Tuberculosis immune reconstitution inflammatory syndrome in countries with limited resources

Mycobacterium tuberculosis infection accounts for probably one third of human immunodeficiency virus (HIV) related immune reconstitution inflammatory syndrome (IRIS) events, particularly in developing countries where HIV and tuberculosis (TB) co-infection is very common. Small cohort studies of HIV-positive patients with active TB treated with antiretroviral therapy (ART) suggest an incidence of TB IRIS varying between 11% and 45%. Risk factors for TB IRIS that have been suggested in certain studies but not in others include: starting ART within 6 weeks of starting TB treatment; extra-pulmonary or disseminated disease; a low CD4+ lymphocyte count and a high viral load at the start of ART; and a good immunological and virological response during highly active antiretroviral therapy (HAART). It is important to agree on a clinical case definition of TB IRIS that could be used in resource-limited settings. Such a case definition could be used to determine the exact incidence and consequences of TB IRIS and would be valuable worldwide in clinical trials that are needed to answer questions on how this phenomenon could be prevented and treated.