Fibrosis is scarring due to the replacement of tissue architecture by extracellular matrix (ECM), which consists largely of collagen. Scarring progressively destroys organ structure and thereby impairs function. Accumulation of collagen is thought to be due to an increase in production, a reduction in degradation of collagen or a combination of both.1 If so, we might expect the ratio of production to degradation to increase with increasing fibrosis. Biomarkers of type III and VI collagen production (PRO-C3 and PRO-C6) and degradation (C3M and C6M), called neoepitopes, have been developed to measure these processes.1 In diseases such as idiopathic pulmonary fibrosis, where fibrosis is the dominant pathophysiological feature, neoepitope levels align closely with disease progression.2 Whether these collagen markers are relevant in other diseases has been less well explored. In sarcoidosis, fibrosis in affected organs, especially the lungs and heart, accounts for most of the long-term morbidity and mortality that is directly attributable to sarcoidosis itself (rather than due to attempts to treat the disease). Fibrosis in sarcoidosis is thought to occur in the setting of persistent granulomatous inflammation but is likely modulated by other factors besides duration of disease alone since not all patients with chronic sarcoidosis develop substantial fibrosis. A major clinical challenge is to identify whether the dysfunction of an affected organ is predominantly due to granulomatous inflammation or fibrosis. Thus, a blood marker of sarcoidosis fibrosis would be an extremely helpful clinical tool. Recently, Sand and co-workers3 hypothesised that patients with sarcoidosis may have increased plasma levels of collagen neoepitopes and that …

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结节病中的胶原新表位：它们告诉我们什么？


纤维化是由于细胞外基质 （ECM） 取代组织结构而形成的疤痕，ECM 主要由胶原蛋白组成。瘢痕形成逐渐破坏器官结构，从而损害功能。胶原蛋白的积累被认为是由于产量的增加、胶原蛋白降解的减少或两者的结合。如果是这样，我们可以预期产量与降解的比率会随着纤维化的增加而增加。III 型和 VI 型胶原蛋白生成（PRO-C3 和 PRO-C6）和降解（C3M 和 C6M）的生物标志物（称为新表位）已被开发出来来测量这些过程.1 在特发性肺纤维化等疾病中，纤维化是主要的病理生理特征，新表位水平与疾病进展密切相关.2 这些胶原蛋白标志物是否与其他疾病相关尚未得到充分探索。在结节病中，受影响器官的纤维化，尤其是肺和心脏，占直接归因于结节病本身（而不是由于尝试治疗该疾病）的长期发病率和死亡率的大部分。结节病的纤维化被认为发生在持续性肉芽肿性炎症的情况下，但除了病程之外，可能受其他因素的调节，因为并非所有慢性结节病患者都会发展为严重的纤维化。一个主要的临床挑战是确定受累器官的功能障碍是否主要由肉芽肿性炎症或纤维化引起。因此，结节病纤维化的血液标志物将是一个非常有用的临床工具。最近，Sand 及其同事3 假设结节病患者的血浆胶原新表位水平可能升高，并且......