Plasma bioavailable interleukin-6 is elevated in human immunodeficiency virus-infected patients who experience herpesvirus-associated immune restoration disease after start of highly active antiretroviral therapy

This study compared plasma bioavailable interleukin (IL)-6 levels in 3 grou ps: human immunodeficiency virus (HIV)-infected patients who had a human he rpesvirus (HHV)-associated immune restoration disease (IRD) during highly a ctive antiretroviral therapy (HAART); patients who experienced an IRD initi ated by Mycobacterium avium complex, hepatitis C virus, or human papillomav irus; and control patients who had uneventful immune reconstitution. Total IL-6, soluble IL-6 receptor (sIL-6R), and soluble gp130 were measured by EL ISA, and levels of free IL-6 and sIL-6/IL-6R complex were modeled mathemati cally. Persons who had an HHV-associated IRD had increased plasma bioavaila ble IL-6 before HAART, compared with patients who experienced a non-HHV-ass ociated IRD and with control patients, and their plasma bioavailable IL-6 i ncreased progressively over 3-4 years of treatment. Increased IL-6 producti on may be a feature of HAART-induced restoration of immune responses to HHV infections and may have long-term immunopathologic consequences.