Human leukocyte antigen-G molecules are constitutively expressed by synovial fibroblasts and upmodulated in osteoarthritis

• Published in: Human immunology Vol. 71; no. 4; pp. 342 - 350
• Main Authors: Ongaro, Alessia, Stignani, Marina, Pellati, Agnese, Melchiorri, Loredana, Massari, Leo, Caruso, Gaetano, De Mattei, Monica, Caruso, Angelo, Baricordi, Olavio R., Rizzo, Roberta
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2010
• Subjects: Aged; Aged, 80 and over; Allergy and Immunology; Cell Separation; Cells, Cultured; Female; Fibroblasts - immunology; Fibroblasts - metabolism; Fibroblasts - pathology; Flow Cytometry; Fluorescent Antibody Technique; Gene Expression Regulation - immunology; Histocompatibility Antigens Class I - genetics; Histocompatibility Antigens Class I - immunology; Histocompatibility Antigens Class I - metabolism; HLA Antigens - genetics; HLA Antigens - immunology; HLA Antigens - metabolism; HLA-G; HLA-G Antigens; Humans; IL-10; Inflammation; Interleukin-10 - immunology; Interleukin-10 - metabolism; Lipopolysaccharides - immunology; Lipopolysaccharides - metabolism; Male; Middle Aged; Osteoarthritis; Osteoarthritis - genetics; Osteoarthritis - immunology; Osteoarthritis - metabolism; Osteoarthritis - pathology; Synovial fibroblasts; Synovial Membrane - pathology; Synovial fibroblasts; Inflammation; HLA-G; Osteoarthritis; IL-10
• ISSN: 0198-8859; 1879-1166; 1879-1166
• DOI: 10.1016/j.humimm.2010.01.015

Human leukocyte antigen (HLA)-G molecules are nonclassical HLA class I antigens expressed as membrane bound and soluble isoforms (sHLA-G) with a restricted tissue distribution and anti-inflammatory functions. Because inflammation is involved in the pathogenesis of osteoarthritis (OA), we have analyzed the expression and production of HLA-G molecules in in vitro cultured synovial fibroblasts (SFs) from OA patients and control subjects. We have analyzed the levels of sHLA-G1 and HLA-G5 isoforms by immunoenzymatic assay (enzyme-linked immunosorbent assay) in the SF culture supernatants from six OA patients and six control subjects in 70-day in vitro cultures and after the addition of lipopolysaccharide or recombinant interleukin (IL)-10 (rIL-10). We have confirmed HLA-G modulation by cytofluorimetry and immunofluorescence. The results have demonstrated the spontaneous production of sHLA-G1 molecules by both OA and control SFs. The expression was confirmed by cytofluorimetry and immunofluorescence. OA SFs produce both sHLA-G1 and HLA-G5 molecules during the first 23 days of culture and higher levels of sHLA-G1 during the first 40 days of in vitro culture and after lipopolysaccharide or rIL-10 activation compared with control SFs. The production of HLA-G1 molecules, constitutively expressed by control and OA SFs, is significantly increased in OA, suggesting a possible mechanism to counteract the inflammation of the synovial joints.