T-cadherin loss induces an invasive phenotype in human keratinocytes and squamous cell carcinoma (SCC) cells in vitro and is associated with malignant transformation of cutaneous SCC in vivo.

BACKGROUND: Cadherins play important roles in controlling keratinocyte growth, differentiation and survival. Atypical glycosylphosphatidylinositol-anchored T-cadherin (T-cad) is highly expressed in the basal keratinocyte layer of skin. The role of T-cad in keratinocyte biology and pathology is unclear. OBJECTIVES: To define the role of T-cad in the pathogenesis of cutaneous squamous cell carcinoma (SCC) through gain-of-function and loss-of-function studies in vitro and through examination of T-cad expression patterns in human cutaneous SCC specimens in relation to histological classification of degree of tumour differentiation. METHODS: In vitro studies employed lentiviral-mediated overexpression/silencing of T-cad in normal human keratinocyte (HaCaT) and SCC (A431) cell lines, monolayer and multicellular spheroid culture models, cell morphology analyses and assays of random motility and invasion. Immunohistochemistry was performed on skin specimens from patients with actinic keratosis, Bowen disease or SCC. RESULTS: In vitro, silencing of T-cad induced a morphologically elongated and disorganized cell phenotype, increased random motility and markedly enhanced invasive potential. Overexpression of T-cad induced a morphologically spread and compact cell phenotype and blunted invasive potential. In vivo, regional loss of T-cad expression was more frequent and prominent in SCC classified as moderately-to-poorly differentiated than in SCC classified as well differentiated. However, in both categories aberrant and/or absence of T-cad expression was associated with histological features of a potentially more malignant and invasive phenotype of cutaneous SCC. CONCLUSIONS: T-cad is a controlling determinant of SCC phenotype and invasive behaviour and its loss is associated with the process of malignant transformation from noninvasive to invasive SCC.

Regression of basal cell carcinoma by intralesional interferon-alpha treatment is mediated by CD95 (Apo-1/Fas)-CD95 ligand-induced suicide.

Basal cell carcinoma (BCC) is the most common skin cancer in humans, and although metastasis rarely occurs, the tumor cells are nevertheless able to invade and destroy the surrounding tissue. Intralesional injection of IFN-alpha has been found to be highly effective in inducing BCC regression by an unknown mechanism. We show that in untreated patients, BCC cells express CD95 ligand, but not the receptor, which may allow tumor expansion by averting the attack of activated CD95 receptor-positive lymphoid effector cells. The CD95 ligand of BCC cells is functional as CD95-positive cells incubated on BCC cryosections become apoptotic and are lysed. In IFN-alpha-treated patients BCC cells express not only CD95 ligand but also CD95 receptor, whereas the peritumoral infiltrate that mainly consists of CD4+ T cells predominantly contains CD95 receptor and only few CD95 ligand-positive cells. Thus, in treated patients BCC most likely regresses by committing suicide through apoptosis induction via CD95 receptor-CD95 ligand interaction.

Ultraviolet light downregulates CD95 ligand and TRAIL receptor expression facilitating actinic keratosis and squamous cell carcinoma formation.

Long-term ultraviolet light exposure of human skin epidermis in Caucasians is associated with an increased risk for the development of melanoma and nonmelanoma skin cancers. Ultraviolet radiation not only induces DNA damage in epidermal cells, it also interferes with skin homeostasis, which is maintained by a unique distribution pattern of apoptosis-inducing and apoptosis-preventing molecules. We demonstrate that, beside CD95 ligand, TRAIL and TRAIL receptors also function as important sensors in the human epidermis preserving skin integrity and preventing cell transformation. Ultraviolet irradiation extensively changes the expression pattern of some of these molecules, diminishing their sensor function. In particular, CD95 ligand and to a somewhat lesser extent TRAIL receptors are downregulated upon ultraviolet light exposure. CD95 ligand downregulation is not due to protein degradation as in situ hybridization experiments strongly support a transcriptional regulation. The downregulation of these molecules with sensor function increases the risk that aberrant cells are less efficiently eliminated. This concept is supported by the fact that the expression of these molecules is also low or absent in actinic keratosis, a precancerous state that has developed as the consequence of long-term ultraviolet exposure. Progression to invasive neoplasms is then accompanied by an upregulation of CD95 ligand and a downregulation of CD95 and of the TRAIL receptors. The high expression of CD95 ligand, TRAIL, and FLIP in squamous cell carcinoma may then contribute to the immune escape of the tumor, whereas the lack of expression of CD95 and TRAIL receptors prevents autolysis of the tumor.

Segmental forms of autosomal dominant skin disorders: the puzzle of mosaicism.

Autosomal dominant inherited disorders of the skin sometimes present as a segmental phenotype. In recent years molecular studies have demonstrated that genetic mosaicism leads to such a clinical manifestation. In general the skin outside the segmental disorder is normal. This rather common variant of segmental manifestation has been termed type 1. Recently, Happle delineated a second type of segmental manifestation of autosomal dominant genodermatosis. This variant is characterized by a more diffuse clinical presentation of the disease, and a very marked linear pattern can be recognized. An explanation of this phenotype is a germline mutation of the gene manifests after a postzygotic mutation leading to double inactivation of the gene. The severe linear manifestation then reflects a doubling of the genetic burden. We present a number of clinical cases to demonstrate this phenomenon, and we present a case of the segmental Naegeli-Franceschetti-Jadassohn syndrome born to a mother with the diffuse manifestation of the disorder.

Pre-Sézary erythroderma evolving to Sézary syndrome. A report of seven cases.

Seven patients with pre-Sézary erythroderma were followed up for three to 16 years as Sézary erythroderma syndrome developed. With the transition, the clinical and skin manifestations of the disease became chronic, more florid, and more resistant to therapy. Four patients had multiple contact allergies or drug reactions, and one patient had severe atopic dermatitis. Lymphoma developed in one patient, and multiple myeloma developed in a second patient. An increased absolute number of Sézary cells to more than 1,000/cu mm occurred in all patients with Sézary syndrome. Histologic study showed chronic dermatitis in most patients with the pre-Sézary condition and subepidermal lymphocytic band inflammation in most patients with the Sézary syndrome.

Sézary syndrome. A clinicopathologic study of 39 cases.

The histopathologic and clinicopathologic characteristics of 121 skin biopsy specimens from 39 patients with Sézary syndrome were reviewed. The most frequently noted histologic type was a lymphomatoid subepidermal band infiltrate, composed predominantly of atypical lymphoid cells with cerebriform nuclei, found in 53 (44%) of the skin biopsy specimens. A lymphocytic band infiltrate, characterized by a predominance of small lymphocytes and a variable admixture of atypical lymphoid cells, was found in 47 (39%) of the specimens. Only 18 (15%) of the lymphomatoid band specimens from ten patients demonstrated epidermal involvement suggesting mycosis fungoides. Twenty-one (17%) of the biopsy specimens were interpreted as showing changes consistent with those of chronic dermatitis. Despite multiple skin biopsy specimens, there was a weak association noted between the histologic patterns and the clinical stage of disease or the prognosis.

Lymphoproliferative responses to Borrelia burgdorferi in patients with erythema migrans, acrodermatitis chronica atrophicans, lymphadenosis benigna cutis, and morphea.

BACKGROUND AND DESIGN: Specific humoral and cell-mediated immune responses play an important role in the pathogenesis of Lyme borreliosis. Several previous studies demonstrated that a specific cellular immune response to Borrelia burgdorferi can occur independently of a diagnostic humoral response. Little is known about T-cell reactivities against B burgdorferi in early and late cutaneous manifestations of Lyme borreliosis. We studied the lymphoproliferative response of peripheral blood mononuclear cells to B burgdorferi antigen from 99 patients (25 with erythema migrans, 16 with acrodermatitis chronica atrophicans, 13 with lymphadenosis benigna cutis, and 45 with localized scleroderma) and 21 control subjects. The results are expressed as a stimulation index (SI) (mean count per minute of triplicate cultures with stimulant divided by mean count per minute without stimulant). The serum samples from all patients and control subjects were tested for antibodies to B burgdorferi by indirect immunofluorescence assay. RESULTS: The 21 healthy seronegative controls had an SI of 3.3 +/- 2.0 (mean +/- SD). Compared with that of control subjects, the SIs were significantly elevated in patients with erythema migrans (9.8 +/- 9.1), acrodermatitis chronica atrophicans (11.8 +/- 8.2), and lymphadenosis benigna cutis (7.2 +/- 6.2). The 45 patients with localized scleroderma had elevated proliferative responses, with an SI of 6.5 +/- 7.3, but these responses did not significantly differ from those of controls. Elevated titers of antibodies to B burgdorferi were present in six (24%) of 25 patients with erythema migrans, five (38%) of 13 patients with lymphadenosis benigna cutis, and 13 (29%) of 45 patients with localized scleroderma. All 16 patients with acrodermatitis chronica atrophicans had markedly elevated antibody titers. CONCLUSIONS: Our findings show that a significant lymphoproliferative response to B burgdorferi occurs in the majority of patients with cutaneous manifestations of Lyme borreliosis. The lymphocyte proliferation assay may be of diagnostic value in patients in whom Lyme borreliosis is strongly clinically suspected and who have nondiagnostic levels of antibodies against B burgdorferi.

Identification of T-cell subpopulations in granuloma annulare.

Granuloma annulare is a lymphohistiocytic process of unknown cause characterized by necrobiotic dermal papules. Acetone-fixed frozen sections of eight granuloma annulare lesions were studied for the presence of T-cell subsets, using monoclonal antibodies to T-cell surface antigens. The palisading and perivascular lymphocytic infiltrate shows that most of the mononuclear cells are reactive with LEU-1 antibody, which characterizes peripheral T cells and activated T cells. Numerous cells were reactive with LEU-3a antibody, which identifies the helper-inducer T-cell subset. Some cells were positive with LEU-2a antibody, which detects suppressor-cytotoxic cell populations. Masses of histiocytes were identified infiltrating between the collagen fibers and surrounding the central necrobiosis area; the histiocytes showed a very strong diffuse acid phosphatase and nonspecific esterase activity. These findings suggest that a cell-mediated immune response may be the dominant pathogenic event in granuloma annulare.

T cells in cutaneous lesions of Sézary syndrome and T-cell leukemia. Characterization by monoclonal antibodies.

Anti-T-cell monoclonal antibodies (LEU series) immunoperoxidase technique study for the presence of T cells in cutaneous lesions from four patients with Sézary syndrome and one patient with chronic T-cell leukemia showed that most dermal-lymphoid cells from three patients with Sézary syndrome were reactive with monoclonal antibodies to anti-pan T-cell (LEU-1) and helper T-cell (LEU-3a) subsets but not with those to suppressor-cytotoxic T-cell (LEU-2a) subsets. One patient with progressive disease had atypical dermal-lymphoid cells positive for pan T-cell (LEU-1). Epidermotropic cells were reactive to LEU-1 in all four patients, LEU-2a in one patient, and LEU-3a in one patient. Neoplastic cells in skin lesions of chronic T-cell leukemia showed strong positive staining with LEU-1, but were reactive with both anti-T-cell subset, monoclonal antibodies. The atypical, dermal-lymphoid cells in Sézary syndrome represent mature, helper T cells in most cases. The absence of T-cell subset antigens in one patient with fulminant Sézary syndrome and the finding of both T-cell subset antigens on T-cell leukemia cells suggest the presence of actively proliferating, immature T cells in those cases.

T-cell subsets in cutaneous sarcoidosis.

Skin lesions from four patients with systemic and cutaneous sarcoidosis were studied, by the use of monoclonal antibodies, for the presence of T cells and T-cell subsets. Large numbers of lymphoid cells reacting with anti-pan T-cell (LEU-1) and anti-helper and inducer subset (LEU-3) monoclonal antibodies were observed around and within the sarcoid granulomas in three of the four patients. Only rare LEU-2-reactive suppressor cells were observed in all four patients. Activated T lymphocytes with focal acid phosphatase activity, together with epithelioid cells and multinucleated giant cells with strong diffuse activity of acid phosphatase and nonspecific esterase, were identified within the granulomas. The two patients with active disease demonstrated substantially more T cells in the sarcoid granulomas than did the two patients with chronic disease. Our study results suggest the importance of helper T cells in the formation of the sarcoid granuloma by mononuclear phagocytes and imply that the activity and duration of disease may be related to the T-cell populations.

T cells and T-cell subsets in mycosis fungoides and parapsoriasis. A study of 18 cases with anti-human T-cell monoclonal antibodies and histochemical techniques.

Skin lesions from 15 patients with mycosis fungoides (MF) and from three with parapsoriasis were studied immunohistochemically with monoclonal antibodies against T cells (Leu 1) and against T-cell subsets (Leu 2a, Leu 3a). Lymphoid cell reactivity was diverse among these sampled cases. In two cases of parapsoriasis and nine of MF, there was a predominance of helper/inducer (Leu-3a-reactive) cells over suppressor/cytotoxic (Leu-2a-reactive) cells. In one case of parapsoriasis and one (advanced tumor stage) of MF, there was suppressor/cytotoxic cell predominance. One case of MF showed strong reactivity for both T-cell subset markers. Four cases of MF (two plaque-stage and two tumor-stage) featured a predominant cell type in the dermis which was nonreactive for all three antibodies. The intraepidermal lymphoid cellularity was Leu-1-reactive in ten cases of MF and two of parapsoriasis. Among these 12 cases, the intraepidermal cellularity was Leu-2a-reactive in four and Leu-3a-reactive in three. The use of such studies of T-cell subsets on in situ cutaneous lymphoid infiltrates may demonstrate a correlation with cytomorphology, clinical stage, and disease prognosis.

Fas-ligand gene silencing in basal cell carcinoma tissue with small interfering RNA.

Basal cell carcinoma (BCC) is the most frequent cancer in the Caucasian population. Cells of BCC strongly express Fas-ligand (FasL), a member of the tumor necrosis family, which induces apoptosis in Fas receptor-expressing cells. It has been suggested that by expression of FasL, BCC cells may evade the attack of Fas-positive immune effector cells allowing the tumor to expand. Thus, downregulation of FasL should prime BCC to the assault of immune effector cells. Recently, it has been shown that RNA interference is a highly successful approach to specifically silence a gene of interest in single cells and some animal models. However, RNAi in human tissues has not been shown so far. Here, we provide evidence that small interfering RNAs (siRNAs) efficiently transfect tumor tissue ex vivo and silence the gene of interest. We demonstrate that a specific siRNA efficiently downregulates FasL not only in FasL-positive indicator cells but also in surgically excised BCC tissue at both the protein and the mRNA level. The successful transfection of tumor tissues with siRNAs now allows to test the function of the molecule under study and opens up the investigation of other target genes in the tumor.

Changes of epidermal mu-opiate receptor expression and nerve endings in chronic atopic dermatitis.

There is increasing evidence that neuropeptides such as a substance P, neurotrophins or beta-endorphin, an endogenous agonist for mu-opioid receptor, are involved in the pathogenesis of atopic dermatitis in which mental stress and scratching deteriorate the disease. mu-Opioid receptor, a G-protein-coupled receptor, can be downregulated and internalized by agonists and other factors in vitro. In this study, we investigated the regulation of mu-opioid receptor and nerve endings in atopic dermatitis patients. Skin biopsies from atopic dermatitis patients revealed a significant downregulation of mu-opiate receptor expression in epidermis of atopic dermatitis. Permeabilization of the skin showed that the receptor in keratinocytes from atopic dermatitis is internalized. The mRNA expression pattern of the mu-opiate receptor is different in epidermis taken from patients with chronic atopic dermatitis compared to normal skin. In atopic dermatitis, the mRNA is concentrated in the subcorneal layers of the epidermis and in normal skin in the suprabasal layers. Staining of the nerve endings using protein gene product 9.5 shows a different pattern of epidermal nerve endings in normal skin compared to atopic dermatitis. In normal skin, the epidermal nerve endings are rather thick. However, in atopic dermatitis, the epidermal nerve endings are thin and run straight through the epidermis. Based on these observations and combining the 'intensity' and 'pattern' hypothesis, we propose a new theory especially for histamine-unrelated, peripheral induction of chronic pruritus. We suggest that 'itch' is elicited in the epidermal unmyelinated nerve C-fibers and 'pain' in the dermal unmyelinated nerve fibers. The downregulation of the opioid receptor in the epidermis contributes to the chronic itching. We call this new hypothesis the 'layer hypothesis'.

Intralesional interferon alfa-2b in the treatment of basal cell carcinoma. Immunohistochemical study on cellular immune reaction leading to tumor regression.

Four patients with basal cell carcinomas were treated with intralesional injections of interferon alfa-2b (1.5 million IU per injection) three times a week for 2 weeks. Histopathologic examination of biopsy specimens of the lesions confirmed the absence of basal cell carcinoma in all cases 4 weeks after completion of therapy. A dense mononuclear cell infiltrate and numerous ectatic blood vessels were present in the dermis at the sites of previous basal cell carcinoma. Immunohistologic analysis of the dermal infiltrate revealed a marked increase of Leu-4+ T cells with a slight predominance of Leu-3+ helper/inducer T cells over Leu-2+ suppressor/cytotoxic T cells. Most of the dermal infiltrate expressed HLA-DR antigen. In addition, Leu-11+ natural killer cells were observed in the dermal infiltrate. Immunohistologic changes in the skin lesions at the sites of previous basal cell carcinoma suggest that intralesional interferon alfa-2b acts on tumor cells by enhancement of local T-cell-mediated immune responses.

Common skin disorders of the penis.

Diseases of the male genitalia range from infectious lesions to inflammatory and neoplastic conditions, including many genital manifestations of more general skin diseases. This review highlights the clinical features, diagnosis and treatment of the most common dermatoses of the male genitalia. Herpes genitalis and infections caused by human papillomavirus (HPV) are increasing, particularly in young sexually active people. Herpes simplex virus infection is the commonest infectious cause of genital ulceration, with evidence that many infections are asymptomatic. HPV infection may be latent, subclinical and clinical. The most common causal agents for condyloma acuminatum are low-risk HPV 6 and 11; high-risk HPV types 16 and 18 are associated with premalignant and malignant lesions. Treatment for genital warts remains unsatisfactory; recurrences are common. Imiquimod, a new topical immunotherapeutic agent, which induces interferon and other cytokines, has the potential to be a first-line therapy for genital warts. Scabies and pediculosis are transmitted by skin-to-skin contact and sexual transmission is common, with the penis and scrotum favourite locations for scabious lesions. Oral ivermectin, a highly active antiparasitic drug, is likely to be the treatment of choice, but until approval is granted it should be reserved for special forms of scabies. Common skin diseases, e.g. psoriasis and lichen planus, may have an atypical appearance in the genital area. The typical psoriatic scale is usually not apparent because of moisture and maceration. Allergic contact dermatitis of the genital area may result from condoms, lubricants, feminine hygiene deodorant spray and spermicides. More often, contact dermatitis is irritant, resulting from persistent moisture and maceration. Lichen sclerosus is a chronic inflammatory disease that occurs as atrophic white patches on the glans penis and foreskin. The penile form is a common cause of phimosis in uncircumcised men; involvement of the urethral meatus may lead to progressive meatal stenosis. Plasma cell balanitis is a benign, idiopathic condition presenting as a solitary, smooth, shiny, red-orange plaque of the glans and prepuce of a middle-aged to older man. Squamous cell carcinoma (SCC) in situ, e.g. erythroplasia of Queyrat and Bowen's disease, cannot be excluded clinically; their apparent clinical benignity may lead to lengthy periods of misdiagnosis and biopsy is required to confirm the diagnosis. SCC is the most common malignancy of the penis and the role of oncogenic HPV-types has been also established in SCC of the penis. Prevention of SCC of the penis presupposes an identification of risk factors, early detection of all pre-cancerous lesions and treatment of phimosis.

T cell subsets and macrophages in lichen planus. In situ identification using monoclonal antibodies and histochemical techniques.

Skin lesions from 6 patients with lichen planus were studied for the presence of T cells and T cell subsets using monoclonal antibodies and indirect immunoperoxidase technique. Small numbers of Leu-2a-reactive suppressor-cytotoxic cells were present early in the basal cell layer in 2 patients with recent lesions. The analysis of T cell subsets revealed the predominance of anti-pan-T-cell (Leu-1)- and Leu-3a-reactive helper-inducer cells in 4 patients with older active lichen planus lesions. Significant numbers of suppressor-cytotoxic cells were observed in the papillary dermis and within the epidermis associated with hydropic degeneration of the basal cell layer. Activated T lymphocytes with focal acid phosphatase activity, together with activated histiocytes-macrophages with strong diffuse activity of acid phosphatase and non-specific esterase, were identified in the dermis and within the epidermis. These findings suggest that a cytotoxic immune process directed against the basal cell layer of the epidermis is the dominant pathogenic event in lichen planus.

Cutaneous myiasis due to Dermatobia hominis.

Cutaneous myiasis caused by the human botfly Dermatobia hominis involves the infestation of tissue with dipterous fly larvae and is common in the neotropical region of the New World. We report a case of D. hominis imported in Switzerland from Costa Rica. In the past, various approaches to extract the botfly larva have been reported.

Atrophoderma of Pasini and Pierini. Clinical and histopathologic findings and antibodies to Borrelia burgdorferi in thirty-four patients.

BACKGROUND: Idiopathic atrophoderma of Pasini and Pierini (IAPP) is a distinctive form of dermal atrophy, usually appearing as one or more sharply demarcated depressed areas. Little is known about the clinical variants of IAPP, and limited data are available on antibiotic therapy for this condition. OBJECTIVE: Our purpose was to define the various types of IAPP clinically and histologically and to investigate a possible association with Borrelia burgdorferi infection. METHODS: The records of 34 patients with IAPP were reviewed. Skin biopsy specimens for routine histologic examination were obtained from 17 patients. Serum from 26 patients was analyzed for antibodies against B. burgdorferi. RESULTS: Of the 34 patients (21 female, 13 male, 7 to 66 years of age), 23 had well-circumscribed brown, depressed plaques. The back was most frequently involved (82%). Eleven patients had a superficial variant of IAPP, characterized by slightly atrophic brown macules forming large hyperpigmented patches with an irregular border. Secondary areas of induration developed in 7 of 34 patients. Ten of 26 patients (38%) had elevated serum antibodies to B. burgdorferi. Twenty of the 25 patients treated with oral antibiotics had clinical improvement with no evidence of new active lesions. CONCLUSION: IAPP is an abortive, primarily atrophic variant of morphea. The clinical appearance of IAPP may be variable according to the stage of dermal atrophy and distribution of the lesions.