Intrathecal production of HIV antibodies in suspected AIDS encephalopathy

Summary Thirty-one serum and CSF samples from 21 HIV-antibody-positive patients with neurological deficits were examined to prove or exclude intrathecal production of HIV antibodies. By dilution, sera were adjusted to the IgG concentration of the corresponding CSF samples. Both samples were then serially diluted in log₂ steps down to the detection limit and were tested in an anti-HIV ELISA. From the dilution obtained at the cut-off level, a quotient Q_HIV was derived as an indicator of intrathecal production of HIV antibodies. Six of a total of eight samples with a Q_HIV value of 2 were correlated which the clinical diagnosis of AIDS-related dementia complex (ARDC). However, a Q_HIV less than 1 did not exclude the development of ARDC, as was shown during follow-up in one case. Different methods are compared for the determination of intrathecal production of IgG and anti-HIV. A quotient Q_HIV 2 is suggested to be highly indicative of intrathecal production of anti-HIV as well as of the development of ARDC.