Interleukin-4 and interferon-gamma interactions in the induction of intercellular adhesion molecule-1 and major histocompatibility complex class II antigen expression of normal human keratinocytes

Keratinocytes Present Staphylococcus aureus Enterotoxins and Promote Malignant and Nonmalignant T Cell Proliferation in Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma is characterized by malignant T cells proliferating in a unique tumor microenvironment dominated by keratinocytes (KCs). Skin colonization and infection by Staphylococcus aureus are a common cause of morbidity and are suspected of fueling disease activity. In this study, we show that expression of HLA-DRs, high-affinity receptors for staphylococcal enterotoxins (SEs), by KCs correlates with IFN-γ expression in the tumor microenvironment. Importantly, IFN-γ induces HLA-DR, SE binding, and SE presentation by KCs to malignant T cells from patients with Sézary syndrome and malignant and nonmalignant T-cell lines derived from patients with Sézary syndrome and mycosis fungoides. Likewise, preincubation of KCs with supernatant from patient-derived SE-producing S aureus triggers proliferation in malignant T cells and cytokine release (including IL-2), when cultured with nonmalignant T cells. This is inhibited by pretreatment with engineered bacteriophage S aureus-specific endolysins. Furthermore, alteration in the HLA-DR-binding sites of SE type A and small interfering RNA-mediated knockdown of Jak3 and IL-2Rγ block induction of malignant T-cell proliferation. In conclusion, we show that upon exposure to patient-derived S aureus and SE, KCs stimulate IL-2Rγ/Jak3-dependent proliferation of malignant and nonmalignant T cells in an environment with nonmalignant T cells. These findings suggest that KCs in the tumor microenvironment play a key role in S aureus-mediated disease activity in cutaneous T-cell lymphoma.

Chloroquine treatment reduces the number of cutaneous HLA-DR+ and CD1a+ cells in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that can be exacerbated by exposure to ultraviolet radiation (UVR). The number and phenotype of antigen presenting cells in the skin play a role in cutaneous immune response generation. Although antimalarials are widely used in SLE treatment, their mode of action is not completely elucidated. The aim of our study was to determine the effect of chloroquine treatment on HLA-DR+ and CD1a+ cell number in locally irradiated (three minimal erythema doses of UVB) and normal appearing skin in SLE patients and healthy subjects. A significantly higher number of HLA-DR+ and CD1a+ cells were found in both locations in SLE patients compared with controls. Following three months of daily chloroquine treatment (250 mg), the HLA-DR+ and CD1a+ cell counts were significantly reduced in both irradiated and unirradiated sites of SLE patients, although still higher than in controls. Chloroquine treatment reduces the number of antigen presenting cells in the skin of SLE patients, and this effect may explain the antimalarials beneficial immunoregulatory and anti-inflammatory properties.

CD4+ T-cells from peripheral blood of a patient with psoriasis recognize keratin 14 peptide but not 'homologous' streptococcal M-protein epitope

Psoriasis has been recognized as an immunologically mediated inflammatory skin disease that has been associated with group A, beta-haemolytic streptococcal infections. Notably cross-reactive autoimmune mechanism, which is mediated by T cells reacting to epitopes that are common to streptococcal M-protein and keratin, has been proposed in psoriasis. In order to investigate this possibility, peptides corresponding to M-protein and human epidermal keratin, which share some amino acid sequence between them, were synthesized and tested for their ability to stimulate T-cells of patients with psoriasis. Among five cases examined, we isolated a CD4(+) T-cell line that recognized the type I keratin (K14)(p168-181) when it was presented by the patient's HLA-DR molecules from a single psoriatic patient, whose MHC allele was HLA-A2/A26, -B27/B16, -DR4/DR8, -DQ8. Further analysis disclosed that the critical peptide recognized by the T-cell line was 10-mer keratin(p171-180) (DLRNKILTAT). However, corresponding M6 protein with homology to K14 did not stimulate the T-cell response and no evidence for cross-reactivity was obtained. The K14-responsive T cell line produced IFN-gamma, but little IL-4 when stimulated with irradiated autologous PBMC pulsed with this peptide. Thus, the finding that human epidermal keratin peptide is immunogenic in a psoriasis patient may provide the evidence that T lymphocytes play an important role in the pathogenesis of psoriasis as an autoimmune disorder participated with Th1 like cells. However, the keratin-responsive T cell line was detected in only one of five cases of psoriasis examined, suggesting that such T cell line appears to be not so popular in psoriatic patients. No evidence for cross-reactivity to streptococcal M protein also suggests that the contribution of streptococci may simply be inducing proliferation of various repertoire of T cells (including K14-responsive T cells) possibly through a superantigen-dependent process.

IL-4 and interferon-gamma differentially modulate vascular endothelial growth factor release from normal human keratinocytes and fibroblasts

IL-4 and interferon-gamma (IFN-gamma) are crucial modulators of the immune system and are reported as active antitumor agents and potent inhibitors of angiogenesis. We investigated the effects of these two cytokines on the expression of vascular endothelial growth factor (VEGF), a mediator of major importance in the angiogenesis associated with inflammation, wound healing and tumor invasion and expressed by activated keratinocytes and dermal fibroblasts. Human keratinocytes (HK) and fibroblasts (HF) derived from foreskins, were further cultured during 24 h in defined medium, supplemented or not with the selected growth factors, EGF and TGF-beta1, respectively, before receiving the addition of either IL-4 or IFN-gamma during 24 and 48 h. In basal conditions, fibroblasts produced smaller amounts of VEGF than keratinocytes; the addition of growth factors to the skin cells induced a drastic increase of VEGF secretion. In HF, the basal level of VEGF secretion was reduced by IFN-gamma and slightly increased by IL-4 whereas in HK, IFN-gamma enhanced the secretion of VEGF after 48 h and IL-4 either tended to reduce VEGF secretion or did not exert any effect. Similar but more significant results were observed in skin cells activated by growth-stimulating factors. The association of IL-4 and IFN-gamma mimicked the effects of IFN-gamma alone both in HF and HK. Taken together, these results indicate opposite effects of IFN-gamma and IL-4 on VEGF expression from normal and activated HF and HK. IL-4 may be considered as a poor modulator of VEGF secretion by dermal and epidermal cells. Conversely, IFN-gamma appears as a prominent and versatile mediator in the desregulated angiogenesis associated with inflammatory skin reactions characterized by a T-helper type 1 cell-mediated response.

CD9 and HLA-DR expression by crevicular epithelial cells and polymorphonuclear neutrophils in periodontal disease

BACKGROUND, AIMS

The composition of gingival crevicular fluid (GCF) is likely to reflect inflammatory modifications that take place in the gingiva during periodontal diseases.

METHOD

In this study, GCF was collected at 3 different sites from 23 periodontal patients. The sites were assessed to be healthy, presenting gingivitis or periodontitis. 10 healthy individuals without any form of periodontal disease formed the control group and were sampled at one site each. The cell content of GCF was collected using Durapore Millipore strips, and 2 types of cells were studied: epithelial cells (EC) and polymorphonuclear neutrophils (PMN). The expression of CD9 and HLA-DR within or on the surface of these cells was studied in immunofluorescence on cytospin smears.

RESULTS

Both CD9 and HLA-DR expression on EC differed significantly from control subjects, and the latter decreased according to the severity of the pathology. None of the PMN found in controls expressed CD9 or HLA-DR. However, in periodontal patients, the expression of HLA-DR within PMNs was detectable and increased according to the severity of lesions. CD9 expression on PMNs also increased with inflammation.

CONCLUSION

This study shows that clinically healthy sites of periodontal patients already present signs of immunological activation characterised by a down modulation of HLA-DR expression on EC and an upregulation of these 2 molecules in PMN.

Interleukin-17 is produced by both Th1 and Th2 lymphocytes, and modulates interferon-gamma- and interleukin-4-induced activation of human keratinocytes

Interleukin-17 is a T-cell-derived cytokine, detected in skin affected by allergic contact dermatitis and psoriasis, which regulates keratinocyte expression of adhesion molecules and chemokines. In this study, we have analyzed whether interleukin-17 production segregates with a particular T helper (Th) cell subset, and have examined the capacity of interleukin-17 to modulate the activation of keratinocytes induced by Th1 and Th2 cytokines. A panel of 80 nickel-specific CD4+ T cell clones (36 Th0, 30 Th1, and 14 Th2) was isolated from peripheral blood or lesional skin of allergic contact dermatitis patients. Significant amounts (> 50 pg per ml) of interleukin-17 were released by about 50% of activated Th0, Th1, and Th2 cells. Interleukin-17 alone and in cooperation with interleukin-4, or to a lesser extent with interferon-gamma, decreased the interleukin-1 receptor antagonist to interleukin-1alpha ratio in the supernatants as well as in cell lysates from keratinocytes. In addition, interleukin-17 stimulated the release of growth-regulated oncogene-alpha, granulocyte-macrophage colony stimulating factor, and interleukin-6, with synergistic or additive effects when used together with interferon-gamma or interleukin-4. Interleukin-17 and interleukin-4 also increased stem cell factor release, a function that was inhibited by interferon-gamma. Moreover, interleukin-17 and interleukin-4 enhanced interferon-gamma-induced expression of intercellular adhesion molecule 1, but not CD40, on keratinocytes. The constitutive expression of interleukin-17 and interferon-gamma receptors on keratinocytes was not modulated by interleukin-17, interferon-gamma, or interleukin-4, whereas the interleukin-4 receptor was significantly downregulated by interferon-gamma. As a whole, the results indicate that interleukin-17 can participate relevantly in T-cell-mediated skin immune responses by amplifying both interferon-gamma- and interleukin-4-induced activation of keratinocytes.

Treatment of T lymphocytes with 8-methoxypsoralen plus ultraviolet A induces transient but biologically active Th1-skewing cytokine production

8-Methoxypsoralen plus ultraviolet A light is suggested to shift T lymphocytes from Th2 to Th1 cells. To clarify this issue, we examined the effects of 8-methoxypsoralen/ultraviolet A on the expression/production of cytokines in peripheral blood mononuclear cells from normal subjects and a Sézary syndrome patient. 8-Methoxypsoralen/ultraviolet A augmented the expression of mRNAs for interferon-gamma and interleukin-2 and reduced those for interleukin-4 and interleukin-10. It seems that this enhancement of Th1 cytokines is caused by increment of cytokine production by Th1 cells but not by conversion of Th2 cells to produce Th1 cytokines. The number of interferon-gamma-secreting lymphocytes was markedly increased in 8-methoxypsoralen/ultraviolet A-treated peripheral blood mononuclear cells 20 h after treatment, whereas that of Th2 cytokine-producing cells was decreased. Accordingly, the amount of interferon-gamma was elevated in culture supernatants from 8-methoxypsoralen-phototreated peripheral blood mononuclear cells, whereas interleukin-4 was significantly reduced. This enhanced production of interferon-gamma, however, was found only until 3 d after 8-methoxypsoralen phototreatment and was declined by 5 d after treatment. Finally, 8-methoxypsoralen/ultraviolet A treatment of T cells regulated their ability to induce keratinocyte CD54 expression. Our results show that 8-methoxypsoralen/ultraviolet A has a transient but biologically active Th1-skewing action in human T cells, suggesting that 8-methoxypsoralen/ultraviolet A exerts a beneficial therapeutic effect on Th2-mediated or Th2-malignant diseases.

Langerhans cells in prurigo nodularis investigated by HLA-DR and S-100 immunofluorescence double staining

The Langerhans cell is one of the antigen-presenting cells in the immune system. To study the presence of cutaneous Langerhans cells in prurigo nodularis, age- and sex-matched prurigo nodularis patients and healthy volunteer skin biopsies were investigated by an HLA-DR and S-100 immunohistochemical double staining method. The results showed that the HLA-DR- and S-100-immunoreactive (IR) Langerhans cells were altered in prurigo nodularis epidermis and dermis. The number of epidermal Langerhans cells in the prurigo nodularis patients was decreased in five and increased in two cases. In the dermis, the HLA-DR- and S-100-IR cells were apparently more numerous than in the controls. In the involved skin there were also more S-100-IR coarse nerve fibres in the dermis as compared to controls. The results indicate that dermal Langerhans cells (HLA-DR and S-100 double-labeled) as well as other dermal HLA-DR- and S-100-IR dendritic cells, but most likely not epidermal Langerhans cells, may be critically involved in the development or persistence of prurigo nodularis.

Regulation of epidermal expression of keratin K17 in inflammatory skin diseases

Keratin K17, the myoepithelial keratin, is expressed in psoriasis but is not present in healthy skin. Psoriasis is associated with production of gamma interferon (IFN gamma), which induces the expression of keratin K17 by activating transcription factor STAT1. Our hypothesis states that the induction of K17 is specific for the inflammatory reactions associated with high levels of IFN gamma and activation of STAT1. One of the corollaries of the hypothesis is that the STAT1-activating cytokines should induce the expression of keratin K17, whereas those cytokines that work through other mechanisms should not. Furthermore, because the STAT activation pathway is dependent upon protein phosphorylation events, phosphorylation inhibitors should attenuate the induction of keratin K17, whereas protein phosphatase inhibitors should augment it. To test this hypothesis, we analyzed lesional samples of inflammatory diseases using immunofluorescence, transfected keratinocytes with K17 gene promoter DNAs in the presence of various cytokines, and followed nuclear translocation of STAT1 in keratinocytes using specific antibodies. Confirming the hypothesis, we found that K17 is induced in psoriasis and dermatitis caused by delayed type hypersensitivity, which are associated with high levels of IFN gamma, but not in samples of atopic dermatitis, which is not. Two cytokines, interleukin-6 and leukemia inhibitory factor, which can induce phosphorylation of STAT1, can also induce K17 expression, whereas interleukin-3, interleukin-4, interleukin-10, and granulocyte macrophage colony stimulating factor have no effect on K17 expression. As expected, staurosporine and genistein inhibited, whereas okadaic acid augmented, the induction of K17 by IFN gamma. Our data indicate that in inflammatory skin diseases, lymphocytes, through the cytokines they produce, differently regulate not only each other, but also keratin gene expression in epidermis one of their target tissues.

Differences of reactivity to interferon gamma in HeLa and CaSki cells: a combined immunocytochemical and flow-cytometric study

We characterized the changes induced by treatment for 48 h with 100 U/ ml interferon gamma (IFN-gamma) on HeLa and CaSki cells, derived from human uterine carcinomas and containing human papillomavirus (HPV) type 16 and HPV type 18 respectively, by studying cell growth, cell morphology, the cell cycle and expression of epidermal growth factor (EGF) receptor, filaggrin-profilaggrin and MHC class II antigen, HLA-DR. The response of the two cell lines to IFN gamma differed in some cases. In both cell lines, the cells remained viable; cell growth was similarly inhibited as shown by cell counts. Signs of morphological changes were essentially observed in HeLa cells. The cell cycle phases, analyzed by flow cytometry were more disturbed in CaSki than in HeLa cells; the proportion of CaSki cells in S phase increased and those in G2 + M decreased. Expression of EGF receptors related to proliferation increased only in CaSki cells while expression of filaggrin-profilaggrin, a marker of differentiation, and HLA-DR, a marker of epithelial cell immune response, was enhanced in both cell lines. The presence of filaggrin-profilaggrin being unexpected in these cells, the specificity of the reaction with the monoclonal antibody AKH1 was confirmed by immunoblotting. In conclusion, our results show that the two cell lines reacted differently to IFN gamma although they are of similar origin and the different antigens studied may be useful to predict the progression of lesions infected with HPV towards malignancy or the reactivity to IFN gamma of such lesions. However, enhanced synthesis of EGF receptors is probably independent of the antiproliferative effect of IFN gamma but an increase in HLA-DR antigen expression by epithelial cells, which corresponds to an immune response favored by IFN gamma, could act synergistically with cell growth inhibition and differentiation to exclude tumoral and/or HPV-infected cells.