Cerebrospinal fluid anti-cardiolipin antibodies in patients with hiv-1 infection

Both cerebrospinal fluid (CSF) immunologic abnormalities and serum anti-cardiolipin antibodies (aCL) have been reported in patients with HIV-1 infection. The antibody specificity of only a small amount of the total CSF IgG in these patients is known, and is directed against a variety of HIV-1 antigens. The specificity of the remaining CSF IgG is unknown. We report the results of the first study of CSF aCL in an HIV-1-infected population. We measured aCL IgG and IgM in the CSF of 21 HIV-1-infected patients without nervous system symptoms or AIDS, and in four HIV-1-negative controls. Twelve HIV-1-infected patients had an abnormal serum aCL value and CSF immunologic abnormalities and 9 HIV-1-infected patients had either abnormal serum aCL or CSF immunologic abnormalities but not both, or were normal in both regards. There was no difference between any HIV-1-infected patient and controls for CSF aCL IgM. Nine of 12 patients with an abnormal serum aCL and CSF immunologic abnormalities had CSF aCL IgG values that were at least 5 SD above normal control values, whereas none of the remaining patients had abnormal CSF aCL IgG values. All patients with abnormal CSF aCL IgG values had an intact blood-brain barrier as evidenced by an albumin index of less than 9, and all had nonreactive CSF VDRL tests. These data demonstrate that aCL IgG is produced intrathecally in some HIV-1-infected patients.