GPI and Arthritis: Collagen-induced arthritis in the C57BL/6 background is markedly suppressed in IL-17-deficient mice [6], and glucose-6-phosphate isomerase (GPI)-induced arthritis in the DBA/1 background and antigen-induced arthritis in the C57BL/6 background are also suppressed by the administration of anti-IL-17 antibodies (Abs) [7,8].