Immune reconstitution inflammatory syndromes: what's new?

The immune reconstitution inflammatory syndrome (IRIS) is characterized by worsening clinical, laboratory, or radiologic findings despite improvements in the HIV RNA level and CD4 count after the introduction of antiretroviral therapy and is due to the restoration of pathogen-specific immune responses. IRIS may occur during or shortly after the treatment of an opportunistic infection or as a "new" clinical syndrome resulting from a previously unrecognized occult infection. Risk factors for IRIS include a low CD4 count, the presence of latent infection(s), and a robust virologic and immunologic response to HAART. In addition to infectious pathogens, IRIS is associated with autoimmune or malignancy-related conditions. Given the increasing availability of HAART, the number and types of IRIS encountered by HIV care providers will also increase. The prognosis for most IRIS cases is favorable because a robust inflammatory response may predict an excellent response to HAART in terms of immune reconstitution and, perhaps, improved survival. This article summarizes the various clinical presentations of IRIS and discusses the diagnosis and treatment of these immune-related syndromes.