The invention provides anti-14-3-3 eta antibodies that specifically bind to the human 14-3-3 eta protein isoform in its natural configuration while exhibiting selectivity over human 14-3-3 alpha, beta, delta, epsilon, gamma, tau, and zeta protein isoforms. Methods, kits and pharmaceutical compositions comprising said specific anti-14-3-3 eta antibodies are further provided for the diagnosis and treatment of arthritis.