Episode 120: Immune Reconstitution Inflammatory Syndrome (IRIS)

Episode 120: Immune Reconstitution Inflammatory Syndrome (IRIS) Abeda Faharti and Dr. Schlaerth present the definition, diagnosis, and treatment of IRIS. Moderated by Dr. Arreaza. Written by Abeda Farhati, MS4, Ross University School of Medicine. Editing and comments by Katherine Schlaerth, MD, and Hector Arreaza, MD.You are listening to Rio Bravo qWeek Podcast, your weekly dose of knowledge brought to you by the Rio Bravo Family Medicine Residency Program from Bakersfield, California, a UCLA-affiliated program sponsored by Clinica Sierra Vista, Let Us Be Your Healthcare Home. This podcast was created for educational purposes only. Visit your primary care provider for additional medical advice.Definition.Have you heard of IRIS? No, not the color portion of our eyes. IRIS is short for Immune Reconstitution Inflammatory Syndrome. This condition occurs in immunocompromised patients with HIV/AIDS due to an overactive inflammatory response. In most cases, it occurs after initiating antiretroviral therapy (ART). To understand IRIS in HIV patients, we must first understand HIV.HIV.<br />The Human Immunodeficiency Virus (HIV) infection was first reported in 1981. The virus attacks the immune system, destroying white blood cells called CD4+ T lymphocytes, which are part of our body's defense mechanism. These cells are also known as "helper T cells" and are responsible for destroying viruses, bacteria, and other germs that make us sick.When your CD4+ count is low, you are more likely to get serious infections from viruses, bacteria, and fungi, which usually do not cause problems in otherwise healthy individuals. These infections are called Opportunistic infections, and they can be deadly. To restore CD4+ T lymphocytes, HIV patients are started on ART to normalize their immune response to pathogens. As a result of these treatments, HIV patients' lives have been significantly improved and prolonged. [Comment by Dr. Arreaza: It is paradoxical, but some HIV patients are among the healthiest patients I have seen.]Despite this, no treatment is guaranteed to be without side effects. Increases in CD4+ T lymphocytes trigger the immune system to respond to any persisting antigen, regardless of whether it is fragments or intact organisms. As a result, a hyperinflammatory response may occur.Diagnosis.There are no established criteria for diagnosing IRIS. It is generally accepted that IRIS requires the worsening of an existing infection or an unrecognized, preexisting infection in the context of improved immune function. For a diagnosis to be made, most, if not all of the following features must be present:The presence of a low CD4 count (less than 100 cells) before initiating treatment with ART (Except IRIS secondary to preexisting TB infection can occur with CD4 counts >200 cells).The presence of an inflammatory condition, especially after ART is initiated.The absence of drug-resistant infection, bacterial superinfection, drug allergy, or other adverse drug reactions.The absence of patient noncompliance or reduced drug levels due to drug-drug interactions or malabsorption.Clinical Manifestations.IRIS can be presented in patients in 2 ways:Patient’s with a preexisting infectious disease that has NOT been treated, getting paradoxically worse after initiating treatment with ART ---this is known as “unmasking IRIS” ORPatient’s with a preexisting infectious disease that has been previously diagnosed and treated but regained capacity after treatment with ART, causing it to mount an inflammatory response – this is known as “paradoxical IRIS.”In summary: Unmasking IRIS and paradoxical IRIS.Patients with IRIS have clinical featu