IL-10 levels are decreased in psoriatic lesional skin as compared to the psoriatic lesion-free and normal skin suction blister fluids

IL-10 is a cytokine produced by B and T-cells, monocytes and keratinocytes with pleiotropic effects, some of which are directed towards suppressing monocyte activities (anti-inflammatory cytokine). No information at the protein level is available concerning IL-10 in suction blister fluids from psoriatic skin, even if contrasting data have been reported on IL-10 mRNA of psoriatic biopsies and on the cytokine patterns of the T-cell clones, isolated from psoriatic skin. The IL-10 blister fluid concentrations in psoriatic lesions were compared to those found in the non-lesional skin of 14 patients effected with plaque-type psoriasis, and to those found in the skin of healthy controls (9 subjects sharing sex ratio and age with psoriatic patients). No difference in the IL-10 levels was found between non-lesional and control skin. In contrast, lower IL-10 levels were observed in blister fluids obtained from lesional psoriatic skin (p < 0.0005). The possible meanings of these results have been evaluated in the context of the mechanisms activating or maintaining the chronic inflammatory components of psoriasis.     

Oxidative activity of the type 2 isozyme of 17beta-hydroxysteroid dehydrogenase (17beta-HSD) predominates in human sebaceous glands

Interactions between infiltrating T cells and keratinocytes via the secretion of the TH1 cytokines interleukin (IL) 2 and interferon gamma (INF-gamma), the keratinocyte growth factor transforming growth factor alpha (TGF-alpha) and the cytokines IL-6 and IL-8 are thought to be the predominant mechanisms inducing skin lesions in psoriatic patients. Systemic treatment of psoriasis with fumaric acid derivatives (FAEs) has been reported to be effective in the treatment of psoriasis, but the mode of action is still unknown. To clarify this phenomenon, keratinocytes from psoriatic patients as well as from healthy volunteers were mono- and cocultured with HUT 78 T cells with/without the addition of FAEs; the cytokine concentrations were then measured in the culture supernatants. Furthermore, mRNA expression was determined in epidermal growth factor (EGF) -activated keratinocytes as well as in phytohaemagglutinin (PHA)-activated HUT 78 T cells. Only dimethylfumarate (DMF) diminished IL-6 and TGF-alpha secretion in the psoriatic cocultures. However, it did not have this effect on cocultures from control subjects or on monocultures. DMF suppresses EGF-induced TGF-alpha mRNA induction in psoriatic keratinocytes. DMF inhibited INF-gamma secretion in all cultures but stimulated the IL-10 secretion. This immunomodulation away from the TH1 cytokine IFN-gamma to the TH2 cytokine IL-10 was confirmed in HUT 78 T cells by Northern blot analysis. An increased number of eosinophils is a known side-effect in patients treated with this drug, suggesting a clinical relevance of this immunomodulation in vivo. This immunomodulation and the suppression of cytokines from the psoriatic cytokine network could be responsible for the beneficial effect of DMF in the treatment of a hyperproliferative and TH1 cytokine-mediated skin disease.     

Intraepidermal nerve fiber expression of calcitonin gene-related peptide, vasoactive intestinal peptide and substance P in psoriasis

In order to evaluate more fully the role of neuropeptides in the pathogenesis of psoriasis, skin biopsies were obtained from 36 patients with psoriasis to identify substance P (SP), vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP). Lesional and nonlesional skin was examined from these biopsies and the results compared with those from biopsies taken from patients with a variety of other inflammatory dermatoses, including lichen planus, lichen simplex chronicus, spongiotic dermatitis, and seborrheic dermatitis. Also studied was a series of nine biopsies taken from patients with no known skin disorders. We found an increase in the number of SP-positive nerve fibers within the epidermis in biopsies from lesional skin of psoriasis patients (8.4 nerves per 3-mm biopsy) compared with nonlesional psoriatic skin (2.6 nerves per 3-mm biopsy) and normal skin (2.0 nerves per 3 mm biopsy). Other inflammatory disorders also demonstrated fewer SP-positive nerves than lesional psoriatic skin; lichen planus (0 nerves per 3 mm biopsy) and lichen simplex chronicus (1.3 nerves per 3 mm biopsy). The difference in SP-positive nerve expression between lesional psoriatic skin and the group comprising nonlesional skin, normal skin, lichen planus, and lichen simplex chronicus attained statistical significance (P < 0.013). SP-positive intraepidermal nerve fibers in lesional psoriatic specimens were fewer than in spongiotic dermatitis (17.4 nerves per 3 mm biopsy). There was no significant difference in numbers of VIP- or CGRP-immunopositive intraepidermal nerve fibers between psoriatic skin and the group comprising all other material tested. However, in five patients with psoriasis, there was a marked increase in the expression of intraepidermal CGRP (up to 10.7 nerves per 3-mm biopsy) and VIP (up to 8.3 nerves per 3-mm biopsy) which was not observed in control groups. These findings suggest that neuropeptides SP, CGRP, and VIP play a role in the pathogenesis of psoriasis.     

Mast cells of psoriatic and atopic dermatitis skin are positive for TNF-alpha and their degranulation is associated with expression of ICAM-1 in the epidermis

The release of cytokines from cutaneous cells may be of major importance in the initiation and development of many inflammatory skin disorders. For example, tumor necrosis factor-alpha (TNF-alpha), which in healthy skin is found preformed only in mast cells, is able to induce the expression of several adhesion molecules including intercellular adhesion molecule-1 (ICAM-1). Increased expression of ICAM-1 occurs in keratinocytes in lesional skin of psoriasis and atopic dermatitis (AD) and it is considered to be an important initiator of leucocyte/keratinocyte interactions in skin inflammation. We counted the mast cells showing TNF-alpha immunoreactivity using a double-staining method in nonlesional and lesional skin sections from 12 patients with AD and 12 patients with psoriasis. The percentage of TNF-alpha+ mast cells in lesional and nonlesional AD skin was 36 +/- 22% and 21 +/- 15% (P < 0.018, paired t-test), respectively, and in psoriatic skin was 16 +/- 25% and 15 +/- 15%, respectively (P < 0.89, paired t-test). We also cultured whole skin biopsies taken from the healthy-looking skin of psoriatic and AD patients in the presence of mast cell degranulator compound 48/80, which resulted in focal expression of ICAM-1 in the epidermis. In cultured keratinocytes, both histamine and an extract of a human mast-cell line (HMC-1) induced ICAM-1 immunostaining only in occasional cells, but the combination of histamine and the HMC-1 extract resulted in intense ICAM-1 staining in numerous cells. This enhancement of ICAM-1 staining was abolished by preincubation of the HMC-1 extract with anti-TNF-alpha antibody. These results suggest that the degranulation of mast cells induces the expression of ICAM-1 in keratinocytes probably via TNF-alpha and histamine.     

Comparison of the Interplak and manual toothbrushes in a population with mental retardation/developmental disabilities (MR/DD)

A still debated question in the field of the cytokine network in psoriasis is represented by contrasting data reported on the local amount of IL-1 beta amounts, of IL-1 in this dermatosis. In fact previous studies have suggested that there were decreased Il-1 alpha amounts at the lesional level but increased nonfunctional IL-1 beta concentrations as compared to the non-lesional and normal epidermis. However, recent data suggest that IL-1 alpha and, to a lesser extent, IL-1 beta amounts, are both increased and biologically active in the epidermal cell suspension of lesional psoriatic skin as compared to those of normal skin. The data reported in the present paper show that IL-1 alpha levels are decreased in psoriatic lesional extracts of whole skin (mean 2.9 +/- 2 pg/mg) as compared to non-lesional (mean 6.7 +/- 6.2 mg/mg; p = 0.02) or normal skin (mean 13.8 +/- 9.4 pg/mg; p = 0.0002). IL-1 alpha concentrations were also significantly lower in the non-lesional skin than in normal skin (p = 0.02). In contrast, the IL-1 beta levels (mean 1.2 +/- 0.74 pg/mg were higher in the lesional samples than in the non-lesional ones (mean 0.5 +/- 0.4 pg/mg; p = 0.0004) or in normal skin (mean 0.4 +/- 0.2 pg/mg; p = 0.004). No differences in IL-1 beta levels were observed between non-lesional and normal skin (p = 0.3). In addition both IL-1 alpha and IL-1 beta are directly correlated with the disease severity and each other. Our data, extending the Il-1 determination to the whole skin, seem to confirm the previously reported findings at the epidermis level and provide new light on possible interpretation of literature discrepancies.     

Low sensitivity of adrenal chromaffin cells to acetylcholine, neostigmine and oxotremorine in 21-day-old rats

To evaluate the immunological function of peripheral blood monocytes (PBMC) in psoriasis, we measured spontaneous production of the inflammatory cytokines, TNF-alpha, IL-1beta and IL-6 from the PBMC of psoriasis patients, by enzyme linked immunosorbent assay (ELISA). The production of all three inflammatory cytokines by psoriatic PBMC was significantly higher than that by normal control PBMC. PBMC sampled from active psoriasis produced three cytokines significantly higher than samples from inactive psoriasis. In addition, IL-1beta and TNF-alpha production showed a positive relation to clinical severity, but IL-6 did not. TNF-alpha production increased much more than did the others. Therefore, the TNF-alpha to IL-1beta ratio was significantly higher, even in inactive psoriasis, than that of the normal control. In relation to focal infection, psoriatic PBMC sampled 3 h after a tonsillar provocation test increased cytokine production, compared with the level before provocation. The cases which responded to tonsillectomy or systemic methotrexate therapy, but not the non-responding cases, showed a significant decrease in PBMC cytokine productivity. These results strongly suggest that inflammatory cytokines, especially TNF-alpha, from monocytes are involved in the pathogenesis of psoriasis, and activated monocytes may work as an effective mediator of focal infection in skin lesions.     

Uptake of Leishmania major amastigotes results in activation and interleukin 12 release from murine skin-derived dendritic cells: implications for the initiation of anti-Leishmania immunity

Epidermal Langerhans cells (LC) are immature dendritic cells (DC) located in close proximity to the site of inoculation of infectious Leishmania major metacyclic promastigotes by sand flies. Using LC-like DC expanded from C57BL/6 fetal skin, we characterized interactions involving several developmental stages of Leishmania and DC. We confirmed that L. major amastigotes, but not promastigotes, efficiently entered LC-like DC. Parasite internalization was associated with activation manifested by upregulation of major histocompatibility complex (MHC) class I and II surface antigens, increased expression of costimulatory molecules (CD40, CD54, CD80, and CD86), and interleukin (IL)-12 p40 release within 18 h. L. major-induced IL-12 p70 release by DC required interferon gamma and prolonged (72 h) incubation. In contrast, infection of inflammatory macrophages (Mphi) with amastigotes or promastigotes did not lead to significant changes in surface antigen expression or cytokine production. These results suggest that skin Mphi and DC are infected sequentially in cutaneous leishmaniasis and that they play distinct roles in the inflammatory and immune response initiated by L. major. Mphi capture organisms near the site of inoculation early in the course of infection after establishment of cellular immunity, and kill amastigotes but probably do not actively participate in T cell priming. In contrast, skin DC are induced to express increased amounts of MHC antigens and costimulatory molecules and to release cytokines (including IL-12 p70) by exposure to L. major amastigotes that ultimately accumulate in lesional tissue, and thus very likely initiate protective T helper cell type 1 immunity.     

Patterns of cytokine production in psoriatic synovium

OBJECTIVE: To determine patterns of cytokine production and mRNA expression in synovium from patients with psoriatic arthritis (PsA) and to compare the profile of cytokine production in PsA explants with those derived from rheumatoid (RA) and osteoarthritic (OA) synovia and psoriatic skin. METHODS: Cytokine levels were measured in supernatants from synovial and dermal explant cultures at Day 10 by ELISA. Cytokine mRNA expression in PsA whole tissue was determined by multi-gene assay. Cytokine levels in explant supernatants were compared between PsA, RA and OA, and psoriatic skin. Synovial tissues were scored histologically by a pathologist blinded to the clinical diagnosis. RESULTS: PsA explants released elevated levels of interleukin (IL)-1beta, IL-2, IL-10, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha, but not IL-4 or IL-5. A similar pattern of gene expression was detected in whole synovial tissue. These cytokine levels were greater in PsA than RA, despite higher histopathologic scores in RA explants. Production of IL-1beta, IFN-gamma, and IL-10 were strongly correlated. Levels of IFN-gamma, IL-1beta, and IL-10 were higher in psoriatic synovium than psoriatic dermal plaques. CONCLUSION: The cytokine profile in PsA is characterized by the presence of Th1 cytokines and the monokines TNF-alpha and IL-1beta and very elevated levels of IL-10. The higher levels of these cytokines in PsA compared to RA suggest the presence of different underlying mechanisms.     

Effect of calcitriol on the production of T-cell-derived cytokines in psoriasis

Although the use of vitamin D analogues in the treatment of psoriasis has been an important new development, the mechanisms of action of these drugs are not fully understood. Psoriasis results from hyperproliferation of keratinocytes, and various studies attribute a crucial role to the locally infiltrating T lymphocytes. In an attempt to add to the understanding of the mechanisms of calcitriol therapy, we determined the effect of this drug on T cells by studying its effect on proliferation and on the production of various cytokines by T-cell clones prepared from psoriatic skin after non-specific activation with the combination of phytohaemagglutinin (PHA) and phorbol myristate acetate (PMA). The addition of increasing doses (10(-9)-10(-5) mol/l) of calcitriol to these T cells resulted in a dose-dependent inhibition in lymphocyte proliferation and in production of the type 1 cytokines IFN-gamma and IL-2, the type 2 cytokines IL-4 and IL-5. The general cytokines TNF-alpha and GM-CSF were not significantly inhibited. These data suggest that calcitriol is involved in the treatment of psoriasis via inhibition of the expansion, and cytokine production, of skin-infiltrating T lymphocytes.     

Interleukin-12 primes human CD4 and CD8 T cell clones for high production of both interferon-gamma and interleukin-10

Interleukin-12 (IL-12) induces differentiation of T helper 1 (Th1) cells, primarily through its ability to prime T cells for high interferon-gamma (IFN-gamma) production. We now report that the presence of IL-12 during the first several days of in vitro clonal expansion in limiting dilution cultures of polyclonally stimulated human peripheral blood CD4+ and CD8+ T cells also induces stable priming for high IL-10 production. This effect was demonstrated with T cells from both healthy donors and HIV+ patients. Priming for IL-4 production, which requires IL-4, was maximum in cultures containing both IL-12 and IL-4. IL-4 modestly inhibited the IL-12-induced priming for IFN-gamma, but almost completely suppressed the priming for IL-10 production. A proportion of the clones generated from memory CD45RO+ cells, but not those generated from naive CD45RO- CD4+ T cells, produced some combinations of IFN-gamma, IL-10, and IL-4 even in the absence of IL-12 and IL-4, suggesting in vivo cytokine priming; virtually all CD4+ clones generated from either CD45RO(-) or (+) cells, however, produced high levels of both IFN-gamma and IL-10 when IL-12 was present during expansion. These results indicate that each Th1-type (IFN-gamma) and Th2-type (IL-4 and IL-10) cytokine gene is independently regulated in human T cells and that the dichotomy between T cells with the cytokine production pattern of Th1 and Th2 cells is not due to a direct differentiation-inducing effect of immunoregulatory cytokines, but rather to secondary selective mechanisms. Particular combinations of cytokines induce a predominant generation of T cell clones with anomalous patterns of cytokine production (e.g., IFN-gamma and IL-4 or IFN-gamma and IL-10) that can also be found in a proportion of fresh peripheral blood T cells with "memory" phenotype or clones generated from them and that may identify novel Th subsets with immunoregulatory functions.     

An increased ratio of interleukin-1 receptor antagonist to interleukin-1alpha in inflammatory skin diseases

IL-1 receptor antagonist (IL-1ra) is a cytokine that competitively binds the IL-1 receptor to antagonize IL-1 activity without any agonist function. Previous experiments indicated that the ratio of IL-1ra to IL-1alpha in the normal stratum corneum (SC) was much higher in the sun-exposed face than in the sun-protected area, upper arms. It was also reported by another laboratory that IL-1ra is increased in the lesional skin of psoriatic patients. This study was designed to measure the contents of IL-1alpha and IL-1ra in non-lesional and pathological SC obtained from inflammatory skin diseases including psoriasis and non-psoriatic dermatoses such as atopic dermatitis. The SC materials were obtained with a non-invasive tape-stripping method. Their soluble fractions were prepared and assayed for IL-1alpha and IL-1ra by enzyme-linked immunosorbent assays. As a result we confirmed the previous findings that the ratio of IL-1ra to IL-1alpha in the normal SC was much higher in the face than in the sun-protected sites, the trunk as well as extremities. Next, we found that IL-1alpha contents were significantly reduced in the SC samples obtained from inflammatory skin regardless of whether their IL-1ra contents increased or unchanged. Moreover, we noted that an increased ratio of IL-1ra to IL-1alpha in the SC was not specific to psoriasis, but was also found in other inflammatory skin diseases including atopic dermatitis. This ratio was found to become lower after successful treatment of these skin lesions with topical glucocorticoids. We conclude from these observations that the increased ratio of IL-1ra to IL-1alpha in the SC is a non-specific phenomenon that can occur in any inflammatory skin diseases regardless of the inflammatory pattern, probably reflecting a skin regulation process against various kinds of inflammation.     

Interleukin-12 p40 mRNA expression in bovine leukemia virus-infected animals: increase in alymphocytosis but decrease in persistent lymphocytosis

Interleukin-12 (IL-12), a key cytokine in immune regulation, has an important role in activating the cell-mediated immune response in infectious diseases. Recently, a dichotomy between IL-12 and IL-10 regarding progression of a variety diseases has emerged. IL-12 activates type 1 cytokine production and has an antagonistic effect on type 2 cytokines. Here, by using quantitative competitive PCR, we show that peripheral blood mononuclear cells from bovine leukemia virus-infected animals in the alymphocytotic stage of disease express an increased amount of IL-12 p40 mRNA. In contrast, IL-12 p40 mRNA expression by cells from animals with late-stage disease, termed persistent lymphocytosis, was significantly decreased compared to that by normal and alymphocytotic animals. Interestingly, IL-12 p40 mRNA was also detected in tumor-bearing animals. IL-12 p40 expression occurred only in monocytes/macrophages, not B or T lymphocytes. The present study combined with previous findings suggest that IL-12 in bovine leukemia virus-infected animals may regulate production of other cytokines such as gamma interferon and IL-10 and the progression of bovine leukosis in animals that develop more advanced disease such as a persistent lymphocytosis of B cells or B-cell lymphosarcoma.     

Interleukin-12 release by mitogen-stimulated mononuclear cells in the elderly

Defects involving cellular expression of activation molecules, cell mediated immune response and natural killer (NK) activity are commonly observed in the elderly. Herein, data are reported on the evaluation of IL-12 production by old subjects. IL-12 is, actually, considered the key molecule for the induction of a T helper 1 (Th1) -type and NK response. IL-12 production from old subjects peripheral blood mononuclear cells (PBMNC) was evaluated using T-independent (bacterial lipopolysaccharide, LPS) or -dependent (phytoemagglutinin, PHA; immobilized anti-CD3 monoclonal antibodies, anti-CD3) mitogens. The IL-12 production after LPS stimulation was not reduced in cultures from old subjects when compared to that from young ones. On the contrary, IL-12 production by PHA or anti-CD3 stimulated PBMNC from old subjects was decreased. Furthermore, we have demonstrated a reduced CD40 and CD40 ligand (CD40L) expression on PBMNC from old subjects. This finding fits very well with the reduced cytokine production observed in the T-dependent stimulation systems, being the CD40-CD40L interaction mandatory for an efficient IL-12 production. All together, these results seem to suggest that defects in cell expression of activation molecules can affect the IL-12 secretion and in consequence other Th1-type cytokines.     

Expression of cytokine messenger RNA after heart transplantation: relationship with rejection and serum cytokines

Different groups of cytokines may initiate or inhibit the rejection process. We used the polymerase chain reaction to study the expression of cytokine mRNA for interleukin (IL)-2, -4, -6 and -10, tumor necrosis factor-alpha, and interferon-gamma in 187 biopsy specimens from 24 human cardiac transplant recipients 5-555 days after transplantation. Cytokine levels in the serum were also measured. Cytokine mRNA was detected in 38.5% of biopsy specimens. IL-10 mRNA was detected more frequently with mild or absent rejection (11.6% in grades 0 and 1 - vs. 1.4% in grades 2 and 3, P=0.01). Up to 90 days after transplantation, IL-2 mRNA was detected more frequently with moderate rejection (13% in grades 2 and 3 vs. 0% in grades 0 and 1, P=0.076), and IL-4 mRNA was detected more frequently with mild or absent rejection (16% in grades 0 and 1 - vs. 0% in grades 2 and 3, P=0.061). More than 90 days after transplantation, IL-2 mRNA was detected more frequently with mild or absent rejection (10% in grades 0 and 1 vs. 0% in grades 2 and 3, P=0.078). Serum IL-4 levels corresponding to biopsy specimens positive for IL-4 mRNA were higher than those corresponding to specimens negative for IL-4 mRNA (59 pg/ml vs. 32 pg/ml medians, P=0.028). Our results suggest that IL-10 and possibly IL-4 (T helper 2 cytokines) may suppress graft rejection, whereas IL-2 (T helper 1 cytokine) may promote cellular rejection. In addition, cytokine profiles may change with length of time after transplantation. The association of elevated serum levels of IL-4 with increased expression of intragraft IL-4 mRNA may suggest release of this cytokine from the graft into the circulation.