Gene Expression Profiling of Lichen Planus Reflects CXCL9+-Mediated Inflammation and Distinguishes this Disease from Atopic Dermatitis and Psoriasis

Here, we present data of a gene expression profiling approach to apply the diagnostic value and pathological significance of this method in different inflammatory skin diseases, using whole skin biopsies. Initially, SAGE was performed to identify frequent tags differentially expressed in various skin diseases. On the basis of these results, a new skin pathology-oriented PIQOR microarray was designed. Lichen planus (LP) was chosen as a model disease to evaluate this system. Controls included healthy skin, atopic dermatitis (AD), and psoriasis (Pso). Gene expression analyses using the topic-defined microarray followed by unclassified clustering was able to discriminate LP from AD and Pso. Genes significantly expressed in LP included type I IFN inducible genes and a specific chemokine expression pattern. The CXCR3 ligand, CXCL9, was the most significant marker for LP. In situ hybridization and immunohistochemistry confirmed the results and revealed that keratinocytes are type I IFN producers in LP skin lesions. Our results show that gene expression profiling using a skin-specific microarray is a reliable method to identify patients with LP in the chosen context and reflect recent models concerning the pathogenesis of this disease. Gene expression profiling might complement the diagnostic spectrum in dermatology and may provide new pathogenetic insights.

Subpopulations of human dendritic cells display a distinct phenotype and bind differentially to proteins of the extracellular matrix

CD1a(pos) dendritic cells (DCs) and Langerhans cells (LCs) are highly specialized antigen-presenting cells mainly localized in the skin. Various cells have been identified as precursors of cutaneous DCs, but the definitive precursor subpopulations remain to be defined and characterized in detail. In this study, DCs were generated in vitro from monocytes (monocyte-derived DCs, MoDCs) and from CD34(pos) stem cells (CD34(pos) cell-derived DCs, CD34DCs). By virtue of their CD14 and CD1a expression, four CD34DC subpopulations were characterized while MoDCs contain three different subpopulations. Of these, CD14-expressing cells are considered to be precursors of fully differentiated DCs, which themselves are CD14(neg)CD1a(pos). Both, MoDCs and CD34DCs expressed the alpha integrins LFA-1, Mac-1, CR4, VLA-4, VLA-5 and the beta2 integrin CD18. CD34DCs and MoDCs were negative for VLA-3, whereas MoDCs, but not CD34DCs expressed VLA-6. Phenotypic and functional characterization of the cells generated herein at earlier time points revealed that DCs at day 3 of culture may reflect the in vivo situation more closely than at day 7. Adhesion of DC precursors to endothelial cells and to components of the extracellular matrix is a prerequisite for their migration towards the epidermis. To this end, we investigated adhesion of CD34DCs and MoDCs to components of the cutaneous extracellular matrix. Distinct DC subsets showed a differential binding pattern to proteins of the extracellular matrix. MoDCs and CD34DCs bound preferentially to laminin 332 via CD49f and to fibronectin via CD49e, but only weakly to laminin 111 or to collagens. While CD14(pos) cells preferentially bound to laminin 332, CD1a(pos) cells adhered to fibronectin. In summary, subpopulations of CD34DCs and MoDCs are phenotypically related to each other, but not identical and display differential binding to components of the extracellular matrix.

Indoleamine 2,3-dioxygenase (IDO): the antagonist of type I interferon-driven skin inflammation?

Recent studies have provided evidence that a type I interferon (IFN)-driven immune response might play an important role in the pathogenesis of lichen planus (LP), an inflammatory disorder of the skin of unclear etiology. Plasmacytoid dendritic cells in affected skin from LP have been proposed to produce IFN-alpha/beta locally, which leads to the expression of IFN-inducible chemokines such as IP10/CXCL10 in the epidermis. This chemokine recruits chemokine receptor CXCR3-expressing T-lymphocytes into the skin via CXCR3/IP10 interactions. Indoleamine 2,3-dioxygenase (IDO), which degrades tryptophan and suppresses T-cell proliferation, is induced by IFNs and other inflammatory cytokines. We show that type I IFN-mediated skin disorders, such as LP, strongly express IDO in lesional skin. This expression closely correlates to the expression of the highly specific type I IFN marker MxA. We further demonstrate that the IDO+ cells in LP are large myeloid CD11c+S100+CD68(-) dendritic cells. Accordingly, CD11c+ antigen-presenting cells significantly up-regulate IDO gene expression and intracellular IDO protein expression after stimulation with IFN-alpha in vitro. These findings reveal that both proinflammatory and counterregulatory mechanisms are operative in cutaneous lesions of LP. We propose that the balance of these mechanisms may be involved in the pathogenesis of this disorder.

Inhibitory oligodeoxynucleotides downregulate herpes simplex virus-induced plasmacytoid dendritic cell type I interferon production and modulate cell function

Recognition of nucleic acids by TLR9 expressed by human plasmacytoid dendritic cells (PDC) plays a key role in the defense against viral infections. Upon microbial pathogen stimulation, PDC secrete large amounts of type I interferon and arbitrate thereby both innate and adaptive immune mechanisms. Unmethylated CpG motifs, which are an integral part of bacterial or viral DNA, are used in vitro and in vivo to activate the TLR9 pathway, whereas inhibitory oligodeoxynucleotide (iODN) are capable of depressing TLR9 signaling. In this study we demonstrate that TTAGGG motifs containing iODN efficiently block the TLR9 signaling in terms of herpes simplex virus (HSV)-induced type I interferon production by PDC. However, iODN, as well as control ODN, still promote PDC maturation with upregulated expression of costimulatory molecules, major histocompatibility complex molecules, and other signs for PDC maturation. Furthermore, iODN and control ODN incubated PDC demonstrate increased T-cell stimulatory functions. Coculture experiments with autologous T cells indicate that iODN-treated PDC induce more CD4(+)CD25(+)Foxp3(+) T regulatory cells from naive CD4(+) T cells and preincubation of HSV-stimulated PDC with iODN upregulated T cells' IFN-gamma production. These data indicate that iODN, while blocking type I interferon production by PDC, modify PDC activation and maturation as well as T-cell priming and stimulation. Knowledge about the different functions of iODN on PDC elucidated might be crucial for immunotherapeutic strategies in which iODN motifs are used to prevent the interaction of CpG-DNA with TLR9 to calm down specific immunological responses, because our data indicate that iODN might not only have inhibitory functions but also be effective activators of immune cells.

Steroid-sparing effect of pimecrolimus cream 1% in children with severe atopic dermatitis

OBJECTIVE

To investigate if pimecrolimus cream 1% reduces the need for steroids in the long-term management of severe pediatric atopic dermatitis (AD).

METHODS

A total of 184 pediatric patients (aged 2-17 years) with a history of severe AD according to Rajka and Langeland were enrolled. Patients were randomized to treatment with pimecrolimus cream or vehicle cream for a 24-week period. Prednicarbate 0.25% was applied as rescue medication.

RESULTS

Patients on pimecrolimus required steroids on a mean of 29% of study days, compared with 35% of patients on vehicle (p = 0.1841). On the head and neck only, the respective figures were 10 versus 19% (p = 0.0009). In patients enrolled with acute severe disease (Investigator's Global Assessment > or = 4), steroids were used on 28% of the days in the pimecrolimus group compared to 45% in the control group (p = 0.0024). On the head and neck, steroids were used on 10% of study days with pimecrolimus versus 30% with vehicle (p < 0.0001).

CONCLUSION

The results indicate that the need for topical steroids on the head and neck is reduced with pimecrolimus cream 1% in the management of severe pediatric AD according to the definition of Rajka and Langeland.

Clinical improvement and immunological changes in atopic dermatitis patients undergoing subcutaneous immunotherapy with a house dust mite allergoid: a pilot study

BACKGROUND

House dust mites (HDMs) represent significant indoor allergen sources for patients with atopic dermatitis (AD). Subcutaneous allergen-specific immunotherapy (SCIT) has been shown to be successful in patients with allergic rhinitis and mild asthma and might represent an attractive therapeutic option for the long-term treatment of HDM sensitizations in AD patients. However, only a few studies have been conducted on the effectiveness of HDM SCIT in AD, resulting in controversial clinical results. Data on immunological changes induced by SCIT in AD patients are rare.

OBJECTIVES

We performed an open pilot study to assess clinical changes and objective laboratory parameters and evaluate the benefit of HDM SCIT in 25 AD patients with IgE-mediated sensitization against HDM.

METHODS

The severity of AD was evaluated by the severity scoring of atopic dermatitis system (SCORAD). Specific IgE and IgG4 against HDM and serum levels of TARC/CCL17, MDC/CCL22, IL-16, IL-4, IFN-gamma, IL-10 and TGF-beta1 were measured during SCIT.

RESULTS

Subjective and objective SCORAD improved significantly within only 4 weeks of treatment. The level of the tolerogenic cytokine IL-10 increased, whereas CCL17 and IL-16 decreased in the sera of the patients during SCIT. Allergen specific IgE decreased, while IgG4 increased during SCIT.

CONCLUSION

In this open-label pilot study, SCIT with an HDM extract in patients with AD led to a significant improvement of AD mirrored by a reduction of SCORAD as well as serological and immunological changes, which might serve as valuable parameters to estimate the therapeutic effect of SCIT.

The expression pattern of interferon-inducible proteins reflects the characteristic histological distribution of infiltrating immune cells in different cutaneous lupus erythematosus subsets

BACKGROUND

Plasmacytoid dendritic cells and type I interferons (IFNs) are supposed to play a central proinflammatory role in the pathogenesis of cutaneous lupus erythematosus (LE). The IFN-inducible chemokines CXCL9 and CXCL10 are involved in recruiting CXCR3+ effector lymphocytes from the peripheral blood into skin lesions of LE. We hypothesized that the expression pattern of IFN-inducible proteins reflects the characteristic distribution of the inflammatory infiltrate in different subsets of cutaneous LE.

OBJECTIVES

To test this hypothesis in patients with LE.

METHODS

Lesional skin biopsies taken from patients with different subsets of LE [chronic discoid LE (CDLE), n = 12; subacute cutaneous LE (SCLE), n = 5; LE tumidus (LET), n = 4; LE profundus (LEP), n = 6] were investigated by immunohistochemistry using monoclonal antibodies to the lymphocyte surface markers CD3, CD4, CD8, CD20 and CD68, the cytotoxic proteins Tia1 and granzyme B, the chemokine receptor CXCR3, the specifically type I IFN-inducible protein myxovirus protein A (MxA) and the chemokines CXCL9 and CXCL10.

RESULTS

The expression pattern of MxA followed the distribution of the inflammatory infiltrate typically seen in the investigated cutaneous LE subsets. In CDLE and SCLE, expression was focused in the epidermis and upper dermis, while in LET a perivascular and in LEP a subcutaneous pattern was found. Similar findings were obtained for CXCL9 and CXCL10.

CONCLUSIONS

Our results demonstrate a close morphological association between the expression pattern of IFN-inducible proteins and the distribution of CXCR3+ CD3+ lymphocytes in all investigated subsets of cutaneous LE. This supports the importance of an IFN-driven inflammation in this condition. Infiltrating lymphocytes carrying CXCL10 in their granules might amplify the lesional inflammation and be responsible for the chronic course of this disease.

Generalized lichen nitidus with involvement of the palms following interferon alpha treatment

Lichen nitidus is an uncommon dermatosis of unknown etiology. Here we present the case of a generalized lichen nitidus with involvement of the palms in a patient with hepatitis C after systemic treatment with interferon alpha and ribavirin. Furthermore in our patient we could show a strong lesional expression of MxA, a protein specifically induced by type I interferon. It is tempting to speculate that interferon alpha may be involved in the pathogenesis of lichen nitidus.

IP10/CXCL10 - CXCR3 interaction: a potential self-recruiting mechanism for cytotoxic lymphocytes in lichen sclerosus et atrophicus

Lichen sclerosus et atrophicus is a chronic inflammatory skin disease of unknown aetiology. Recent studies have indicated that autoimmune mechanisms might be involved in its pathogenesis and have suggested a role for autoreactive cytotoxic T-lymphocytes. Based on recent observations we now hypothesize that a type I interferon-driven inflammation might be involved in the pathogenesis of this disease. Lesional skin biopsies were analysed by immunohistochemistry (CD3, CD4, CD8, CD68, CD123, Tia1, Granzyme B, Myxovirus resistance A, IP10/CXCL10 and CXCR3). Sequential double staining was performed to analyse co-expression of Tia1 and CXCR3. Significant expression of Myxovirus resistance A was found, indicating type I interferon production. This expression was closely associated with the expression of the interferon-inducible protein IP10 and the recruitment of CXCR3+ cytotoxic T-lymphocytes. Plasmacytoid dendritic cells appeared to be a major source of type I interferon in lichen sclerosus et atrophicus. Interestingly, several infiltrating lymphocytes contained IP10 in their granules. This is the first study providing evidence that a type I interferon-associated recruitment of CXCR3+ cytotoxic T-lymphocytes is involved in the pathogenesis of lichen sclerosus et atrophicus. Infiltrating lymphocytes, containing IP10 in their granules, could provide an important self-perpetuating mechanism.

Putative association of a TLR9 promoter polymorphism with atopic eczema

BACKGROUND

Toll-like receptors (TLR) play a pivotal role in the induction of first-line defense mechanisms of the innate immune system and trigger adaptive immune responses to microbial pathogens. Genetic variations in innate immunity genes have been reported to be associated with a range of inflammatory disorders. Deficiencies on the level of immunity receptors such as pathogen-recognition receptors are suspected to affect the maturation of our immune system and to avail thereby the high prevalence of atopic diseases and susceptibility of atopic patients to microbial infections.

AIMS OF THE STUDY

We evaluated TLR9 as susceptibility gene for atopic eczema (AE).

METHODS

Analyses of four tag single-nucleotide polymorphisms in two panels of families containing a total of 483 parent-affected offspring trios as well as a cohort of 274 unrelated adult AE cases and 252 hypernormal population-based controls have been performed.

RESULTS

In both family cohorts, polymorphism C-1237T, which is located within the promoter region of the TLR9 gene, was significantly associated with AE, in particular the intrinsic subtype of AE. No associations were seen in the case-control cohort. Luciferase reporter gene assays revealed significantly higher promoter activity of the TT allelic variant at this single nucleotide polymorphism site.

CONCLUSION

These observations suggest that the TLR9 promoter polymorphism C-1237T might affect AE susceptibility in particular in patients with the intrinsic variant of AE.

Effects of high-dose itraconazole treatment on lipoproteins in men

OBJECTIVE

Epidemiological studies have convincingly demonstrated a positive association between LDL-cholesterol (LDL-C) and coronary artery disease but, in the case of HDL-C, there is an inverse association. Administration of high doses of the antifungal agent ketoconazole (800 mg/d) reduces serum concentrations of total cholesterol and LDL-C and there is a tendency for an increase in HDL-C. Our goal was to examine whether high-dose itraconazole raises HDL-C in subjects with normal levels of cholesterol.

PATIENTS AND METHODS

8 male patients with onychomycosis received 2 one-week cycles of treatment with itraconazole at a dose of 400 mg once daily in an open, prospective exploratory trial. Serum levels of itraconazole and its active metabolite hydroxyitraconazole were determined using high-performance liquid chromatography at the end of each treatment cycle. Fasting levels of serum lipoproteins and triglycerides were measured twice using routine enzymatic assays at the beginning and end of each cycle. The effects of itraconazole and hydroxyitraconazole on HDL-C metabolism were assessed in vitro using a human Caco-2 cell line and analyzing apoA-I levels with an enzyme-linked immunosorbent assay.

RESULTS

During itraconazole treatment total cholesterol and LDL-C decreased on average by 12% (p < 0.001) and 17% (p < 0.001), respectively, whereas HDL-C increased by 21% (p < 0.001). The ratio LDL: HDL-C, an index of atherogenic risk, decreased by 30% (p < 0.001). Incubation of Caco-2 cells in the presence of itraconazole and hydroxyitraconazole for 3 hours resulted in a significant increase in apoA-I concentration in the medium (913 and 412%, respectively) compared with control.

CONCLUSION

In addition to its inhibitory effect on cholesterol synthesis, high-dose itraconazole (400 mg/d) causes a significant decrease in serum LDL-C and, in contrast to ketoconazole, a significant increase in HDL-C. In vitro studies with Caco-2 cells indicate that the latter observation might be caused by an increase in apoA-I levels.

The pro- and anti-inflammatory properties of human antigen-presenting cells expressing the high affinity receptor for IgE (FcεRI)

Almost 20 years after the first description of IgE on the surface of epidermal Langerhans cells (LC) and the subsequent characterization of the trimeric Fc epsilon RI on human antigen-presenting cells (APC), we have gained profound insights into the receptor responsible for this binding. Fc epsilon RI may act as a pro-inflammatory structure on some APC such as inflammatory dendritic epidermal cells (IDEC) in the skin of patients with atopic dermatitis while it can also be an important instrument in mechanisms leading to tolerance on other APC such as LC of the oral mucosa. By virtue of Fc epsilon RI, APC can initiate inflammation by secretion of a wide spectrum of pro-inflammatory cytokines and chemokines. Fc epsilon RI+DC can induce either Th2 or Th1 profile in T-cells. In contrast, the production of the tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) as well as IL-10 and TGFss may contribute to the tolerogenic properties of DC.

Flushing and increase of serum tryptase after mechanical irritation of a solitary mastocytoma

Solitary mastocytomas are infiltrates of mast cells in the upper corium, appearing at any side of the body as brownish-reddish plaques in the first months of life. Their course is benign with a spontaneous regression in most cases. A 5-month-old boy presented a 5 x 3 cm sized brownish-yellow plaque on the back of his right hand. His parents reported repeated episodes of swelling and blistering of the skin lesion as well as recurrent systemic flush-reactions. General laboratory parameters were without pathological findings including a normal serum tryptase (5.5 microg/L). A few minutes after rubbing, the lesion became urticarially swollen and the infant developed a general flush reaction accompanied by a bilateral miosis and asthma-like symptoms which disappeared completely after oral administration of 7 drops of dimentinden. Assessment of the serum tryptase two hours after the provocation revealed a more than 5-fold increase (29.3 microg/L) compared to the basic value. We conclude that uncontrolled stroking of mastocytomas should be avoided in patients with a systemic reaction in their history, since this case demonstrates that despite its limited size, mechanical irritation of a solitary mastocytoma may induce strong systemic symptoms as witnessed by transient increase of the serum tryptase, which to our knowledge has not been described in the literature before.

CXCR3-mediated recruitment of cytotoxic lymphocytes in lupus erythematosus profundus

BACKGROUND

Lupus erythematosus profundus (LEP) is a rare variant lupus erythematosus with unclear etiology characterized by lobular panniculitis. Recently, we observed a case of LEP involving the lower right eyelid. Our immunohistological analyses of lesional skin biopsies revealed a type I IFN signature in the context of cytotoxic lobular panniculitis.

OBJECTIVE

Since type I IFNs have been shown to be involved in other cutaneous LE subtypes, especially in chronic discoid LE, we hypothesized that a type I IFN driven immune response might play an important role in the pathogenesis of LEP.

METHODS

In addition to the above case, 9 skin biopsies taken from 5 patients with LEP were analyzed for a type I interferon signature by immunohistochemistry. Furthermore, 8 skin biopsies taken from patients with active chronic discoid LE and 5 biopsies of healthy skin were included for control purposes. The inflammatory infiltrate was characterized using monoclonal antibodies specific for CD3, CD4, CD8, CD20, CD68, and CD123. Subsequently, we analyzed the expression the type I IFN Marker MxA, the cytotoxic molecules granzyme B and Tia1, the chemokine receptor CXCR3 and its ligand, the interferon inducible protein IP10/CXCL10.

RESULTS

LEP skin lesions were characterized by a lobular panniculitis, dominated by cytotoxic CXCR3(+) lymphocytes. Strong MxA expression indicated extensive type I IFN production within the fat lobules. Numerous plasmacytoid dendritic cells appear to be the major source of type I IFNs. Lesional expression of IP10 links the type I IFN production and recruitment of CXCR3(+) lymphocytes.

LIMITATIONS

The study was based on histological and immunohistological analyses in a limited number of patients, due to the rareness of the investigated disease.

CONCLUSION

Our results demonstrate a type I IFN driven immune response in active LEP skin lesions. We suggest that this type I IFN driven inflammation is responsible for the recruitment of CXCR3(+) lymphocytes into fat lobules and enhance their cytotoxic capacity.

Efficacy and safety of methylprednisolone aceponate ointment 0.1% compared to tacrolimus 0.03% in children and adolescents with an acute flare of severe atopic dermatitis

BACKGROUND

Topical glucocorticosteroids are the gold standard in treatment of atopic dermatitis (AD). Recently, topical calcineurin inhibitors have been developed for treatment of this condition. This study compared efficacy and safety of 0.1% methylprednisolone aceponate (MPA) ointment with 0.03% tacrolimus ointment for 3 weeks, in children and adolescents with severe to very severe flare of AD.

METHODS

The primary end point was treatment success, defined as a score of 'clear' or 'almost clear' in the static Investigator's Global Assessment (IGA) score. Secondary end points were the percentage change in the Eczema Area and Severity Index (EASI) and patients' assessment of itch and sleep, Children's Dermatology Life Quality Index, patient's assessment of global response, affected Body Surface Area and medication costs.

RESULTS

265 patients were randomized to either MPA (n = 129) or tacrolimus (n = 136) treatment, 257 patients completed the study. Methylprednisolone aceponate 0.1% ointment once daily provided rapid and relevant clinical benefit. Tacrolimus 0.03% ointment twice daily was equally effective with regard to success rate. Methylprednisolone aceponate was superior to tacrolimus for EASI, itch and sleep. Both treatments were well tolerated. Drug-related adverse events were only observed in the tacrolimus group. Medication costs were significantly lower for MPA.

CONCLUSIONS

While both treatment groups showed similar efficacy results regarding treatment success (IGA), significant advantages were observed for EASI, itch and sleep with MPA 0.1%. These advantages and the significantly lower treatment costs highlight the benefits of MPA treatment, underlining its first-line role in treatment of children and adolescents with severe AD.

Long-term Treatment with 0.1% Tacrolimus Ointment in Adults with Atopic Dermatitis: Results of a Two-year, Multicentre, Non-comparative Study

Atopic dermatitis often requires long-term treatment. This European, multicentre, non-comparative, 24-month, follow-up study investigated the efficacy and safety of 0.1% tacrolimus ointment applied to adults with atopic dermatitis. Patients (n=672) applied a thin layer of 0.1% tacrolimus ointment twice daily for 3 weeks to all affected body areas. After 3 weeks, ointment was applied once daily. Clinical improvement became apparent after 2 weeks of treatment and 65.5% of patients had a rating of clearance, excellent or marked improvement by month 3. Skin burning (31.7%) was the most common causally-related adverse event, followed by pruritus (11.3%) folliculitis (6.4%), alcohol intolerance (5.7%), herpes simplex (5.7%), skin infection (4.6%), skin erythema (3.3%) and hyperaesthesia (2.4%). The most commonly reported infections were flu syndrome (12.9%), skin infection (9.8%), folliculitis (7.4%) and herpes simplex (7.0%). Long-term treatment up to 24 months with 0.1% tacrolimus ointment is safe and efficacious in adults with atopic dermatitis.