SERUM AND CEREBROSPINAL-FLUID LEVELS OF SOLUBLE INTERCELLULAR-ADHESION MOLECULE-1 (SICAM-1) IN PATIENTS WITH HIV-1 ASSOCIATED NEUROLOGICAL DISEASES

We measured levels of soluble intercellular adhesion molecule 1 (sICAM -1) in paired serum and CSF samples of 110 HIV-1-positive patients wit h and without neurological symptoms and 40 HIV-negative non-immune neu rological controls, and in sera of 26 asymptomatic HIV-1-positive pati ents. Serum sICAM-1 levels in asymptomatic HIV-1-positive patients wer e significantly increased in comparison to HIV-negative controls. More over, they were significantly higher in HIV-1-positive patients with A IDS-defining diseases than in the asymptomatic HIV-1-positive group. I n subgroups of patients with neurological disease, the highest serum v alues were found in HIV encephalopathy. CSF levels of sICAM-1 were ele vated only in HIV-l-positive patients with neurological disease mainly due to passive diffusion through a defective blood-brain barrier. An sICAM-1 index was calculated as a measure for intrathecal production o f sICAM-1 but showed no significant differences between patients with and without neurological involvement. However, increased levels of the sICAM-1 index were found in some patients with opportunistic CNS infe ction of bacterial or fungal origin. Serum and CSF levels of sICAM-1 c orrelated with neopterin levels, a marker of interferon-gamma-mediated macrophage activation and CSF sICAM-1 levels were inversely correlate d to numbers of CD4(+) T cells. Elevated serum sICAM-1 levels already in asymptomatic HIV-1-positive individuals add to the evidence for an early immune activation in HIV infection. With the further increase of serum and CSF s-ICAM-1 in patients with AIDS-defining diseases sICAM- 1 could serve as a new surrogate marker similar to neopterin.