The Effect on Human Immunodeficiency Virus Type 1 RNA Levels in Cerebrospinal Fluid after Initiation of Zidovudine or Didanosine

Human immunodeficiency virus type 1 (HIV-1) RNA, neopterin, and beta2-microglobulin levels were analyzed in cerebrospinal fluid (CSF) and serum before and 3-13 months after initiation of antiretroviral monotherapy in 16 HIV-1-infected persons. Twenty-one treatment periods, 13 after initiation of zidovudine and 8 after initiation of didanosine, were studied. During zidovudine treatment, CSF HIV RNA levels decreased by a mean of 1.05 log10 (-91%, P < .01), and CSF neopterin and beta2-microglobulin levels by 57% and 33%, respectively (P < .01). No reduction was seen during didanosine treatment in CSF HIV RNA (+0.13 log10, not significant), CSF neopterin, or beta2-microglobulin levels. Changes in CSF HIV RNA levels correlated with changes in CSF neopterin and beta2-microglobulin (r(s) = .81 and .83, respectively, P < .001). The decrease in HIV RNA was significantly larger in CSF than in serum following zidovudine treatment (P < .01). These data demonstrate that zidovudine is a potent reducer of central nervous system virus load, which may be important for long-term neuroprotection.