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International Journal of Rheumatology
Volume 2015, Article ID 316421, 6 pages
Research Article

Ectopic Germinal Centers and IgG4-Producing Plasmacytes Observed in Synovia of HLA-B27+ Ankylosing Spondylitis Patients with Advanced Hip Involvement

1Department of Rheumatology, Fuzhou General Hospital of Nanjing Command, PLA, Fuzhou 350025, China
2Department of Pathology, Fuzhou General Hospital of Nanjing Command, PLA, Fuzhou 350025, China

Received 11 December 2014; Revised 28 March 2015; Accepted 28 March 2015

Academic Editor: Ruben Burgos-Vargas

Copyright © 2015 Xiugao Feng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Introduction. Ectopic lymphoid neogenesis and the presence of IgG4-positive plasmacytes have been confirmed in chronic inflammatory sclerosing diseases. This study aims to investigate hip synovial tissues of ankylosing spondylitis (AS) patients for IgG4-positive plasma cells and ectopic lymphoid tissues with germinal centers (GCs). Methods. Synovial samples were collected from 7 AS patients who received total hip replacement and were evaluated using immunohistochemistry for the presence of CD20+ B-cells, CD3+ T-cells, CD21+ follicular dendritic cells (FDC), and CD38+ plasma cells. Furthermore, immunoglobulin G (IgG and IgG4), IgA, IgM, and complement components C3d and C4d in synovia were evaluated. Both synovial CD21+ FDCs and IgG4-producing plasmacytes were analyzed. Results. All seven patients had severe fibrosis. Massive infiltrations of lymphocytes were found in 5 out of 7 patients’ synovia. Ectopic lymphoid tissues with CD21+ FDC networks and IgG4-positive plasma cells were observed coincidentally in two patients’ synovia. Conclusion. The pathophysiological mechanism of AS patients’ hip damage might be related to the coincidental presence of ectopic lymphoid tissue with FDCs network and IgG4-positive plasma cells identified here for the first time in AS patients’ inflamed synovial tissue.