Autoantibodies against galectin-8: their specificity, association with lymphopenia in systemic lupus erythematosus and detection in rheumatoid arthritis and acute inflammation

• Published in: Lupus Vol. 18; no. 6; pp. 539 - 546
• Main Authors: Massardo, L, Metz, C, Pardo, E, Mezzano, V, Babul, M, Jarpa, E, Guzmán, AM, André, S, Kaltner, H, Gabius, HJ, Jacobelli, S, González, A, Soza, A
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.05.2009; Sage Publications Ltd
• Subjects: Adolescent; Adult; Aged; Antigens, Neoplasm; Arthritis, Rheumatoid - complications; Arthritis, Rheumatoid - genetics; Arthritis, Rheumatoid - immunology; Autoantibodies - blood; Autoantibodies - immunology; Blotting, Western; Child; DNA - genetics; Electrophoresis, Polyacrylamide Gel; Female; Follow-Up Studies; Galectins - blood; Galectins - genetics; Galectins - immunology; Gene Expression; Humans; Lupus Erythematosus, Systemic - complications; Lupus Erythematosus, Systemic - genetics; Lupus Erythematosus, Systemic - immunology; Lymphopenia - complications; Lymphopenia - genetics; Lymphopenia - immunology; Male; Middle Aged; Polymerase Chain Reaction; Prospective Studies; Young Adult; autoantibodies; SLE; galectin-8; lymphopenia
• ISSN: 0961-2033; 1477-0962
• DOI: 10.1177/0961203308099973

The role of autoantibodies in the pathogenesis of systemic lupus erythematosus (SLE) has not been completely defined. From more than a hundred autoantibodies described in SLE, relatively few have been associated with clinical manifestations. The glycan-binding proteins of the galectin family can modulate the immune system. Anti-galectin autoantibodies thus could have functional and/or pathogenic implications in inflammatory processes and autoimmunity. We previously reported function-blocking autoantibodies against galectin-8 (Gal-8) in SLE. Here we tested these autoantibodies against a series of other human galectins and demonstrated their specificity for Gal-8, being detectable in 23% of 78 SLE patients. Remarkably, they associated with lymphopenia (50% of 18 anti-Gal-8-positive versus 18% of 60 anti-Gal-8-negative cases, Fisher’s Exact test two-tailed: P < 0.012). Lymphopenia is a common clinical manifestation in SLE, yet of unknown mechanism. In addition, six of eight patients with both lymphopenia and malar rash had anti-Gal-8 in their sera. Occurrence of these autoantibodies was not confined to SLE as we also found them in sera of patients with rheumatoid arthritis (16%) and septicemia (20%). This study thus establishes occurrence of specific anti-Gal-8 autoantibodies in autoimmune rheumatic diseases and in acute inflammation, with an apparent association to a clinical subset in SLE.