«Detección y caracterización inicial de fragmentos del recubrimiento sinovial en el líquido sinovial.»L. Dai1,5, F. Pessler3, L. X. Chen1,2,4, G. Clayburne2 and H. R. Schumacher1,2 1 University of Pennsylvania, 2 Philadelphia VA Medical Center, 3 The Children’s Hospital of Philadelphia, 4 Presbyterian Medical Center, Philadelphia, PA, USA and 5 The 2nd Affiliated Hospital, Sun Yat-sen University, Guangzhou, People’s Republic of China.
Objective. Free fragments of synovium have occasionally been seen in synovial fluid but have not been studied systematically. We wished to establish a method for the reliable detection of these fragments in joint and bursa effusions and begin to characterize them by histochemical and immunohistochemical methods.
Methods. Cell smears, wet drop preparations and cytospins were prepared from 39 consecutive joint and bursa effusions. Paraffin cell blocks were prepared from a subset. Analysis encompassed standard and polarized light microscopy, histochemistry, immunohistochemistry and transmission electron microscopy (EM). Synovial biopsy tissue from one different patient was examined for comparison.
Results. Tissue fragments were not seen in Wright-stained cell smears and only rarely in wet drop preparations. In contrast, variously sized fragments with the histological appearance of hyperplastic synovial lining were detected in ethanol-fixed, haematoxylin/eosin-stained cytospins from bursitis and all arthropathies studied [17/24 (71%) of non-inflammatory and 12/15 (80%) of inflammatory specimens]. Immunostaining revealed CD68 expression in a subset of cells in a pattern characteristic of hyperplastic synovial lining. Juxtaposed cells with morphological features of macrophage-like and fibroblast-like synoviocytes were seen by EM.
Conclusions. Synovial lining fragments can be detected in effusions from diverse arthropathies and bursitis. They maintain important properties of the synovial lining and can be analysed by immunohistochemistry. They may afford the opportunity to study a relatively pure preparation of synovial lining cells without the need for cell culture, and to evaluate their possible role in augmenting or perpetuating synovitis or joint damage.
Rheumatology 2006 45(5):533-537.