Because clinical deterioration occurs during immune recovery, this phenomenon has been described as immune restoration disease (IRD), immune reconstitution syndrome (IRS), and paradoxical reactions. Given the role of the host inflammatory response in this syndrome, the term immune reconstitution inflammatory syndrome (IRIS) has been proposed [21] and has become the most widely used and accepted term to describe the clinical entity. Possible infectious and noninfectious etiologies of IRIS are summarized in Table 1 .