Sarcoidosis Vasc Dif
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Sarcoidosis is a multi-organ granulomatous disorder that is characterised by the accumulation of CD4+ T-lymphocytes resulting in a Th-1 type immune response. Although our understanding of the immune response in sarcoidosis has improved in recent years through studies of bronchoalveolar lavage cells and fluid, the genetic predisposition and trigger factors (and their interrelationship) remain unclear. ⋯ This review focuses specifically on two pivotal areas that have been the subjects of intensive investigation recently: a) triggering by infective agents and b) host genetic susceptibility and relates these to broader issues of pathogenesis. It is concluded that one or more microbes behaving in a non-infectious fashion in a genetically predisposed individual trigger the sarcoidosis granulomatous response.
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Sarcoidosis Vasc Dif · Oct 2000
ReviewStructural basis for airflow limitation in chronic obstructive pulmonary disease.
The airflow limitation that characterises chronic obstructive pulmonary disease (COPD) has two main components: an increased resistance, which is due to airway obstruction, and a loss of the elastic recoil pressure of the lung, which is due to parenchymal destruction. Although it has long been known that the major site of increased resistance in COPD is the peripheral airways, recent studies have shown that central airways are involved in the disease as well. The purpose of this review is to describe the major structural and cellular changes present in peripheral airways, central airways and lung parenchyma of patients with COPD, and to underline the possible mechanisms contributing to airflow limitation in these subjects.
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Sarcoidosis Vasc Dif · Mar 2000
ReviewNew perspectives in pulmonary angiitis. From pulmonary angiitis and granulomatosis to ANCA associated vasculitis.
Traditionally clinical and histopathological features were mainly relied on for classification of vasculitis and granulomatosis of the lung. These can be complemented by immunodiagnostic features which contribute to the classification as well as to the understanding of the pathogenesis of these disorders. Previously five conditions were classified together under the heading "pulmonary angiitis and granulomatosis" (PA & G), mainly on the basis of histological similarities. ⋯ The granulomatous and vasculitic disorders WG and CSS together with the non-granulomatous small-vessel vasculitis MPA now form a new group of diseases ('ANCA-associated vasculitides') which have many clinical, serological and immunohistochemical features in common. Collagen vascular diseases (CVD) are serologically characterized by distinct subspecificities of antinuclear antibodies (ANA), sometimes pronounced hypergammaglobulinaemia, complement consumption and immune deposits (antigen-antibody-complement complexes) which are common in situ in immune-complex vasculitis. In this article newer aspects of the clinical course, the immunodiagnostic procedure, and the immunopathogenesis of the relatively large group of pulmonary angiitis will be described.
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Sarcoidosis Vasc Dif · Mar 1999
ReviewCells and cytokines involved in the pathogenesis of sarcoidosis.
Granulomatous inflammation develops under the regulatory influence of cytokines produced by local mononuclear phagocytes, T cells, dendritic cells, fibroblasts, and other local cells. In sarcoidosis, granulomatous inflammation is characterized by dominant expression of T helper 1 (Th1) cytokines such as IFN gamma and interleukin (IL)-2 with low levels of expression of T helper 2 (Th2) cytokines such as IL4 and IL5. Recent studies show that the cytokine IL12, the most important regulator of Th1 immune responses currently known, is upregulated at sites of inflammation in sarcoidosis. ⋯ Whether these same type 1 cytokines drive granulomatous inflammation in patients with extensive fibrocystic lung disease remains unknown. TGF beta, a known inhibitor of IL12 and IFN gamma production, is produced at higher levels by lung cells from those patients who undergo remission of their disease, suggesting that TGF gamma is important in downregulating granulomatous inflammation in sarcoidosis. These studies offer new insight into the molecular mechanisms of granuloma formation in sarcoidosis and provide a framework for developing new therapeutic strategies for the treatment of this disease.