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

β 2 -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 β 2 -microglobulin levels increased as the CD4 + T cell count decreased