CSF protein and cellular profiles in various stages of HIV infection related to neurological manifestations.

CSF protein and cellular profiles were studied in 28 HIV-infected patients. Twenty of them had neurological complaints, but only 6 patients had objective neurological deficits such as dementia, ocular motility disorders or polyneuropathy. The serum/CSF HIV antibody ratio was on average lowest in acquired immunodeficiency syndrome (AIDS) (4 patients) and highest or almost normal in lymphadenopathy syndrome (LAS) (11) and asymptomatic seropositivity (ASX) (7), while it varied between these extremes in AIDS-related complex (ARC) (6). However, low values of the ratio were also found in the HIV-infected patients free of neurological symptoms and even in one ASX patient. The CSF IgG index was elevated in all these 4 general stages of HIV infection without any significant differences between them. The CSF/serum albumin ratio was slightly increased in patients with neurological deficits, but this ratio showed no association with any other clinical factor analysed. CSF leucocytes were increased in the early stages of the disease, but later the cellular reaction subsided. HIV was isolated from post mortem brain tissue of two AIDS patients and from the CSF of one of them. The results suggest increased intrathecal virus-specific IgG synthesis, not only in patients with neurological deficits and at advanced stages of infection, but also in neurologically symptom-free subjects and at early infection. The lack of correlation between the increased virus-specific IgG synthesis within the CNS and the presence of neurological symptoms suggests that neurologically "silent" areas of brain white matter are often affected in HIV infection.