Conditions and symptoms
What Is Immune Reconstitution Syndrome (IRIS)?
Immune reconstitution syndrome · say it: ih-MYOON ree-kon-stih-TOO-shun SIN-drohmAlso written: IRIS, immune reconstitution inflammatory syndrome
Short answer
Immune reconstitution syndrome is when a recovering immune system reacts strongly to an existing infection, causing new or worse symptoms.
What it means
Immune reconstitution syndrome, also called IRIS, can happen when a weakened immune system starts to recover, most often in people starting HIV treatment. As the immune system gets stronger, it may suddenly 'notice' an infection that was already in the body, such as tuberculosis or a fungal infection, and react with inflammation. This can cause fever, swelling or worsening of the old infection's symptoms. New or worsening symptoms after starting treatment should be reported to your clinic promptly.
HIV medicine labels list it in the 'Warnings' section because it usually appears in the first weeks or months of treatment, and it can look like the medicine is not working or is causing harm. In fact, it is linked to immune recovery. The label asks people to report any new symptoms so their doctor can check for an underlying infection.
IRIS is different from an allergic reaction or a side effect of the medicine itself. It is the immune system's response to an infection, not to the drug.
Where you may see it
- The 'Warnings and Precautions' section of antiretroviral medicine labels
- HIV clinic letters and notes
- Tuberculosis and HIV treatment plans
📄 How it looks on a report
Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy.
🙅 What it does not mean
- IRIS does not mean the HIV medicine has failed. It often happens because the immune system is recovering.
- It does not mean you should stop your treatment. Contact your clinic instead.
- It is not the same as an allergy to the medicine.
🎯 Check yourself
Which of these is the right meaning of “Immune reconstitution syndrome”?
🗒️ Questions to ask your doctor
💊 Medicines whose labels mention “Immune reconstitution syndrome”
Plain-English explanations of each medicine, from its official FDA label.
- Dolutegravir
an HIV-1 integrase strand transfer inhibitor (INSTI), a type of HIV medicine
🔗 Read more from trusted sources
- “Immune reconstitution syndrome” on MedlinePlus ↗
US National Library of Medicine
- NCI Dictionary definition ↗
US National Cancer Institute: “iris”
Seeing this word on your own report? Get every line of it explained, free.
Explain my report🧩 Related words
🔎 Look up another word
More words: conditions and symptoms
General information about a medical word, not advice about your own results. Ask the clinician who ordered the test what it means for you.