il-18 inhibitor, antibody, methods for treating an il-18 associated disease or disorder in an individual, to determine the amount of free il-18 in a sample or in situ, to diagnose a predisposition to a disease or an il-18 associated disorder, to monitor minimal residual disease in a patient following treatment with the il-18 inhibitor or composition and to predict a patient's response to treatment with the il-18 inhibitor or composition, and diagnostic kit to detect free il-18.