Cutaneous T-Cell Lymphoma. A hypothesis on disease pathophysiology involving deficiency in DNA repair.

Cutaneous T-cell lymphoma (CTCL) is a rare disease occurring in Europe among two persons per million per year. It affects men more often than women (2:1). It is primarily a skin disease. In about 20% of patients, it becomes fatal with tumours in the skin and spreading to lymph glands. Approximately 3% of patients show a leukemic form called Sezary's syndrome, where malignant cells are present in blood with accompanying erythrodermia. CTCL is a T-lymphocyte disease occurring late in life as the average age of patients is around 66 years in Europe, Japan and the US. This article focuses on cell lines and immune surveillance in CTCL, and especially the pronounced chromosomal instability. It leads to the hypothesis that chromosomal changes is the key event linked to DNA repair deficiencies, which in a subpopulation of T cells leads to CTCL development over years.

Human Atopic Dermatitis Skin-derived T Cells can Induce a Reaction in Mouse Keratinocytes in vivo.

In atopic dermatitis (AD), the inflammatory response between skin-infiltrating T cells and keratinocytes is fundamental to the development of chronic lesional eczema. The aim of this study was to investigate whether skin-derived T cells from AD patients could induce an inflammatory response in mice through keratinocyte activation and consequently cause the development of eczematous lesions. Punch biopsies of the lesional skin from AD patients were used to establish skin-derived T cell cultures, which were transferred to NOD.Cg-Prkd(scid) Il2rg(tm1Sug) /JicTac (NOG) mice. We found that the subcutaneous injection of the human AD skin-derived T cells resulted in the migration of the human T cells from subcutis to the papillary dermis followed by the development of erythema and oedema in the mouse skin. Furthermore, the human T cells induced a transient proliferative response in the mouse keratinocytes shown as increased numbers of Ki-67(+) keratinocytes and increased epidermal thickness. Out of six established AD skin-derived T cell cultures, two were superior at inducing a skin reaction in the mice, and these cultures were found to contain >10% CCR10(+) T cells compared to <2% for the other cultures. In comparison, blood-derived in vitro-differentiated Th2 cells only induced a weak response in a few of the mice. Thus, we conclude that human AD skin-derived T cells can induce a reaction in the mouse skin through the induction of a proliferative response in the mouse keratinocytes.

IL-8 induces T cell chemotaxis, suppresses IL-4, and up-regulates IL-8 production by CD4+ T cells.

Interleukin-8 (IL-8), a neutrophil-activating cytokine, also activates certain T cell functions such as chemotaxis. We additionally find (n = 6) that recombinant (rIL-8; 1-100 ng/ml), when added to 24 h culture of human CD4+ T cells, suppressed the spontaneous production of IL-4 (50-85%). Steady state production of Il-4 was typically around 30 pg/ml, determined by use of a solid- phase immunoabsorbant assay. De novo synthesis of IL-4 from CD4+ T cells cultured for 3 days was also evaluated by use of detection of [35S]methionine incorporation, as visualized by autoradiography of 2-D gels, and showed that IL-8 suppressed IL-4 production. This suppression of IL-4 production was confirmed in the cytosol fraction by use of Western blotting. The effect of IL-8 (100 ng/ml) was comparable to that of 10 ng/ml recombinant interferon-gamma, both strongly suppressing IL-4 production. The regulatory effect of IL-8 on IL-4 production was also indicated by the fact that addition of a neutralizing monoclonal anti-IL-8 antibody (WS.4) enhanced the spontaneous IL-4 production when added to the culture of CD4+ T cells, thereby probably inactivating the effect of IL-8 originating from the cultured T cells. Also, we observed that IL-4 mRNA expression was down-regulated when the CD4+ T cells were cultured for 12 h in the presence of 100 ng/ml IL-8. The suppression of IL-4 mRNA expression could be prevented by adding anti-IL-8 (20 microgram/ml) or IL-10 (100 ng/ml) l h before adding rIL-8. Thus, IL-8 may be an important regulator of CD4+ T cell-derived IL-4, thereby possibly regulating the balance between humoral and cellular T cell-dependent responses.

Interferon alpha and etretinate combination treatment of cutaneous T-cell lymphoma.

Eleven patients suffering from cutaneous T-cell lymphoma (mycosis fungoides) were treated with recombinant interferon alpha-2A in combination (seven patients) or alone. Two patients, one in combined treatment, went into clinical complete remission, and five experienced partial remission. Two patients progressed during therapy, and two were nonevaluable because they stopped treatment early due to side effects. Dosages of interferon were from 3 to 36 million units daily for 3 months, and thereafter 3 times weekly. Etretinate (0.7 mg/kg) was given orally. The study showed that recombinant interferon alpha-2A in combination with etretinate or alone can induce remission of cutaneous T-cell lymphoma.

Epidermis and lymphocyte interactions during a tuberculin skin reaction. II. Epidermis contains specific lymphocyte chemotactic factors.

Lymphocyte chemotaxis was studied in a blind-well chamber assay by measuring the passage of 51Cr-labeled cells through a polycarbonate filter with a pore size of 5 micron. Monocyte-depleted lymphocytes were divided into T cells (E receptor-positive lymphocytes) and non-T cells. T lymphocytes showed pronounced migration after exposure to leukotriene B4 (LTB4) and casein, and weak migration after exposure to N-formyl-methionyl-leucyl-phenylalanine (FMLP). Non-T cells showed strong migration after exposure to FMLP, but weak migration after exposure to casein and LTB4. Supernatants of homogenized suction blisters from normal skin did not induce active migration. However, if the epidermis came from an area overlying a positive tuberculin skin reaction, there was a significant migration mostly of T, but also of non-T cells. Supernatants from phytohemagglutinin (PHA)-stimulated lymphocyte cultures also contained lymphocyte chemotactic factor(s), which, however, had an effect only on T lymphocytes. Purified protein derivative of tuberculin (PPD)-stimulated lymphocytes did not produce chemoattractants either for T or for non-T cells. These studies show that lymphocytes can show active, directed migration following exposure to well-known chemotaxins for granulocytes and monocytes although their migrational capability differs for different subpopulations. Epidermis overlying a cell-mediated immune reaction (tuberculin) contains epidermal lymphocyte chemotactic factor(s). This factor(s) may be of importance for the type of cell infiltrate occurring in certain dermatologic disorders.

Use of the polymerase chain reaction in quantification of interleukin 8 mRNA in minute epidermal samples.

Quantitative studies of cytokine gene expression in vivo are necessary in order to properly describe the cytokine network and to elucidate its role in skin inflammation. Ideally, one should be able to follow cytokine gene expression in epidermal, dermal, and blood compartments. However, such studies are limited by small amounts of available material. Here we report a polymerase chain reaction (PCR) cDNA amplification protocol useful for quantification of specific mRNAs in small skin samples. We found that analysis of dilution series of each sample permitted establishment of quantitative PCR amplification conditions using only picogram to nanogram amounts of total RNA. Cytokine mRNA amounts could then be measured relative to an internal standard species, co-reverse transcribed, and co-amplified with the cytokine species as a measure of cDNA input. Large numbers of samples can be screened rapidly with initial short dilution series identifying cytokine-positive samples and the correct dilution range for each, followed by closer analysis in this range. Epidermal samples obtained through curettage of a small skin area, 2-mm dermal biopsies from the scraped sites, and a few blood drops from the biopsy sites all yielded sufficient RNA for analysis by this protocol. Any mRNA of known sequence can be studied. We analyzed interleukin 8 mRNA levels in more than a hundred epidermal samples from patients and normal test persons and found a variation over several orders of magnitude that seemed to follow the degree of inflammation of the skin.

Modulating effects of enzymes on T gamma and T mu cells in patients with atopic dermatitis.

Ten patients with moderate to severe atopic dermatitis had increased levels of IgE in the blood and a reduced level of T cells with Fc receptors for IgG (T gamma). After pronase and trypsin digestion of Fc receptors, cultured T cells regenerated the Fc receptors, but preserved the difference between patients and controls. Neuraminidase treatment increased the T gamma-cell level in both patients and controls. Serum from patients with atopic dermatitis could not reduce the T gamma-cell expression in the controls. With regard to Fc receptors, no qualitative difference was observed between patients and controls, but a genuine quantitative difference accounts for the observed reduction of T gamma cells in blood.

Expression and secretion of leukocyte chemotactic cytokines by normal human melanocytes and melanoma cells.

The capacity of human melanocytes and melanoma cells to produce IL-8 and monocyte chemotactic and activating factor (MCAF) was investigated. Melanocytes expressed mRNA for IL-8 and MCAF, when stimulated with either IL-1 alpha or TNF alpha, but not when stimulated with IL-6, IFN gamma, or LPS alone. IL-8 and MCAF could be induced in a dose-dependent fashion with doses as low as 0.1 ng/ml TNF alpha and 0.5 ng/ml IL-1 alpha. IL-8 and MCAF mRNA were rapidly expressed and peaked between 2 and 4 h for IL-8 and between 4 and 8 h for MCAF. This correlated well with the accumulation of IL-8 antigen as measured by a radioimmunoassay. Supernatants from melanocyte cultures stimulated with either IL-1 alpha or TNF alpha and separated on a heparin-Sepharose column became positive for neutrophil and monocyte chemotactic activity in a dose- and time-dependent fashion. When IFN gamma was added to melanocyte cultures stimulated with suboptimal doses of TNF alpha there was a synergistic increase in secreted IL-8 protein and monocyte chemotactic activity. These data provide further evidence for the possible role of melanocytes in the initiation of an inflammatory reaction. Three different malignant melanoma cell lines stimulated with either TNF alpha or IL-1 alpha expressed IL-8 mRNA, but not mRNA for MCAF. The IL-8 mRNA signal corresponded well with the amount of secreted IL-8 protein. These data suggest that IL-8 and MCAF may play a role in growth regulation and spreading of melanomas.

Epidermis and lymphocyte interactions during an allergic patch test reaction. Increased activity of ETAF/IL-1, epidermal derived lymphocyte chemotactic factor and mixed skin lymphocyte reactivity in persons with type IV allergy.

Recently, we have found an increased activity of epidermal-derived thymocyte-activating factor (ETAF/IL-1) and epidermal lymphocyte chemotactic factor (ELCF) in epidermis overlying a positive tuberculin skin reaction. In the present study, we investigated 20 patients with confirmed or suspected allergic contact dermatitis by using the suction blister technique before and during patch testing. The ETAF/IL-1 was found in epidermis before patch testing. Its presence increased 2.8-fold in epidermis overlying a positive patch test compared with pretesting values. This increase was statistically significant. Interestingly, nontested skin also showed a significant increase of ETAF/IL-1, which was 1.9-fold higher than pretest values. The ETAF/IL-1 activity in patch test areas was significantly correlated with the clinical response. ELCF is not present in epidermis from noneczematous persons. We observed a significant content of ELCF in three of seven patients with eczema prior to patch testing. After patch testing, all patients showed ELCF in epidermis. Nontested skin showed a 1.5-fold higher content of ELCF compared with pretest values, and in the test area ELCF was 1.8-fold higher. The increases were statistically significant. We performed mixed skin lymphocyte reactions in seven patients using epidermal cells from the patch test area. All patients with a positive patch test had an increased mixed skin lymphocyte reactivity compared with epidermis coming from a negative reaction.

Modulation of natural killer cell activity in patients with atopic dermatitis.

The peripheral blood lymphocytes of 36 adult patients with moderate to severe atopic dermatitis had reduced natural killer (NK) cell activity when measured against 51Cr-labeled K 562 cells. The decrease in NK cells activity was not related to the serum IgE level, but was related to the severity of the skin disease. Addition of autologous monocytes of the assay reduced the NK cell activity and concealed the enhancing effect of gamma-interferon addition in a 4-h assay. The NK cell activity of lymphocytes could be reduced in vitro by addition of prostaglandin E1, or increased by addition of gamma-interferon similar to lymphocytes from persons without atopic disease. Our present findings raise the possibility that the reduced NK cell activity may be secondary to the skin disease, and due to in vivo interaction between NK cells and monocytes, or to low numbers of NK cells in peripheral blood.

Psoriasin: a novel chemotactic protein.

Inflammatory skin disorders such as psoriasis show a preferential epidermal infiltration of neutrophils and T lymphocytes. This observation raises a question as to which factors determine the appearance and composition of leukocyte tissue infiltrations. Previously, we described a low molecular mass calcium-binding protein (psoriasin, molecular mass 11,457 Da, pI 6.77) belonging to the S1OO family that is highly upregulated in psoriatic keratinocytes and whose expression patterns implied a role in the inflammatory response. Here we report that human psoriasin is a potent and selective chemotactic inflammatory protein for CD4+ T lymphocytes and neutrophils at concentrations of about 10(-11) M. Psoriasin is not structurally related to the alpha or the beta chemokine subfamilies or to lymphotactin, a member of a newly described class of chemokines. Thus, we have observed a chemotactic protein outside the chemokine subfamilies that could be an important new inflammatory mediator.

Recombinant human interleukin-8 is a potent activator of canine neutrophil aggregation, migration, and leukotriene B4 biosynthesis.

Interleukin-8 (IL-8), formerly known as NAP-1, is formed by a variety of cells upon stimulation with IL-1 or tumor necrosis factor (TNF). The biologic activity of the cytokine involves activation of almost every neutrophil function studied so far in different species. In the present study, we compared the effects of recombinant human IL-8 (rIL-8) and the lipid mediators, leukotriene B4 (LTB4) and platelet-activating factor (PAF), on neutrophil functions in dogs. All three chemotactic factors induced neutrophil aggregation and chemotaxis, with rIL-8 being far more potent than LTB4 and PAF. The migration induced by rIL-8 was significantly greater than that observed towards LTB4 and PAF. In the aggregation assay, rIL-8 was shown for the first time to be a potent stimulant. The aggregation response was more persistent than that obtained with LTB4 and PAF and the potency of rIL-8 was greater. An intradermal dose-response study showed that rIL-8 is an extremely potent inducer of selective neutrophil infiltration in canine skin. The infiltration was more pronounced than following injection of LTB4 or PAF. It was proposed that the superior effect of rIL-8 was caused by a synergistic effect between injected rIL-8 and LTB4, which was shown to be produced in biologically active amounts by canine neutrophils stimulated with rIL-8. From a therapeutic point of view, the simultaneous presence of rIL-8 and LTB4 in inflammatory skin diseases highlights the need to develop drugs that inhibit the production and/or effect of both mediators.

Quantitative determination of IL-1 alpha-induced IL-8 mRNA levels in cultured human keratinocytes, dermal fibroblasts, endothelial cells, and monocytes.

The presence of the leukocyte chemotactic cytokine interleukin 8 (IL-8) in psoriatic scales and in epidermal tissue overlying allergic patch test reactions suggests a role for this cytokine in certain inflammatory skin diseases. IL-8 can be produced by several cell types present in the skin. Their relative potentials for IL-8 expression has, however, not yet been studied, due to the lack of convenient methods for quantitative comparison of specific mRNA amounts in different cell types. Using a new method for quantification, we compared specific IL-8 mRNA amounts in cultures of keratinocytes, dermal fibroblasts, endothelial cells, and monocytes, stimulated with interleukin 1 alpha (IL-1 alpha). Endothelial cells produced very high, fibroblasts and monocytes intermediate, and keratinocytes low amounts of IL-8 mRNA. We also studied the time course of IL-8 mRNA levels in the four cell types following IL-1 alpha stimulation, and found a clear difference both in onset and stability of the response. We discuss the different strength of the response at different time points in the cell types analyzed in relation to their possible role in regulation of the normal response to stimulation.

Chemotaxis of human osteoblasts. Effects of osteotropic growth factors.

The in vitro chemotactic response of human osteoblasts was investigated towards the following growth factors: TGF-beta, PDGFs, FGFs and IGFs. Human osteoblasts grown from trabecular bone after enzymatic digestion were studied. TGF-beta stimulated the migration of human osteoblasts in a dose-dependent manner with a four-fold increase in migrated cells at 100 pg/ml, which was the optimum concentration. PDGF-BB also stimulated migration four-fold in a dose-dependent manner with a maximum response at 10 ng/ml. PDGF-AA, IGF-I and IGF-II stimulated migration two-fold at 100 ng/ml. The results show that TGF-beta and PDGF-BB are important regulators of human osteoblast migration, but other growth factors IGF-I, IGF-II and PDGF-AA may also stimulate osteoblast migration. Our results additionally suggest that TGF-beta and PDGF-BB may participate in the recruitment of osteoblasts during bone remodeling since both TGF-beta and PDGF-BB are found in bone matrix and could be released during osteoclastic bone resorption. They furthermore support a possible use of TGF-beta and PDGF-BB in growth factor-induced osteogenesis.

Telomerase activity is spontaneously increased in lymphocytes from patients with atopic dermatitis and correlates with cellular proliferation.

Telomerase is a ribonucleoprotein enzyme involved with cellular proliferation and cellular senescence. The aim of the present study was to investigate telomerase activity in lymphocytes from patients with atopic dermatitis (AD) and to observe its regulation of cellular proliferation. Peripheral blood mononuclear cells (PBMC) were isolated from 15 patients with AD and 13 healthy donors. Cells were stimulated with purified protein derivative (PPD) of tuberculin (10 microg/ml), interleukin 2 (IL-2) (100 U/ml), anti-CD3 monoclonal antibody (anti-CD3) (1 microg/ml), anti-CD3 plus IL-2, and staphylococcal enterotoxin A (SEA) (0.1 microg/ml). Telomerase activity was measured by the telomeric repeat amplification protocol-based telomerase polymerase chain reaction enzyme-linked immunosorbent assay at 0 and 72 h of incubation. In addition, DNA synthesis of the cells was assayed using 3H-thymidine incorporation. We found that telomerase activity in non-stimulated PBMC from patients with AD was significantly up-regulated without any stimulation during the 72 h of in vitro incubation. The most potent stimulator of telomerase activity was SEA, followed by anti-CD3 plus IL-2, anti-CD3 alone, and PPD. IL-2 did stimulate telomerase activity and DNA proliferation with increasing dosage of IL-2. The DNA proliferation was paralleled by increase in telomerase activity. There was no significant difference between telomerase activity in stimulated lymphocytes from AD patients and normal donors, but the relative increase in telomerase activity tended to be less in AD patients. A spontaneously higher telomerase activity in lymphocytes from AD patients could indicate that T lymphocytes are already stimulated in vivo or that a population of T cells in peripheral blood exhibits an increased telomerase activity compatible with cellular immaturity.

Monocyte chemotactic and activating factor (MCAF/MCP-1) has an autoinductive effect in monocytes, a process regulated by IL-10.

MCAF (MCP-1) a member of the chemokine-beta-family known to be chemotactic for monocytes is believed to play a significant role in several inflammatory processes, both immuno-pathological disorders, such as atherosclerosis, psoriasis, chronic inflammatory diseases of the liver and lungs, and during the normal immune response against microorganisms. This chemokine is produced spontaneously by monocytes, and in the present article we also demonstrate that MCAF induces its own production in monocytes. The methods used are two dimensional SDS-PAGE gel electrophoresis. Western-blotting and ELISA quantification of supernatant from monocyte cultures stimulated with MCAF (1, 10, 100 ng ml). Also, we found that this process is regulated by IL-10 (100 ng ml). Our results suggest that monocytes migrating to a site of inflammation due to the local production of the chemokine MCAF/MCP-1 further enhance the focal accumulation of monocytes by producing and releasing bioactive MCAF MCP-1.

Appearance of isochromosome 18q can be associated with in vitro immortalization of human T lymphocytes.

T lymphocytes cultured from a skin biopsy specimen of a patient with atopic dermatitis developed isochromosome 18q concomitant to escape from replicative senescence. Furthermore, two T-cell lines established from patients with cutaneous T-cell lymphoma also developed isochromosome 18q during continuous growth. The results indicate that a pathway leading to immortalization of human T lymphocytes could involve genes located at chromosome 18.

Common clonal chromosome aberrations in cytokine-dependent continuous human T-lymphocyte cell lines.

Antigen-mediated T-cell proliferation is a transient phenomenon. Like other somatic cells, T lymphocytes generally show replicative senescence in vitro. However, we here show that cytokine-dependent continuous (immortal) T-cell lines can be established from skin biopsy specimens of inflammatory skin diseases. Continuous growth can be obtained by culturing T cells in medium supplemented with interleukin-2 and interleukin-4, but without antigen or antigen-presenting cells added. Loss of the T-cell antigen receptor complex is observed in some of the continuous T-cell lines. Most T-cell lines develop clonal chromosome aberrations during continuous growth. Aberrations for chromosomes 1, 2, 8, 16, and 18 are most commonly observed.

Bowen's disease and internal malignant diseases. A study of 581 patients.

In a retrospective study of 581 patients with a diagnosis of Bowen's disease (BD) treated over a 40-year period, we traced patient records to identify later diagnoses of nonskin cancer. Fifty patients had nonskin cancer, as against an expected number of 40, but this difference was not significant. The lack of association was equally true for BD on sun-exposed and non-sun-exposed skin. Our findings support the view that BD is not a skin marker for internal malignant disease.