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

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