Evolution of innate defense in human skin.

More often as compared to other barrier systems (gastrointestinal, urogenital, and respiratory linings) human skin over millions of years has been subject to fundamental changes in structure and function. When life on land started, the first changes consisted in the formation of a coherent impermeable stratum corneum. Two-legged locomotion was followed by loss of body hair and formation of sweat glands. Major changes took place after the agricultural revolution, investigating settlements with domestication of animals and plants. Living together after giving up nomadic life, hairless skin became a battlefield for pathogens, members of the skin microbiome, and arthropod visits. Human skin became exceptional in showing a boosted, highly developed immune system which is much more complex as compared to the "skins" of other species. A recently found skin disinfection system ("Cationic Intrinsically Disordered Antimicrobial Peptides, CIDAMPs") dates back to the origins of life and still is active in present-day integuments. As a skin-restricted and effective principle, keratinocyte- myeloid synergy (KMS) is recognized. As a consequence of such highly developed immune defense, the basic contributions of KMS - cells (keratinocytes, neutrophils, macrophages) in regulating innate immunity is emphasized. Antimicrobial peptides and chemokines became major keratinocyte products. The formation of impermeable str. corneum membrane has enabled KMS - cells to accumulate within upper skin levels and cause a special group of human skin diseases, pustular dermatoses.

Epidemiology and Comorbidity in Children with Psoriasis and Atopic Eczema.

BACKGROUND: First studies have shown that juvenile psoriasis is associated with an increased prevalence of comorbidity. OBJECTIVES: We carried out a data analysis to characterise the profiles of comorbidity in children with psoriasis and atopic eczema. METHODS: Prevalence data were derived from the database of a German statutory health insurance company according to ICD-10 codes L40 (psoriasis) and L20 (atopic eczema) of children up to 18 years insured in 2009. RESULTS: Data sets included 1.64 million persons and 293,181 children. 1,313 children = 0.45% (0.42-0.47) had a diagnosis of psoriasis and 30,354 = 10.35% (10.24-10.47) had a diagnosis of atopic eczema. Obesity, hyperlipidaemia, arterial hypertension and diabetes were more often diagnosed in children with psoriasis in comparison to all children without psoriasis and to those with atopic eczema. CONCLUSION: Children with psoriasis and atopic eczema show different and specific patterns of comorbidity which should be detected early and treated adequately.

Interleukin-4 therapy of psoriasis induces Th2 responses and improves human autoimmune disease.

Selective skewing of autoreactive interferon-gamma (IFN-gamma)-producing T helper cells (Th1) toward an interleukin-4 (IL-4)-producing (Th2) phenotype can in experimental animals alleviate autoimmune disease without inducing general immunosuppression. In a prospective dose escalation study, we assessed treatment with human IL-4 (rhuIL-4) in 20 patients with severe psoriasis. The therapy was well tolerated, and within six weeks all patients showed decreased clinical scores and 15 improved more than 68%. Stable reduction of clinical scores was significantly better at 0.2-0.5 microg rhuIL-4 than at < or =0.1 microg rhuIL-4 (P = 0.009). In psoriatic lesions, treatment with 0.2-0.5 microg/kg rhuIL-4 reduced the concentrations of IL-8 and IL-19, two cytokines directly involved in psoriasis; the number of chemokine receptor CCR5+ Th1 cells; and the IFN-gamma/IL-4 ratio. In the circulation, 0.2-0.5 microg/kg rhuIL-4 increased the number of IL-4+CD4+ T cells two- to three-fold. Thus, IL-4 therapy can induce Th2 differentiation in human CD4+ T cells and has promise as a potential treatment for psoriasis, a prototypic Th1-associated autoimmune disease.

Therapy of psoriasis in childhood and adolescence - a German expert consensus.

Psoriasis of childhood shows an annual prevalence of 0.71 % and accordingly has to be regarded as a frequent chronic inflammatory skin disorder of this age. The impact on the quality of life as well as development of the afflicted children and their parents is evident. On the other side, therapy is demanding with regard to the specific juvenile metabolism, physical development and skin penetration of topical drugs. Long-term treatment at an early age has to be critically judged regarding the chronicity of the disease. Topical corticosteroids, alternatively dithranol may be used first-line, followed by vitamin D derivatives. A combination with UV-light, preferably UV-B, has to be decided on an individual basis. Systemic treatment may be initiated in recalcitrant disease with methotrexate and cyclosporine where long-term experience is available from juvenile rheumatology and transplantation medicine. Alternatively fumaric acid esters or retinoids are available. Rehabilitation procedures will help the children and their parents to cope with the disease and its treatment. The different treatment options are presented here as a German expert consensus, as clinical studies are hardly available and only a few therapeutics are licensed for this age. In any case the therapy has to be individually planned and decided together with the patients and their parents to gain maximal safety, comfort and success.

Comorbidities in psoriasis.

Epidemiological studies have shown that, in psoriasis patients, associated disorders may occur more frequently than expected. Such comorbidities include psoriatic arthritis, psoriatic pustular diseases, Crohn disease, and signs of metabolic syndrome, which leads to atherosclerosis with coronary heart disease. Although the disorders represent separate entities, they appear to follow overlapping pathogenic pathways. Comorbidities often become clinically manifest years after onset of psoriasis and are frequently seen in severe disease. Persistent low-grade inflammation with secretion of proinflammatory cytokines (eg, tumor necrosis factor alpha) favors the development of insulin resistance and metabolic syndrome. In addition, biochemical and immunologic observations point toward an inflammatory immune mechanism that uses tools of the innate defense armamentarium.

Increased prevalence of the metabolic syndrome in patients with moderate to severe psoriasis.

The role of chronic inflammation causing metabolic and vascular disorders is increasingly recognized. It is hypothesized that proinflammatory cytokines contribute to atherogenesis, peripheral insulin resistance, and the development of hypertension and type II diabetes. Psoriasis as a chronic inflammatory skin disorder is characterized by a variety of immunologic and inflammatory changes and may similarly predispose for those disorders. The objective of this study was to elucidate the association of psoriasis with chronic vascular and metabolic disorders. We investigated a total of 581 adult patients hospitalised for plaque type psoriasis as compared to 1,044 hospital-based controls. A distinct pattern of chronic disorders was found to be significantly associated with psoriasis, including diabetes mellitus type II [odds ratio (OR)=2.48], arterial hypertension (OR = 3.27), hyperlipidemia (OR = 2.09), and coronary heart disease (OR = 1.95). The combined presence of these conditions together with obesity, known as the metabolic syndrome, was clearly more prevalent in psoriasis patients (OR = 5.29). In addition, psoriasis patients were significantly more likely to be smokers (OR = 2.96) and to have a regular or heavy consumption of alcohol (OR = 3.33 and 3.61, respectively). In conclusion, psoriasis patients appear to be at higher risk for diabetes mellitus and cardiovascular disease. This could likely be due to the effects of chronic inflammatory changes, in particular the secretion of proinflammatory cytokines. The risk of late term cardiovascular complications might support the use of systemic treatment in psoriasis.

CARD15 mutations in patients with plaque-type psoriasis and psoriatic arthritis: lack of association.

Psoriasis has a strong genetic component in the development of the disease as indicated by familial occurrence and a high concordance rate among monozygotic twins. In genome-wide scans for psoriasis several susceptibility loci have been detected, but the disease-causing genes have not yet been identified. A recent scan, performed on psoriatic arthritis (PsA), which occurs in about 15% of the psoriasis patients showed a significant locus on chromosome 16 in a region that was already described by genome scan for psoriasis. CARD15, a major susceptibility gene for Crohn's disease (CD) on chromosome 16q, is an interesting candidate gene for psoriasis, because there is a documented clinical association of CD with psoriasis, and recently the association of CARD15 mutations with PsA was reported in Newfoundland population. We investigated the association of this variant with PsA and the overall psoriasis genotype in 59 independent patients with PsA in comparison with 361 age and sex-matched controls. In addition, a second cohort of 89 independent North American PsA patients was included. The diagnosis of psoriasis was made by a dermatologist based on standard clinical criteria. In these patients, PsA was defined as an inflammatory joint disease, negative rheumatoid factor, and lack of another causative condition for arthritis. Using case-control analysis, the G908R mutation was weakly associated with psoriasis and PsA, but due to the low frequency of this mutation statistical significance was not reached. All other variants including leu1007fsinsC and R702W did not show any association with psoriasis or PsA. In conclusion, a disease-causing role for CARD15 mutations could not be confirmed in German or American subjects with PsA.

Halo dermatitis followed by the development of vitiligo associated with Sutton's nevi.

Halo dermatitis (Meyerson's nevus) is an inflammatory, sometimes itchy, eczematous eruption usually encircling a preexisting melanocytic nevus that can be mistaken for malignant melanoma or Sutton's nevus. Unlike the latter, it mostly resolves spontaneously within weeks and never causes regression of the central lesion. Sutton's nevi, however, are frequently found in otherwise healthy individuals and patients suffering from vitiligo or malignant melanoma. The simultaneous appearance of Sutton's nevus and halo dermatitis has been reported before. However, the causes of both diseases remain unclear. We report a 16-year-old female who developed vitiligo and Sutton's nevi 6 months after a halo dermatitis lesion was excised. The coincidence of these disorders suggests common or similar immunological mechanisms induced by pigment cells and/or their components.

Interleukin-1-stimulated secretion of interleukin-8 and growth-related oncogene-alpha demonstrates greatly enhanced keratinocyte growth in human raft cultured epidermis.

The CXC chemokines, interleukin-8 and growth-related oncogenealpha, are known to play a prominent part in wound healing as well as inflammatory skin disorders, including psoriasis. Both chemokines are potent neutrophil activators and were discussed as potential stimuli in keratinocyte growth. We examined the action of growth-related oncogene alpha and interleukin-8 in organotypic raft culture, which resembles in vivo skin in several respects. Addition of growth-related oncogene alpha and interleukin-8 resulted in a time- and concentration-dependent epidermal hyperproliferation in organotypic cultures. In cryostat sections an increased number of epidermal layers as well as significantly elevated number of Ki-67-stained keratinocytes indicate marked hyperproliferation with no evidence for the reduction of apoptotic cells. Terminal differentiation was shown to proceed in a regular fashion with formation of a cornified layer and the expression of suprabasal keratins in addition to the presence of differentiation markers. Interleukin-8-mediated hyperproliferation was inhibited by a blocking human monoclonal antibody. To demonstrate a specific receptor-mediated action of growth-related oncogene and interleukin-8, we used a CXC receptor 2 monoclonal antibody or a CXC receptor 2 selective nonpeptide antagonist, both of which lead to inhibition of interleukin-8-mediated hyperproliferation. Interleukin-1alpha caused induction of interleukin-8 and growth-related oncogene alpha mRNA as well as marked epidermal hyperproliferation. The interleukin-1alpha-mediated hyperproliferation was markedly reduced by both the interleukin-8-specific antibody and the CXC receptor 2 antagonist, indicating close correlation between the interleukin-8/CXC receptor 2 pathway and interleukin-1-induced keratinocyte growth stimulation. Our data indicate that interleukin-1 induces overexpression of interleukin-8 and growth-related oncogene alpha in human keratinocytes. These changes correlate with characteristic functional alterations of the epidermis as observed in psoriasis and wound healing.

Risk of malignancies in psoriasis patients treated with cyclosporine: a 5 y cohort study.

This prospective long-term cohort study investigated the incidence of malignancies in severe psoriasis patients treated with cyclosporine. A total of 1252 patients were followed prospectively for up to 5 y. Malignancies were recorded prospectively. Incidence rates for malignancies were compared with the general population using standardized incidence ratios. The effect of duration of exposure to cyclosporine and to previously administered anti-psoriatic treatments on the incidence of malignancies was investigated using Poisson regression models. The mean age of patients was 43 y and on average, patients received cyclosporine for 1.9 y. Malignancies were diagnosed in 47 patients (3.8%), 49% of them had skin malignancies. The standardized incidence ratio in the study cohort was 2.1 as compared with the general population. The higher incidence of malignancies was attributed to a 6-fold higher incidence of skin malignancies, most of which were squamous cell carcinoma. The incidence of nonskin malignancy overall was not significantly higher in this study than in the general population. Duration of exposure to cyclosporine, exposure to psoralen and ultraviolet A, exposure to methotrexate, and exposure to immunosuppressants showed a significant effect on the incidence of nonmelanoma skin malignancies. In conclusion, treatment of psoriasis with cyclosporine is associated with an increased risk of nonmelanoma skin cancer. Patients treated for more than 2 y with cyclosporine were shown to have a higher risk. In addition, exposure to psoralen and ultraviolet A and to other immunosuppressants was shown to contribute to the overall risk.

Combined segregation and linkage analysis of HLA markers in familial psoriasis.

Marker-based segregation analysis (MBSA) is a modification of a published method of combined linkage and segregation analysis (Am J Hum Genet 51: 1111-1126, 1992), to determine whether a candidate gene known to be associated with the disease of interest is truly segregating with the disease in families. Here we outline the conceptual basis of MBSA and present a Monte Carlo method for significance testing. The method is applied to PSORS1, a locus within the major histocompatibility complex (MHC) for which linkage and linkage disequilibrium with psoriasis has already been demonstrated. The results are very consistent with our current knowledge of PSORS1, and suggest that MBSA can provide useful information on genotype-phenotype relationships such as penetrance and allelic heterogeneity.