What Is IRIS Like in the U.S.?

Paul E. Sax, MD


AIDS Clinical Care 

In This Article

Abstract and Introduction


Approximately 10% of patients responding to antiretroviral therapy developed immune reconstitution inflammatory syndrome, which was, in turn, associated with increased mortality risk.


Most data on immune reconstitution inflammatory syndrome (IRIS) have come from developing countries, where tuberculosis (TB) is often the leading cause. How is IRIS different in the U.S., where rates of TB are substantially lower?

Investigators from the U.S.-based HIV Outpatient Study reviewed data on 2610 patients who, between 1996 and 2007, started a new combination antiretroviral regimen that induced either a viral-load decline ≥0.5 log copies/mL or a CD4 cell–count gain ≥50%. IRIS was defined as the occurrence of a new HIV-related type B or C condition or any of several mucocutaneous disorders or autoimmune diseases.

Overall, 276 patients (10.6%) developed IRIS, with the most common diagnosis being mucosal candidiasis. Mycobacterial infections were the most common type C cause of IRIS, occurring in 15 cases (4.1%), but only one of these infections was TB. Severe immunosuppression (CD4 count <50 cells/mm3) and viral load >100,000 copies/mL were each independently associated with an increased risk for IRIS. Patients who developed IRIS with a type B or C condition were more than twice as likely to die during follow-up as patients who did not develop IRIS.