The resolution of immune responses is characterized by extensive apoptosis of activated T cells. However, to generate and maintain immunological memory, some antigen-specific T cells must survive and revert to a resting G0/G1 state. Cytokines that bind to the common gamma chain of the IL-2 receptor promote the survival of T cell blasts, but also induce proliferation. In contrast, soluble factors secreted by stromal cells induce Tcell survival in a resting G0/G1 state. We now report that interferon-beta is the principal mediator of stromal cell-mediated Tcell rescue from apoptosis. Interferon-alpha and -beta promote the reversion of blast Tcells to a resting G0/G1 configuration with all the characteristic features of stromal cell rescue; such as high Bcl-XL expression and low Bcl-2. Type I interferons and stromal cells stimulate apparently identical signaling pathways, leading to STAT-1 activation. We also show that this mechanism may play a fundamental role in the persistence of T cells at sites of chronic inflammation; suggesting that chronic inflammation is an aberrant consequence of immunological memory.
The term 'sclerosing diseases of the skin' comprises specific dermatological entities which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present guideline focuses on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, current strategies in the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 2 of this guideline provides clinicians with an overview of the diagnosis and treatment of scleromyxedema, scleredema (of Buschke) and nephrogenic systemic sclerosis (nephrogenic fibrosing dermopathy).
The extent of human memory T cell proliferation, differentiation, and telomere erosion that occurs after a single episode of immune challenge in vivo is unclear. To investigate this, we injected tuberculin purified protein derivative (PPD) into the skin of immune individuals and isolated responsive T cells from the site of antigenic challenge at different times. PPD-specific CD4+ T cells proliferated and differentiated extensively in the skin during this secondary response. Furthermore, significant telomere erosion occurred in specific T cells that respond in the skin, but not in those that are found in the blood from the same individuals. Tissue fluid obtained from the site of PPD challenge in the skin inhibited the induction of the enzyme telomerase in T cells in vitro. Antibody inhibition studies indicated that type I interferon (IFN), which was identified at high levels in the tissue fluid and by immunohistology, was responsible in part for the telomerase inhibition. Furthermore, the addition of IFN-α to PPD-stimulated CD4+ T cells directly inhibited telomerase activity in vitro. Therefore, these results suggest that the rate of telomere erosion in proliferating, antigen-specific CD4+ T cells may be accelerated by type I IFN during a secondary response in vivo.
The FOS database is a useful epidemiological tool in establishing the variety and relevance of cutaneous manifestations in Fabry disease. The present study confirms that the presence of dermatological manifestations appears to be a marker of greater severity of systemic disease, which emphasizes the importance of the dermatological assessment of these patients.
Two caucasian patients are described in whom oral mucosal lesions were the first manifestation of systemic lupus erythematosus. In both cases the diagnosis was delayed despite histological examination of oral lesions. Treatment with antimalarials and azathioprine was of significant benefit. In the absence of cutaneous or systemic features, distinguishing oral lupus erythematosus from lichen planus and epidermal dysplasia can be difficult, both clinically and on histology, and requires a high index of suspicion.
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