Evidence for non-adaptive immune response in HIV infection

Increased levels of soluble forms of adhesion molecules such as intercellular adhesion molecule 1 (ICAM-1) and E-selectin have been found in the sera of HIV-infected patients and have been associated with disease progression. The aim of the present study was to investigate whether this phenomenon reflects activation of the non-adaptive immune response in HIV infection. Fifty-one patients with HIV infection (42 men, nine women) were classified into two subgroups: those with HIV infection but without evidence of AIDS indicator conditions (HIV infected non-AIDS cases, n = 27) and those with AIDS (AIDS cases, n = 24). The activation of non-adaptive immune response was evaluated as the production of reactive oxygen species that cause lipid peroxidation, which was assessed by measuring thiobarbituric reactive substances (TBARS) using the thiobarbituric acid assay (TBA). Plasma levels of von Willebrand factor (vWF), measured by rocket immunoelectrophoresis, were used to show activation of endothelial cells even in the absence of any other causative agent, in these patients. TBARS levels in non-AIDS cases were significantly higher than in control subjects (n = 17) or AIDS cases (P < 0.001). The mean vWF levels were higher in AIDS cases than in non-AIDS cases or normal subjects (P < 0.05). TBARS levels remained significantly higher in non-AIDS cases after adjusting for age, CD4 T-cell and neutrophil counts, antiretroviral therapy and vWF plasma levels. The above findings indicate that in HIV infection, the virus per se is responsible for the increased oxidative stress that in turn activates various transduction pathways, may be leading to endothelial cell activation and shedding of adhesion molecules from the cell surface.