1,997 research outputs found
Pathogenesis of histiocytoses
No full textLangerhans cell histiocytosis (LCH) is a disease of unknown etiology showing clonal proliferation of Langerhans-like cells or their precursors [1, 16]. Pathologic LCH cells appear to be in an immature state of activation and/or differentiation [1]. They accumulate in peripheral tissue and express inflammatory cytokines resulting in their own recruitment and retention [21]. Moreover, activated CD40 ligand expressing T helper cells are found to be the predominant source of cytokines and growth factors in LCH lesions [3]. The “cytokine storm” seems to be further enhanced by the interaction of CD40 expressing LCH cells and CD40 ligand expressing T-cells [3]. High levels of granulocyte-macrophage colony-stimulating factor, tumor-necrosis factor alpha, interleukin-3, and other cytokines are potential chemoattractants for recruiting eosinophils, neutrophils, marcrophages, and CD34+ Langerhans cell precursors into the LCH lesion [3, 7]. These cytokines are known to contribute directly to the development of fibrosis, necrosis, and osteolysis [11]. They are also supposed to play a role in the presence of several other myeloid cell types; the multinucleated giant cell (MGC), amongst others, was found in LCH lesions [8]. MGCs are believed to play a major role in tissue destruction, as they are express osteoclast markers [8]. Remarkably, though various inflammatory cytokines are present in LCH lesions, LCH cells remain immature and do not maturate [3]. Lesional microenvironment seems to play a role in the maintenance of the phenotype of LCH cells [3]
Epidemiology of histocytoses
No full textLangerhans cell histiocytisis (LCH) is the most common of the histiocytic disorders [39]. It represents a spectrum of several clinical entities chracterized by a disorder of antigenpresenting dendritic cells of the immune system. Its epidemiology is poorly understood and based mainly on a few international and regional studies of defined populations [34]. The overall incidence rate varies from 2.6 to 8.9 children per million per year [1, 19, 34, 36]. Children of any age can be affected, however the peak age of presentation, in children, is between the ages of one and three [34]. LCH is also diagnosed in adults [37] but only a few reports are available describing LCH patients with onset during adulthood [3]. Some studies reveal a greater prevalence of LCH among male children [19]. On the other hand, in adults, a preponderance of females is documented with onset as late as the ninth decade of life [26]. Dissemitaned LCH is described to present most frequently in the first year of life [19]. Congenital self-healing LCH is an uncommon form of LCH, which is usually present at birth or in the neonatal period [23]
Dermoscopy
No full textBecause melanoma in advanced stages is still incurable, early detection is indispensable to reduce mortality. With the introduction of dermoscopy into the clinical practice, the diagnostic accuracy of pigmented skin lesions can be improved. Dermoscopy is a noninvasive diagnostic technique for the in vivo observation in dermatology. This technique enables the clinician to visualize pigmented structures of the epidermis, dermo–epidermal junction, and papillary dermis, which are not visible to the naked eye. The structures observed by dermoscopy correlate with histopathological findings. Dermoscopy opens a new dimension in the clinical morphology of pigmented skin lesions but diagnostic accuracy depends significantly on the experience of the examiner
Cutaneous lymphoma
No full textCutaneous lymphomas, like other lymphomas, are systemic diseases by definition. Therefore, surgery has limited indications. However, primary cutaneous B-cell lymphomas (CBCL), such as follicle center lymphomas and large cell primary cutaneous CD30+ T-cell lymphomas, may present as a single nodule in the skin. In these cases, because investigation on tumor material is necessary, an excision biopsy might be a good alternative to an incisional biopsy. In the case of surgical treatment of a nodule in primary cutaneous lymphomas, a safety margin of at least 1 cm should be applied, although there are no supporting clinical trails
Proteomic scan for tyrosinase peptide antigenic pattern in vitiligo and melanoma: role of sequence similarity and HLA-DR1 affinity
No full textImmune responses contribute to the pathogenesis of vitiligo and target melanoma sometimes associated with vitiligo-like depigmentation in some melanoma patients. We analyzed the sera from patients with vitiligo and cutaneous melanoma for reactivity toward tyrosinase peptide sequences 1) endowed with low level of similarity to human proteome, and 2) potentially able to bind HLA-DR1 Ags. We report that the tyrosinase autoantigen was immunorecegnized with the same molecular pattern by sera from vitiligo and melanoma patients. Five autoantigen peptides composed the immunodominant anti-tyrosinase response: aa95-104FMG FNCGNCK; aa175-182 LFVWMHYY; aa 176-190FVWMHYYVSMDALLG; aa222-236IQKLTGDENFTIPYW, and aa233-247 IPYWDWRDAEKCDIC. All of the five antigenic peptides were characterized by being (or containing) a sequence with low similarity level to the self proteome. Sera from healthy subjects were responsive to aa 95-104FMGFNCGNCK, aa222-236IQKLT GDENFTIPYW, and aa 233-247 IPYWDWRDAEKCDIC, but did not react with the aa 175-182LFVWMHYY and aa176-190FVW MHYYVSMDALLG peptide sequences containing the copper-binding His180 and the pculocutaneous albinism I-A variant position F176. Our results indicate a clear-cut link between peptide imnninogenkiiy and low similarity level of the corresponding amino acid sequence, and are an example of a comparative analysis that might allow to comprehensively distinguish the epitopic peptide sequences within a disease from those associated to natural autoantibodies. In particular, these data, for the first time, delineate the linear B epitope pattern on tyrosinase autoantigen and provide definitive evidence of humoral immune responses against tyrosinase. Copyright © 2005 by The American Association of Immunologists, Inc
Proteomic scan for tyrosinase peptide antigenic pattern in vitiligo and melanoma: role of sequence similarity and HLA-DR1 affinity
No full textCutaneous lymphoma, leukemia and related disorders
No full textMycosis fungoides (MF) is a general indolent peripheral T-cell lymphoma initially and preferentially present in the skin and showing distinct clinical, histological (except in early stages), immunophenotypical, and genotypical features. It is the most common cutaneous lymphoma [75, 100], characterized by the sequential appearance of patches, developing into plaques and finally into tumors, which tend to ulcerate
Identification of monoclonal anti-HMW-MAA antibody linear peptide epitope by proteomic database mining
No full textMelanocytic tumors
No full textMelanoma is a tumor derived from melanocytes. As such, it can originate from the retina, meninges or even the bronchi, but in the overwhelming majority of cases the primary tumor arises in the skin
- …
