RESUMO
Dendritic cells (DCs) play an important role in both immunological tolerance and immunity as well as in pro- and anti-inflammatory responses. Upon uptake of apoptotic cells and apoptotic bodies, DCs degrade self antigens from them and induce anti-inflammatory response and T regulatory (Treg) cells resulting in the maintenance of tolerance to self antigens. Ageing is characterized by progressive immunodeficiency, inflammation, and autoimmunity. In this paper we will review the role of DCs in inflammation and autoimmunity in human ageing and will highlight the observations that DCs from aged humans display impairment in their capacity to uptake apoptotic cells, and paradoxically induce proinflammatory response and increased reactivity to self antigen (DNA). DNA from aged is hypomethylated and hypomethylation is associated with increased immunogenecity of self DNA.
RESUMO
Mediastinal parathyroid cyst is a rare cause of space occupying lesion in the mediastinum. No specific symptomatology may be attributed to the non-functioning parathyroid cyst. The diagnosis is rarely made before exploration. The cysts are thin walled, smooth, of varying sizes and contained clear, opalescent or haemorrhagic fluid. Histopathological examination reveals clusters of parathyroid cells dispersed in the wall of the cyst. Surgical removal is the treatment of choice and can be performed with minimal morbidity.