Barbara Pigozzi

Detection of autoantibodies against recombinant desmoglein 1 and 3 molecules in patients with pemphigus vulgaris: correlation with disease extent at the time of diagnosis and during follow-up.

The recent availability of cDNA clones for pemphigus antigens has allowed the production of recombinant desmoglein 1 and desmoglein 3 molecules and the development of an ELISA approach in order to determine levels of antibodies to them. The aim of the study was to determine the relationship between autoantibodies levels and the extent of both mucosal and skin lesions in 20 patients with pemphigus vulgaris at the time of diagnosis and during follow-up. For the detection of autoantibodies by ELISA we used the recombinant proteins expressing overlapping sequences with the entire extracellular desmoglein 1 and desmoglein 3 domains. We showed that in presence of mucosal lesions there was a correlation between extension of mucosal involvement and autoantiboidies titres against both desmoglein 1 and desmoglein 3, whereas in presence of skin lesions there was a statistically significant correlation between extension of skin lesions and autoantibodies titres against desmoglein 3, but not against desmoglein 1. A not negligible number of patients showed variations of the desmoglein 3 autoantibodies titre which did not correlate with the severity of both cutaneous and mucosal involvement. Similar results were obtained analyzing autoantibodies titres against desmoglein 1. In conclusion, we believe that the utilization of recombinant desmoglein 1 and desmoglein 3 proteins by ELISA should be used with caution to monitor disease severity and response to therapy, although it remains a high specific test for the initial diagnosis of pemphigus and the identification of a change in the clinical phenotype of this condition.

Pemphigus foliaceus evolving into pemphigus vulgaris: a probable example of ‘intermolecular epitope spreading’ confirmed by enzyme-linked immunosorbent assay study

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The role of immunohistochemical analysis in the diagnosis of parapsoriasis.

Parapsoriasis is a chronic dermatosis whose biological distinction from early mycosis fungoides, the most frequent form of cutaneous T-cell lymphoma, is still not clearly defined. Two types of parapsoriasis have been delineated: large-plaque parapsoriasis and small-plaque parapsoriasis. The lack of clinical and histological features, which may allow distinguishing parapsoriasis from early mycosis fungoides has prompted several investigations to assess the role of immunohistochemistry in establishing a conclusive diagnosis of these conditions. However, the additional data obtained by immunohistochemical analysis concerning the CD4/CD8 ratio, the aberrant expression of T-cell antigens and the expression of proliferation markers has not generally helped establish a more definitive diagnosis. This review critically discusses these immunohistochemical markers and their use in diagnosis of parapsoriasis.

Is Sézary syndrome a true primary cutaneous lymphoma

The classification of cutaneous lymphomas has been recently reviewed by the World Health Organization and the European Organization for Research and Treatment of Cancer (EORTC). 1 According to this classification, Sézary syndrome is considered to be an erythrodermic expression of cutaneous T-cell lymphoma (CTCL) in whom hematological involvement is, by definition, present at diagnosis. Clinically, Sézary syndrome is characterized by generalized exfoliative erythroderma, intense pruritus, peripheral lymphadenopathy, and atypical lymphocytes with highly convoluted or cerebriform nuclei (Sézary cells) in the skin, lymph nodes, and peripheral blood. Several hematologic criteria have been proposed for the definition of Sézary syndrome. The “EORTC cutaneous lymphoma group” suggested that a peripheral blood T-cell clone plus a CD4 : CD8 ratio of 10 or higher were useful criteria in diagnosing Sézary syndrome. 1 The International Society for Cutaneous Lymphoma defined Sézary syndrome by the presence of one or more of the following: (i) an absolute Sézary cell count of at least 1000 cells/mm 3 or more; (ii) a CD4 : CD8 ratio of 10 or higher caused by an increase in circulating T-cells and/or an aberrant loss or expression of panT cell markers by flow cytometry; (iii) increased lymphocyte counts with evidence of a T-cell clone in the blood by the Southern blot or polymerase chain reaction technique; or (iv) a chromosomally abnormal T-cell clone. 2

Clinical tip: use of a manual dermatoscope with a compact digital camera in a pigmented lesion clinic.

DERMATOSCOPY IS a non-invasive diagnostic technique that allows the in vivo visualization of morphological structures that are not evident with a simple clinical examination. The origin of dermatoscopy goes back as far as the 17th century, with the examination of the ungual matrix vessels under the microscope by Kohlhaus (1). Diascopy was then introduced by Unna in the 19th century (2). Saphier introduced the term ‘dermoscopy’ in the mid-20th century, but in that period, the technique needed large and expensive machines. A couple of years later, Mackie (3) demonstrated the usefulness of dermatoscopy in the preoperative assessment of pigmented lesions of the skin. Modern dermatoscopy began when it was defined as the pattern analysis and the correlation between dermatoscopic patterns and histological structures (4, 5). Since then, dermatoscopy became a widely discussed topic in the literature. In a consensus meeting via the Internet (6), the basic criteria for dermatoscopy were established. A series of pattern analysis algorithms have been proposed (7, 8) thus trying to standardize a pattern analysis protocol. The commercially available instruments commonly used to performing dermatoscopy are a dermatoscope, a dermaphot, a stereomicroscope and a videodermatoscope. Dermatoscope (e.g. Heine Delta 20, Heine Optotechnik, Herrsching, Germany) is a hand-held device similar to an otoscope with a spherical lens and a halogen or an LED light source giving a bright light beam and a 10-fold magnification. Non-polarized dermatoscopes are commonly used with a liquid interface that reduces the reflection of the light by the stratum corneum optically matching the refractive index of the glass plate of the dermoscope with the stratum corneum (9). A manual dermatoscope is economic, ergonomic and easy to use but it lacks the possibility of image storage and retrospective analysis. Dermaphot (Heine Optotechnik) is a device designed to be connected on a photocamera to acquire clinical macrophotographs as well as dermoscopic pictures at 10-fold magnification. This device gives a good image quality and allows picture storage but it lacks the possibility of direct dermatoscopic examination of the lesion through the optics. A stereomicroscope is a binocular optical instrument providing high-quality visualization of dermatoscopic epidermal and sub-epidermal structures with different magnifications ranging from 6 to 60. This device can be connected to a photo or a video camera and to a personal computer, thus enabling the operator to store images. A portable version of this device, easier to use and less expensive, is commercially available. This instrument gives an excellent image quality at different magnifications but is very expensive. Image acquisition and the storage process is time consuming and requires training. Moreover, the whole machinery is usually cumbersome and difficult to shift. Videodermato-

The role of γδ T cells in human cutaneous oncology

The T-cell receptor is a heterodimeric compound made either of α and β chains or γ and δ chains, which are covalently associated with the CD3 molecule. Whereas αβ T-cell receptors recognize peptide antigens bound to major histocompatibility complex molecules, γδ cells seem to recognize and respond to antigens directly, without processing peptides. γδ T cells seem to play a role in immunological surveillance of epithelia against cancer. However, it has been demonstrated that in normal human skin, γδ T-cells are infrequently seen in either the epidermal or dermal compartments. In contrast to normal human skin, it has been demonstrated that γδ T cells may costitute from 15 to 25% of lymphocyte infiltrate in cutaneous primary melanoma. In malignant melanoma, the percentage and the absolute number of circulating γδ T cells were significantly reduced. It is possible that γδ T cells play a role in antitumor surveillance in malignant melanoma and that their numerical and functional impairment could create difficu...

In situ expression of LAT (linker for activation of T cells) in pathological human skin with T-lymphoid infiltrate

LAT is a 36-kDa transmembrane protein that plays an important role in linking engagement of the T-cell antigen receptor (TCR) to the biochemical events of T-cell activation. It has been shown that LAT reacts with human T cells in normal and neoplastic lymphoid tissues, without restriction to any T cell subpopulation. This suggests that the expression of LAT in vivo may be a valuable addition to the panel of immunohistochemical markers used for immunostaining T cells. The expression of LAT has not yet been studied in human pathological skin conditions. We present our experience concerning LAT expression in both neoplastic and inflammatory dermatoses using an immunohistochemical approach on frozen sections from 42 patients. A variable reduction in LAT expression was observed in almost all the inflammatory and neoplastic skin conditions investigated, irrespective of the particular disease. Our study indicates that LAT− T cells are more common within the skin T-lymphoid infiltrate than was previously demonstrated in both normal and neoplastic lymphoid tissues. These findings suggest that, using a conventional immunoenzymatic approach on fresh frozen sections, LAT staining is an unreliable marker for the identification of T cells in human pathological skin conditions.

Absent or low expression of T-cell receptor zeta-chain in T-cells infiltrating human pathological skin conditions

Abstract. The T-cell receptor (TCR) ζ-chain is involved in signal transduction necessary for T-cell activation and subsequent proliferation. Expression of the TCR ζ-chain in vivo has been studied by a variety of technical approaches on different cell and tissue specimen. However, the in situ situation concerning the expression of the TCR ζ-chain has not yet been investigated on infiltrating T lymphocytes in neoplastic and inflammatory cutaneous diseases. In this study, we analysed the expression of the TCR ζ-chain in a number of skin tissues affected by established inflammatory and neoplastic conditions. Serial sections of different tissue specimens were stained immunoenzymatically for CD3 and TCR ζ-chain expression. No or at most scarce expression of TCR ζ-chain was detectable in the inflammatory and neoplastic skin conditions investigated as compared to CD3-positive cells. It is possible that this TCR ζ-chain deletion is induced by the skin microenvironment as an effect of local immunoregulatory influences. Alternatively, lymphocytes located in the skin may generally not express this molecule. In our study, tumour-infiltrating T lymphocytes of CTCL were negative for TCR ζ-chain expression. It has been hypothesized that downregulation of the TCR ζ-chain on tumour-infiltrating T lymphocytes is a mechanism by which neoplastic cells escape the cellular immune response. Our findings showing the absence or reduction of TCR ζ-chain expression also in inflammatory skin lymphocytic infiltrates is not consistent with a pivotal role of the TCR ζ-chain in the process of immune escape of tumour cells.