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The role of interleukin-4 (IL-4) in the induction of IL-4 in mouse T cells is well established, but conflicting results have been reported with anti-CD3-primed human T cells and T cell clones. Therefore, IL-4 regulation was investigated in short-term cultured human T cells primed in vitro with either a superantigen or a hapten, nickel sulfate (NiSO4), for 3 days and expanded with IL-2 for another 5 days. Under these conditions, antigen-specific IL-4 producing T cells were generated in 35/40 cultures. Priming for IL-4 production was abrogated in all cultures by anti-IL-4 antibody or soluble IL-4 receptor (sIL-4R). Primed T cells that were IL-4- when cultured with IL-2 only developed an IL-4 producing phenotype when primed and expanded in the presence of exogenous IL-4. T cells primed in the presence of either endogenous or exogenous IL-4 produced 10-200-fold more IL-4 than T cells primed in the presence of anti-IL-4 antibody or sIL-4R. While IL-4 induction was absolutely dependent on IL-4, neither endogenous nor exogenous IL-4 influenced IFN-gamma synthesis. Most importantly, IL-4 induced and sIL-4R abolished priming for IL-4 production even in NiSO4-specific memory T cells from sensitized individuals. Thus, IL-4 induction in antigen-specific human memory T cell populations absolutely required IL-4. The IL-4 pathway of memory T cells retained a remarkable plasticity in sensitized individuals.

Organ-specific autoimmune diseases arc mediated by interferon γ (IFN-γ)-producing T helper 1 (Th1) cells. Here, Martin Rocken and colleagues review the experimental basis for an antigen-specific therapeutic approach to inflammatory autoimmune diseases. This strategy involves selective deviation of harmful Th1 responses towards an anti-inflammatory, interleukin 4 (IL-4)-producing Th2 phenotype.

A HIV-infected patient in stage CDC 3A with porphyria cutanea tarda (type I) was treated with chloroquin for some months and this led to full remission. The patient course is compared with earlier reports on HIV-infected patients with porphyria cutanea tarda. Possible provocation factors for porphyria cutanea tarda in HIV infection are considered. The increased prevalence of porphyria cutanea tarda in HIV infection, the interaction of HIV and UV irradiation as a prediposing factor for porphyria cutanea tarda and the photosensitivity present in HIV infection are discussed.

Through the release of distinct sets of cytokines, Th1 and Th2 cells exert characteristic and often mutually exclusive or antagonistic immune effector functions. In the present report, we document and discuss several findings on the induction mechanisms of these cellular subtypes and present recent findings on their respective functions in vivo. The preferential induction of Th1 or Th2 cytokine patterns in mature CD4+ T cells is generally attributed to the action of cytokines. In addition, there is evidence that prolonged T-cell receptor occupancy may induce the development of the Th2 phenotype. Prolonged occupancy of the T-cell receptor provides enough autocrine inter-leukin-4 to permit induction of the Th2 phenotype. Both Thl and Th2 cells may be derived from a single mature CD4+ T cell, providing strong evidence for post-thymic modulation of the T-cell cytokine profile and rendering the possibility of predetermined cytokine patterns in T cells unlikely. CD4+ Th1 cells mediate the tumor necrosis factor– and interferon-γ– dependent classic delayed type hypersensitivity reaction. We found that Th2 cells were also capable of mediating local inflammatory reactions that depended on their prototypic lymphokine interleu-kin-4, and, in high tumor necrosis factor-producing mouse strains, upon tumor necrosis factor-α. Both Th-cell subsets induced cellular infiltrates that were not distinguishable on histologic grounds. In contrast to the widely accepted belief that only Th1 cells can mediate delayed hypersensitivity reactions, our results demonstrate that T cells with either lymphokine profile can cause tissue inflammation with leukocytic infiltrates. J Invest Dermatol 105:8S-13S, 1995

The aim of this work was to study the feasibility of measuring cell proliferation noninvasively in vivo during different stages of experimental arthritis using the PET proliferation tracer 3′-deoxy-3′-18F-fluorothymidine (18F-FLT). Methods: We injected mice with serum containing glucose-6-phosphate-isomerase–specific antibodies to induce experimental arthritis, and we injected control mice with control serum. Animals injected with 18F-FLT 1, 3, 6, and 8 d after the onset of disease were analyzed in vivo by PET, PET/CT, or PET/MR imaging followed by autoradiography analysis. The 18F-FLT uptake in the ankles and forepaws was quantified on the basis of the PET images by drawing standardized regions of interest. To correlate the in vivo PET data with cell proliferation, we performed Ki-67 immunohistochemistry of diseased and healthy joints at the corresponding time points. Results: Analysis of the different stages of arthritic joint disease revealed enhanced 18F-FLT uptake in arthritic ankles (2.2 ± 0.2 percentage injected dose per gram [%ID/g]) and forepaws (2.1 ± 0.3 %ID/g), compared with healthy ankles (1.4 ± 0.3 %ID/g) and forepaws (1.5 ± 0.5 %ID/g), as early as 1 d after the glucose-6-phosphate-isomerase serum injection, a time point characterized by clear histologic signs of arthritis but only slight ankle swelling. The 18F-FLT uptake in the ankles (3.5 ± 0.3 %ID/g) reached the maximum observed level at day 8. Ki-67 immunohistochemical staining of the arthritic ankles and forepaws revealed a strong correlation with the in vivo 18F-FLT PET data. PET/CT and PET/MR imaging measurements enabled us to identify whether the 18F-FLT uptake was located in the bone or the soft tissue. Conclusion: Noninvasive in vivo measurement of cell proliferation in experimental arthritis using 18F-FLT PET is a promising tool to investigate the extent of arthritic joint inflammation.

Assessing information on tumor progression in the RIP1-Tag2 mouse in vivo is a great challenge because the tumors form spontaneously throughout the pancreas and are difficult to detect with current imaging modalities. In this study, we focused on non-invasive magnetic resonance imaging, providing information on tumor growth. Tissue relaxation times were measured over time and were compared between tumors and healthy pancreatic tissue. The effects of age and body temperature on these relaxation times, possibly influencing image contrast and therefore detection capabilities, were evaluated. Tumors appeared hyperintense in T2-weighted images when they exceeded 0.8 mm in diameter, and both relaxation times showed significantly higher values in tumors than in the healthy pancreas. Visualization and monitoring of these small tumors in vivo is feasible, even under adverse conditions of permanent gut movement. In the mouse model studied, the relaxation times of tumors differed significantly from healthy pancreatic tissue.

Propranolol has become the treatment of choice of large and complicated infantile hemangiomas. There is a controversy concerning the safety of systemic propranolol. Here we show that topical use of the beta-blocker timolol can also inhibit the growth and promote regression of infantile hemangiomas. In this case series we treated 11 infantile hemangiomas in nine children including six preterm babies with the nonselective betablocker timolol. A timolol containing gel was manufactured from an ophthalmic formulation of timolol 0.5% eyedrops. This gel was applied using a standardized occlusive dressing (Finn-Chambers) containing approximately 0.25 mg of timolol. In all infants topical timolol was associated with growth arrest, a reduction in redness and thickness within the first 2 weeks. Seven hemangiomas showed almost complete resolution, and four became much paler and thinner. No data are available on the transdermal absorption of timolol. Even supposing complete absorption of timolol from the occlusive dressing, a maximum dose of 0.25 mg of timolol would result per day and hemangioma. Regression of infantile hemangiomas treated using 0.5% timolol gel in this case series occurred earlier than spontaneous regression which is generally not observed before the age of 9-12 months. The promising results need to be verified in prospective randomized trials on topical beta blocker administration for infantile hemangiomas which should address dose, duration, and mode of application.

During inflammation and in transplantable tumor models, natural killer (NK) cells are recruited to pathologic tissues and activated to produce proinflammatory cytokines favoring adaptive immune responses of the T-helper type 1 (Th1) type. Interferon (IFN)-γ is needed to induce chemokines that attract NK cells in transplanted tumors. Nothing, however, is known on NK-cell migration in spontaneous tumors. As effective recruitment is a prerequisite for therapeutic NK-cell transfer, we investigated the cytokine milieu and the mechanisms that are instrumental for NK-cell accumulation in an endogenous tumor model. We make use of λ-myc transgenic mice that harbor the c-myc oncogene and develop spontaneous B-cell lymphoma. In contrast to lymphomas induced by tumor cell injection, virtually no IFN-γ produced by NK or by other cells was present in the tumor environment, particularly in advanced stages. Dendritic cells showed an impaired expression of interleukin-12, which is suggestive of deficient Th1 priming. The IFN-γ-dependent chemokines CXCL9 and CXCL10 were pivotal for NK-cell migration in the endogenous lymphoma model. Although IFN-γ was absent in late tumor stages, there was still expression of CXCL9 and CXCL10 with an ongoing influx of NK cells. The results demonstrate that transplantable tumor models do not reflect the situation as found in endogenously arising neoplasia, because in the latter, effective Th1 and cytotoxic T-lymphocyte responses are presumably not induced because of impaired IFN-γ production. The data also suggest that CXCL9 and CXCL10 production and NK-cell migration become independent of IFN-γ during tumor progression, and therefore support approaches of adoptive NK-cell transfer that hold promise for treatment of cancer.

Transgenic (Tg) mouse models of autoimmunity have been utilized to express model antigens that can be recognized by T cells or by autoantibodies. To identify mechanisms of CD8-mediated tissue-specific autoimmune reactions and to identify potential treatments, we generated a double transgenic (DTg) murine model of autoimmunity by crossing K14-sOVA mice, which express soluble chicken ovalbumin (OVA) predominantly in external ear skin, with OT-I mice whose CD8 T cells express Vα2/Vβ5 regions of the T cell receptor and are specific for SIINFEKL peptide (OVA 257-264) in association with class I MHC. The K14-sOVA/OT-I DTg mice develop a destructive process selectively targeting the external ear pinnae in the first 6 days of life. The ear bud area develops an intense inflammatory infiltrate of OT-I cells. Administration of the SIINFEKL peptide i.v. to pregnant F1 mice and subsequently i.p. to newborn pups resulted in normal external ear development. Treatment with this self-peptide markedly reduced OT-I cell numbers as well as down-regulated the CD8 co-receptor. This model can be useful in studying localized, tissue-specific, immune-mediated skin disease and inform us about potential therapies for autoimmune diseases in which specific molecular targets are known.

It is possible that reduced function of DNA repair and cell-cycle control genes increases the individual susceptibility to malignant melanoma. As CHEK2 is a cell-cycle master controller, we tested the hypothesis that heterozygosity for the frameshift alteration CHEK2*1100delC is associated with increased risk of malignant melanoma. First, we performed case-control studies of 1,152 Danish and 752 German individuals with malignant melanoma compared with 9,142 Danish and 3,718 German controls. Second, we performed a meta-analysis of CHEK2*1100delC and malignant melanoma, involving 2,619 cases and 17,481 controls. Third, we examined the risk of malignant melanoma associated with CHEK2*1100delC heterozygosity in an analysis stratified for sun exposure, as well as for subtype and location on the body. The odds ratios for malignant melanoma for CHEK2(*)1100del heterozygotes compared with those for noncarriers were 2.01 (95% confidence interval (CI), 1.03-3.91) in Danes, 1.42 (95% CI, 0.46-4.31) in Germans, and 1.79 (95% CI, 1.02-3.17) in Danes and Germans combined. In a meta-analysis, the odds ratio of malignant melanoma for CHEK2*1100delC heterozygotes compared with that for noncarriers was 1.81 (95% CI, 1.07-3.05). Stratifications did not alter these results. CHEK2*1100delC heterozygotes have a twofold risk of malignant melanoma compared with noncarriers.Journal of Investigative Dermatology advance online publication, 29 September 2011; doi:10.1038/jid.2011.303.

The properties and outcome of an immune response are best predicted by the lymphokine phenotype of the responding T cells. Cytokines produced by CD4+ T helper type 1 (Th1) T cells mediate delayed type hypersensitivity (DTH) and inflammatory responses, whereas cytokines produced by Th2 T cells mediate helper T cell functions for antibody production. To determine whether induction of Th2-like cells would modulate an inflammatory response, interleukin 4 (IL-4) was administered to animals with experimental allergic encephalomyelitis (EAE), a prototypic autoimmune disease produced by Th1-like T cells specific for myelin basic protein (MBP). IL-4 treatment resulted in amelioration of clinical disease, the induction of MBP-specific Th2 cells, diminished demyelination, and inhibition of the synthesis of inflammatory cytokines in the central nervous system (CNS). Modulation of an immune response from one dominated by excessive activity of Th1-like T cells to one dominated by the protective cytokines produced by Th2-like T cells may have applicability to the therapy of certain human autoimmune diseases.

Immunologists are just beginning to understand the early signals required to recruit memory T cells to sites of antigen-specific inflammation. Now it seems that activation of κ light chain–sensitized mast cells by antigen-specific recognition initiates local immune responses (pages 694–701).

TNM classifications are the basis for diagnostic and therapeutic procedures in oncology. Histopathological reports have to enable a proper indexing of tumor specific findings into recent classifications.A systematic review of the literature was performed to identify reports dealing with the assessment of mitotic rate and the processing and evaluation of sentinel node biopsies in malignant melanoma. On the basis of this review an expert panel of dermatopathologists and general pathologists discussed and agreed recommendations for general practice.Following recommendations were agreed with a broad consensus (93-100 % agreement): The determination of the mitotic rate in primary melanoma is performed on HE slides. The evaluation of an area of 1 mm(2) is sufficient. Only dermal mitoses are considered. The counted number of mitoses is provided as an integer value. The mitotic rate shall be determined in primary melanomas of ≤1.00 mm vertical tumor thickness according to the hot-spot method and provided as an integer value in relation to an area of 1 mm(2) . The determination of the mitotic rate in the case of thicker primary melanomas is desirable. In general, for the evaluation of each sentinel lymph node, 4 slides should be prepared. For diagnostic purposes, immunohistochemistry (preferably with antibodies against S100ß, Melan A and HMB-45) should be performed in addition to HE staining. The pathology report should provide information about micro-metastases and their longest extension (one-tenth of a millimeter).These recommendations are suitable for standardizing the histopathological diagnosis of malignant melanoma and for providing a common basis for clinical decisions and scientific research.

Our understanding of oncogenetics and of the molecular mechanisms involved in melanoma development and signaling has dramatically changed in recent years. Today, melanomas are also classified based on molecular alterations. Emerging molecular therapies are targeted against specific mutations in melanoma. An example of targeted therapies is the successful treatment of KIT-mutant melanoma with the kinase inhibitor imatinib. Highly selective BRAF-inhibitors are likewise under clinical development and show encouraging clinical responses. An increasing number of targeted drugs will emerge in the coming years, based on molecular diagnostics and classification. The present article reviews signaling pathways in melanocytes and alterations in melanoma that are a prerequisite to understanding modern cancer therapies in melanoma.

The term autoimmunity signifies the presence of specific memory-type immune reactions that are directed against one or more self-epitopes. Under most conditions, autoimmunity is determined in terms of immunoglobulins that react with either unknown or well-defined human antigens. Today it is supposed that the production of these autoantibodies requires prior activation of potentially autoreactive B cells by memory T cells. These T cells must not only recognize a closely related peptide structure. Importantly, these T cells can stimulate B cells only when primed by activated antigen presenting cells.

BRAF exon 15 mutations have been identified in a large proportion of malignant melanomas, melanoma metastases and melanocytic nevi. Mutated BRAF is one of the potential activators of the mitogen-activated protein kinase (MAPK) signaling pathway by phosphorylating ERK (extracellular signal-regulated kinase). We therefore analyzed the correlation of BRAF V600E and ERK-activation in 20 malignant melanomas and 21 subsequently evolved, paired metastases of the same donor by BRAF exon 15 DNA sequencing and phospho-specific immunohistochemistry for ERK. Phospho-ERK expression was present in 84% of primary melanomas and in all 19 metastases analyzed. In contrast, BRAF mutational status was concordant in only 12/20 pairs (60%) of the primary melanoma and metastasis of the same patient. Surprisingly, the BRAF mutation did not correlate with pERK expression. As even single tumors showed heterogeneous staining for pERK, we used laser-capture microdissection to study BRAF V600E status in pERK positive and pERK negative cells separately. Even on the single cell level ERK activation did not correlate with the BRAF mutation. Our results demonstrate that, in melanomas, activation of the MAPK pathway can occur through signaling pathways operating independently of BRAF T1799A.

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder characterized by an increased skin cancer risk due to defective repair of ultraviolet (UV)-radiation induced DNA damage. Therefore patients with XP are required to apply stringent sun-protection. Since the skin needs UV-B irradiation for de novo vitamin D synthesis, it has been postulated that sun-protection may lead to a clinically relevant reduction of vitamin D levels. To investigate whether reduced vitamin D levels in XP-patients are caused by the stringent sun-protection measures employed, in this study we examined 15 patients with XP. The 25-hydroxyvitamin (25-OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) serum levels were measured. Additionally, patients received a questionnaire about their sun-protection-behaviour. Serum levels for 25-OHD were decreased in 10 of 15 (67%) patients, however there was no statistically significant association between decreased 25-OHD serum levels and duration of sun-protection (p = 0.84). Results for 1,25-(OH)2D levels showed a probability of < 0.16 and between 0.16 and 0.77 for sun-protection duration of < 20 and 20 to 40 years, respectively (p = 0.0058). There was no statistically significant association between the duration of sun-protection with drometrizole trisiloxane and the probability of reduced 25-OHD and 1,25-(OH)2D levels. In conclusion, this investigation indicates that vitamin D serum levels in patients with XP may be normal, increased or decreased but this is not causally linked to the stringent photoprotective measures carried out in our group of investigated XP-patients.

The classical model of metastasis is that tumor cell dissemination occurs late in tumor development, after the primary tumor has grown, and that only then will tumor cells invade the local tissue, enter the blood or lymphatic vessels, and colonize new sites to cause metastases. However, evidence increasingly indicates that single tumor cells spread to distant sites much earlier than previously believed. In this issue of the JCI, Eyles and colleagues provide new insight into the mechanisms underlying early tumor cell dissemination, formation of metastases, and tumor immunosurveillance using transgenic mice that spontaneously develop melanomas of the uvea. The authors provide striking evidence that tumor cells start to disseminate during the initial steps of tumor development, that late appearing metastases arise from these early disseminated tumor cells, and that CD8+ T cells inhibit the growth of disseminated tumor cells, surprisingly, not by cytotoxic effects, but through cytostatic effects.

Defects in the DNA repair mechanism nucleotide excision repair (NER) may lead to tumors in xeroderma pigmentosum (XP) or to premature aging with loss of subcutaneous fat in Cockayne syndrome (CS). Mutations of mitochondrial (mt)DNA play a role in aging, but a link between the NER-associated CS proteins and base excision repair (BER)-associated proteins in mitochondrial aging remains enigmatic. We show functional increase of CSA and CSB inside mt and complex formation with mtDNA, mt human 8-oxoguanine glycosylase (mtOGG)-1, and mt single-stranded DNA binding protein (mtSSBP)-1 upon oxidative stress. MtDNA mutations are highly increased in cells from CS patients and in subcutaneous fat of aged Csbm/m and Csa−/− mice. Thus, the NER-proteins CSA and CSB localize to mt and directly interact with BER-associated human mitochondrial 8-oxoguanine glycosylase-1 to protect from aging- and stress-induced mtDNA mutations and apoptosis-mediated loss of subcutaneous fat, a hallmark of aging found in animal models, human progeroid syndromes like CS and in normal human aging.

In recent years, in vivo confocal laser scanning microscopy (CLSM) has become an established method for the non-invasive examination of the skin. In vivo CLSM allows for real-time imaging of micro-anatomic cutaneous structures. It has been used to diagnose ambiguous skin tumors and to measure subclinical tumor spread prior to surgery. By additionally providing high power morphologic information, in vivo CLSM helps to reduce unnecessary biopsies. A multitude of diagnostic features for skin tumors has been published. Here we review published diagnostic in vivo CLSM features, and compare them to our own experience in 100 tumors. In combination with clinical examination and dermatoscopy, in vivo CLSM is a valuable additional tool for non-invasive skin tumor diagnosis.

Patients sensitized to para-phenylenediamine (PPD) by semi-permanent tattoos increasingly develop threatening allergic reactions in response to black hair dye. The gold standard to diagnose allergic contact dermatitis is to perform epicutaneous patch tests, however, iatrogenic sensitizations and severe patch test reactions to PPD have been described, the latter especially in patients with severe allergic reactions. We examined nine patients with severe allergic reactions in response to permanent hair dyes. Patch tests using the standard concentration of 1% or 0.5% PPD resulted in severe and sometimes even bullous reactions in all patients responsive to PPD. Titration revealed that at 1% of the standard concentration (0.01% PPD), patch test sensitivity decreased and only 50% of patients responded. Consequently, we established an in vitro assay to diagnose PPD allergy. Freshly isolated peripheral blood mononuclear cells (PBMC) were cultured with titrated concentrations of PPD with or without IL-2 supplementation, and cell proliferation was determined by [3H]-thymidine incorporation. Lymphocyte activation test (LAT) detected PBMC cell proliferation specific to PPD, with at least 3.5-fold increase in [3H]-thymidine uptake in all PPD allergic patients. Most importantly, PPD-LAT without IL-2 supplementation remained negative in three out of eight PPD allergic patients. Thus, PPD-LAT with IL-2 supplementation demonstrated a sensitivity of 100%, remained unresponsive in controls not sensitized to PPD, and in one patient sensitive to other p-amino compounds. These data demonstrate that LAT with PPD can be used to detect PPD sensitization as a possible alternative to patch testing at least in patients with severe allergic reactions to PPD.

Clonal deletion or clonal anergy establish tolerance in T cells that bear potentially autoreactive antigen receptors. Here we report that concomitant infection with the nematode Nippostrongylus brasiliensis breaks an established T-cell tolerance induced by injection of mice with Staphylococcus enterotoxin B (SEB). CD4+ T cells from SEB-tolerant mice did not produce either interleukin-2 or interleukin-4 when challenged in vitro with SEB. N. brasiliensis infection of SEB-primed animals resulted in a normal expansion of SEB-tolerant CD4+V beta 8+ T cells in vivo as well as an equivalent increase of SEB-reactive, interleukin-4-producing CD4+V beta 8+ T cells both in SEB-tolerant and in normal animals. Thus, infection with N. brasiliensis circumvented the tolerance established with SEB. Activation of anergic, potentially autoreactive CD4+ T cells by infectious agents seems to be a major pathway for the initiation of autoimmune diseases. Our results suggest that infectious agents may break tolerance in potentially autoreactive CD4+ T cells by activation of alternative reaction pathways.

Psoriasis pathogenesis is closely associated with disease-inducing Th1 and Th17 cells. Yet, several studies suggest that aberrant keratinocyte or endothelial cell signalling significantly contributes to disease manifestation. Histological hallmarks of psoriatic skin include the infiltration of multiple immune cells, keratinocyte proliferation and increased dermal vascularity. Formation of new blood vessels starts with early psoriatic changes and disappears with disease clearance. Several angiogenic mediators like vascular endothelial growth factor, hypoxia-inducible factors, angiopoietins and pro-angiogenic cytokines, such as tumour necrosis factor (TNF), interleukin (IL)-8 and IL-17, are up-regulated in psoriasis development. Contact- and mediator-dependent factors derived from keratinocytes, mast cells and immune cells may contribute to the strong blood vessel formation of psoriasis. New technologies and experimental models provide new insights into the role of angiogenesis in psoriasis pathogenesis. Interestingly, many therapies target not only immune cells, but also protein structures of endothelial cells. Here we summarize the role of pro-angiogenic factors in psoriasis development and discuss angiogenesis as a potential target of novel therapies.

As patients with atopic dermatitis (AD) frequently have elevated serum IgE levels, the relation of this disease to CD23/Fc epsilon RII, a low affinity Fc receptor for IgE, and its soluble forms, sCD23, was studied. We examined the expression of CD23 on peripheral blood mononuclear cells (PBMC) as well as the serum IgE and sCD23 levels in 33 patients with AD and in 9 patients with psoriasis in comparison with 10 healthy donors. In AD patients, the numbers of CD23+ unfractionated PBMC and CD23+ small adherent cells were significantly elevated (P less than 0.05, resp. P less than 0.005). In psoriatic patients however, CD23 was also significantly elevated on PBMC (P less than 0.05) and on small adherent cells (P less than 0.05). There was no significant difference in the frequencies of CD23+ cells between AD and psoriasis patients. In all donors, CD23 could be detected only on B cells, but not on monocytes/macrophages. In AD patients who were examined twice, an increase or decrease of the clinical AD score was always accompanied by an increase or decrease, resp., of cell-bound CD23. The serum sCD23 level was not significantly increased in either group of patients. Our results suggest that CD23 should be considered as a nonspecific marker for B cell activation in the context of inflammation and not as a specific marker for AD.

Pagetoid reticulosis (Woringer-Kolopp disease) is a rare subtype of cutaneous CD8-positive T-cell lymphoma. A 41-year-old man presented with a 7-year history with a slowly progressive erythematous plaque on his right buttocks. With the working diagnosis of psoriasis, he was treated with topical corticosteroids which produced no improvement. Histological examination showed an epidermotropic T-cell lymphoma with predominance of CD8- vs.CD4-positive lymphocytes. Based on the clinical picture and the histological findings, we diagnosed pagetoid reticulosis. Excision of the plaque and cream PUVA photo-chemotherapy produced long-term remission.

IL-4 is expressed at high levels in allergic diseases and dominates the early phases of multiple acquired immune responses. However, the precise role of IL-4 during early inflammation and its impact on the differentiation of newly recruited DC precursors remains elusive. In order to characterize the impact of IL-4 on the differentiation of human DC, we investigated the role of IL-4 on the differentiation of monocytes into DC. Human DC were differentiated from peripheral blood precursors under either low or high concentrations of IL-4. We analyzed their cytokine profile and capacity to polarize T-cell differentiation. Concentrations of 5 (low) and 50 (high) ng/mL IL-4 induced two distinct types of DC. DC differentiated under low-dose IL-4 (5 ng/mL) produced almost no IL-12p70, and primed naive CD4+ T cells allowing IL-4 secretion and Th2 induction. In contrast, DC generated under high concentrations of IL-4 (50 ng/mL) produced large amounts of IL-12p70, low IL-10 and primed naive CD4+ T cells to become Th1 cells. Thus, we demonstrate that the Th2 cell cytokine IL-4 decisively determines the phenotype of ongoing immune responses by orchestrating the functional phenotype of newly immigrating DC precursors.

Summary Background Erosive oral lichen planus (EOLP) is a T-cell mediated inflammatory disease leading to severe pain and impairment. As current therapies are of limited efficacy, application of calcineurin inhibitors is considered to be a potential option. Objectives To investigate the efficacy of pimecrolimus cream 1% (Elidel®) compared with vehicle cream in the treatment of EOLP. Methods Twenty patients were enrolled in a prospective, double-blind, randomized, vehicle-controlled trial and assigned to either pimecrolimus or vehicle group. Study medication was applied for 30 days followed by 30 days of observation without therapy. In case of unresponsiveness, treatment was continued for 30 days with open-label pimecrolimus. EOLP was monitored on days 0, 30 and 60. Safety was assessed by patient documentation, measurement of pimecrolimus levels and blood counts. Results Within 30 days erosions cleared completely in seven of 10 patients treated with pimecrolimus and in two of 10 patients treated with vehicle. The clinical EOLP ‘composite score’ including mucosal erosions and pain sensation was significantly reduced in the pimecrolimus-treated group compared with vehicle (P = 0·025). In the three of 10 patients not responding to pimecrolimus, EOLP cleared after an additional 30 days of treatment with pimecrolimus. Following termination of the therapy, sustained remission of EOLP was detected in 83% of patients demonstrating long-lasting effects of pimecrolimus treatment. No severe adverse events were observed. In five patients pimecrolimus blood levels were detected, all of which stayed below 4 ng mL−1. Conclusions Pimecrolimus cream 1% effectively treats EOLP with long-lasting therapeutic effects and is therefore a promising therapeutic option for EOLP.

Chronic graft-versus-host disease (GVHD) is almost always associated with skin diseases appearing either as lichenoid GVHD, sclerodermatous GVHD (sGVHD) or as eosinophilic fasciitis-like disease. The two latter frequently result in severe and deep sclerosis. Immunosuppressive therapy is of little help in sclerodermatous or eosinophilic fasciitis-like types of GVHD. Based on data showing that PUVA-bath photochemotherapy is effective in the treatment of severe localized sclerosis of the skin, we investigated the efficacy of PUVA-bath photochemotherapy and isotretinoin in sGVHD. In a retrospective study we analyzed fourteen consecutive patients with sGVHD who received PUVA-bath photochemotherapy, five in combination with oral isotretinoin. Seven patients improved and four showed complete remission. Surprisingly, the therapy was complicated by the development of ulcers within the sclerotic plaques during the early periods of treatment. These ulcers cleared in most patients when PUVA-bath photochemotherapy was continued. Thus, PUVA-bath photochemotherapy alone or in combination with isotretinoin may resolve or improve GVHD associated sclerosis in selected patients.