The immune reconstitution inflammatory syndrome related to HIV co-infections: a review

The immune reconstitution inflammatory syndrome (IRIS) is a consequence of an excessive pathogen-specific immune recovery reaction and occurs in a subset of patients on antiretroviral therapy (ART). Infective forms of IRIS may present either as an 'unmasking' of a previously subclinical infection or the paradoxical clinical deterioration of an infection for which the patient received appropriate antimicrobial therapy. The most important risk factors for IRIS are a low CD4+ T-cell count and a short time between treatment of the infection and the commencement of ART. The general approach to the treatment of IRIS is to continue ART and provide antimicrobial therapy for the provoking infection. The majority of cases are self-limiting; however, mortality and hospitalisation rates are particularly high when tuberculosis- or cryptococcal-IRIS affects the central nervous system (CNS). Corticosteroid therapy should be considered in certain forms of IRIS after the exclusion of other conditions that could explain the inflammatory manifestations in the patients. Given that a low CD4+ T-cell count is a major risk factor for the development of IRIS, commencing ART at a CD4+ T-cell count of >350/μL will prevent most cases.