Comparison of spinal fluid β2-microglobulin levels with cd4⁺ t cell count, in vitro t helper cell function, and spinal fluid igg parameters in 163 neurologically normal adults infected with the human immunodeficiency virus type 1

β₂-microglobulin levels were measured in the cerebrospinal fluid (CSF) and serum of 163 human immunodeficiency virus-positive (HIV⁺) persons with normal neurologic physical examinations. None were on antiretroviral therapy. Only 3% had a positive CSF HIV p24 antigen test. The CSF β₂-microglobulin levels increased as the CD4⁺ T cell count decreased. Intrathecal production of β₂-microglobulin was suggested by finding CSF concentrations greater than serum concentrations in 15% of patients. The CSF β₂-microglobulin levels rose as in vitro T helper cell function deteriorated, independent of CD4⁺ T cell count. CSF β₂-microglobulin levels paralleled CSF IgG, IgG index, and IgG synthesis. Higher CSF β₂-microglobulin levels were found in persons with positive CSF oligoclonal bands. CSF β₂-microglobulin concentration may serve as a marker for subclinical neurologic damage due to HIV. If this is established, defining the effect of anti-HIV interventions on CSF β₂-microglobulin would be warranted.