ADA and Behcet disease: As activated T lymphocytes cause neutrophil hyperfunction with overproduction of NO, O2−, H2O2, OH, and singlet oxygen (1O2) that is one of main ROS-generation system in BD patients, the increased production of ADA and LPO system confirms aggravated lymphocyte function and ROS production, suggesting a possible new and simple biochemical activity marker for ADA in BD.