Immune reconstitution inflammatory syndrome associated with bacterial infections

Immune reconstitution inflammatory syndrome (IRIS) is defined by various clinical manifestations following the initiation of antiretroviral treatment (ART) in HIV patients primarily infected with Mycobacteria. IRIS has clinical similarities with lepromatous reactions in patients with leprosy following antibiotic initiation.

Tuberculosis and more rarely lepromatous leprae and Whipple's disease are the main diseases caused by actinobacteria associated with IRIS, regardless of HIV status. The pathogenesis of this syndrome remains complex and partially understood. The treatment for IRIS is non-evidence-based, except for corticosteroids in tuberculosis-IRIS. Thalidomide and other immunomodulatory drugs have been successfully used in case series.

IRIS is mainly observed during infections (viral, fungal or bacterial) which involve inefficient macrophages for the clearance of bacteria, namely Actinobacteria such as Mycobacterium leprae, M. tuberculosis and Tropheryma whipplei. The restoration of macrophage competence after ART or antibiotic initiation results from a complex mechanism, probably involving a sudden and violent immune reaction with a cytokine storm, such as TNF-α and IFN-γ. This overreaction might be controlled using corticosteroids and thalidomide.