[Structurally functional modifications of the human lymphocytes induced by influence of UV-light]

The influence of UV-light (240-390 nm) in dose 75.5-1510 J/m2 on the structural functional qualities (cytotoxic activity, antibody-produced ability, a level of expression of superficial receptors, a level cAMP) of lymphocytes peripheral blood of donors was investigated. Corregative action of UV-radiation on cytotoxic activity of lymphocytes in relation to cells of Ehrlich ascite carcinoma was revealed. The interrelation of modification types of plasmatic membrane components with a level of functional activity of lymphocytes was established. Was shown, that UV-light induces the decrease in a secondary level of messenger cAMP in cytosol of the photomodified cells. It is revealed, that UV-radiation causes stimulation of antibody-independent mechanism of cytotoxic lymphocytes, which is connected with activation of T-cells and with inhibition of antibody-dependent mechanism of cytotoxic activity.

Trogocytosis of MHC-I/peptide complexes derived from tumors and infected cells enhances dendritic cell cross-priming and promotes adaptive T cell responses

The transporter associated with antigen processing (TAP) and the major histocompatibility complex class I (MHC-I), two important components of the MHC-I antigen presentation pathway, are often deficient in tumor cells. The restoration of their expression has been shown to restore the antigenicity and immunogenicity of tumor cells. However, it is unclear whether TAP and MHC-I expression in tumor cells can affect the induction phase of the T cell response. To address this issue, we expressed viral antigens in tumors that are either deficient or proficient in TAP and MHC-I expression. The relative efficiency of direct immunization or immunization through cross-presentation in promoting adaptive T cell responses was compared. The results demonstrated that stimulation of animals with TAP and MHC-I proficient tumor cells generated antigen specific T cells with greater killing activities than those of TAP and MHC-I deficient tumor cells. This discrepancy was traced to differences in the ability of dendritic cells (DCs) to access and sample different antigen reservoirs in TAP and MHC-I proficient versus deficient cells and thereby stimulate adaptive immune responses through the process of cross-presentation. In addition, our data suggest that the increased activity of T cells is caused by the enhanced DC uptake and utilization of MHC-I/peptide complexes from the proficient cells as an additional source of processed antigen. Furthermore, we demonstrate that immune-escape and metastasis are promoted in the absence of this DC ‘arming’ mechanism. Physiologically, this novel form of DC antigen sampling resembles trogocytosis, and acts to enhance T cell priming and increase the efficacy of adaptive immune responses against tumors and infectious pathogens.

Effects of ozone, ultraviolet and peracetic acid disinfection of a primary-treated municipal effluent on the immune system of rainbow trout (Oncorhynchus mykiss)

Municipal sewage effluents are complex mixtures that are known to compromise the health condition of aquatic organisms. The aim of this study was to evaluate the impacts of various wastewater disinfection processes on the immune system of juvenile rainbow trout (Oncorhynchus mykiss). The trout were exposed to a primary-treated effluent for 28 days before and after one of each of the following treatments: ultraviolet (UV) radiation, ozonation and peracetic acid. Immune function was characterized in leucocytes from the anterior head kidney by the following three parameters: phagocytosis activity, natural cytotoxic cells (NCC) function and lymphocyte (B and T) proliferation assays. The results show that the fish mass to length ratio was significantly decreased for the primary-treated and all three disinfection processes. Exposure to the primary-treated effluent led to a significant increase in macrophage-related phagocytosis; the addition of a disinfection step was effective in removing this effect. Both unstimulated and mitogen-stimulated T lymphocyte proliferation in fish decreased dramatically in fish exposed to the ozonated effluent compared to fish exposed to either the primary-treated effluent or to aquarium water. Stimulation of T lymphocytes proliferation was observed with the peracetic acid treatment group. In conclusion, the disinfection strategy used can modify the immune system in fish at the level of T lymphocyte proliferation but was effective to remove the effects on phagocytosis activity.

The nuclear factor-kappaB and p53 pathways function independently in primary cells and transformed fibroblasts responding to genotoxic damage

With nuclear factor-kappaB (NF-kappaB) and p53 functions generally having disparate outcomes for cell survival and cell division, understanding how these pathways are coordinated following a common activation signal such as DNA damage has important implications for cancer therapy. Conflicting reports concerning NF-kappaB and p53 interplay in different cell line models prompted a reexamination of this issue using mouse primary thymocytes and embryonic fibroblasts, plus fibroblasts transformed by E1A12S. Here, we report that following the treatment of these cells with a range of stress stimuli, p53 and NF-kappaB were found to regulate cell cycling and survival independently.

[Ultraviolet: a regulator of immunity]

Humans establish acquired immune systems during the growth, which can sufficiently eliminate pathogen avoiding immune responses to self, such as allergy and autoimmunity. An imbalance of the acquired immune system leads up to immune-mediated disorders. Ultraviolet (UV) exposure helps to establish the normal peripheral tolerance to contact allergen avoiding excessive immune responses. By contrast, UV develops kinds of autoimmune diseases on rare occasions, suggesting that abnormality in the process of UV-induced peripheral tolerance may induce these diseases. To elucidate the mechanism of UV-induced tolerance is possible to provide a new approach for the management of immune diseases. In the current review, focus is on the suggested players of UV-induced tolerance, blocking mechanisms on the elicitation phase of contact hypersensitivity, and the association between UV and autoimmunity. The major impact in basic immunology in this area is the discovery of cell surface marker of regulatory T cells. Therefore, we first discuss about the association of regulatory/suppressor T cells with UV-induced tolerance. Since the elicitation phase depends on cellular influx into the inflammatory sites, which is tightly regulated by adhesion molecules, we also focused on the role of adhesion molecules. Finally, this paper also includes statistical findings concerning the association between UV-radiation and the prevalence of a myositis specific autoantibody. Thus, UV is one of the nice regulators of an immune network and the knowledge of UV-mediated immune regulation will be translated into new therapeutic strategies to human immune-mediated disorders.

Studies of thioguanine-resistant lymphocytes induced by in vivo irradiation of mice

The frequency of Hprt-deficient lymphocytes in mice after in vivo gamma irradiation, has been found to vary as a function of time elapsed after exposure and irradiation dose. The frequency of mutant lymphocytes in spleen was determined using an in vitro, clonogenic assay for thioguanine-resistant T-lymphocytes. Mice were exposed to single doses of 0-400 cGy from cesium-137 or to eight daily doses of 50 cGy. The time to maximum-induced mutant frequency was 3 weeks. The dose response was strikingly curvilinear at 3-5 weeks after irradiation, but less precisely defined for 10-53 weeks after exposure, being fit by either linear or quadratic dependence. Three weeks after eight daily 50 cGy exposures, mutant frequency was elevated above controls and mice exposed to 50 cGy (which were not distinct from the nonirradiated controls), but only 17% in that of mice given a single 400 cGy fraction. This fractionation effect and the curvilinearity of the early dose-response curve suggested that saturation of repair increased the yield of mutations at higher acute doses. The decline of spleen mutant frequency in mice observed between 5 and 10 weeks after irradiation may reflect selection against some mutants. The marked variation of mutant frequency, as a function of time after irradiation and of dose rate, emphasize the need to evaluate these variables carefully and consistently in future studies.

Tovaxin, radiation-attenuated, patient-specific T-cells for the therapeutic vaccination of multiple sclerosis

Opexa Pharmaceuticals Inc is developing Tovaxin, a trivalent formulation of attenuated myelin-peptide-reactive T-cells, for the potential treatment of multiple sclerosis. Tovaxin is being evaluated in phase II clinical trials. Opexa was previously investigating Tovaxin for the potential treatment of rheumatoid arthritis; however, no development has been reported for this indication since December 2002.

Differential effects of low- and high-dose X-rays on N-ethyl-N-nitrosourea-induced mutagenesis in thymocytes of B6C3F1 gpt-delta mice

Carcinogenesis in humans is thought to result from exposure to numerous environmental factors. Little is known, however, about how these different factors work in combination to cause cancer. Because thymic lymphoma is a good model of research for combined exposure, we examined the occurrence of mutations in thymic DNA following exposure of B6C3F1 gpt-delta mice to both ionizing radiation and N-ethyl-N-nitrosourea (ENU). Mice were exposed weekly to whole body X-irradiation (0.2 or 1.0 Gy), ENU (200 ppm) in the drinking water, or X-irradiation followed by ENU treatment. Thereafter, genomic DNA was prepared from the thymus and the number and types of mutations in the reporter transgene gpt was determined. ENU exposure alone increased mutant frequency by 10-fold compared to untreated controls and over 80% of mutants had expanded clonally. X-irradiation alone, at either low or high dose, unexpectedly, reduced mutant frequency. Combined exposure to 0.2 Gy X-rays with ENU dramatically decreased mutant frequency, specifically G:C to A:T and A:T to T:A mutations, compared to ENU treatment alone. In contrast, 1.0 Gy X-rays enhanced mutant frequency by about 30-fold and appeared to accelerate clonal expansion of mutated cells. In conclusion, repeated irradiation with 0.2 Gy X-rays not only reduced background mutation levels, but also suppressed ENU-induced mutations and clonal expansion. In contrast, 1.0 Gy irradiation in combination with ENU accelerated clonal expansion of mutated cells. These results indicate that the mode of the combined mutagenic effect is dose dependent.

Sensors of ionizing radiation effects on the immunological microenvironment of cancer

PURPOSE

When cancer develops in an immunocompetent host it represents the result of a successful deception of the immune system as to the nature of the danger and the type of response needed to reject the neoplastic tissue. We will briefly review some of the recently emerged evidence that irradiation of the tumor and its microenvironment can induce essential molecular signals required for an effective response of the immune system to the tumor.

CONCLUSIONS

The subversion of a highly organized tissue architecture is a hallmark of cancer, and results in uneven distribution of oxygen and nutrients, interstitial pressure gradients and areas of patchy necrosis and inflammation. In this microenvironment, cancer cells that carry mutations favoring survival rather than cell death in response to stress find a selection advantage. Importantly, the signals derived from the disruption of orderly physiology within tissues are also what the immune system has evolved to respond to. The type of response is tuned to be adequate to the cause of the disruption. An infectious organism will carry or elicit from the involved tissue a number of 'danger signals' leading to development of cell mediated and humoral responses to both eliminating the invader and preventing future infections. In contrast, a simple wound will call for a repair response. The sensors of the type of damage are complex molecular interactions between the damaged organ and cells of the innate and adaptive immune system. Progress in the identification of these interactions elucidates which pathways are specifically altered in cancer. It also provides a novel understanding of the radiation-induced effects on tumor immunogenicity. We propose that specific radiation-induced effects could be successfully exploited to improve the effectiveness of immunotherapy.

S179D prolactin diminishes the effects of UV light on epidermal gamma delta T cells

Epidermal gamma delta T cells (gammadeltaT) and Langerhans cells (LC) are immune cells altered by exposure to ultraviolet radiation (UVB), a powerful stressor resulting in immune suppression. Prolactin (PRL) has been characterized as an immunomodulator, particularly during stress. In this study, we have asked whether separate administration of the 2 major forms of prolactin, unmodified and phosphorylated, to groups of 15 mice (3 experiments, each with 5 mice per treatment group) affected the number and morphology of these epidermal immune cells under control conditions, and following UV-irradiation. Under control conditions, both PRLs reduced the number of gammadeltaT, but a molecular mimic of phosphorylated PRL (S179D PRL) was more effective, resulting in a 30% reduction. In the irradiated group, however, S179D PRL was protective against a UV-induced reduction in gammadeltaT number and change in morphology (halved the reduction and normalized the morphology). In addition, S179D PRL, but not unmodified (U-PRL), maintained a normal LC:gammadeltaT ratio and sustained the dendritic morphology of LC after UV exposure. These findings suggest that S179D PRL may have an overall protective effect, countering UV-induced cellular alterations in the epidermis.

Winter day lengths enhance T lymphocyte phenotypes, inhibit cytokine responses, and attenuate behavioral symptoms of infection in laboratory rats

Annual variations in day length (photoperiod) trigger changes in the immune and reproductive system of seasonally-breeding animals. The purpose of this study was to determine whether photoperiodic changes in immunity depend on concurrent photoperiodic responses in the reproductive system, or whether immunological responses to photoperiod occur independent of reproductive responses. Here we report photoperiodic changes in enumerative, functional, and behavioral aspects of the immune system, and in immunomodulatory glucocorticoid secretion, in reproductively non-photoperiodic Wistar rats. T-cell numbers (CD3+, CD8+, CD8+CD25+, CD4+CD25+) were higher in the blood of rats housed in short as opposed to long-day lengths for 10 weeks. Following a simulated bacterial infection (Escherichia coli LPS; 125 microg/kg) the severity of several acute-phase sickness behaviors (anorexia, cachexia, neophobia, and social withdrawal) were attenuated in short days. LPS-stimulated IL-1beta and IL-6 production were comparable between photoperiods, but plasma TNFalpha was higher in long-day relative to short-day rats. In addition, corticosterone concentrations were higher in short-day relative to long-day rats. The data are consistent with the hypothesis that photoperiodic regulation of the immune system can occur entirely independently of photoperiodic regulation of the reproductive system. In the absence of concurrent reproductive responses, short days increase the numbers of leukocytes capable of immunosurveillance and inhibition of inflammatory responses, increase proinflammatory cytokine production, increase immunomodulatory glucocorticoid secretion, and ultimately attenuate behavioral responses to infection. Seasonal changes in the host immune system, endocrine system, and behavior may contribute to the seasonal variability in disease outcomes, even in reproductively non-photoperiodic mammals.

The influence of low-power helium-neon laser irradiation on function of selected peripheral blood cells

The effects of low-level laser light irradiation are debatable and the mechanisms of its action are still unclear. This study was conducted to test the effects of low-level laser irradiation on human blood cells: erythrocytes, granulocytes, and lymphocytes. Whole blood obtained by phlebotomy was irradiated at 632.8 nm by using energy fluences 0.6 J/cm2. An analysis of blood gases revealed an increase in PO2 and SaO2 (P<0.001) in irradiated blood. No shifts in PCO2 and pH were recorded. Spontaneous synthesis of DNA in T and B blood lymphocytes decreased significantly after laser irradiation (P<0.02 and P<0.04, respectively). Phytohemagglutinin (PHA)-induced proliferation of T cells and SAC proliferation of B cells, expressed as a stimulation index, were statistically higher in the samples of irradiated than in non-irradiated blood (P<0.01). Chemiluminescence of fMLP-stimulated granulocytes from irradiated blood increased in comparison with non-irradiated samples (P<0.001). No changes of spontaneous and stimulated chemiluminescence kinetics in irradiated samples were observed. These results reveal the influence of photodynamic reactions on the ability of blood to transport oxygen and on immunomodulatory effects on leukocytes.

UV Light and Its Interaction with Cutaneous Receptors

Phototherapy (UV-A and UV-B) has become one of the most commonly used modalities for the treatment of a variety of skin diseases, although the action mechanisms have not been fully understood. Inhibition of DNA synthesis by UV radiation may be one of the therapeutic effects in proliferating skin diseases; however, phototherapy is also used for the treatment of allergic or autoimmune diseases.

Photoimmunology--illuminating the immune system through photobiology

We review the field of photoimmunology with emphasis on immunosuppression induced by ultraviolet B radiation. Recent studies have focused on UVB-induced alterations in epidermal Langerhans cell function, resulting in a shift from Th1 to Th2 phenotype and the activation of regulatory T cells as the source of IL-10 that is central to this form of immunosuppression.

Individual radiosensitivity does not correlate with radiation-induced apoptosis in lymphoblastoid cell lines or CD3+ lymphocytes

BACKGROUND AND PURPOSE

Spontaneous and radiation-induced apoptosis of lymphoblastoid cell lines (LCLs) derived from healthy donors, cancer patients and donors with radiosensitivity syndromes as well as CD(3+) lymphocytes from patients with > or = grade 3 late toxicity were investigated as a possible marker for the detection of individual radiosensitivity. These investigations are based on the hypothesis that hypersensitive patients have reduced levels of apoptosis after in vitro irradiation as a result of a defect in the signaling pathway.

MATERIAL AND METHODS

Epstein-Barr virus-(EBV-)transformed LCLs derived from five healthy donors, seven patients with heterozygous or homozygous genotype for ataxia-telangiectasia or Nijmegen breakage syndrome and five patients with > or = grade 3 late toxicity (RTOG) were investigated. In addition, CD(3+) lymphocytes from 21 healthy individuals and 18 cancer patients including five patients with a proven cellular hypersensitivity to radiation were analyzed. Cells were irradiated in vitro with a dose of 2 and 5 Gy and were incubated for 48 h. Apoptotic rates were measured by the TUNEL assay followed by customized image analysis.

RESULTS

Four out of seven radiosensitivity syndrome patients were identified to have an increased cellular radiosensitivity as determined by reduced apoptotic rates after irradiation of their respective LCLs. Comparatively, only two of the five hypersensitive cancer patients were clearly identified by reduced apoptotic rates. Spontaneous apoptotic rates were very homogeneous among all 39 samples from controls and patients, while lymphocytes of all cancer patients showed significantly lower radiation-induced rates.

CONCLUSION

Only a subgroup of hypersensitive patients may be identified by reduction of radiation-induced apoptotic rate. It is concluded that the hypothesis according to which hypersensitive cells have reduced levels of apoptosis is only conditionally true. The authors suggest that this assay can be used in combination with additional tests evaluating DNA double-strand break repair, cell-cycle control and chromosomal aberrations for the evaluation for individual hypersensitivity.

Radiation and a metalloporphyrin radioprotectant in a mouse prostate tumor model

BACKGROUND

Antioxidants have the potential to protect normal tissues against radiation-induced damage, but must not protect tumor cells during radiotherapy. The major objectives were to determine whether a metalloporphyrin antioxidant affects prostate tumor response to radiation and identify possible mechanisms of interaction.

MATERIALS AND METHODS

C57BL/6 mice with RM-9 tumor were treated with manganese (III) meso-tetrakis (1,3-diethylimidazolium-2-yl) porphyrin (MnTDE-2-ImP) and 10 gray (Gy) radiation. Tumor volume was quantified and a subset/group was evaluated for hypoxia-inducible factor-1alpha (HIF-1alpha), bone marrow-derived cell populations and cytokines.

RESULTS

The addition of MnTDE-2-ImP transiently increased tumor response compared to radiation alone. The group receiving drug plus radiation had reduced intratumoral HIF-1alpha and decreased capacity to secrete TNF-alpha, whereas production of IL-4 was increased. There were no toxicities associated with combination treatment.

CONCLUSION

The results demonstrate that MnTDE-2-ImP did not protect the RM-9 prostate tumor against radiation; instead, radiation effectiveness was modestly increased. Possible mechanisms include reduction of radiation-induced HIF-1alpha and an altered cytokine profile.

A new light on T cell activation shed by a photoactivatable agonist

Which molecular events control the initiation of a T cell response? In this issue of Immunity, Huse et al. (2007) describe a photoactivatable agonist that will substantially improve our ability to investigate this phenomenon.

Excimer laser for psoriasis: a review of theories regarding enhanced efficacy over traditional UVB phototherapy

BACKGROUND

Fiber-optically targeted ultraviolet B (UVB) therapy has been shown to clear plaques of psoriasis in a significantly fewer number of treatments and reduce overall cumulative UVB dose than traditional UVB phototherapy.

OBJECTIVE

This article reviews existing theories in the literature attempting to explain the superior efficacy of targeted UVB.

METHODS

Medline was used to perform a comprehensive review of the literature from 1965 to present. Only information from the English language journals are reported in this study.

RESULTS

The theories proposed to explain the higher efficacy of the excimer (XeCl) laser relative to traditional UVB include the ability to use higher intensities of ultraviolet (UV) light and a more efficient induction of T cell apoptosis.

CONCLUSION

The possible explanations for the superior efficacy of the excimer laser over traditional UVB therapy for psoriasis include: 1) a higher intensity UV light to plaques, which is more effective in clearing psoriasis; 2) penetration into the dermis where it may induce T cell apoptosis, potentially to a greater extent than the wavelength or given energy level predicts; and 3) the difference in the delivery of UVB light may result in cell death and skin immune system suppression more effectively than traditional UVB.

Spatial and temporal dynamics of T cell receptor signaling with a photoactivatable agonist

The precise timing of signals downstream of the T cell receptor (TCR) is poorly understood. To address this problem, we prepared major histocompatibility complexes containing an antigenic peptide that is biologically inert until exposed to ultraviolet (UV) light. UV irradiation of these complexes in contact with cognate T cells enabled the high-resolution temporal analysis of signaling. Phosphorylation of the LAT adaptor molecule was observed in 4 s, and diacylglycerol production and calcium flux was observed in 6-7 s. TCR activation also induced cytoskeletal polarization within 2 min. Antibody blockade of CD4 reduced the intensity of LAT phosphorylation and the speed of calcium flux. Furthermore, strong desensitization of diacylglycerol production, but not LAT phosphorylation, occurred shortly after TCR activation, suggesting that different molecular events play distinct signal-processing roles. These results establish the speed and localization of early signaling steps, and have important implications regarding the overall structure of the network.

Prolonged Increase in T-Cell Receptor (TCR) Variant Fractions of Spleen T Lymphocytes in Pregnant Mice after γ Irradiation

To investigate the relationship between the radiation-induced increase of T-cell receptor (TCR) defective variant fractions and physiological status such as pregnancy, C57BL/ 6N mice were irradiated with 3 Gy of gamma rays at various days of gestation, just before and just after pregnancy. While the highest level of variant fractions in spleen T lymphocytes appeared at 9 days postirradiation and resolved fairly rapidly for nonpregnant mice, the increased variant fractions for pregnant mice irradiated at 16.5 days of gestation reached a plateau at 14 days postirradiation and remained at high levels until 28 days after irradiation. Therefore, variant fractions 28 days postirradiation were measured to determine the overall effect of radiation on the kinetics of TCR variant fractions during gestation. There was no significant difference in the baseline TCR variant fraction between unirradiated nonpregnant and pregnant mice. TCR variant fractions after irradiation were about twofold higher in pregnant mice (from 10.5 days of gestation until delivery) than those in nonpregnant mice. Both gamma radiation and pregnancy caused a decrease in the proportion of naïve T-cell subsets and an increase in TCR variant fractions of naïve T cells. In addition, the prolonged postirradiation increase in the TCR variant fractions of pregnant mice was associated with an increase in serum progesterone level. Differences between pregnant and nonpregnant mice in the kinetics of postirradiation restoration of T-cell systems may be involved in producing the differences in residual TCR variant fractions of these mice.

Overexpression of p101 activates PI3Kgamma signaling in T cells and contributes to cell survival

p101, the regulatory subunit of phosphatidylinositol-3-kinase-gamma (PI3Kgamma), was recently reported as a common site of retroviral insertion in T-cell lymphomas induced in mice by MoFe2-MuLV, a unique recombinant gammaretrovirus. The common interruption of p101 by retroviral integration suggests that the locus encodes an oncogene whose altered expression is related to the induction of T-cell malignancy. To examine a possible role in the malignant process, p101 was overexpressed in human T-cell lines Molt-4 and Jurkat. Transient overexpression of p101 induced apoptosis in recipient cells; however, stable expression could be established in cells that expressed moderate levels of p101. Constitutive p101 overexpression in those cells conferred significant protection against ultraviolet-induced apoptosis. Protection against apoptotic induction was attributed to p101-mediated activation of the Akt pathway. Constitutive overexpression of p101 enhanced the activity of p110gamma and further sensitized it to activation upon stimulation of G protein-coupled receptor. These findings are the first to implicate altered expression of p101 in malignancy, specifically in T-cell lymphoma. The findings further provide insight into the regulation of p110gamma, indicating that the stoichiometry of p110gamma and p101 are important in regulating PI3Kgamma signaling.

Evaluation of micronucleus induction in lymphocytes of patients following boron-neutron-capture-therapy: a comparison with thyroid cancer patients treated with radioiodine

This study evaluated micronuclei induction in peripheral T-lymphocytes after BNCT (boron neutron capture therapy) irradiation of 15 brain tumor and 20 head-and-neck cancer patients. In all of these patients, the micronucleus frequency increased after BNCT; the number of micronuclei per 1000 binucleated T-lymphocytes after BNCT increased by 33.0 +/- 12.2 for brain tumor patients and 22.8 +/- 10.3 for head-and-neck cancer patients. In 14 thyroid cancer patients who were administered radioiodine (3.3-5.6 GBq) treatment, the frequency of micronuclei after internal radioiodine therapy increased to 105.0 +/- 30.5 per 1000 binucleated T-lymphocytes. The increased micronucleus frequency of BNCT patients was less than one-third that seen for thyroid cancer patients after radioiodine treatment. These results demonstrate the usefulness of BNCT for selective high-LET radiotherapy, in association with a low irradiation effect of cytological radiation damage after BNCT, which provides a high tumor target dose for each cancer patient.

Pulsed dye laser versus treatment with calcipotriol/betamethasone dipropionate for localized refractory plaque psoriasis: effects on T-cell infiltration, epidermal proliferation and keratinization

BACKGROUND

Selective photothermolysis of diseased capillaries by pulsed dye laser (PDL) treatment has been described as a mechanism for long-lasting clearance of psoriatic plaques.

AIM

To evaluate PDL and a two-compound formulation of calcipotriol/betamethasone dipropionate ointment for the treatment of localized, recalcitrant plaque psoriasis.

METHODS

Eight psoriatic patients were treated for 4 weeks with both PDL and topical calcipotriol/betamethasone dipropionate in an open, intra-patient, left-right comparison. Biopsies were analyzed for T-cell subsets, cells expressing NK-receptors, epidermal proliferation, differentiation and epidermal thickness.

RESULTS

After active treatment, both treatments showed statistically significant but comparable improvements of T-cell subsets, epidermal proliferation, differentiation and epidermal thickness. In line with the clinical results, after an 8-week follow-up period statistically significant further reductions were observed for dermal CD3(+), CD4(+), CD45RO(+), CD2(+) T cells, epidermal CD3(+), CD8(+), CD45RO(+), CD2(+), CD25(+) T cells and the epidermal parameters for the PDL-treated plaques, in contrast to the topically treated plaques.

CONCLUSION

After 8 weeks of follow-up, PDL treatment for localized and recalcitrant plaque psoriasis resulted in persistent reductions of activated and memory effector T-helper cells in the dermis, cytotoxic T cells in the epidermis, and normalization of epidermal proliferation and keratinization, in contrast to treatment with calcipotriol/betamethasone dipropionate ointment.

Fox-P3-positive regulatory T cells are present in the skin of generalized atopic eczema patients and are not particularly affected by medium-dose UVA1 therapy

BACKGROUND

Regulatory T cells (T-reg cells) have been described as an important cell population in the UV treatment of inflammatory skin diseases.

METHODS

We have treated five patients with generalized atopic eczema (AE) using medium-dose (15 cycles of 50 J/cm(2), total dose of 750 J/cm(2)) UVA1 therapy and have analyzed the skin-infiltrating T-cellular subsets before and after therapy. Skin biopsies were split for immunohistochemistry and Real-time PCR and analyzed for CD4, Fox-P3, GATA-3, and IL-10 transcription as well as for CD3, CD4, CD152, Fox-P3, and GITR staining.

RESULTS

In all the investigated patients, we observed a good clinical response to UVA1. As described previously, the number of epidermal T cells slightly declined after irradiation. However, we did not observe a general decrease in T cell numbers. Within the population of T cells, no specific difference in the kinetics of Fox-P3-positive cells and Fox-P3-specific mRNA was noted as compared with GATA-3 positive T cells. These results were paralleled by RT-PCR for IL-10 and staining for CD152, a surface molecule that has been described for T-reg cells.

CONCLUSION

In our hands, the clinical benefit of UVA1 treatment in AE patients does not seem to be due to a preferential survival/proliferation of T-reg cells.