by normal peripheral blood lymphocytes. Furthermore, AMSWC was able to amend the clinical features as well as the immunological Th2 profile of atopic dermatitis.     

Bacterial superantigens and inflammatory skin diseases

Bacteria seem to play an important role in the induction and maintenance of inflammatory skin diseases such as psoriasis and atopic dermatitis. Toxins from bacteria including Streptococcus and Staphylococcus aureus, have been shown to function as a new type of allergen termed 'superantigen'. Superantigens bypass the normal control of T-cell activation and activate all T-cell clones bearing certain types of variable chain on the T-cell receptor: this leads to vigorous T-cell activation and cytokine release. These bacterial superantigens may be involved in induction and aggravation of inflammatory skin diseases. Guttate psoriasis is often preceded by a streptococcal throat infection and T cells specific for streptococcal superantigens have been identified in the skin of patients. The skin of patients with atopic dermatitis is often colonized with superantigen-releasing Staph. aureus, and application of a staphylococcal superantigen to human skin induces an eczematoid reaction.     

Ultraviolet-B irradiation decreases IFN-gamma and increases IL-4 expression in psoriatic lesional skin in situ and in cultured dermal T cells derived from these lesions

Type 1 cytokine producing T cells play an important role in the pathogenesis of psoriasis. Ultraviolet-B (UVB) irradiation is effective in the treatment of this disease. In normal skin, UVB causes a change in dermal microenvironment, leading to a decrease of IFN-gamma expressing type 1 T cells and a concurrent increase of IL-4 expressing type 2 T cells. The aim of this study was to show whether UVB irradiation causes a like-wise shift of type 1 and type 2 responses in psoriatic skin. For this purpose, biopsies were obtained from the lesional skin of psoriatic patients before, 2 days and 14 days after a single exposure to 4 MED UVB. Sections from these biopsies were immunostained (CD3, IFN-gamma and IL-4) or RNA was extracted and analyzed for the expressions of IFN-gamma and IL-4 by PCR. In addition, primary cultures of T cells from dermal cell suspensions were stained intracellularly for IFN-gamma and IL-4 expression and CD4+ and CD8+ T subsets were analyzed by flow cytometry. IFN-gamma was abundantly expressed in situ before irradiation and decreased in all patients after UVB irradiation, whereas IL-4 expression was variably expressed before irradiation and increased in different degrees after irradiation. Cytokine mRNA expressions determined by PCR showed a clear decrease of IFN-gamma and increase of IL-4 following UVB irradiation. Both CD4+ and CD8+ dermal T cells were found to produce less IFN-gamma and more IL-4 following UVB irradiation as determined by flow cytometry. Decrease in IFN-gamma expression and increase in IL-4 expression of dermal T cells in psoriatic lesions after UVB irradiation may lead to decrease in local immunoreactivity. These changes could be part of the therapeutic effects of UVB on psoriasis.     

Peripheral blood mononuclear cells proliferation and Th1/Th2 cytokine production in response to streptococcal M protein in psoriatic patients

BACKGROUND: Psoriasis is a chronic skin disease that is probably a T cell-mediated autoimmune condition which is strongly associated with streptococcal throat infections. Although some groups have associated the involved response with different streptococcal antigens, M protein has been described as the major virulence factor of Streptococcus pyogenes. Thus, it is necessary to describe some features of the cellular responses to this streptococcal antigen. METHODS: Proliferation and Th1/Th2 cytokine production of peripheral blood mononuclear cells (PBMC) in response to total soluble extracts from type M5 S. pyogenes with (TSE37Sp) and without (M(-)TSESp) M protein were analyzed in 10 psoriatic patients and 10 healthy controls. RESULTS: PBMC from both patients and controls proliferated to both extracts. Responses to M(-)TSESp were significantly lower than those to TSE37Sp (P < 0.05). PBMC IL-2 and gammaIFN production after TSE37Sp stimulus was much higher than after M(-)TSESp antigenic stimulation in both groups (P < 0.05). Meanwhile, IL-4 production was quite low in both groups and in response to both extracts. We found a differential production of IL-10 between groups. PBMC from healthy controls responded to TSE37Sp with a much higher production of this cytokine as compared to the responses showed to M(-)TSESp while the cells from psoriatic patients responded without differences in the production of IL-10. CONCLUSION: Results obtained suggest an important Th1 response to M protein in psoriatic patients which could be associated with the cellular responses involved in psoriasis, while healthy subjects respond in a probably non-Th2 IL-10 producing regulatory T cells fashion.     

SAg作用的银屑病T细胞对表皮c-myc bcl-2及P53蛋白的影响

目的探讨链球菌超抗原与银屑病的关系,揭示银屑病患者外周血T细胞的特殊活性。方法将银屑病患者和正常人外周血T细胞及链球菌超抗原(SAg)刺激的银屑病和正常人T细胞分别与皮肤组织共同培养,免疫组化法检测不同T细胞对表皮cmyc,bcl2及P53蛋白的影响。结果正常人皮肤、银屑病患者未受累皮肤受银屑病患者T细胞作用后,表皮cmyc,bcl2及P53蛋白与正常人T细胞作用组比较有显著性差异(P均<0.05);受SAg刺激的银屑病患者T细胞对表皮cmyc,bcl2及P53蛋白的影响与未受SAg刺激组比较差异无显著性(P均>0.05),SAg非特异性活化的正常人T细胞对表皮cmyc,bcl2及P53蛋白不能产生显著影响(P均>0.05)。结论银屑病患者T细胞在外周血已处于活化状态,其活性与链球菌超抗原多克隆激活的正常人T细胞在功能上有本质区别,这一特殊的活性,可能在诱导表皮动力学紊乱及银屑病发病中发挥重要的作用。     

链球菌M6蛋白诱导点滴型银屑病样动物模型的研究

目的利用链球菌M6蛋白建立严重联合免疫缺陷鼠(SCID鼠)银屑病样动物模型。方法将点滴型银屑病患者非皮损区全层皮片、正常对照全层皮片移植到不同的SCID鼠背部,分别在移植皮片皮内多次注射经链球菌M6蛋白刺激后和未经链球菌M6蛋白刺激的外周血单一核细胞(PBMC)悬液,4周后对移植皮片行组织活检。结果光学显微镜下观察,13例点滴型银屑病患者非皮损区皮片内注射经链球菌M6蛋白刺激后的PBMC有12例产生银屑病样改变;9例正常对照皮片内注射经链球菌M6蛋白刺激后的PBMC均未出现银屑病样改变;10例点滴型银屑病患者非皮损区皮片及9例正常对照皮片内注射未经链球菌M6蛋白刺激后的PBMC均未出现银屑病样改变。经统计学处理两组间差异有显著性(P<0.001)。结论本试验利用链球菌M6超抗原成功建立了银屑病样动物模型,从而进一步证实链球菌M6蛋白在点滴型银屑病发病中发挥着重要的作用。     

Skin CD4+ T cells produce interferon-gamma in vitro in response to streptococcal antigens in chronic plaque psoriasis

Recently, we have demonstrated that group A streptococcal antigen reactive T cells are present in the skin lesions of chronic plaque psoriasis. To determine the cytokine profile (interferon-gamma, interleukin-4 and interleukin-10) of these T cells in response to streptococcal antigens, T cell lines were cultured from untreated lesional skin of 13 patients with chronic plaque psoriasis and 12 patients with other inflammatory skin diseases. T cell lines were incubated with or without a sonicated heat-killed mixture of group A streptococcal isolates for 18 h in the presence of a transport inhibitor, stained for surface CD4 or CD8 and intracellular cytokine expression, and analyzed by flow cytometry. Psoriatic T cell lines were grown from 10 of 13 patients and were predominately CD4+ (64%-85%) with 10%-32% CD8+ T cells. Variable numbers of CD4+ T cells produced interferon-gamma (0.8%-35%, median 13.9) in eight of 10 T cell lines (p < 0.02). In contrast, CD4+ T cells in five of 12 T cell lines obtained from disease controls did not produce or produced minimal interferon-gamma in response to group A streptococcal isolates; this was significantly different from the psoriatic T cell lines (p < 0.05). Small numbers of interleukin-10 positive (0.8%-1.3%) and interleukin-4 positive (2.1%-2.5%) CD4+ T cells induced by group A streptococcal isolates were also present in two out of five and three out of five psoriatic T cell lines, respectively. This was significantly less in each case than the numbers of CD4+/interferon-gamma+ T cells (p < 0.05). Cytokine-positive CD8+ T cells were rarely observed. These findings demonstrate that a subpopulation of CD4+ T cells in chronic plaque psoriasis skin lesions produces interferon-gamma in response to streptococcal antigens and may be relevant to the pathogenesis of psoriasis.     

The effects of ultraviolet B treatment on the expression of adhesion molecules by circulating T lymphocytes in psoriasis

BACKGROUND: T lymphocytes are believed to play a role in the pathogenesis of psoriasis; > 80% of T lymphocytes that infiltrate psoriatic lesions express the surface glycoprotein cutaneous lymphocyte-associated antigen (CLA), compared with < 20% in the blood. Exposure to ultraviolet (UV) B is an effective treatment for psoriasis. OBJECTIVES: To compare the effects of UVB treatment of psoriasis on the expression of CLA and several other surface markers expressed by circulating T lymphocytes. METHODS: Peripheral blood mononuclear cells from psoriatic patients were stained for adhesion molecules and stimulated with streptococcal antigens before and once weekly during 3 weeks of UVB treatment. RESULTS: A marked and progressive decrease was observed during the treatment in expression of the CLA and the very late antigen-4alpha by T cells; this decrease correlated closely with clinical improvement (Psoriasis Area and Severity Index). T-cell expression of intercellular adhesion molecule-1 was not significantly affected during the treatment and no change was observed in the activation markers CD25 and CD69 or lymphocyte proliferation after stimulation with streptococcal antigens or superantigens. CONCLUSIONS: UVB treatment is associated with a marked reduction in the expression of skin-homing molecules by circulating T cells. This may be relevant to the therapeutic effect of UVB in psoriasis.