[Current concepts of the pathogenesis of acquired XXXX ].

@entity650 @entity1476 @entity409 @entity5298 @entity5479 @entity3540 @entity281 @entity1192 @entity1495 @entity1199
The pathogenesis of acquired @entity5479 is still unknown and subject of controversial discussions. Based on clinical and histological findings, several theories for @entity3540 pathogenesis have been developed: 1) retraction pocket theory; 2) proliferation theory; 3) immigration theory, and 4) metaplasia theory. Additionally @entity3540 development was grouped in particular stages. Immunohistochemical examinations of the matrix and perimatrix have considerably improved the knowledge of @entity3540 pathogenesis. In this review the current concepts of @entity3540 pathogenesis are discussed: a retraction pocket occurs due to a @entity409 . @entity281 leads to a disturbance of self-cleaning mechanisms, with cell debris and keratinocytes accumulate inside the retraction pocket, and this is followed by an immigration of immune cells, i. e. Langerhans' cells, T-cells, macrophages. There is an imbalance and a vicious circle of epithelial proliferation, keratinocyte differentiation and maturation, prolonged apoptosis, and disturbance of self-cleaning mechanisms. The inflammatory stimulus will induce an epithelial proliferation along with expression of lytic enzymes and cytokines. As a consequence, some "microcholesteatoma" occur which will confluent. Bacteria inside the retraction pocket produce some antigens which will activate different cytokines and lytic enzymes, i. e. ICAM, @entity5298 , @entity1192 , @entity1199 , @entity650 , @entity1476 , and @entity1495 . These cytokines lead to activation and maturing of osteoclasts with the consequence of degradation of extracellular bone matrix and hyperproliferation, bone arrosion and finally progression of the disease. The question why not all @entity3540 show the same progression process is still unclear. A probable explanation could be that in most retraction pockets migration and self-cleansing mechanisms for keratinocytes are well functioning, with normal migration of the squamous epithelium from the basal layers to the surface. Nevertheless, future research will have to evaluate this topic which might be crucial for the understanding of @entity3540 pathogenesis and for therapy.
