Cerebrospinal fluid antibodies directed against neuron-associated gangliosides in HIV-1 infection

Background: Loss of synapses and neurons is a common finding in HIV-1 infection. Since the in vivo infection of neurons by HIV-1 is limited, indirect factors are likely to contribute to the pathogenesis, Patients and Methods: We have analyzed cerebrospinal fluid (CSF) and serum samples from 25 HIV-1-infected individuals (nine with and 16 without CNS complications) and 19 HIV-negative controls with aseptic meningitis or viral encephalitis, for the presence of antibodies directed against the neuron-associated gangliosides GM1, GD1a and GD1b. Results: Positive antibody titers to greater than or equal to 1 of the gangliosides were found in 13/25 HIV-1-infected patients in CSF and in 17/25 in serum. Significant correlations were found between the presence and titers of CSF antibodies against GM1, GD1a, and GD1b. Six out of nine patients with, and 3/16 without neurological complications (p < 0.05) had positive CSF titers of greater than or equal to 1 of the ganglioside antibodies combined with negative serum titers, indicating intrathecal antibody production. In contrast, only 1/19 controls had detectable anti-ganglioside antibodies in the CSF. Conclusion: The results should be interpreted with caution and CSF anti-ganglioside antibody production might be a part of a non-specific intrathecal polyclonal immunoactivation. Nevertheless, autoantibodies directed against neuron-associated gangliosides might be involved in the neuropathogenesis in HIV-1 disease.