[Phototherapy and carcinogenesis]

Phototherapy successfully uses the short-term effects of ultraviolet light against inflammation and proliferation. For its long-term effects, however, ultraviolet light was recently classified as a carcinogen. The wave spectrum employed in phototherapy has various carcinogenic effects in experimental systems, most notably DNA mutations in keratinocytes. Clinically, PUVA increases the risk for squamous cell carcinoma of the skin, especially after following 350 or more phototherapy sessions over a lifetime. Melanoma and genital skin cancer are not increased by PUVA alone. Previous UV damage, immunosuppression and other systemic treatments increase cutaneous carcinogenesis through PUVA. In contrast, broad-band UVB, narrow-band UVB and UVA1 have not yet been linked to cutaneous carcinogenesis, but will need careful follow-up in larger studies. Phototherapy remains a safe treatment modality, provided that the indication is well-founded, previous exposure and co-carcinogens are considered, and short and dose-intensive treatment protocols are favored, PUVA is chosen as second-line treatment that should not be used for more than a lifetime total of 250-300 phototherapy sessions.

Long-term (6 and 12 months) follow-up of two prospective, randomized, controlled phase III trials of photodynamic therapy with BF-200 ALA and methyl aminolaevulinate for the treatment of actinic keratosis

Background

Two phase III trials of photodynamic therapy (PDT) with BF-200 ALA, a recently approved nanoemulsion formulation of 5-aminolaevulinic acid (ALA) demonstrated high clearance rates in mild-to-moderate actinic keratosis (AK). The comparison to a registered methyl aminolaevulinate (MAL) cream demonstrated significantly superior total patient clearance rates.

Objectives

To evaluate long-term efficacy and safety of PDT for AK 6 and 12 months after the last PDT with BF-200 ALA, MAL or placebo.

Methods

The follow-up phase (FUP) was performed with patients of two phase III studies. Both studies compared BF-200 ALA with placebo, one of the studies additionally with MAL. Overall recurrence rates and various subgroups (light source, lesion severity, lesion location, complete responders after first PDT) were assessed 6 and 12 months after the last PDT.

Results

Recurrence rates were similar for BF-200 ALA and MAL, with a tendency to lower recurrence rates for BF-200 ALA. The proportion of patients who were fully cleared during PDT and remained completely clear for at least 12 months after PDT were 47% for BF-200 ALA (both studies) and 36% for MAL treatment. The subgroup that was illuminated with narrow wavelength LED lamps reached 69% and 53% for BF-200 ALA (both studies, respectively) and 41% for MAL. No safety concerns were reported.

Conclusions

The FUP data confirmed the high efficacy and safety of PDT with BF-200 ALA. The slightly lower recurrence rates after BF-200 ALA treatment compared with MAL treatment enhanced the better treatment outcome due to the significantly superior efficacy.

Photodynamic therapy with BF-200 ALA for the treatment of actinic keratosis: results of a multicentre, randomized, observer-blind phase III study in comparison with a registered methyl-5-aminolaevulinate cream and placebo

BACKGROUND

Photodynamic therapy (PDT) with 5-aminolaevulinic acid (ALA) or its methylester [methyl-5-aminolaevulinate (MAL) or 5-amino-4-oxopentanoate] was recently ranked as first-line therapy for the treatment of actinic keratosis (AK) and is an accepted therapeutic option for the treatment of neoplastic skin diseases. BF-200 ALA (Biofrontera Bioscience GmbH, Leverkusen, Germany) is a gel formulation of ALA with nanoemulsion for the treatment of AK which overcomes previous problems of ALA instability and improves skin penetration.

OBJECTIVES

To evaluate the efficacy and safety of PDT of AKs with BF-200 ALA in comparison with a registered MAL cream and with placebo.

METHODS

The study was performed as a randomized, multicentre, observer-blind, placebo-controlled, interindividual trial with BF-200 ALA, a registered MAL cream and placebo in a ratio of 3:3:1. Six hundred patients, each with four to eight mild to moderate AK lesions on the face and/or the bald scalp, were enrolled in 26 study centres in Germany, Austria and Switzerland. Patients received one PDT. If residual lesions remained at 3months after treatment, PDT was repeated.

RESULTS

PDT with BF-200 ALA was superior to placebo PDT with respect to patient complete clearance rate (78·2% vs. 17·1%; P<0·0001) and lesion complete clearance rate (90·4% vs. 37·1%) at 3months after the last PDT. Moreover, superiority was demonstrated over the MAL cream regarding the primary endpoint patient complete clearance (78·2% vs. 64·2%; P<0·05). Significant differences in the patient and lesion complete clearance rates and severity of treatment-related adverse events were observed for the narrow- and broad-spectrum light sources.

CONCLUSIONS

BF-200 ALA is a very effective, well-tolerated new formulation for AK treatment with PDT and is superior to a registered MAL medication. Efficacies and adverse events vary greatly with the different light sources used.

The Pictorial Representation of Illness and Self Measure (PRISM) instrument reveals a high burden of suffering in patients with chronic urticaria

BACKGROUND

Chronic urticaria severely affects quality of life. To date, no gold standard has been established to measure the burden of suffering, which often correlates poorly with the skin symptoms observed in patients with chronic urticaria.

OBJECTIVE

To investigate the effect of psychological factors on the course of urticaria.

METHODS

Health-related quality of life was assessed in 95 patients with chronic urticaria using the following instruments: Pictorial Representation of Illness and Self Measure (PRISM), Dermatology Life Quality Index (DLQI), and Skindex-29. Correlations were calculated. Cognitive flexibility and its correlation with the course of urticaria were assessed. Two case reports are presented to further elucidate features of PRISM.

RESULTS

PRISM revealed a high burden of suffering that was consistent with considerably impaired quality of life as measured by DLQI and Skindex-29 in the same patients. However, no significant correlation was observed between PRISM and the 2 quality of life questionnaires. From the baseline visit to the follow-up visit, quality of life scores improved significantly (DLQI, P = .001; Skindex-29, P = .001), whereas the PRISM score remained unchanged (P = .085). Disease course was favorable more often in cognitively flexible patients (n=54) (91%) than cognitively inflexible patients (P = .007).

CONCLUSIONS

PRISM revealed a high burden of suffering in chronic urticaria and provided helpful additional information for the management of these patients. In our cohort, cognitive flexibility was a positive predictive marker for the course of chronic urticaria.

[Immunosuppressive therapy after transplantation. Dermatologic relevance and pathomechanisms]

Immunosuppressive therapy keeps rejection in check following solid organ transplantation. Drug reactions, inflammatory and infectious skin conditions frequently follow. Specific side effects can be avoided by switching individual agents. In addition to UV light, immunosuppressants are the most important driver for squamous cell carcinoma of the skin (SCC). Beyond immunosuppression, cyclosporine A promotes carcinogenesis by TGF beta and VEGF, while mTOR inhibitors are antiproliferative. Azathioprine photosensitizes to UVA and enables UVA to damage DNA directly. To fight skin cancer, global reduction of immunosuppression is the most effective measure. Switching calcineurin inhibitors to mTOR inhibitors is probably to be recommended, while omitting azathioprine may potentially be advisable in recurrent SCC.

[Swiss clinical practice guidelines for skin cancer in organ transplant recipients]

Swiss clinical practice guidelines for skin cancer in organ transplant recipients Transplant patients have increased over the last decades. As a consequence of long-term immunosuppression, skin cancer, in particular squamous cell carcinoma (SCC), has become an important problem. Screening and education of potential organ transplant recipients (OTRs) regarding prevention of sun damage and early recognition of skin cancer are important before transplantation. Once transplanted, OTRs should be seen yearly by a dermatologist to ensure compliance with sun avoidance as well as for treatment of precancerosis and SCC. Early removal is the best treatment for SCC. Reduction of immunosuppression, switch to mTOR inhibitors and chemoprevention with acitretin may reduce the incidence of SCC. The dermatological follow-up of OTRs should be integrated into a comprehensive post-transplant management strategy.

[Vitamin D, ultraviolet rays and skin cancer]

Vitamin D, ultraviolets and skin cancer The vitamin D supply is fundamental for the prevention of falls and fractures in aged people, among other effects. UVB triggers vitamin D synthesis in the skin. This relationship has recently gained attention both with the general public and with health care professionals. Some authors suggest a relaxation of UV protection measures, while others even advocate regular sunlight exposure in order to increase cutaneous vitamin D synthesis. However, the UV irradiation responsible for vitamin D synthesis also is a known carcinogen. UV exposure is an insufficient and harmful method to increase vitamin D synthesis. Oral supplementation is the recommended way to prevent and cure vitamin D deficiency.

Safety of specific immunotherapy using a four-hour ultra-rush induction scheme in bee and wasp allergy

BACKGROUND

Ultra-rush induction of immunotherapy with Hymenoptera venom is a reliable and efficacious alternative to the rush induction protocol, though not widely used in European countries yet. Its safety, however, has been intensively discussed over the last few years. The aim of this retrospective case study was to examine the rate of allergic side-effects during our four-hour ultra-rush hymenoptera venom induction regimen. We evaluated risk factors for observed side-effects such as age, gender, severity of previous insect sting reactions according to the H.L. Mueller classification, concentration of venom inducing positive skin tests, level of specific IgE, serum tryptase concentration, and hymenoptera venom used for treatment.

METHODS

67 outpatients with Hymenoptera venom allergy received 80 courses of ultra-rush immunotherapy. Diagnosis and selection of patients for venom immunotherapy were carried out according to the European Academy of Allergology and Clinical Immunology. We applied a four-hour regimen, and local or systemic reactions were documented.

RESULTS

In 78 courses (97.5%) the maintenance dose of 111.1 microg was reached within 4 hours and it was tolerated in 82.5% without any hypersensitivity reaction. Allergic side-effects were observed in only 17.5% (n=14): four severe local reactions (5%), eight grade I (10%) and two grade II (2.5%) systemic reactions. There was no significant difference in the number of systemic reactions comparing patients receiving wasp or honeybee venom extract. The number of systemic reactions was neither higher in patients with a severe prior insect sting reaction (grade III or IV) nor dependent on age, gender, skin test reaction, level of specific IgE or tryptase. Epinephrine as rescue medication was never needed. Interestingly, patients with a severe prior wasp sting reaction showed a significantly lower incidence of allergic side-effects during ultra-rush immunotheraphy with wasp venom extract as compared to grade III or IV honeybee venom allergic patients.

CONCLUSION

Our ultra-rush immunotherapy induction regimen shows a low incidence of systemic reactions. It proved to be safe and convenient for the patient, as it could be applied in a four-hour outpatient regimen.

Characterization of the Cytokine Pattern of Porcine Bone Marrow-Derived Cells Treated with 1alpha,25(OH)2D3

The biologically active form of vitamine D(3) [1alpha,25(OH)(2)D(3)] has recently been described not only to influence bone metabolism but also to exert immunomodulating activities, which may have an impact on bone formation/resorption as well. In this study, we analysed the effects of 1alpha,25(OH)(2)D(3) on the cytokine pattern of porcine bone marrow-derived cells from piglets aged 1-3 weeks. After culture for 1 week, the number of osteoclasts was determined, with tartrate-resistant acid phosphatase (TRAP)-positive, multinucleated cells being considered osteoclasts. Cultured bone marrow cell-derived mRNA was subjected to semiquantitative RT-PCR specific for a panel of porcine cytokines (IL-1alpha, IL-6, IL-8, IL-10, and TNF-alpha). In addition, an immunofluorescence analysis using anti-porcine mAbs specific for IL-1beta, IL-2, IL-4, IL-6, IL-12, TNF-alpha, and IFN-gamma was performed. In order to prove the existence of a porcine homologue of the receptor activator of NF-kappaB ligand (RANKL) bone marrow cell- as well as porcine white blood cell-derived mRNA was investigated by RT-PCR using primer pairs specific for murine RANKL. Cell culture supernatant was analysed for soluble RANKL by means of an ELISA designed for quantification of human RANKL. By means of RT-PCR, expression of IL-1alpha, IL-6, IL-8, IL-10 and TNF-alpha mRNA could be found in cells cultured with and without 1alpha,25(OH)(2)D(3). Immunofluorescence analysis revealed that IL-1, IL-6, and TNF-alpha were produced by both stromal cells and osteoclasts. Besides its known osteoclastogenic effects, 1alpha,25(OH)(2)D(3) tended to downregulate the respective cytokines, but significantly upregulated RANKL expression. The homology between the porcine RANKL-specific sequence and the corresponding human RANKL sequence was 79%. The data found support the idea that porcine bone marrow cell cultures may provide a suitable alternative to murine systems in human osteological research.

Porcine dermatitis and nephropathy syndrome (PDNS) is associated with a systemic cytokine expression profile indicative of proinflammation and a Th1 bias

Porcine dermatitis and nephropathy syndrome (PDNS) is broadly discussed as a porcine circovirus type 2 (PCV2)-associated disease, although PCV2, in contrast to postweaning multisystemic wasting syndrome (PMWS), has to date not been proven to be the aetiologic agent. In order to better understand the complex immunopathology of PDNS, the systemic cytokine expression profiles of (i) five pigs suffering from PDNS, (ii) five animals suffering from naturally acquired PMWS and (iii) five controls were investigated at mRNA and protein levels by means of multiplex real-time RT-PCR and flow cytometric intracellular cytokine detection, respectively. IL-1alpha, IL-6 and IFN-gamma mRNA expressions were found to be elevated in PDNS pigs. At the protein level, an increased capacity of peripheral blood mononuclear cells to produce IL-2, IL-4, IL-6, IL-12, TNF-alpha and IFN-gamma was evident. Hematological investigations revealed a hypochromic anemia while basophils and monocytes were relatively and neutrophils absolutely increased in PDNS pigs. PCV2 antibody levels did not differ significantly between PDNS and PMWS affected animals. Taken results together, the cytokine profile of the PDNS affected animals together with hematological data pointed towards a proinflammatory condition supporting a Th1 bias. Cytokine data of PMWS affected animals exhibited only minor non-significant differences when compared to controls, only IL-10 was significantly decreased at the mRNA level.

Atypical Poorly Differentiated Cutaneous T-Cell Lymphoma with an Angiocentric Growth Pattern Presenting Histologically as Vasculitis

We report the case of a 41-year-old patient with an aggressive cutaneous T-cell lymphoma (CTCL) initially presenting on histology as lymphocytic vasculitis. On repeated histological examination and by molecular biology work-up, the diagnosis of an unclassifiable CTCL could eventually be established. This atypical poorly differentiated lymphoma was of a CD4+ CD8- CD56- phenotype and followed an unfavourable course. The patient died despite chemo- and immunotherapy 7 months after the first consideration of lymphoma as diagnosis.

Evaluation of the Suitability of Monoclonal Antibodies for Flow Cytometric Intracellular Cytokine Detection in Porcine Peripheral Blood Lymphocytes

Panels of monoclonal antibodies (mAbs) specific for porcine interleukin (IL)-2, IL-4, IL-6, IL-12, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha were evaluated for their applicability in flow cytometric intracellular cytokine detection. Peripheral blood mononuclear cells were short-time stimulated in the presence of brefeldin-A, ionomycin and phorbol-12-myristate-13-acetate, fixed and incubated with the respective mAbs as well as phycoerythrin-conjugated second-step antibodies. Suitability of mAbs was judged by use of statistical data and by visual control of scattergrams, considering the capability of mAbs to discriminate between cytokine-positive and cytokine-negative cell populations. The number of suitable clones differed to a high degree between the investigated cytokines, but at least one mAb fitting for flow cytometric intracellular cytokine detection could be identified within each panel. Monoclonal Abs producing scattergrams with a clear demarcation between positive and negative cell populations were found within the anti-IL-2, IL-6 and IFN-gamma panels, whereas less well defined positive and negative cell populations could be generated by use of mAbs within the anti-IL-4 and TNF-alpha panels. Only one moderately fitting mAb was identified within the anti-IL-12 panel. After having evaluated the best fitting mAbs, these were used to obtain reference levels for the physiological range of porcine lymphocytic cytokine production in a second set of experiments. For that reason, 13 clinically healthy pigs aged between 6 weeks and 6 months were investigated. Data presented are given as mean +/- SD of the percentage of positive-staining lymphocytes: IL-2, 45.5 +/- 27.6; IL-4, 34.1 +/- 21.3; IL-6, 45.4 +/- 23.8; IL-12, 13.9 +/- 8.6; TNF-alpha, 43.4 +/- 11.3; IFN-gamma, 65.5 +/- 14.8.

Systemic cytokine profile in feeder pigs suffering from natural postweaning multisystemic wasting syndrome (PMWS) as determined by semiquantitative RT–PCR and flow cytometric intracellular cytokine detection

Postweaning multisystemic wasting syndrome (PMWS) is an economically important disease in pigs caused by porcine circovirus type 2 (PCV2). Development of this disease is presumably associated with an impairment of the immune system. We, therefore, investigated the systemic expression of relevant cytokines (IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p40, TNF-alpha, IFN-gamma) and IL-2Ralpha at mRNA (semiquantitative RT-PCR) and at protein level (flow cytometric intracellular cytokine detection after short-time stimulation of peripheral blood mononuclear cells) in 10 feeder pigs aged 14 weeks suffering from natural PMWS and in 10 clinically healthy pen-mates. Hematological examination revealed a significant (p < 0.001) relative lymphopenia in the diseased animals when compared to reference pigs. IL-1alpha and IL-10 mRNA levels were notably increased in the affected pigs, whereas IL-2 and IL-2Ralpha (CD25) mRNA levels tended to be down-regulated. IL-8, TNF-alpha and IFN-gamma mRNA expressions appeared to be slightly increased. Intracellular cytokine levels as measured by flow cytometry revealed an increase of IL-1beta, IL-2, and IL-6, whereas IL-12 and TNF-alpha expressions were not affected. IFN-gamma was slightly decreased in the diseased animals. In conclusion, despite the assumption, that the cellular immune response to PMWS as a virus-induced disease should be characterized by either a Th1 driven cytokine profile or a cytokine profile indicative of T cell immunosuppression, our results did not support that hypothesis. Nevertheless, data from intracellular cytokine detection suggest an even increased percentage of the remaining lymphocytes capable to produce IL-2 upon in vitro stimulation, which is in contrast to the slightly diminished IL-2 mRNA levels reflecting the in vivo situation at least at the mRNA level.

[Granulomatous slack skin: partial remission following intralesional administration of interferon-alpha and PUVA]

Granulomatous slack skin (GSS) is a rare cutaneous T-cell lymphoma which typically runs a protracted and indolent course. On histopathological assessment lymphoid infiltrates with multinucleated giant cells in the dermis and subcutis with elastophagocytosis can be observed. Skin lesions are characterized by pendulous folds. We report on the successful response of the lesions to intralesional interferon alpha combined with PUVA.

Differential expression of cytotoxic molecules and killer cell inhibitory receptors in CD8+ and CD56+ cutaneous lymphomas

Cutaneous lymphomas of the cytotoxic phenotype, including CD8+ and CD56+ lymphomas, have only recently been recognized. To characterize the phenotypic profile of these lymphomas, we investigated the expression of both cytotoxic molecules and killer cell inhibitory receptors by immunohistochemistry techniques. Frozen sections from four CD8+ and from three CD56+ cutaneous lymphomas were stained for the cytotoxicity markers including T-cell restricted intracellular antigen-1, perforin, granzyme B, and for expression of the inhibitory receptors including p58.1, p58.2, p70, p140, CD94, NKG2, and leukocyte immunoglobulin-like receptor (LIR-1). Apart from LIR-1, the CD8+ lymphomas in our series express p70 and p140 from the inhibitory receptors and only one or two of the cytotoxic proteins. The CD56+ lymphomas, on the other hand, express only LIR-1 of the set of inhibitory receptors and the whole panel of cytotoxic antigens. Various subtypes of cytotoxic cutaneous lymphomas (CD8+ and CD56+) differ in regard to their phenotypic and functional profile, which may explain differences in their biological behavior.

Biological activity and safety of adenoviral vector-expressed wild-type p53 after intratumoral injection in melanoma and breast cancer patients with p53-overexpressing tumors

p53 mutations are common genetic alterations in human cancer. Gene transfer of a wild-type (wt) p53 gene reverses the loss of normal p53 function in vitro and in vivo. A phase I dose escalation study of single intratumoral (i.t.) injection of a replication-defective adenoviral expression vector containing wt p53 was carried out in patients with metastatic melanoma or breast cancer with increased p53 protein immunoreactivity in pretreatment tumor biopsies. The biological activity of the injected wt p53 was assayed by reverse transcriptase-polymerase chain reaction in tumor tissue. A total of six (five melanoma and one breast adenocarcinoma) patients were treated at dose levels dependent upon tumor size/dose escalation sequence. Five of six patients became positive for the transfer of wt p53 into tumor tissue 2 days after injection of the vector. Of the four patients assayed, all developed anti-adenoviral antibodies. Adverse reactions associated with i.t. injection were mild, with no obvious correlation between the incidence, severity, or relationship of the events and drug dose. p53 gene therapy by i.t. injection of a replication-defective adenoviral expression vector is safe, feasible, and biologically effective (with respect to transduction frequency) in patients with either metastatic melanoma or breast cancer.

Mutation analysis of the MEN1 tumour suppressor gene in malignant melanoma

During the initiation and progression of malignant melanoma a series of genetic events accumulate, including alterations of chromosome 11q. Recently, an important tumour suppressor gene, the multiple endocrine neoplasia type 1 (MEN1) gene, has been mapped on 11q13 and has been cloned. To assess whether the MEN1 region is involved in tumour initiation and progression, we analysed 23 primary cutaneous melanomas and 17 metastases for loss of heterozygosity (LOH) using two informative polymorphic markers closely linked to the MEN1 gene (PYGM and D11S449). To search for mutations within the gene, single-strand conformation polymorphism (SSCP) analysis was performed using 13 primer sets with designed intronic sequences to amplify the MEN1 coding sequence exons 2 to 10. None of the cases showed LOH at the MEN1 gene locus. By SSCP analysis, no aberrant bands were identified on exons 3 to 10. Analysis of exon 2 revealed the presence of aberrant bands in two of the analysed melanomas. Sequencing analysis revealed a genetic polymorphism at S145S (AGC-->ACT) in both sections. None of the cases analysed showed MEN1 gene mutations. This study represents the first genetic analysis of the MEN1 gene in sporadic melanomas. Our data demonstrate no evidence of deletion or mutation of the MEN1 gene in primary or metastatic melanoma. Therefore, MEN1 gene alterations appear not to be associated with tumorigenesis of malignant melanoma. The MEN1 gene appears to be a highly specific tumour suppressor gene only involving tumours within the spectrum of MEN1 disease.

[Systemic therapy of metastatic melanoma]

Therapy of metastatic melanoma still remains difficult. All therapeutic strategies have to consider the individual patient's condition and number and localisation of the metastases. Solitary metastases in lung, CNS, soft tissues and lymph nodes have to be removed by surgery. Multiple metastases are treated with a systemic chemoimmunotherpy. Promising approaches use interleukin-2, interferons, DTIC, temozolamide, vindesine and cisplatin. Radiotherapy is the treatment of first choice for bone and CNS metastases. These therapeutic strategies have improved the prognosis of metastatic melanoma. Additional multi-center trials and experimental approaches will help to reach the goal of a curative systemic therapy for metastatic melanoma.

Expression of the proliferation and apoptosis-associated CAS protein in benign and malignant cutaneous melanocytic lesions

We have examined the expression of the cellular apoptosis susceptibility protein, a nuclear transport factor that plays a role in apoptosis and cell proliferation, in benign and malignant melanocytic lesions. Tissue samples of 55 formalin-fixed, paraffin-embedded melanoma (primary n=32, metastatic n=23) and of 27 control cases (junctional dermal, compound, Spitz, Reed, blue nevi, balloon-cell nevus, lentigo maligna) were analyzed by immunohistochemistry with anti-cellular apoptosis susceptibility antibodies. The percentage of cellular apoptosis susceptibility-positive cells as well as the intensity on a four-point scale was evaluated. In normal skin, expression of cellular apoptosis susceptibility was primarily found in the basal cell layer of the epidermis. Benign melanocytic lesions that stained positive for cellular apoptosis susceptibility (13 of 27) showed a homogeneously distributed staining pattern with a mean of 5+/-12% cellular apoptosis susceptibility positive cells. Five out of 7 lentigo maligna melanoma, 11 out of 12 superficial spreading melanoma and all acrolentiginous (n=7) and nodular (n=6) melanoma showed immunoreactivity of medium (++) to high ( ) intensity. Vertical growth phases of primary cutaneous melanoma stained stronger than horizontally growing cell clusters. All metastases (n= 23) stained strongly positive, the staining pattern being inhomogeneous. Cellular apoptosis susceptibility detection in clinical stages according to UICC showed an increase from 43+/-34% cellular apoptosis susceptibility positive cells in stage I, to 53+/-26% in stage II, 68+/-24% in stage III and 72+/-24% in stage IV, respectively. Because the expression of cellular apoptosis susceptibility correlates predominantly with advanced stages of melanoma, staining with anti-cellular apoptosis susceptibility antibodies may be useful for diagnosis of melanoma and possibly as an immunohistochemical prognostic factor in cutaneous melanocytic lesions.

Immune escape mechanisms in malignant melanoma

Malignant melanoma is an antigenic tumor recognized by specific lymphocytes. Several melanoma-associated antigens have been shown to cause tumor rejection in vitro. Escape from immunosurveillance by melanoma cells is the result of several mechanisms such as total loss or decreased expression of HLA antigens, alterations in the expression of tumor-associated antigens or deficiencies in the antigen-processing machinery. Additional important features include the influence of endogenous and exogenous cytokines such as interferons or interleukins and expression of adhesion molecules or co-stimulatory molecules. All these factor have to be considered for the development of new immunoregulatory treatment modalities against advanced melanoma.

[Therapy of cutaneous melanoma]

Therapy of melanoma considers the individual prognosis. Primary low-risk melanomas with tumor-thickness below 1 mm can be treated by surgery with a safety margin of 1 cm. If the tumor-thickness is more than 2 mm the safety margin should be 3 cm. Elective lymph node dissection for melanomas at the extremities is widely substituted by the sentinel lymph node procedure. This new technique shall be applied only in specialised centers in the context of clinical trials. After the resection of lymph node metastases adjuvant treatment using Interferon-alpha should be considered. Palliative therapy of metastases includes surgery, radiotherapy and chemo-immunotherapy depending on the number and location of the metastases. Recent progress in understanding the immunobiology of melanoma and the development of gene therapy has offered new perspectives for future therapeutical intervention including peptide vaccination alone or loaded on dendritic cells and gene therapy.

The PTEN tumour suppressor gene and malignant melanoma

A candidate tumour suppressor gene, PTEN, has recently been identified within chromosome 10q23, the locus of the Cowden syndrome/Lhermitte Duclos disease susceptibility gene. Cowden disease is an autosomal dominant cancer predisposition syndrome associated with tumours of the breast, thyroid and, less frequently, malignant melanoma. Based on the identification of mutations in sporadic breast, brain and prostate tumours, we decided to examine the potential role of PTEN in sporadic malignant melanoma. Frozen tissue from primary cutaneous melanomas (n = 23) and metastases (n = 17) were microdissected, and microsatellite markers D10S541 and D10S547, flanking the gene on both sides, were used to search for loss of heterozygosity (LOH) in the PTEN gene locus. To identify mutations within the putative tumour suppressor gene, we performed single strand conformation polymorphism (SSCP) analysis using intronic primers to amplify exons 5, 6, 7 and 8 of the PTEN gene. No LOH was detected using the polymorphic markers D10S541 and D10S547. SSCP analysis revealed no aberrant bands in the tumour specimen. Our results suggest that the PTEN gene does not play a major role in the initiation and progression of melanoma.

Interleukin-10 is a growth factor for human melanoma cells and down-regulates HLA class-I, HLA class-II and ICAM-1 molecules

IL-10 is a cytokine which shows various effects including inhibition of T-cell proliferation or HLA-dependent antigen presentation. In this study, we analysed the effects of exogenous or autocrine IL-10 on proliferation and expression of immunocritical surface molecules. Fourteen cultures of human melanoma cells were established from primary melanomas, locoregional lymph-node or distant metastases. In 5 melanoma cell cultures, proliferation in the presence of IL-10, anti-IL-10 antibodies (Ab) or control Ab was assessed with colorimetric and [3H]thymidine uptake assays. Flow cytometric analysis was used to quantify the expression of human leukocyte antigen (HLA) class-I, HLA class-II and intercellular adhesion molecule (ICAM)-1 and the IL-10 receptor (IL-10R). IL-10 production of melanoma cells was documented by RT-PCR and IL-10 protein was detected in the supernatants by means of ELISA. IL-10 enhanced proliferation and prolonged survival of melanoma cells in 5 out of 5 cultures. Anti-IL-10 Ab decreased proliferation. IL-10R expression was found in 12 out of 14 (86%) melanoma cell cultures. The expression of HLA-I, HLA-II and ICAM-1 on all melanoma cells that were positive for IL-10R showed a reduction of 10-60% by IL-10, whereas the surface levels of HLA-I, HLA-II and ICAM-1 in 5 out of 5 cell cultures revealed an increase of 10-170% by anti-IL-10 Ab. These findings suggest that IL-10 is an autocrine growth factor with significant impact on immunocritical molecules in melanoma. IL-10 effects have to be considered when planning therapeutic immunointerventions in melanoma patients.

Interleukin-10 is a growth factor for human melanoma cells and down-regulates HLA class-I, HLA class-II and ICAM-1 molecules

IL-10 is a cytokine which shows various effects including inhibition of T-cell proliferation or HLA-dependent antigen presentation. In this study, we analysed the effects of exogenous or autocrine IL-10 on proliferation and expression of immunocritical surface molecules. Fourteen cultures of human melanoma cells were established from primary melanomas, locoregional lymph-node or distant metastases. In 5 melanoma cell cultures, proliferation in the presence of IL-10, anti-IL-10 antibodies (Ab) or control Ab was assessed with colorimetric and [3H]thymidine uptake assays. Flow cytometric analysis was used to quantify the expression of human leukocyte antigen (HLA) class-I, HLA class-II and intercellular adhesion molecule (ICAM)-1 and the IL-10 receptor (IL-10R). IL-10 production of melanoma cells was documented by RT-PCR and IL-10 protein was detected in the supernatants by means of ELISA. IL-10 enhanced proliferation and prolonged survival of melanoma cells in 5 out of 5 cultures. Anti-IL-10 Ab decreased proliferation. IL-10R expression was found in 12 out of 14 (86%) melanoma cell cultures. The expression of HLA-I, HLA-II and ICAM-1 on all melanoma cells that were positive for IL-10R showed a reduction of 10-60% by IL-10, whereas the surface levels of HLA-I, HLA-II and ICAM-1 in 5 out of 5 cell cultures revealed an increase of 10-170% by anti-IL-10 Ab. These findings suggest that IL-10 is an autocrine growth factor with significant impact on immunocritical molecules in melanoma. IL-10 effects have to be considered when planning therapeutic immunointerventions in melanoma patients.