The pathomechanisms of psoriasis; the skin immune system and cyclosporin

Gene Expression Analysis of Inflammatory Cytokines in Korean Psoriatic Patients

Background

Although phenotypic heterogeneity of psoriasis is suggested by the alternate activation of either T-helper (Th)1-related or Th17-related cytokines, little is known about the mRNA levels of inflammatory cytokines.

Objective

To investigate whether there is differential expression of Th1-related and Th17-related inflammatory cytokine genes 1) between psoriatic patients and healthy controls, and 2) between patients with different psoriasis phenotypes.

Methods

Twenty-five patients with psoriasis (10 with guttate psoriasis and 15 with plaque psoriasis) and 5 healthy volunteers were enrolled in this study. The mRNA levels of circulating cytokines (interleukin [IL]-2, IL-12p40, interferon-γ, IL-17A, IL-22, and IL-23R) were measured by real-time reverse transcription polymerase chain reaction.

Results

The comparison between psoriatic and healthy control samples revealed that IL-12p40, IL-17A, and IL-22 mRNA levels were significantly higher (approximately 4∼6 folds) in the patients with psoriasis. The mRNA levels of these six cytokines in the blood did not differ between the guttate and plaque psoriasis groups.

Conclusion

We found that the mRNA levels of blood inflammatory cytokines (IL-12p40, IL-17A, and IL-22) were significantly elevated in patients with psoriasis compared to the levels in healthy controls, but they did not significantly differ between patients with guttate and plaque type psoriasis.

Tissue and Serum Inflammatory Cytokine Levels in Korean Psoriasis Patients: A Comparison between Plaque and Guttate Psoriasis

Background

The phenotypic heterogeneity of psoriasis could be explained by the alternate activation of either T-helper (Th)-1- or Th-17-related cytokines. However, evidence directly supporting this hypothesis is scarce.

Objective

To characterize the expression of Th-1- and Th-17-related cytokines according to the morphological psoriasis phenotype: guttate vs. plaque.

Methods

In this study, we enrolled 68 patients exhibiting either guttate or plaque psoriasis, and 10 healthy controls. To avoid age-related bias, age matching was performed for each group. Circulating levels of interferon (IFN)-γ, interleukin (IL)-1RA, IL-2, IL-12p40, IL-17A, IL-22, and IL-23 were measured with an enzyme-linked immunosorbent assay (ELISA). Psoriasis-affected tissue was obtained through biopsy sampling from the eight patients who exhibited the most typical morphology. Levels of IL-1RA, IL-12p40, IL-17, IL-22, and IL-23 in the psoriasis tissue samples were measured with western blot analysis.

Results

ELISAs of the serum samples showed higher levels of inflammatory cytokines such as IL-1RA, IL-2, IL-23, and IFN-γ in patients with psoriasis than in healthy controls. However, the inflammatory cytokine levels did not differ significantly between guttate and plaque psoriasis patients. Western blot analysis of psoriatic tissue revealed higher protein levels of Th-1- and Th-17-related cytokines in patients than in healthy controls. The levels of IL-12p40 and IL-23 were unexpectedly higher in plaque tissue than in guttate tissue.

Conclusion

The morphological phenotype of psoriasis does not appear to be determined by a specific activation of either the Th-1 or Th-17 pathway. Rather, the cytokine profile influences disease activity and is altered according to the status of the lesion (early or chronic).

Molecular mimicry between HSP 65 of Mycobacterium leprae and cytokeratin 10 of the host keratin; role in pathogenesis of leprosy

Mycobacteria are known to induce autoimmune response in the host. Anti-host keratrin antibodies (AkAbs) might be responsible for the autoimmune phenomena in leprosy patients as majority of leprosy lesions are manifested in the skin and occurrence of keratosis is not an uncommon feature. The aim of this study was to find out the level of AkAbs in leprosy patients across the spectrum and to explore its correlation with the clinical manifestation of the disease. Further, mimicking epitopes of keratin and Mycobacterium leprae components were characterized. We screened 140 leprosy patients (27 BT, 28 BL, 41 LL, 25 T1R, 19 ENL), 74 healthy controls (HC) and 3 psoriasis patients as positive control. Highest AkAbs level was observed in the psoriasis patients followed by T1R, LL, BL, ENL, TT/BT. AkAbs level was significantly (p<0.05) higher in all the groups of leprosy patients except TT/BT in comparison to HC. Significant positive correlation was found between number of lesions and level of AkAbs in leprosy patients. Highest lympho-proliferation for keratin protein was observed in T1R, followed by BL/LL, TT/BT, ENL. Lympho-proliferation was significantly (p<0.05) higher in all groups of leprosy patients except ENL in comparison to HC. Interestingly, it was noted that hyperimmunization of inbred strains of female BALB/c mice and rabbit with M. leprae soluble antigen (MLSA) induce higher level of AkAbs. The percentage of FoxP3(+) expressing Treg cells (total CD4(+)CD25(+)FoxP3(+) andCD4(+)CD25(+hi)FoxP3(+)) in splenocytes and lymph nodes of hyperimmunized mice were declined in comparison to control mice. Further, it was found that this autoimmune response can be adoptively transferred in naïve mice by splenocytes and lymph node cells as well as T cells. Comparative molecular characterization between keratin and MLSA noted a cross-reactivity/similarity between these two antigens. The cross-reactive protein of keratin was found to be in molecular weight range ≈74-51kDa and at pI 4.5 while the cross-reactive protein of MLSA was found to be in molecular weight ≈65kDa and at pI 4-4.5. Cross-reactive protein of keratin and MLSA was identified and characterized by MALDI-TOF/TOF analysis and Mascot software. It was found that the keratin (host protein) which reacted with anti-M. leprae sera is cytokeratin-10 and MLSA which reacted with anti-keratin sera is heat shock protein 65 (HSP 65). Seven B-cell epitopes of cytokeratin-10 and HSP 65 was found to be similar by multiple sequence alignment using ClustalW server and out of which 6 B-cell epitopes were found to be on the surface of HSP 65. In conclusion, our study provides evidence for the existence of molecular mimicry between cytokeratin-10 of keratin (host protein) and 65kDa HSP (groEL2) of M. leprae. Presence of heightened CMI response of leprosy patients to keratin and positive correlation of AkAbs level with number of lesions of leprosy patients showed the clinical evidence for its role in the pathogenesis in leprosy.

Calcipotriol/betamethasone dipropionate in the treatment of psoriasis vulgaris

Psoriasis is one of the most common skin diseases. The mainstay of treatment for the vast majority of patients is topical therapy. A rising first-line treatment modality for psoriasis vulgaris is the two-compound ointment containing calcipotriol 50 mug/g plus betamethasone dipropionate 0.5 mg/g (Dovobet((R)), Daivobet((R)), Taclonex((R))), which combines a vitamin D analog and a corticosteroid. This innovative formulation preserves the activity and bioavailability of the two components and many clinical studies have demonstrated that it has a greater efficacy, tolerability, and a rapid onset of action compared with its individual ingredients or tacalcitol.

Cyclosporine A in the treatment of psoriasis: a clinical and mechanistic perspective

Cyclosporine A, a unique immunomodulatory agent, has been used increasingly over the last 5 years in the management of severe psoriasis. The remarkable efficacy of this drug coupled with its known immunosuppressive properties have enabled a further appreciation of the role of the immune system in the induction and maintenance of psoriatic plaques. Although acting primarily on T lymphocytes, there is also evidence for an effect of cyclosporine A on other constitutive cell types within the skin. The future use of systemically administered cyclosporine A in the treatment of psoriasis and other cutaneous diseases is dependent on the successful balance of efficacy and side-effect profile; namely, the dose-related problems of hypertension and nephrotoxicity. As a result of the toxicity encountered with systemically administered cyclosporine A, attempts to formulate a successful topical preparation for use in cutaneous disease are being made. The advent of cyclosporine A provides the dermatologist with a new therapeutic strategem in the management of psoriasis, although the long-term safety of such interventional therapy remains to be discerned.

Calcipotriol/betamethasone dipropionate for the treatment of psoriasis

The two-compound product calcipotriol/betamethasone dipropionate is arising as a first-line treatment for mild-to-moderate plaque psoriasis. Its beneficial action is attributed to the synergistic effect of its components on keratinocyte proliferation and differentiation, and on inflammation. The good tolerability of the two-compound product is thought to be due to the anti-inflammatory effect of betamethasone. Evidence from short-term (4-12 weeks) and long-term use (> 1 year) has shown a good safety profile. Areas such as the face or skin folds, which are sensitive to the components of the combination, should be avoided. Finally, it is unsuitable for use in unstable psoriasis, in which potent steroids may lead to an increased inflammatory response.

Prospects for vaccines for allergic and other immunologic skin disorders

The human skin hosts a variety of immune response-associated components that together form the skin immune system. Any abnormality in the functioning of the skin immune system leads to a variety of dermatologic complications, including dermatitis, psoriasis, and eczema. Exposure to antigens/allergens can lead to allergic skin disorders such as atopic dermatitis, urticaria, and allergic contact dermatitis. Recent investigations have provided new insights into the immunologic processes leading to the development of skin diseases. T cells play a central role in the activation and regulation of immune responses by recognizing antigen and inducing cytokine production. Despite advances in the understanding of the immunologic events leading to the development of skin diseases, no effective prevention measure exists. Current therapeutic treatments are based on either alleviating the symptoms or suppressing the immune system with immunosuppressive drugs. Allergen-specific immunotherapy is expected to induce specific T cells that abolish allergen-induced proliferation of T helper cells, as well as their cytokine production. Recent approaches using recombinant protein, polycytosine guanine oligonucleotides, and plasmid DNA for vaccination suggest the possibility of protection against these skin disorders. The involvement of T cells in psoriasis indicates that the development of a T-cell receptor peptide vaccine may be beneficial. Dendritic cell-based vaccines using tolerogenic dendritic cells that can induce T-cell tolerance have been shown to be useful in dealing with autoimmune disorders and allergic conditions. In the light of these developments, this article presents the current status and prospects of developing vaccines for allergic and other immunologic skin disorders.

Peripheral blood mononuclear cells proliferation and Th1/Th2 cytokine production in response to streptococcal M protein in psoriatic patients

BACKGROUND

Psoriasis is a chronic skin disease that is probably a T cell-mediated autoimmune condition which is strongly associated with streptococcal throat infections. Although some groups have associated the involved response with different streptococcal antigens, M protein has been described as the major virulence factor of Streptococcus pyogenes. Thus, it is necessary to describe some features of the cellular responses to this streptococcal antigen.

METHODS

Proliferation and Th1/Th2 cytokine production of peripheral blood mononuclear cells (PBMC) in response to total soluble extracts from type M5 S. pyogenes with (TSE37Sp) and without (M(-)TSESp) M protein were analyzed in 10 psoriatic patients and 10 healthy controls.

RESULTS

PBMC from both patients and controls proliferated to both extracts. Responses to M(-)TSESp were significantly lower than those to TSE37Sp (P < 0.05). PBMC IL-2 and gammaIFN production after TSE37Sp stimulus was much higher than after M(-)TSESp antigenic stimulation in both groups (P < 0.05). Meanwhile, IL-4 production was quite low in both groups and in response to both extracts. We found a differential production of IL-10 between groups. PBMC from healthy controls responded to TSE37Sp with a much higher production of this cytokine as compared to the responses showed to M(-)TSESp while the cells from psoriatic patients responded without differences in the production of IL-10.

CONCLUSION

Results obtained suggest an important Th1 response to M protein in psoriatic patients which could be associated with the cellular responses involved in psoriasis, while healthy subjects respond in a probably non-Th2 IL-10 producing regulatory T cells fashion.

Psoriasis: emerging therapeutic strategies

Psoriasis is a chronic inflammatory skin disorder that is characterized by thickened, scaly plaques, and is estimated to affect approximately 1-3% of the Caucasian population. Traditional treatments, although effective in patients with limited disease, have numerous shortcomings, including inconvenience and toxicity. These drawbacks mean that many patients experience cycles of disease clearance, in which normal quality of life alternates with active disease and poor quality of life. However, as this review discusses, recent advances have highlighted the key role of the immune system in the pathogenesis of psoriasis, and have provided new defined targets for therapeutic intervention, offering hope for safe and effective psoriasis treatment.

Systemic therapies for psoriasis: understanding current and newly emerging therapies

The treatment of moderate to severe psoriasis is a rapidly expanding area. Recent insights into the pathogenesis of this disease as a T-cell mediated process has led to a greater understanding of the mechanisms of action of conventional FDA-approved systemic therapies such as methotrexate, cyclosporine, acitretin, and psoralen with ultraviolet A phototherapy. It has also led to the development of rationally targeted therapies against key components of the immune process critical in the generation of the psoriatic plaque. Safety and efficacy data from clinical studies of 4 biologic agents furthest along in their development are reviewed. These results are promising, adding to the armamentarium for treating this disease.

Efficacy and safety of a new combination of calcipotriol and betamethasone dipropionate (once or twice daily) compared to calcipotriol (twice daily) in the treatment of psoriasis vulgaris: a randomized, double-blind, vehicle-controlled clinical trial

BACKGROUND

Calcipotriol and betamethasone dipropionate are both widely used, effective treatments for psoriasis. Vitamin D analogues and topical corticosteroids have different mechanisms of action in the treatment of psoriasis. A new vehicle has been developed in order to contain both calcipotriol (50 micro g g-1) and betamethasone dipropionate (0.5 mg g-1) in an ointment form. By using calcipotriol and a corticosteroid together, greater efficacy may be achieved than by using either compound alone.

OBJECTIVES

The present study was conducted in order to compare the clinical efficacy and safety of the combined ointment formulation used once daily with the vehicle ointment used twice daily, calcipotriol ointment used twice daily and the combined formulation used twice daily in psoriasis vulgaris.

METHODS

This was an international, multicentre, prospective, randomized, double-blind, vehicle-controlled, parallel group, 4-week study in patients with psoriasis vulgaris amenable to topical treatment. Patients were randomized to one of four treatment groups: combined formulation once daily, combined formulation twice daily, calcipotriol twice daily or vehicle twice daily. Efficacy and safety were assessed.

RESULTS

There was no statistically significant difference in the mean percentage change in the Psoriasis Area and Severity Index (PASI) from baseline to end of treatment between the two combined formulation groups, but the difference in PASI reduction was significantly higher in the combined formulation groups (68.6% once daily, 73.8% twice daily) than in both the twice daily calcipotriol group (58.8%) and the vehicle group (26.6%). Safety data showed the frequency of adverse events to be less in the combined formulation groups than in both the calcipotriol group and the vehicle group. The proportion of patients with lesional/perilesional adverse reactions was less in the combined formulation groups and vehicle group than in the calcipotriol group (9.9% combined formulation once daily, 10.6% combined formulation twice daily, 19.8% calcipotriol, 12.5% vehicle).

CONCLUSIONS

No statistically significant nor clinically relevant difference in efficacy was seen between the combined formulation used once daily and twice daily. When compared to vehicle ointment or calcipotriol ointment alone, the combined formulation was shown to be clearly more efficacious.

The immunologic basis for the treatment of psoriasis with new biologic agents

Psoriasis vulgaris is the most prevalent T-cell-mediated inflammatory disease in humans. The pathogenesis of psoriasis is linked to activation of several types of leukocytes that control cellular immunity and to a T-cell-dependent inflammatory process in skin that accelerates the growth of epidermal and vascular cells in psoriasis lesions. Critical steps in immunologic activation include Langerhans cell maturation (activation), T-cell activation, differentiation and expansion of type 1 T cells, selective trafficking of activated T cells to skin, and induction of an inflammatory cytokine and chemokine cascade in skin lesions. In turn, each of these steps offers an opportunity for intervention with engineered biologic therapeutics.

Low dose cyclosporin A treatment in generalized pustular psoriasis

Generalized pustular psoriasis is a rare form of psoriasis, seldom seen in children. Three patients with generalized pustular psoriasis are presented, two of whom were a sister and brother and whose grandfather also had pustular psoriasis. Lesions consisted of pustular, erythematous, scaly, follicular papules located on the trunk, scalp, and extremities. The pustules in some areas coalesced to form lakes. Histologic examination of several biopsy specimens revealed the changes of pustular psoriasis, which were parakeratosis, elongation of the rete ridges, and deep spongioform pustules and Munro abscesses. All patients were treated with cyclosporin A for periods of 2-12 months. The doses ranged from 1 to 2 mg/kg/day. Clearance of psoriatic lesions occurred after 2-4 weeks of therapy.

Anti-CD4 monoclonal antibody treatment of moderate to severe psoriasis vulgaris: results of a pilot, multicenter, multiple-dose, placebo-controlled study

BACKGROUND

OKTcdr4a (IMUCLONE) is a humanized anti-CD4 IgG4 monoclonal antibody that retains the binding and in vitro immunosuppressive properties of the parent murine antibody. Psoriasis is a chronic disease for which treatment with multiple doses of monoclonal antibodies is likely to be required for adequate control.

OBJECTIVE

This study was performed to test the efficacy and safety of OKTcdr4a, given in sequential courses over a period of several weeks, in the treatment of moderate to severe psoriasis vulgaris.

METHODS

Twenty-eight patients (45.6 +/- 10.1 years of age) were studied, with a mean pretreatment Psoriasis Area and Severity Index (PASI) score of 18.3. In the first double-blind phase of the study, patients were randomized to receive OKTcdr4a as a 225 mg/course (low dose), 750 mg/course (high dose), or placebo divided into 3 identical infusions over a 5-day period. After 42 days, patients who met the criteria for re-treatment with OKTcdr4a were re-treated with the 750 mg/course in an open phase of the study.

RESULTS

After the double-blind course of treatment, the mean PASI decreased by 11% in the placebo group, by 4% in the low-dose group, and by 17% in the high-dose group at 15 days. Twenty patients met the criteria for re-treatment (ie, did not experience a decrease in PASI score of 50% at 42 days). They were re-treated with OKTcdr4a at 43 days with the 750 mg/course in the open phase of the study. By day 99, the mean PASI score decreased from 19.9 at baseline to 17 in those patients who had received either placebo or low-dose OKTcdr4a followed by high-dose OKTcdr4a. In contrast, the mean PASI score decreased from 17.4 at baseline to only 7.7 in those patients who had received high-dose OKTcdr4a for both courses. Sustained CD4 saturation was not necessary for sustained clinical response. No patients had significant changes in circulating CD4(+) T-cell counts. The infusions were well tolerated.

CONCLUSION

Targeting CD4 using sequential treatments with a humanized monoclonal antibody (OKTcdr4a) may offer another therapeutic option for the treatment of moderate to severe psoriasis.

Autoantibodies to autologous skin in guttate and plaque forms of psoriasis and cross-reaction of skin antigens with streptococcal antigens

BACKGROUND

Psoriasis is a chronic disease of the skin that appears to be of autoimmune nature. It has a strong association with throat streptococcal infections, as well as with stressful events. Although many groups consider psoriasis to be a T-cell-mediated autoimmune disease, autoantibodies could also play a role in the development of this process.

METHODS

In this work, we looked for autoantibodies to psoriatic skin in 21 psoriatic patients and four healthy donors (controls). The immunoperoxidase technique was used to look for autoantibodies in autologous sera in skin sections obtained from lesions or from healthy areas of the same patient, before and after immunoadsorption with a Streptococcus pyogenes extract. The skin biopsies were also analyzed with a pool of sera from mice immunized with the streptococcal extract.

RESULTS

We found that all psoriatic patients had autoantibodies to antigens present in keratinocytes, whereas healthy subjects did not. These antibodies did not recognize epitopes on healthy skin from the same psoriatic patients or controls. Immunoadsorption of autologous sera removed the reactivity to antigens in skin lesions in all cases. Mouse anti-streptococcal sera recognized epidermal antigens present in lesional psoriatic skin, but not in healthy skin from psoriatic patients or controls. Deposits of immunoglobulin G (IgG) were not detected in the lesions.

CONCLUSIONS

It seems that autoantibodies, although they do not appear to participate in the pathogenesis of psoriasis, are an important feature, and that skin antigens, which appear in lesional immature keratinocytes, cross-react with S. pyogenes and contribute to the autoimmune process in psoriasis.

HLA-CW*0602 is a susceptibility factor in type I psoriasis, and evidence Ala-73 is increased in male type I psoriatics

We investigated the HLA-C locus of 87 unrelated patients with chronic plaque psoriasis by genotyping with sequence-specific amplification primers. The HLA-Cw*0602 allele was significantly increased in male and female type I psoriatics but not significantly increased in either male or female type II psoriatics. The overall frequency of Ala-73 (present in Cw*04, Cw*0602, Cw*07, Cw*12, Cw*1503, and Cw*17) in psoriatics was 88.5% but the incidence of Ala-73 in our Caucasian controls was also high at 84.3%. Ala-73 was present in 97.2% of type I and 85.7% of type II male psoriatics (chi2 = 8.43, p = 0.001; chi2 = 0.01, p = nonsignificant, respectively), in contrast to 81.5% of type I and 80% of type II female psoriatics (nonsignificant). HLA-Cw*0602 appeared more discriminating in determining disease susceptibility in our population than Ala-73, in line with earlier serologic studies implicating HLA-Cw6. Thus, although the frequency of HLA-Cw*0602 decreased from 54.0% in type I to 29.2% in type II psoriatics, the overall frequency of Ala-73, present in 90.4% of type I and 83.3% of type II psoriatics, did not. (i) Thus this study confirms the strong association between psoriasis and HLA-Cw*0602 by using sequence-specific amplification primers. (ii) Results show that Ala-73 on HLA-C molecules is increased in frequency in psoriasis, but results observed show an association more subtle than previously thought, with HLA-Cw*0602 playing the major role. (iii) This report documents the differential association of HLA genes in male and female psoriatic patients. An interaction between gender and immunogenetics may influence susceptibility to psoriasis.

Description of blood pressure changes in patients beginning cyclosporin A therapy

Cyclosporin A (CyA) is the primary immunosuppressive agent for the prophylaxis of rejection episodes in renal, cardiac, liver, and other transplants. Recently, its use in autoimmune diseases has been investigated as well. Although several studies have produced promising results, nephrotoxicity and hypertension can result from CyA treatment, and their development must be understood in order to facilitate patient management. This article describes the diastolic blood pressure (DBP) responses in two populations of patients during three months of CyA therapy. Study A involved psoriasis patients and Study B involved postoperative renal transplant patients. The relationship between blood pressure and systemic CyA exposure and other covariates was evaluated using linear mixed effects modeling. Temporal patterns of blood pressure changes with varying duration of CyA exposure were investigated. In Study A, the psoriasis patients showed transient exposure-related increases in DBP on CyA. These elevations, while statistically significant, were clinically insignificant. In Study B, the renal transplant patients showed no CyA-related rises in DBP. In neither study was there evidence for a difference in effect on DBP between Sandimmune and Neoral, the two formulations of CyA presently approved for marketing by the Food and Drug Administration, after differences in CyA exposure were taken into account.

Stratum corneum structure and function correlates with phenotype in psoriasis

Psoriatic epidermis demonstrates a defective program of growth and differentiation, including an abnormal permeability barrier. Despite the fact that damage to the epidermis often initiates the disease, psoriasis is commonly viewed as triggered by aberrant immune phenomena in deeper skin layers. Permeability barrier homeostasis requires the formation and secretion of lamellar body contents, as well as the extracellular processing of lamellar body contents into lamellar bilayers. To address the hypothesis that psoriasis is triggered by exogenous rather than internal factors, we assessed permeability barrier function, lamellar body structure, and extracellular lamellar bilayer formation in untreated patients with different psoriatic phenotypes. Subjects with erythroderma and active plaque phenotypes displayed elevated transepidermal water loss levels, increased numbers of epidermal lamellar bodies (many of which failed to be secreted); i.e., corneocytes displayed retained cytosolic lamellar bodies, and extracellular domains largely devoid of lamellae. In contrast, patients with chronic plaque psoriasis and sebopsoriasis displayed a lesser increase in transepidermal water loss, normal numbers of lamellar bodies with only a few retained organelles, and abundant extracellular lamellar material (although a normal unit bilayer pattern did not form). Thus, both functionally and structurally, permeability barrier homeostasis was more disrupted in erythrodermic and active plaque psoriasis than in chronic plaque psoriasis and sebopsoriasis; i.e., the extent of defective barrier function correlated with abnormalities in the known mechanisms of barrier repair, including lamellar body production and extracellular bilayer formation. These findings are consistent with the hypothesis that both the initial appearance of psoriasis (Koebner phenomenon) and changes in disease phenotype are driven by alterations in barrier function.

Confirmation of genetic heterogeneity in familial psoriasis

Psoriasis affects approximately 2% of the European population and is often familial. Linkage of a subset of psoriasis families to loci on chromosome 17q has recently been reported. We have studied members of a large multiply affected family from the north east of England and analysed genotypes for markers from 17q, including the polymorphic microsatellite markers AFM210xa5, AFM163yg1, AFM044xg3, AFMa353yg1, and AFM217yd19. Two point and multipoint analysis clearly show exclusion of linkage between the telomeric region of 17q and psoriasis in this family. This confirms the genetic heterogeneity of psoriasis and the existence of at least one other major psoriasis locus.

Axon-reflex-mediated vasodilatation in the psoriatic plaque?

Blood flow in the psoriatic plaque is increased, but the underlying mechanisms are not known. The aim of the present study was to examine whether neurogenic factors are important for blood flow regulation in the plaque. Local neurogenic mechanisms were inhibited by surface anesthesia and central nervous control by conduction anesthesia of nerves to the psoriatic plaque. The differences in skin perfusion before and after anesthesia were measured with a laser Doppler perfusion imager. The skin perfusion in psoriatic plaques located in hairy skin was unaffected by conduction anesthesia, but surface anesthesia of the plaque evoked a marked blood flow reduction. The perfusion in ultraviolet-B-irradiated skin, used as a control for nonspecific phenomena, was reduced after local application of indomethacin but was unaffected or increased after surface anesthesia. The results are compatible with the idea that a local neurogenic mechanism (axon-reflex) contributes to the high blood flow in the psoriatic plaque.

Study of certain clinical variables in patients with psoriasis and their relation to DNA content of keratinocytes

BACKGROUND

In a previous study of 26 patients with psoriasis we analyzed cytophotometrically the nuclear DNA content of the germinative compartment of involved and uninvolved skin by means of the Feulgen technique. These subjects were classified into three groups according to their DNA profile. Group 1 had a monomodal diploid profile, group 2 showed a significantly increased 2C-4C population, and group 3 demonstrated high proportions of 4C and hyperdiploid keratinocytes.

OBJECTIVE

Our purpose was to analyze clinical variables implicated in the development of psoriasis in reference to the three groups.

METHODS

Nuclear DNA content of each group by quantitative histochemical studies was analyzed and correlated with variables such as chronologic age, sex, age at onset, duration of flare during the study, stress, and the Koebner phenomenon.

RESULTS

No significant differences in DNA profile were observed in the involved epidermis among the clinical variables. The only differences in the uninvolved skin pertained to the duration of the flare, where a statistically significant difference was observed between groups 1 and 3 in the basal (p < or = 0.0459) and suprabasal keratinocytes (p < or = 0.06), and in the Koebner phenomenon, which was induced in all subjects (100%) in groups 2 and 3 and in only 44% of subjects in group 1.

CONCLUSION

Uninvolved skin of patients with psoriasis should be included in analysis of the clinical behavior of the disease. Furthermore, the Koebner phenomenon is a good clinical indicator of the DNA profile of these subjects.

Excessive costimulation of CD3-dependent lymphocyte response by extracellular matrix proteins in severe widespread psoriasis

Costimulation of anti-CD3-triggered proliferative T-cell responses by type I and type IV collagen and fibronectin was studied in 25 patients with psoriasis and 12 healthy subjects. The stimulation index of anti-CD3-mediated responses in the presence of type I collagen was about half that in the controls. Although the CD3-dependent proliferative response of psoriatic lymphocytes in patients with active widespread plaque psoriasis was reduced by about 50%, costimulatory responses induced by type IV collagen and fibronectin were found to be enhanced in relation to the controls. The degree of costimulation by type IV collagen and fibronectin was related to disease severity. The highest values of the stimulation index were found in patients with a PASI greater than 24, skin involvement of more than 40% of body surface area, and a duration of psoriatic lesions of more than 3 months. The results indicated that in active widespread plaque psoriasis subpopulations of T cells bearing receptors for some extracellular matrix proteins were increased in the peripheral blood. A factor responsible for this phenomenon may be trafficking of T cells through the basement membrane zone of psoriatic lesions, which presumably causes modification of T cell immunological responsiveness after recirculation.

Low-dose short-term cyclosporine versus etretinate in psoriasis: improvement of skin, nail, and joint involvement

BACKGROUND

High-dose cyclosporine therapy significantly alleviates psoriasis within 2 to 4 weeks but is associated with a high rate of side effects. Reports are conflicting on the frequency and promptness of relapse after discontinuation of cyclosporine therapy.

OBJECTIVE

Our purpose was to compare the efficacy and safety of low-dose cyclosporine with that of etretinate and the stability of remission after replacing cyclosporine therapy with topical anthralin during tapering of cyclosporine.

METHODS

In a multicenter study 210 patients with moderate to severe chronic plaque-type psoriasis were randomly assigned to treatment with cyclosporine or etretinate. The initial dosages were 2.5 mg/kg/day for cyclosporine and 0.5 mg/kg/day for etretinate, which could be individually adjusted to 5.0 and 0.75 mg/kg/day, respectively. After a treatment phase of 10 weeks (phase 1) patients receiving cyclosporine were again randomly assigned to a group in which cyclosporine was replaced by topical dithranol (anthralin), or to another group in which the drug was tapered during the next 12 weeks (phase 2). All patients treated with etretinate discontinued therapy after 10 weeks and used topical dithranol.

RESULTS

Mean Psoriasis Area and Severity Index decreased by 71% in the cyclosporine group and by 47% in the etretinate group during phase 1. After 10 weeks of treatment 47% of the patients treated with cyclosporine and 10% of those treated with etretinate showed a reduction of more than 80% in skin involvement. Sixty-four percent of the cyclosporine group and 48% of the etretinate group did not require an increase in the initial dosage, resulting in a mean daily dose of 3.0 and 0.53 mg/kg, respectively. There was significant alleviation of nail involvement and joint complaints in both groups. In phase 2 the increase in mean Psoriasis Area and Severity Index and the incidence of relapse were significantly higher in patients in whom cyclosporine was discontinued and replaced by dithranol than in patients in whom cyclosporine was tapered or who were pretreated with etretinate. During treatment four patients from the cyclosporine group and three patients of the etretinate group discontinued the study because of side effects.

CONCLUSION

Low-dose short-term cyclosporine therapy for psoriasis is, in comparison with etretinate, highly effective and well tolerated. Individually adjusted cyclosporine therapy allows the majority of patients to continue the low dosage of 2.5 mg/kg/day and still achieve a good clinical response. Remission can be better preserved by tapering the drug than by discontinuing treatment abruptly.

Investigations of the 'active' edge of plaque psoriasis: vascular proliferation precedes changes in epidermal keratin

We have investigated markers of epidermal proliferation and differentiation in terms of keratin expression, the morphology of the cutaneous vasculature, and numbers of cutaneous mast cells, in patients with chronic plaque psoriasis. Using the phenomenon of the 'active edge', we have studied these features in the psoriatic plaque itself, and in the clinically normal active and inactive edges of the same plaque. Our results confirm the anticipated changes in keratin profiles, mast cell numbers and psoriatic morphology of the vasculature within the plaque itself. They further indicate that the vascular changes precede the epidermal and mast cell features at the active edge, and that the inactive edge is inactive for all of these variables. Mediators responsible for the vascular proliferation and elongation must be present in increased amounts at the active edge when compared with the inactive, and include locally produced and circulating factors.

Analysis of TAP2 and HLA-DP gene polymorphism in psoriasis

TAP2 is a gene, located between HLA-DP and HLA-DQ, whose products form a transporter molecule involved in endogenous antigen processing. Polymorphic residues have been described in this gene. TAP2 is of particular interest because its involvement in antigen presentation makes it a candidate for a disease susceptibility gene. In psoriasis, two clinical subtypes analogous to the situation in diabetes type I with early onset and family history and type II with later onset and without family history have been described. We have previously shown that type I but not type II psoriasis is associated with the HLA-DRB1*0701/2, -DQA1*0201, -DQB1*0303 haplotype. To investigate whether this haplotype extends to include particular TAP2 and/or DP alleles, we tested the TAP2 and HLA-DP alleles of a control group (n = 199), patients with psoriasis type I (n = 66), and patients with psoriasis type II (n = 35) by hybridization with SSOs. Our data show that there is no significant correlation between TAP2 and/or HLA-DP gene polymorphism and psoriasis type I and/or type II. We conclude that disease association in type I psoriasis is associated with the extended haplotype HLA-B57, -Cw6, -DRB1*0701/2, -DQA1*0201, -DQB1*0303.

Increased concentration of beta-endorphin in sera of patients with psoriasis and other inflammatory dermatoses

Serum beta-endorphin was quantified by radioimmunoassay in 71 patients with psoriasis vulgaris, other chronic inflammatory skin diseases with T-cell infiltrates [atopic dermatitis (n = 25), and systemic sclerosis (n = 34)], and 100 healthy subjects. The neuropeptide was found to be markedly (P < 0.001) increased in patients with psoriasis (14.4 pg/ml), atopic dermatitis (9.2 pg/ml) and systemic sclerosis (9.8 pg/ml) compared with normal controls (6.1 pg/ml). The highest values of beta-endorphin were found in patients with actively spreading plaque psoriasis (17.3 pg/ml), whereas lesion-free patients showed a reduction in neuropeptide concentration (10.2 pg/ml). The levels were much higher in patients with widespread psoriatic lesions (> 60% body surface; 16.2 pg/ml), which lasted longer than 3 months (15.8 pg/ml), whereas neither the presence of stress nor itching correlated with the serum peptide concentration. Our data suggest that beta-endorphin is produced in psoriatic lesions by inflammatory cells, rather than the increased levels being the result of activation of the pituitary-adrenal axis by chronic stress. The generation of neuropeptide in psoriatic lesions and its antinociceptive effect on the peripheral sensory nerves might explain why pruritus is a relatively rare phenomenon in psoriasis.

Photodynamic therapy in psoriasis: suppression of cytokine production in vitro and recording of fluorescence modification during treatment in vivo

Photodynamic therapy (PDT) consists of the combination of photosensitizers absorbing light mainly in the red spectral region and irradiation with light of corresponding wavelengths. We analysed its effects on the cytokine secretion (IL-1 beta, TNF alpha, IL-6) of freshly isolated peripheral mononuclear cells from six patients with chronic plaque-stage psoriasis in comparison with PUVA. PUVA treatment resulted in a decreased production of all three cytokines, but most pronounced in the case of IL-6. PDT caused a similar change in the cytokine pattern, but its effectiveness was lower. In vivo fluorescence recordings were performed on psoriatic plaque lesions after topical application of the photosensitizer Photosan-3. Under irradiation, progressive photobleaching was noted with increasing radiation dosage. This is the first reported study of photochemical reactions using on-line fluorescence recordings during PDT of psoriatic lesions in vivo. Our results demonstrate the capacity of PDT to cause immunomodulatory effects similar to PUVA, thus indicating its potential application to the treatment of this common disease.

Increased expression of adhesion receptors in both lesional and non-lesional psoriatic skin

Adhesion receptors and their ligands play a vital role in the immune system. We studied the expression of different adhesion receptors, using single- and double-staining immunohistochemical techniques, in both lesional and non-lesional skin specimens from seven psoriasis patients and in skin biopsy specimens from eight normal healthy controls. Our results showed an overall increased expression of several adhesion receptors in both lesional and non-lesional psoriatic skin. We consistently found an increased expression in particular of ICAM-1 and E-selectin on endothelial cells, and ICAM-1 on T cells and Langerhans cells. In contrast, a weak expression of VCAM-1 was found on endothelial cells and mononuclear cells in lesional psoriatic skin specimens alone. Interestingly, LFA-1 was also expressed on Langerhans cells, with a greater frequency in skin from lesional than from non-lesional sites, but was never expressed in skin from normal healthy individuals. Furthermore, significantly increased numbers of Langerhans cells and T cells with a positive reactivity for MAb HECA-452 were found in both lesional and non-lesional psoriatic skin. We hypothesize that the enhanced expression of adhesion receptors on migrating immunocompetent cells and endothelial cells of psoriatic skin in general facilitates the increased influx of activated T lymphocytes and other immunocomponent cells into the skin, and thus underscores the generalized character of the disease.

Psoriasiform architecture of murine epidermis overlying human psoriatic dermis transplanted onto SCID mice

Preliminary observations in a xenogeneic SCID mouse transplantation model indicated that murine epidermis overgrows human dermis from psoriatic skin but not that form normal skin. To investigate the effect of peripheral blood mononuclear cells on the differentiation of murine keratinocytes, we transplanted involved and uninvolved full-thickness skin from patients with psoriasis onto SCID mice and followed this with repeated subcutaneous injections of cells suspended in patient serum. After 6 weeks grafts were analysed morphologically and immunohistochemically. The epidermis in grafts from clinically uninvolved skin appeared normal. The persistence of a psoriasiform epidermis was noted in all grafts from affected sites despite a lack of lymphocytic infiltration. Staining for human and mouse MHC class I antigens revealed the murine origin of keratinocytes forming the psoriasiform epidermis, while the human dermis was retained. Our observations indicate that the defect underlying the pathogenesis of psoriasis is most likely located in the dermal rather than the epidermal compartment. This xenogeneic transplantation model may be useful for future studies of the pathogenesis and treatment of psoriasis.

Human in vivo phosphorus 31 magnetic resonance spectroscopy of psoriasis. A noninvasive tool to monitor response to treatment and to study pathophysiology of the disease

BACKGROUND

There is no objective laboratory technique to measure and to monitor disease activity in psoriasis.

OBJECTIVE

We assessed the effectiveness of using phosphorus 31 (31P) magnetic resonance spectroscopy (MRS) to noninvasively monitor metabolism in psoriasis and to compare these spectroscopic data with chromatographic analysis.

METHODS

Fourteen persons were enrolled in the study. 31P magnetic resonance spectra were obtained from skin of persons without skin disease, uninvolved psoriatic skin, nonpsoriatic erythroderma, and from skin of patients with psoriasis. In three patients with psoriasis 31P magnetic resonance spectra were repeated after treatment with methotrexate, UVB, etretinate, and topical steroids. Finally, shave biopsy specimens were obtained from two patients with psoriasis and submitted for chromatographic evaluation.

RESULTS

In patients with severe psoriasis, in comparison with the control group, elevations in phosphomonoester concentrations and in the phosphomonoester/phosphodiester ratio were observed. These appear to be useful markers to monitor treatment response in patients with psoriasis. Finally, 31P MRS data in conjunction with chromatographic analysis indicated a defect in phosphometabolism in psoriatic skin. However, it is unclear whether this defect is a cause or an epiphenomenon of the disease.

CONCLUSION

31P MRS appears to be a sensitive, noninvasive technique to monitor disease activity in psoriasis. Further studies to characterize the defect in phosphometabolism in psoriatic skin are warranted.

Gene for familial psoriasis susceptibility mapped to the distal end of human chromosome 17q

A gene involved in psoriasis susceptibility was localized to the distal region of human chromosome 17q as a result of a genome-wide linkage analysis with polymorphic microsatellites and eight multiply affected psoriasis kindreds. In the family which showed the strongest evidence for linkage, the recombination fraction between a psoriasis susceptibility locus and D17S784 was 0.04 with a maximum two-point lod score of 5.33. There was also evidence for genetic heterogeneity and although none of the linked families showed any association with HLA-Cw6, two unlinked families showed weak levels of association. This study demonstrates that in some families, psoriasis susceptibility is due to variation at a single major genetic locus other than the human lymphocyte antigen locus.

Skin lesions in psoriasis

Psoriatic skin disease is common; it occurs at all ages and co-exists with joint disease in approximately 10% of cases. All areas of skin, scalp and nails may be involved. In the typical case, the skin lesions are easy to recognize. Atypical forms of skin involvement and lesions at unusual sites are less easily diagnosed by non-specialists. The cause is unknown, but there is a clear genetic element, with external factors being important in precipitation and exacerbations of the condition. Topical treatment is successful in most patients, but in resistant cases combinations of systemic therapy and ultraviolet radiation usually give good control. Although there is no cure, the majority of sufferers live normal lives and, with the exception of severe erythrodermic or generalized pustular psoriasis, there is no mortality. Morbidity, particularly social and occupational, is more of a problem than is often acknowledged.

Neuropeptides in psoriasis: possible role of beta-endorphin in the pathomechanism of the disease

BACKGROUND

An increased concentration of neuropeptides in psoriatic lesional skin may be responsible for alterations in the neurogenic erythematous response and transmission of stimuli through sensory nerve fibers (sensation of pruritus).

METHODS

Increasing doses of capsaicin from 0.125 to 4 micrograms/cm2 were applied to nonlesional psoriatic skin to establish the minimal dose that induced the substance P-mediated neurogenic response in 30 patients with psoriasis. Plasma beta-endorphin was quantitated in 71 psoriatics by radioimmunoassay using NEN 1251-RIA kit.

RESULTS

The mean beta-endorphin concentration was increased about 2-fold compared to normals, whereas doses of capsaicin needed to induce erythema were higher (1-4 micrograms/cm2) in psoriatics (mainly in patients with type II psoriasis) than in healthy subjects (0.125-0.25 microgram/cm2).

CONCLUSIONS

The data indicate that increased beta-endorphin in psoriatic skin might affect both substance P-mediated neurogenic inflammation and transmission of sensory stimuli due to local antinociceptive effects of this opioid. The differences in the neurogenic response in type I and II psoriasis may be related to the degradation of substance P and beta-endorphin by neutral proteinases in the lesional skin.

The fern Polypodium decumanum, used in the treatment of psoriasis, and its fatty acid constituents as inhibitors of leukotriene B4 formation

The fern Polypodium decumanum, commonly called Calaguala, has a clinically documented use in South America and Spain in the treatment of psoriasis. One of the inflammatory mediators isolated in abnormally high quantities in the psoriatic skin is leukotriene B4 (LTB4). Calaguala was tested in an in vitro model using human leukocytes for its ability to inhibit the LTB4 formation. The inhibition was found to be caused by the polyunsaturated fatty acids (PUFAs) linoleic, linolenic and arachidonic acid. IC50 values were determined for the isolated acids and compared to a group of closely related acids also commonly found in nature. The IC50 values for most acids tested were of the same magnitude (20-60 microM) except for arachidonic acid which showed stimulatory activity and 8(R) hydroxylinoleic acid which gave 30% inhibition with the highest dose tested (120 microM). The amounts of PUFAs in different Calaguala extracts were quantitatively analysed and it is concluded that the fatty acid constituents of Calaguala may contribute to the clinical effects of the extract.

Cell membrane, a target for PUVA therapy

The photochemical reactions occurring in the cell membranes, sensitized photo-oxidation and psoralen photoaddition to lipids, are briefly reviewed. Phospholipid dynamics in the membrane structure, based on erythrocyte lipid organization, are described. Evidence for alterations of cell membrane functions under psoralen plus UVA radiation (PUVA) treatment in a variety of mammalian cells is presented. Cell receptor dysfunctions under PUVA treatment are demonstrated in a number of biological investigations. The purpose of this survey is to illustrate the feasibility of studying psoralen photobiology with phospholipids. The reaction of psoralens with phospholipids is considered to be one of the triggering mechanisms of the subsequent physiological responses, which may be relevant to PUVA photochemotherapy.

Cytokine system as potential target for antipsoriatic therapy

Cytokines are produced by a variety of cells and have numerous of overlapping activities. There is increasing evidence that cytokines play a crucial role in the pathogenesis of psoriasis and of other dermatologic diseases. This review summarizes current knowledge as to how the altered cytokine network is involved in the accumulation of inflammatory cells in lesional skin, and how the cytokines are involved in epidermal hyperproliferation. The actions of the most important therapeutic compounds, such as corticosteroids, dithranol, cyclosporine, retinoids, vitamin D3 analogues and ultraviolet radiation, on the cytokine system are also discussed. Consideration is given as to how the effects on the production of cytokines and/or cytokine receptors contribute to their therapeutic action.

The effect of anti-CD4 monoclonal antibody treatment on immunopathological changes in psoriatic skin

Recent clinical studies which showed the therapeutic effect of cyclosporin A and of anti-CD4 MoAb emphasized the role of activated CD4+ T cells infiltrating the lesional skin in the pathogenesis of psoriasis. The aim of the present study was to analyze the mode of action of anti-CD4 MoAb in 3 psoriatic patients who experienced an anti-CD4 MoAb-induced clinical improvement maximal 3-4 weeks after the onset of an 8-day therapy. We evaluated the effect of anti-CD4 MoAb treatment on the phenotype of resident and passenger inflammatory skin cells in lesional skin samples. We observed a gradual improvement of 3 out of 4 histopathologic features including parakeratosis, papillomatosis and acanthosis. In the dermis there was no modification in the density of the dermal mononuclear cell infiltrate, which consisted mainly of CD3+, CD45RO+, TCR alpha beta+, CD11a+, HLA-DR+T cells with a CD4/CD8 cell ratio of 1.5/1. Therefore as previously observed for peripheral blood mononuclear cells, the number of CD4+ T cells infiltrating the dermis remained unaffected by the treatment. In contrast, CD4 MoAb treatment was associated with drastic changes in the epidermis. These included a decrease in both CD4+ and CD8+ epidermal T cell infiltrate, diminished numbers of ICAM-1+ and HLA-DR+ keratinocytes and restored numbers of CD1a+ epidermal Langerhans cells. We conclude from this study that clinical improvement of psoriasis by anti-CD4 MoAb therapy paralleled: (1) a decrease in epidermal T cells, and (2) a down-regulation of keratinocyte activation markers (ICAM-1 and HLA-DR). These results suggest that the observed changes are secondary to down-regulation of inflammatory cytokine production by T cells in situ.