Lymphocyte trafficking in psoriasis: a new perspective emphasizing the dermal dendrocyte with active dermal recruitment mediated via endothelial cells followed by intra-epidermal T-cell activation

Evaluation of IHC Ki-67 with Clinical Correlation in Psoriasis

Introduction. Psoriasis is a chronic inflammatory skin disease with hyperproliferation, abnormal differentiation and inflammatory infiltration in epidermis and dermis. Sometimes it is clinically and histopathologically challenging to distinguish psoriasis from other non-psoriatic psoriasiform dermatoses (NPPD) like eczema, pityriasis rosea, pityriasis rubra pilaris, and lichen simplex chronicus. Ki-67 is a non-histone nuclear protein complex that regulates the cell cycle and is the most widely used proliferation immunohistochemistry (IHC) marker. Its levels have been shown to be raised in psoriasis compared to normal skin.

Aim. To elucidate and compare expression of IHC Ki-67 in psoriasis and NPPD, correlate these levels with clinical variants and disease severity in psoriasis and to observe change in levels with demographic and psoriasis-related variables.

Material and Methods. Thirty patients, each with clinically diagnosed psoriasis (cases), and NPPD (controls) were enrolled. Biopsy was taken for histopathology and IHC Ki-67 immunohistochemistry. Statistical analysis was performed.

Results. We found a significantly higher expression of IHC Ki-67 in psoriasis as compared to all types of NPPD. The higher level of Ki-67 in pustular and erythrodermic psoriasis compared to plaque-type emphasizes the greater severity and activity of these forms. The Ki-67 expression was found to increase with increasing body surface area involvement and disease severity (PASI) in chronic plaque type. Pityriasis rubra pilaris had the highest Ki67 expression among NPPD group.

Conclusion. Ki-67 is a promising tool with diagnostic and prognostic utility in psoriasis, particularly when it comes to its differentiation from nonpsoriasis psoriasiform disorders.

The role of intradermal proliferation of T-cells in the pathogenesis of psoriasis

BACKGROUND

Psoriasis is a common immune-mediated chronic inflammatory disease of the skin and joints, affecting 1-3% of the population. It is generally accepted that the pathogenesis of psoriasis involves accumulation of effector T-cells within lymph nodes and their subsequent migration into the skin through the blood system. Here we provide evidence that psoriatic plaque itself may serve as a source of inflammatory T-cells.

OBJECTIVE

We examined the intradermal proliferation of T-cells and the number of effector/memory (CD45RO+) T-cells in the skin of psoriatic patients at different periods of the disease.

METHODS

Skin samples were obtained from 41 patients with progressive psoriatic lesions; 18 of these patients also donated skin specimens during the remission of the disease. The control group consisted of 16 healthy subjects. Ki-67 immunohistochemical staining was applied to detect proliferating cells, CD3ε served as a T-cell marker, and CD45RA and CD45RO antibodies were utilized to discriminate between naive and effector/memory T-cells, respectively.

RESULTS

Progressive psoriatic lesions demonstrated Ki67 staining both in keratinocytes and in the CD3ε+ cells of dermal infiltrate. Median count of CD45RO+ cells per microscopic field was 15 in healthy controls, 59 in patients in remission and 208 in progressive psoriatic plaques. The observed differences demonstrated high level of statistical significance.

STUDY LIMITATIONS

Limited number of analyzed patients.

CONCLUSION

Progressive phase of psoriasis is characterized by intradermal proliferation of T-cells. Spots of regressed psoriatic lesions contain high number of CD45RO+ cells, which are likely to render an immunological memory.

Factor XIIIa+ dermal dendrocyte parasitism in American tegumentary leishmaniasis skin lesions

Dendritic cells belong to a family of antigen-presenting cells that are localized at the entry sites, such as skin and mucosa. Dendritic cells are related to immune surveillance function. The role of Langerhans cells in the pathogenesis of skin infectious diseases is well studied; however, there are few articles addressing involvement of factor XIIIa-positive dermal dendrocytes (FXIIIa+ DD) in such processes. FXIIIa+ DDs are bone marrow-monocytic lineage-derived cells and members of the skin immune system. Due to their immune phenotype and functional characteristics, they are considered complementary cells to Langerhans cells in the process of antigen presentation and inducing immune response. To verify the interaction between FXIIIa+ DD and Leishmania amastigotes, 22 biopsies of American tegumentary leishmaniasis (ATL) skin lesions were subjected to double staining technique with anti-factor XIIIa and anti-Leishmania antibodies. FXIIIa+ DDs were hypertrophic and abundant in the cutaneous reaction of ATL. FXIIIa+ DDs harboring parasites were observed in 11 of 22 skin biopsies. The data obtained suggest that FXIIIa+ DD plays a role in the pathogenesis of ATL skin lesion as host cell, immune effector, and/or antigen-presenting cell.

CD34-positive dendritic cells disappear from scars but are increased in pericicatricial tissue

CD34-positive stromal cells (CD34SC) are distributed throughout the body, including the dermis. They are thought to play a role in maturation and proliferation of adjacent mesenchymal and epithelial stem cells and in immune responses. To investigate the role of such cells in wound healing after excision of cutaneous lesions, we examined the distribution and quantity of CD34SC in scars from the sites of removal of malignant skin tumors and from reconstructive surgery, as well as in samples of normal skin. In normal skin, CD34 staining was confined to dendritic cells in the dermis, endothelial cells, perifollicular cells and eccrine glands. In cutaneous scars, the cicatricial tissue was totally devoid of CD34SC. However, the dermis adjacent to scar showed increased numbers of CD34SC as compared with normal skin [41.5 cells/mm(2) vs. 24.5 cells/mm(2) (p < 0.001)]. We conclude that CD34SC disappears from scars but are induced to proliferate in pericicatricial tissue. The cells in question may play a role in remodeling of scarred skin. One should be aware that augmented labeling for CD34SC around scars is common; it should not be interpreted as evidence for the persistence or recurrence of tumors that may also express CD34.

The evolution of the psoriatic lesion

Psoriasis comprises a host of abnormalities, and various aspects of the pathogenesis of psoriasis have been suggested to be of primary relevance. The aim of this review is to identity driving factors in the pathogenesis of psoriasis and to explore the dynamics of processes eventually resulting in a psoriatic lesion. In this review observations on the evolution from the symptomless skin to lesional skin in patients with psoriasis will be integrated with observations in various animal models of psoriasis.

Ação da pentoxifilina nos dendrócitos dérmicos FXIIIa de placas de psoríase

FUNDAMENTOS: Não há consenso sobre o papel dos dendrócitos dérmicos (DD) nos eventos fisiopatológicos nos períodos de exacerbação e de acalmia da doença. A pentoxifilina (PTX) é uma metilxantina que inibe vários mecanismos inflamatórios. OBJETIVO: Estudar os efeitos da PTX sobre os dendróticos dérmicos de placas de psoríase com técnicas imuno-histoquímicas. MATERIAL E MÉTODOS: Trinta biópsias de placas de psoríase antes e após oito semanas de uso oral diário de 1.200mg de PTX foram incubadas com anticorpo primário de coelho antiFator XIIIa e anticorpo de ligação conjugado com fosfatase alcalina. RESULTADOS: As células imunomarcadas Fator XIIIa+ foram proeminentes com morfologia dendrítica arborescente na derme papilar formando linha celular logo abaixo da epiderme e exibindo arranjo nodular ao redor dos vasos. Após tratamento, as células apresentaram-se com morfologia dendrítica e fusiforme, distribuídas ao redor dos vasos da derme papilar e predominantemente fusiformes dispostas paralelamente à junção dermoepidérmica retificada. CONCLUSÕES: A PTX promove aumento do fluxo sangüíneo e diminuição da adesividade endotelial, com aumento dos mastócitos e DD FXIIIa. A PTX inibe o TNF-alfa, que implica a diminuição da expressão de receptores pelos DDs, como CCR7 e a manutenção do estímulo tecidual para sinalização e migração dos precursores, uma vez que os processos etiopatogenéticos não são afetados pela droga.

TNF Inhibition Rapidly Down-Regulates Multiple Proinflammatory Pathways in Psoriasis Plaques

The mechanisms of action of marketed TNF-blocking drugs in lesional tissues are still incompletely understood. Because psoriasis plaques are accessible to repeat biopsy, the effect of TNF/lymphotoxin blockade with etanercept (soluble TNFR) was studied in ten psoriasis patients treated for 6 months. Histological response, inflammatory gene expression, and cellular infiltration in psoriasis plaques were evaluated. There was a rapid and complete reduction of IL-1 and IL-8 (immediate/early genes), followed by progressive reductions in many other inflammation-related genes, and finally somewhat slower reductions in infiltrating myeloid cells (CD11c+ cells) and T lymphocytes. The observed decreases in IL-8, IFN-gamma-inducible protein-10 (CXCL10), and MIP-3alpha (CCL20) mRNA expression may account for decreased infiltration of neutrophils, T cells, and dendritic cells (DCs), respectively. DCs may be less activated with therapy, as suggested by decreased IL-23 mRNA and inducible NO synthase mRNA and protein. Decreases in T cell-inflammatory gene expression (IFN-gamma, STAT-1, granzyme B) and T cell numbers may be due to a reduction in DC-mediated T cell activation. Thus, etanercept-induced TNF/lymphotoxin blockade may break the potentially self-sustaining cycle of DC activation and maturation, subsequent T cell activation, and cytokine, growth factor, and chemokine production by multiple cell types including lymphocytes, neutrophils, DCs, and keratinocytes. This results in reversal of the epidermal hyperplasia and cutaneous inflammation characteristic of psoriatic plaques.

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.

Psoriasis genomics: analysis of proinflammatory (type 1) gene expression in large plaque (Western) and small plaque (Asian) psoriasis vulgaris

BACKGROUND

Type 1 T cells are hypothesized to be central in the immunopathogenesis of psoriasis. Through elaboration of interferon (IFN)-gamma, type 1 T cells regulate the expression of many 'downstream' inflammatory genes, including an array of chemokines that regulate leucocyte trafficking and activation in skin lesions. Accordingly, disease progression and/or severity might be controlled by the degree to which differing cytokines and chemokines are overexpressed in focal skin regions. To examine this possibility, we studied two forms of chronic psoriasis vulgaris that differ significantly in overall severity and progression: small plaque (SP) psoriasis occurring in Korean patients, and large plaque (LP) psoriasis occurring in North American patients.

OBJECTIVES

To characterize LP and SP psoriasis vulgaris with respect to expression of proinflammatory genes that define the type 1 T-cell axis in skin lesions [genes encoding interleukin (IL)-12, IFN-gamma, and IFN-gamma-regulated chemokines or inflammatory mediators].

METHODS

Total cellular RNA of skin samples from groups of patients with LP or SP psoriasis was analysed by quantitative reverse transcription-polymerase chain reaction (TaqMan analysis) to compare the differences in mRNA expression of genes related to the IFN-gamma pathway.

RESULTS

The mRNA expression of keratin 16, CD25, IFN-gamma, IL-12 p40, signal transducer and activator of transcription-1, inducible nitric oxide synthase, IL-8, macrophage inflammatory protein-3alpha, monocyte chemoattractant protein-1, S100A12, IFN-gamma-inducible protein of 10 kDa, IFN-inducible T-cell alpha-chemoattractant and monokine induced by IFN-gamma was increased in the lesions of both LP psoriasis and SP psoriasis. However, IL-18 mRNA expression was significantly different in the lesions of LP psoriasis in comparison with those of SP psoriasis.

CONCLUSIONS

The results indicate that proinflammatory type 1 genes regulated by IFN-gamma are similarly increased in both SP and LP psoriasis, but a potential difference in IL-18 exists between these disease forms. The consistent activation of this set of genes argues for a central role of IFN-gamma as a molecular regulator of inflammation in these distinct subtypes of psoriasis vulgaris. In contrast, disease extent/severity must be controlled by yet other factors.

HCR, a candidate gene for psoriasis, is expressed differently in psoriasis and other hyperproliferative skin disorders and is downregulated by interferon-gamma in keratinocytes

We have previously shown that HCR is a good candidate gene for psoriasis based on its location in the PSORS1 locus, predicted secondary structure change of the associated allele, and expression pattern. To understand better the function of HCR, we studied how HCR expression is altered in hyperproliferative skin diseases other than psoriasis and in cancers. We examined also its regulation by different cytokines, growth factors, and antipsoriatic agents using quantitative RT-PCR (TaqMan) analysis and its location by immunostaining of keratinocyte cultures. Compared to psoriasis, HCR protein had a different distribution in chronic dermatitis, pityriasis rubra pilaris, mycosis fungoides, and chronic skin ulcers. In three of six grade III squamous cell carcinomas of the skin, four of four adenocarcinomas of the lung, and two of two ductal breast adenocarcinomas, positive cytoplasmic staining in cancer cells was detected. As in psoriasis, Ki67 did not colocalize with HCR. In cell cultures, HCR staining was detected perinuclearly in the cytoplasm and in the nuclei, suggesting that the protein may have a role in both compartments. A 2-fold downregulation of HCR mRNA expression was observed on stimulation with interferon-gamma. Based on the observations that HCR is detected in cancers of epithelial origin in Ki67-negative areas and that interferon-gamma downregulates its expression, we suggest it to have an antiproliferative function.

Imiquimod-responsive basal cell carcinomas and factor XIIIa-enriched dendrocytes

Dermal dendrocytes (DDs) are dendritic cells that exhibit immunoreactivity for factor XIIIa, and are frequently found in conjunction with basal cell carcinomas (BCCs). Imiquimod was applied to 12 superficial BCCs every 3 days for 8 weeks. One week after completion of treatment, seven lesions appeared to have resolved, while five displayed evidence of residual BCC. Prior to initiation of treatment, the seven imiquimod-responsive BCCs were surrounded by numerous DDs, whereas the five imiquimod-resistant BCCs had fewer DDs next to them at the time of entry into the study. It appears that the pretreatment density in DDs may affect the efficacy of imiquimod in eradicating skin tumours.

Use of common Chinese herbs in the treatment of psoriasis

Chinese herbal medicines have been shown to be effective in the treatment of atopic eczema. However, the Western scientific/medical literature has not fully examined the potential usefulness of herbal treatments in the management of psoriasis. This article aims to provide an Eastern insight into psoriasis, considering the diagnosis of psoriasis using Chinese medical terminology and its treatment using herbal medicine, as well as how these herbs might work.

Quantitative immunohistochemical differences in Langerhans cells in dermatitis due to internal versus external antigen sources

Cutaneous hypersensitivity reactions can develop against antigens delivered through the epidermis (contact dermatitis) or through the blood vessels (e.g., drug eruptions). On routine histology alone, it is not always possible to determine the route of the antigen. Langerhans cells (LC) are the main antigen-presenting cells in contact dermatitis. Dermal dendrocytes (DC) are antigen-presenting cells and may be involved in dermal reactions. We tested the hypothesis that there is a difference between dermatitis due to external and internal antigen sources with regard to the number or function of LC and DC. In 85 cases of dermatitis, numbers of S100 and HLA-DR reactive cells per linear millimetre of epidermis were counted. The amount of epidermal spongiosis was evaluated qualitatively. In 35 cases, the number of DC per mm2 (as defined by Factor XIIIa expression) was evaluated. The patients were then divided into two groups based on whether the final clinical evaluation considered the dermatitis to be secondary to an external (35 cases) or internal antigen (50 cases). Dermatitis due to external antigens had significantly more LC/mm and more frequent HLA-DR expression than dermatitis due to internal antigens, mean +/- SEM; 21.2+/-2.04 vs. 9.1+/-1.02 (p<0.00001) and 16.3+/-2.49 vs. 6.0+/-0.92 (p=0.0001), respectively. Spongiosis was more marked in external antigen cases. DC were more numerous in internal than in external antigen cases, but the differences were not statistically significant. In our model, determination of numbers of LC/mm is the variable with the highest power to discriminate between internal and internal sources. Quantification of HLA-DR+ LC and degree of spongiosis provide little additional discriminatory power.

Factor XIIIa-positive dendrocytes are increased in number and size in recurrent aphthous ulcers (RAU)

The factor XIIIa-positive (FXIIIa+) cell is a potent antigen-presenting cell, which has been described as increasing in numbers in various chronic inflammatory conditions. The purpose of this study was to investigate the distribution and frequency of FXIIIa+ cells in acute recurrent aphthous ulcer (RAU) lesions compared with induced traumatic ulcer (TU) lesions and with clinically healthy oral mucosa. Samples were labeled with polyclonal rabbit anti-human FXIIIa antibodies in avidin-biotin-peroxidase complex (ABC) staining. Most of the FXIIIa-immunoreactive cells in TUs and normal mucosa were spindle-shaped, whereas a relatively large, dendritic-like cell was predominant in RAU lesions. FXIIIa+ cells were quite frequent within mononuclear cell-rich inflammatory cell infiltrates and in perivascular areas in RAU lesions. In contrast, FXIIIa+ cells were not found in mucosal epithelium or in the neutrophil-rich areas. RAU mononuclear cell-rich inflammatory cell infiltrates appeared to have greater numbers of positively stained cells than the TU-inflammatory cell infiltrates (199 +/- 67 vs 110 +/- 31 cells/mm2, P < 0.001). Overall, FXIIIa+ dendrocytes were increased in numbers, and apparently also in size, in RAU lesions (274 +/- 68/mm2) as compared to controls (177 +/- 74/mm2, P < 0.01), and to TU lesions (183 +/- 50 mm2, P < 0.01). Interestingly, relatively high numbers of FXIIIa+ dendrocytes were also found in deep connective tissue in RAU sections compared with TUs (281 +/- 80 vs 166 +/- 57, P < 0.01). The characteristic changes in the size and shape of individual FXIIIa+ cells, their typical distribution and increase in frequency in RAU lesions indicate active involvement in the local pathogenic mechanisms. Localization to perivascular areas/inflammatory cell infiltrates would be compatible with a role in antigen presentation.

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.

Immunotherapy of Psoriasis

Background:

Psoriasis is a common inflammatory skin disease, characterized by epidermal keratinocyte hyperproliferation and an inflammatory infiltrate. Current research indicates that epidermal hyperproliferation is, in part, dependent upon the milieu of cytokines and growth factors produced chiefly by T cells within the infiltrate and that the T cells play a central role in the pathogenesis of psoriasis.

Objective:

Recent developments in the treatment of psoriasis are discussed in the context of current understanding of the pathogenesis of this condition.

Conclusion:

Significant advances are being made in the treatment directed against these specific immunologic aberrations. Efficacy of immunosuppressive agents such as cyclosporine, FK506 (tacrolimus), anti-CD4 monoclonal antibodies, and IL-2 fusion-toxin in the treatment of psoriasis underscore its probable immune basis. Highly specific treatment directed against cytokines, angiogenesis, and adhesion molecules remains experimental, but shows promise for safer systemic treatment in the future.

Factor XIIIa-positive dendrocytes and proliferative activity of cutaneous cancers

Factor XIIIa-positive dendrocytes present at the periphery and inside epithelial neoplasms are an heterogeneous group of cells. They are subsets of mesenchymal cells, cancer-associated macrophages and antigen-presenting cells. Factor XIIIa, other tissue transglutaminases, alpha 2-macroglobulin and tumour necrosis factor-alpha represent a complex network of mediators influencing tumour progression in the skin. In the present study we searched for the presence of dendrocytes and alpha 2-macroglobulin deposits inside and in the vicinity of cutaneous carcinomas (90 basal cell carcinomas and 46 squamous cell carcinomas) and malignant melanomas (69 primary and 28 metastatic tumours). We also studied the proliferation of the same neoplasms by Ki-67 immunohistochemistry. Dendrocytes were numerous, abutting on and infiltrating most basal cell carcinomas and thin malignant melanomas. In contrast, they were present in only low numbers or even absent in thick primary malignant melanomas and in their metastases. They appeared unmodified around squamous cell carcinomas compared with the surrounding skin. Extracellular deposits of alpha 2-macroglobulin were often found in locations where dermal dendrocytes were numerous. No correlation was found between the Ki-67 indices of carcinomas and the density of peritumoral dendrocytes. In contrast, negative relationships were found between the Ki-67 indices and the number of dendrocytes present inside basal cell carcinomas and thin malignant melanomas. This study has yielded circumstantial evidence to link the density of factor XIIIa-positive dendritic cells and a low proliferative rate of neoplastic cells in basal cell carcinomas and malignant melanomas.

Computer-assisted three-dimensional reconstruction of human dermal dendrocytes

We attempted to characterize the three-dimensional structure of dermal dendrocytes and to clarify the spatial relationships between dermal dendrocytes and mast cells, macrophages, and nerves. Normal human adult skin (breast, n = 2) was routinely processed for electron microscopy. Every other section (about 50 per data set) was collected at 80-nm intervals traversing about 8 microns of tissue. Grids showing the same cells were photographed by electron microscopy at a magnification of 4000x. Based on the 10-20 photographs per data set, cell outlines were digitized into the reconstruction program at appropriate layers and aligned. Thin, elongated cytoplasmic "dendrites" of dermal dendrocytes in two-dimensional micrographs proved to be thin, membrane-bound flaps in three-dimensional reconstruction. For dermal dendrocytes concentrated about superficial vessels (perivascular dendrocytes), the flaps enshrouded the vessel wall, and for dermal dendrocytes directly beneath the epidermis (subepidermal dendrocytes), these flaps were aligned parallel to the dermal-epidermal junction. The three-dimensional feature of dermal dendrocytes (perivascular and subepidermal) is quite similar to that of perivascular adventitial veil cells, suggesting ultrastructurally identified perivascular dendrocytes and veil cells must be identical cells. In conventional ultrathin sections, 20-40% of perivascular dendrocytes and occasional subepidermal dendrocytes were closely associated with mast cells. When viewed by computer-assisted three-dimensional reconstruction, membrane flaps of dermal dendrocytes consistently shrouded mast cell membranes for 50-90% of their perimeter; mast cells resembled a ball in a baseball glove (dermal dendrocytes). Occasional dermal dendrocytes surrounded non-myelinated nerves in the superficial dermis. Membrane flaps also enabled dermal dendrocytes to present extensive areas to the plasma membranes of adjacent monocyte/macrophages. These findings indicate that dermal dendrocytes are non-dendritic cells that are spatially related to mast cells, monocyte/macrophages, microvessels, and nerves by their membranous flaps. This suggests the need for further study of functional interactions between these cells.

Short-contact anthralin treatment augments therapeutic efficacy of cyclosporine in psoriasis: a clinical and pathologic study

BACKGROUND

Psoriasis is characterized by immune activation and increased epidermal proliferation. Cyclosporine acts by reducing T lymphocyte numbers and lymphokine production. Anthralin inhibits keratinocyte proliferation.

OBJECTIVE

We investigated whether topical anthralin would augment clearing of psoriasis produced by systemic cyclosporine.

METHODS

Twelve patients with psoriasis were treated with cyclosporine (5 mg/kg per day). Patients applied anthralin only to plaques on half of their body. They were treated until a remission or maximum benefit was achieved. Disease activity was assessed by a severity index and quantitative histopathologic markers.

RESULTS

Of the 12 patients, the skin of five cleared within 10 weeks irrespective of anthralin use. The other seven (slow responders) continued treatment for a mean of 18 weeks. Slow responders had a significantly lower severity index, a thinner epidermis, fewer CD8+ cells, and fewer proliferating keratinocytes on the anthralin-treated side than on the non-anthralin-treated side.

CONCLUSION

The combination of cyclosporine and topical anthralin is effective in patients who are slow to respond to cyclosporine alone.

Expression of ICAM-3/CD50 in normal and diseased skin

ICAM-3 is a newly recognized adhesion molecule, which is a member of the immunoglobulin supergene family of ICAMs, and has been shown to be identical with the CD50 antigen. Recent functional studies have shown that ICAM-3 is a ligand for LFA-1, and plays an important part in immune reactions. To date, very few data exist in the literature concerning its expression in the skin. In the present study, we investigated the expression of ICAM-3 in normal skin and in 98 biopsy specimens of various inflammatory and neoplastic dermatoses. ICAM-3 was found to be expressed by epidermal CD1a+ Langerhans cells, by cells of Langerhans cell histiocytosis, by T and B lymphocytes infiltrating the dermis in cutaneous lymphomas and in a wide spectrum of inflammatory dermatoses. Epidermal keratinocytes were consistently negative; endothelial expression of ICAM-3 was observed in six of the 98 cases. These results show that ICAM-3 is constitutively and widely expressed by cells participating in inflammatory dermatoses (including Langerhans cells and T and B lymphocytes), and that it can be, albeit rarely, induced on endothelial cells and dermal dendrocytes. These results highlight the important part that ICAM-3 may play in cutaneous inflammatory and immune reactions.

Inverse modulation of intraepithelial Langerhans' cells and stromal macrophage/dendrocyte populations in human papillomavirus-associated squamous intraepithelial lesions of the cervix

Ninety-four cervical biopsies from normal tissue to high-grade squamous intraepithelial lesion (SILs) were examined for the presence of intraepithelial Langerhans' cells and subpopulations of stromal macrophages/dendrocytes by immunohistochemistry using anti-S100, -L1, -CD68 and -factor XIIIa antibodies. Human papillomavirus (HPV) detection was performed in all cases by using first a mixture of DNA probes for 14 HPV types commonly found in anogenital biopsies at low stringency conditions (Tm -40 degrees C) and by reanalyzing the tissues at high stringency (Tm -10 degrees C) with HPV 6/11, 16/18 and 31/33/35 biotinylated probe cocktails and individual digoxigenin-labelled probes. SILs and metaplastic tissues were significantly associated with a depletion of S100-positive intraepithelial Langerhans' cells when compared with normal epithelium. In contrast, there was a significant increase in L1-positive stromal macrophages in SIL biopsies compared with normal or metaplastic cervix. A significantly higher density of CD68-positive macrophages was also observed in high-grade SILs compared with normal or metaplastic biopsies and with low-grade SILs. The density of factor XIIIa-positive dendrocytes was found to be higher in SILs compared with metaplastic tissues and in high-grade SILs when compared with normal cervical biopsies. No specific relationship was found between the densities of these cells and the HPV type detected in SILs separated into low grade and high grade. The significance of this inverse modulation of intraepithelial Langerhans' cells and stromal macrophages/dendrocytes in normal and SIL biopsies is discussed in relation to HPV infection and malignant transformation.

Pharmacologic modulation by cetirizine of some adhesion molecules expression in psoriatic skin lesions

BACKGROUND

Adhesion molecules play a major role in the pathogenesis of inflammatory skin diseases by regulating lymphocyte trafficking and homing in an inflamed area.

METHODS

The expression of the lymphocyte function-associated antigen-1 (LFA-1) and of its ligand, the intercellular adhesion molecule-1 (ICAM-1) has been studied in psoriatic skin lesions of 10 patients with guttate, nummular, and palmoplantar psoriasis. In addition, the peculiar immunophenotype of infiltrating cells (CD3, CD4, CD8, CD25) and their correlation with HLA-DR expression before and after treatment with oral cetirizine, a highly selective, third generation H1-receptor antagonist has been examined using the labeled avidin biotin (LAB) system.

RESULTS

Cetirizine treatment modulated in vivo the expression of adhesion molecules LFA-1/CAM-1 as shown in all cases by decreased levels of their expression on keratinocytes and on dermal endothelial cells (P < 0.001). The expression of HLA-DR on keratinocytes and endothelial cells was also inhibited after treatment. The numbers of infiltrating CD3-, CD4-, CD8-positive cells were reduced, whereas there was no significant modification of CD25-positive cells within the epidermis and the dermis.

CONCLUSION

This open clinical trial suggests that cetirizine could be effective in treating psoriasis: (1) for its symptomatic control on itching; (2) for its immunopharmacologic modulation of leukocyte integrins and on the immunophenotype pattern of infiltrating and resident cells, and (3) for contributing to the clearing of the lesions clinically.

The development of manifest psoriatic lesions is linked with the appearance of ICAM-1 positivity on keratinocytes

The development of psoriatic lesions was studied in 36 psoriatic patients using the Koebner reaction induced by tape stripping. Two biopsies per patient were taken from non-lesional psoriatic skin before, and 6 h, 2 days, 7 days, 14 days and 21 days after tape stripping. Alterations in HLA-DR, ICAM-1, Ki-67 and FXIIIa positivities in both the dermis and the epidermis were estimated using immunohistochemical methods. A double staining for CD4+ and CD8+ T cells was also carried out to show their possible Ki-67 positivity. Results were compared with those from lesional (mature plaque) and non-lesional psoriatic skin, and control skin. Of the 36 patients, 9 were Koebner-positive. The most important finding in Koebner-positive psoriatic skin was the appearance of ICAM-1 positivity on epidermal keratinocytes simultaneously with the clinically observed lesion on day 7. The number of FXIIIa+ dendrocytes in the dermis was quite constant, and increased in mature psoriatic lesions only. The number of active HLA-DR+ immunocompetent cells increased in developing psoriatic lesions, being highest in mature lesions, but no Ki-67 positivity was detected in epidermal or dermal T cells in the psoriatic specimens. Based on these results, it is concluded that T cells divide and are activated extracutaneously in psoriasis, and also that ICAM-1/LFA-1 interactions are important in the recruitment of inflammatory cells and in controlling the effector cell functions.

Antigen-presenting capacity in normal human dermis is mainly subserved by CD1a+ cells

A proposed role for antigen-presenting dermal dendrocytes in the pathogenesis of many dermal inflammatory skin diseases remains speculative. We therefore sought to determine the phenotype and functional characteristics of antigen-presenting cells isolated from normal human dermis. Normal adult human skin was incubated overnight with dispase at 4 degrees C, the epidermis was removed, and the residual dermal preparation was then minced and digested with a mixture of hyaluronidase, collagenase, and DNAase at 37 degrees C, prior to filtration through mesh. Dermal cell suspensions thus obtained were stained using specific monoclonal antibodies, and analysed by fluorescence microscopy or flow cytometry. Mean values were as follows: CD45+ leucocytes 39%, HLA-DR+ cells 39%, Ulex europaeus agglutinin I+ endothelial cells 26%, CD1a+ cells 3.9%, CD11b+ cells 16%, CD11c+ cells 6%. Mitomycin C-treated crude dermal cell suspensions induced allostimulation of peripheral blood mononuclear cells in a 7-day culture, as assessed by 3H-TdR incorporation. Depletion of CD1a+ Langerhans-like cells from the dermal cell preparation, by 95, 74 and 90% in three separate experiments using immunomagnetic beads, reduced 3H-TdR incorporation at optimal responder-to-stimulator cell ratios by 90, 64, and 87%, respectively. Our findings suggest that, in normal human dermis, the great majority of the alloantigen-presenting capacity resides in the CD1a+ Langerhans cell-like dendritic antigen-presenting cell population, and not to any great extent in either CD1a- macrophage-like cells, or HLA-DR+ endothelial cells. The relationship of the CD1a+ dermal antigen-presenting cells to the Langerhans cell lineage remains to be determined.

T cell clones from psoriasis skin lesions can promote keratinocyte proliferation in vitro via secreted products

Psoriasis vulgaris has been recognized lately as an immunologically mediated inflammatory skin disease. To analyze the pathogenetic role of T lymphocytes in the generation of psoriatic skin lesions, 105 T cell clones (TCC) and 10 T cell lines (TCL) were differentially isolated from dermis and epidermis of psoriatic skin specimens. Supernatants prepared from these T cells were studied for their effects on keratinocyte proliferation in vitro. Conditioned media from 14 of 77 epidermal TCC, 7 of which were CD8+, and from 8 of 28 dermal TCC, 5 of which were CD8+, reproducibly enhanced keratinocyte proliferation, with more pronounced mitogenic activities found in dermal TCC. Another 9 epidermal and 3 dermal TCC did not affect keratinocyte growth and supernatants from the remaining clones, as well as from the 5 epidermal and 5 dermal TCL, inhibited keratinocyte replication to varying degrees. Both mitogenic and suppressive activities were largely abolished by addition of an antiserum to interferon-gamma (IFN-gamma), while addition of epidermal growth factor or irradiated psoriatic TCL had little effect on the activities of the supernatants. These studies reveal that a subpopulation of lesional psoriatic T lymphocytes is capable of enhancing keratinocyte proliferation in vitro via secreted products. Their mitogenic capacity most likely requires IFN-gamma, but the ultimate effect is apparently determined by the presence of additional cytokines. Activation of T cells secreting such combinations of factors in vivo may contribute to the keratinocyte alterations characteristic of psoriatic skin lesions.

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.

A novel in vitro model for the study of human keratinocyte/leucocyte interactions under autologous conditions

Keratinocyte/leucocyte interactions have become an area of intense investigations in the last decade. However, few convenient in vitro models are available at present. We have therefore designed a novel in vitro system for autologous human keratinocyte/leucocyte co-culture. Non-invasive epidermal cell sampling was achieved by using outer root sheath cells from hair follicles. After one passage, pure keratinocyte cultures (no Langerhans cells or melanocytes) were obtained. Co-culture experiments were performed on a Transwell system: keratinocytes were grown on the porous cupula, and then laid on to wells containing leucocytes. Alternatively, leucocytes can be added to the cupula when contact interactions between the two cell types are to be investigated. Using this system, we demonstrated that Phaesolus vulgaris phytohaemagglutinin-activated T lymphocytes (with 10% monocytes) in the lower compartment induced intercellular adhesion molecule 1 (ICAM-1) and HLA-DR expression, and inhibited methyl-3H-thymidine incorporation in normal human autologous keratinocytes cultured on the cupula. These changes were mediated by soluble factors (no cell contacts between keratinocytes and leucocytes), and required lymphocyte activation. This is the first direct in vitro evidence for leucocyte-induced ICAM-1 and HLA-DR expression on keratinocytes. This system is a potential tool for the study of keratinocyte/leucocyte interactions.(ABSTRACT TRUNCATED AT 250 WORDS)

The cytokine network in lesional and lesion-free psoriatic skin is characterized by a T-helper type 1 cell-mediated response

As a psoriatic lesion develops at sites of previously uninvolved skin, cytokines and their subsequent induction of various adhesion molecules may play important pathophysiologic roles. To further define the cytokine network in psoriasis, biopsies were obtained from both lesional skin and lesion-free skin of individuals with psoriasis and compared to normal skin biopsies from control subjects. Each biopsy was analyzed using polymerase chain reaction for expression of cytokines and immunostaining to detect adhesion molecules. The results indicate that psoriatic lesions have a type 1 cytokine profile (i.e., interleukin[IL]-2, interferon[IFN]-gamma, and tumor necrosis factor[TNF]-alpha), without a significant component of type 2 cytokines (i.e., IL-4, IL-5, and IL-10) accompanied by aberrant expression of endothelial cell leukocyte adhesion molecule (ELAM)-1 and vascular cell adhesion molecule (VCAM)-1 on dermal endothelial cells, and ICAM-1 on epidermal keratinocytes. Four of five lesion-free biopsies from psoriatic patients had prominent cytokine mRNA expression compared with skin from normal donors (particularly TNF-alpha, IL-1 alpha, IL-1 beta, with lesser increases in IFN-gamma and granulocyte/macrophage colony-stimulating factor [GM-CSF]), which was accompanied by aberrant adhesion molecule expression in the same four samples. We conclude that a particular T-cell population producing type 1 cytokines accumulates in psoriatic lesions. In addition, clinically lesion-free skin is characterized by increased levels of various cytokine mRNAs, and aberrant adhesion molecule expression in both dermal and epidermal compartments.

MCP-1 mRNA expression in basal keratinocytes of psoriatic lesions

In addition to hyperproliferation of keratinocytes, psoriasis is characterized by pronounced leukocytic infiltration. In contrast to the epidermal localization of neutrophils and T lymphocytes, macrophages are almost exclusively restricted to the dermal compartment. By immunohistologic analysis, these dermal macrophages were mainly encountered in the papillary dermis and arranged along the rete ridges in close proximity to proliferating keratinocytes. Monocyte chemoattractant protein (MCP-1) anti-sense RNA probes yielded abundant signals over the proliferating basal keratinocytes of the tips of the rete ridges, and, to a lesser extent, in cells in the papillae. Thus, the strongest MCP-1 message in psoriatic lesions is found above the dermal-epidermal junction and this may explain the characteristic sub-basal distribution of dermal macrophages. These results suggest that MCP-1 is important in regulating the interaction between proliferating keratinocytes and dermal macrophages in psoriasis pathogenesis.

Immunohistochemical features in inflammatory linear verrucous epidermal nevi suggest a distinctive pattern of clonal dysregulation of growth. Military Medical Consortium for the Advancement of Retroviral Research

BACKGROUND

We studied biopsy material from four patients with inflammatory linear verrucous epidermal nevi (ILVEN) that had a psoriasiform appearance histologically and seven cases of linear epidermal nevi (LEN). Of the seven LEN, five showed hyperkeratosis, papillomatosis, and varying degrees of acanthosis; two had features of epidermolytic hyperkeratosis. Because these lesions have distinctive histologic patterns, we wanted to determine whether we could also demonstrate a distinctive pattern of immunohistochemical markers.

METHODS

On all 11 cases we performed immunohistochemical stains for PCNA, factor XIIIa, MAC-387, UCHL-1, and OPD-4. In addition, on one case of ILVEN we performed ICAM-1, ELAM-1, and HLA-DR stains.

RESULTS

The pattern of staining of PCNA, factor XIIIa, MAC-387, UCHL-1, and OPD-4 was distinctly different in ILVEN and LEN. Staining for ICAM-1 was present on keratinocytes, and ELAM-1 was present on endothelial cells in two cases of ILVEN. HLA-DR in these same two cases of ILVEN stained mainly dendritic cells in the epidermis.

CONCLUSION

The different pattern of staining of PCNA, factor XIIIa, MAC-387, UCHL-1, and OPD-4 in LEN and ILVEN indicates a different mechanism of growth dysregulation. Stains for ICAM-1, ELAM-1, and HLA-DR in ILVEN suggest that an inability to down-regulate the inflammatory infiltrate may be important in the growth dysregulation in ILVEN. In addition, the onset of ILVEN at the time of HIV-1 infection in one patient suggests that HIV-1 infection may be one of many factors that initiates ILVEN in a susceptible person.

Minocycline hyperpigmentation: model for in situ phagocytic activity of factor XIIIa positive dermal dendrocytes

Pigmentary disorders resulting from the prolonged use of the semisynthetic tetracycline derivative antibiotic, minocycline, are rare but well recognized sequelae of ingestion of this drug. We present two cases of women with bullous pemphigoid who developed blue-black pigmentation in areas of scarring on the legs after oral minocycline therapy. On histologic examination, the deposited pigment was localized within dendritic cells limited to the upper dermis. Immunohistochemical analysis revealed these cells to be factor XIIIa positive dermal dendrocytes which was confirmed by transmission electron microscopy. We believe these cases demonstrate, in-situ, the phagocytic capabilities of this recently described cell population.

Molecular cloning, occurrence, and expression of a novel partially secreted protein "psoriasin" that is highly up-regulated in psoriatic skin

Analysis of the protein patterns of normal and psoriatic noncultured unfractionated keratinocytes has revealed several low-molecular-weight proteins that are highly up-regulated in psoriatic epidermis. Here, we have cloned and sequenced the cDNA (clone 1085) for one of these proteins that we have termed psoriasin. The deduced sequence predicted a protein of molecular weight of 11,457 daltons and a pI of 6.77. The protein co-migrated with psoriasin as determined by two-dimensional (2D) gel analysis of [35S]-methionine-labeled proteins expressed by RK13 cells transfected with clone 1085 using the vaccinia virus expression system. Analysis of the predicted sequence revealed a potential calcium-binding sequence of the EF-hand type, as well as the absence of a signal sequence at its amino terminal. Psoriasin is not related to other proteins that migrate closely in 2D gels (MRP 14, also known as calgranulin B, L1 and calprotectin; MRP 8, or calgranulin A and cystatin A or stefin A), and bears no significant sequence homology with any other protein of known primary structure. Increased expression of psoriasin mRNA in psoriatic keratinocytes was confirmed by Northern blotting and in situ hybridization. Psoriasin showed a restricted occurrence in fetal human tissues as determined by 2D gel electrophoresis. Of 21 tissues analyzed, only ear, skin, and tongue showed significant levels of this protein. Psoriasin was not detected in normal human fibroblasts, lymphocytes, endothelial cells and transformed epithelial cells of keratinocyte origin. Granulocyte extracts contained this protein suggesting that its overexpression by psoriatic keratinocytes may be linked to the inflammatory stimuli.

Detection of interferon-gamma mRNA in psoriatic epidermis by polymerase chain reaction

Psoriatic skin lesions contain HLA-DR positive T lymphocytes, and other activation antigens, which suggest that the T cells may be producing lymphokines. Gamma interferon is produced by activated T cells, and its presence in psoriasis has been inferred by the lesional keratinocyte expression of 3 gamma interferon-inducible proteins i.e. HLA-DR, intercellular adhesion molecule-1, and gamma-IP-10. To determine whether gamma interferon is being produced directly in psoriatic lesions, punch biopsies of normal and diseased skin were separated into epidermal sheets and dermal fragments. Total cellular RNA was isolated from each epidermal and dermal compartment, and reverse transcribed followed by amplification of the resultant DNA by polymerase chain reaction. The amplification process involved the use of 5' and 3' primers for gamma interferon, and tumor necrosis factor-alpha, with beta-actin serving as a control. Gamma interferon mRNA, but not tumor necrosis factor alpha mRNA, was detectable in 4 of 5 psoriatic epidermal specimens. Neither mRNA was detectable in any normal skin dermal/epidermal specimens. Gamma interferon mRNA was also detectable in a single psoriatic dermal specimen. If reverse transcriptase was omitted, no polymerase chain reaction products were detected, indicating that the fragments detected were not derived from contaminating genomic DNA. These results indicate that gamma interferon mRNA can be extracted and successfully detected from human psoriatic lesional skin biopsies, using polymerase chain reaction technology. This molecular approach can easily be expanded to measure many other cytokines in both epidermal and dermal locations. The detection of gamma interferon in this clinical setting may be of particular pathophysiological significance because injection of gamma interferon has been reported to induce psoriatic lesions.

Keratinocytes as initiators of inflammation

Environmental stimuli responsible for inducing cutaneous inflammation include contact allergens and ultraviolet light. We postulate that these diverse stimuli trigger a cutaneous inflammatory response by directly inducing epidermal keratinocytes to elaborate specific pro-inflammatory cytokines and adhesion molecules. The consequences are activation of dermal microvascular endothelial cells and selective accumulation of specific mononuclear cells in the dermis and epidermis. Thus, keratinocytes may act as "signal transducers", capable of converting exogenous stimuli into the production of cytokines, adhesion molecules, and chemotactic factors (acting in an autocrine and paracrine fashion) responsible for initiation of "antigen-independent" cutaneous inflammation. The initiation phase may facilitate or promote an amplification phase with additional production of tumour-necrosis factor alpha and interferon gamma via an "antigen-dependent" pathway, and keratinocyte/T cell/antigen-presenting dendritic cellular associations. The direct activation of keratinocytes, with their ability to produce the complete repertoire of pro-inflammatory cytokines, can profoundly influence endogenous and recruited immunocompetent cells, thereby providing the critical trigger responsible for the swift and clinically dramatic alterations that occur following contact between the epidermis and a host of "noxious" agents.

Abnormal cutaneous topobiology: the molecular basis for dermatopathologic mononuclear cell patterns in inflammatory skin disease

Because of the identification and characterization of various adhesion molecules (lymphocyte function associated antigen-1, intercellular adhesion molecule-1), chemotactic factors (interleukin-8, monocyte chemotactic/activating factor), and their modulatory cytokines (gamma interferon, tumor necrosis factor), it is possible to begin to ascribe specific molecules to cutaneous cellular reaction patterns. The abnormal topobiology, or altered spatial distribution, of mononuclear cells, which gives rise to disease-specific patterns, was described in molecular terms. A large number of diverse skin diseases were classified into six different groups, with each group highlighting distinctive cell types, adhesion molecules, chemotactic factors, and cytokines. The diseases within each group, which share functional anatomical reaction zones, were postulated to share common pathophysiologic pathways. Thus, it is now possible, as one scans the microscopic field, to look past the static images of red- and blue-stained cells and appreciate a dynamic and detailed medley of molecularly defined events emanating from the eyepiece.