Curriculum · Public Health and Communicable Diseases
Immune reconstitution inflammatory syndrome in TB/HIV co-infection
What it is
Immune reconstitution inflammatory syndromes (IRIS) are seen when ART is started in a patient who has TB. There are two forms: paradoxical worsening of TB when ART is started after TB treatment, and unmasking of TB when ART is started in the setting of not-yet-recognized TB.
TB/HIV is counted in Oman: of 327 total TB cases in 2015, 5 were TB/HIV, a rate of 1.5%, and of 344 total TB cases in 2016, 12 were TB/HIV, a rate of 3.5%.
Causes and risk
The risk is not the same in every patient. IRIS is more likely when the CD4 count is below 50, when the pre-ART VL is high, when the TB is severe, and when the interval between initiation of TB tx and ART is short.
HIV also changes the natural history of the infection itself. Latent TB infection turns into active TB disease in 5-10% of HIV-neg people over a lifetime but in 5-10% of HIV-pos people each year. Active TB disease in the first 1-2 yrs after infection follows in 5% of HIV-neg people and is much more likely in HIV-pos people.