Cerebrospinal fluid interferon-gamma-inducible protein 10 (IP-10, CXCL10) in HIV-1 infection.

Interferon-gamma-inducible protein (IP-10 or CXCL10) is a potent chemoattractant and has been suggested to enhance retrovirus infection and mediate neuronal injury. In order to assess this chemokine in central nervous system (CNS) HIV infection, we measured the cerebrospinal fluid (CSF) and plasma concentrations of CXCL10 by immunoassay in samples derived from 97 HIV-infected subjects across a spectrum of immunological progression and CNS complications and from 16 HIV seronegative control subjects studied at three clinical centers between 1994 and 2001. We also examined changes in the CSF and plasma CXCL10 concentrations in 30 subjects starting and three stopping antiretroviral therapy. CSF CXCL10 concentrations: (1) correlated with CSF HIV RNA and white blood cell (WBC) counts, but not with blood CXCL10, HIV RNA, or CD4 counts; (2) were increased in subjects with primary and asymptomatic HIV infections and AIDS dementia complex, but less frequently in those with more advanced infection, with or without CNS opportunistic diseases except cytomegalovirus encephalitis; (3) decreased in subjects starting antiretroviral in association with decreases in CSF and plasma HIV RNA and CSF WBCs; and (4) conversely, increased in subjects stopping treatment in parallel with CSF HIV RNA and WBCs. These results confirm that CSF CXCL10 associates closely with both CSF HIV and WBCs and suggest that this chemokine may be both a response to and contributing determinant of local infection. High CSF levels may be useful in the diagnosis of ADC in subjects with advanced immunosuppression in whom CMV encephalitis has been ruled out, though this issue requires further study.