Immune Reconstitution Inflammatory Syndrome
ART improves immune function and CD4 cell count in HIV-infected children as in adults; within the first few months after starting treatment, HIV viral load sharply decreases and the CD4 T lymphocyte count rapidly increases. This results in increased capacity to mount inflammatory reactions. After initiation of cART, in some patients, reconstitution of the immune system produces a worsening of symptoms of an existing active OI (paradoxical IRIS) or the appearance of new symptoms of a latent or occult OI (unmasking IRIS), where infectious pathogens previously not recognized by the immune system now evoke an immune response. This inflammatory response often is exaggerated in comparison with the response in patients who have normal immune systems. The pathologic process of IRIS is inflammatory and not microbiologic in etiology. Thus, distinguishing IRIS from treatment failure is important. In therapeutic failure, a microbiologic culture should reveal the continued presence of an infectious organism, whereas in paradoxical IRIS, follow-up cultures most often are sterile. However, with "unmasking" IRIS, viable pathogens may be isolated.
In children, the conditions most commonly associated with IRIS include mycobacterial infections, herpes zoster, herpes simplex virus and cryptococcal infection. In addition, reactions related to bacille Calmette-Guérin vaccine have been 1 of the most common IRIS manifestations in children in low-resource settings.[11–13] IRIS is uncommon in children in the United States. No randomized controlled trials have been published evaluating treatment of IRIS in children. Disease-specific information and recommendations for managing IRIS are included in individual sections, as appropriate.
Pediatr Infect Dis J. 2013;32(12):1303-1307. © 2013 Lippincott Williams & Wilkins