CSF levels of beta2-microglobulin (b2m), monocyte chemotactic protein-1 (MCP-1), soluble tumor necrosis factor receptors (sTNFRs), and HIV-1 RNA were determined in 16 neurologically asymptomatic HIV-1 infected patients before and 12 weeks after treatment with lamivudine plus zidovudine or stavudine. b2m levels were significantly higher in patients (1.7 mg/l) compared with controls (0.8 mg/l) (P < 0.001), and decreased to 1.1 mg/l during treatment (P = 0.001). MCP-1 levels were low, and did not change during treatment. Levels of sTNFR type I were elevated in patients (0.92 ng/ml) compared to controls (0.30 ng/ml) (P = 0.03), but did not change during treatment. Levels of sTNFR type II were below the limit of detection in most patients and controls. In conclusion, CSF levels of b2m and HIV-I RNA, but not sTNFRs or MCP-1, are candidate surrogate markers of treatment efficacy in early CNS infection.