[Post infection antiidiotype vaccination against HIV: results of a phase Ia pilot study].

: The mAb IOT4A against the HIV-gp 120 binding site on CD4 was shown to elicit the production of specific anti-idiotypes in rabbits neutralising HIV-1 in vitro. This study was designed in order to determine the safety and efficacy of the mAb IOT4A for the immunization of HIV+ volunteers. 10 patients in stages WR2-WR4B of HIV-disease were given six s.c. injections of the mAb IOT4A as an alum precipitate (each 3 patients receiving 0.6 or 1.2 mg, 4 patients receiving 2.4 mg). 6 patients subsequently received a booster immunization with the same dose of the mAb IOT4A. The immunization schedule was accompanied by monitoring clinical, immunologic and virologic parameters. No systemic toxic or allergic effects of the idiotype vaccine were observed. 8/10 vaccinees displayed a delayed-type hypersensitivity at the location of antibody administration beyond the third injection. The relative and absolute CD4 count showed a sustained increase in 8/10 patients at the end of the booster immunization and an additional raise after booster immunization in 6/6 patients. 624 antigen levels became negative in 2/2 patients during vaccination. In 4/10 patients in increase in HIV/gp 120 antigen binding titres was observed. HIV neutralisation titer remained stable throughout the observation period, and no progression in HIV disease was observed in all patients included in this study. The administration of the mAb IOT4A as a vaccine in HIV-infected volunteers was well tolerated. The mAb ITO4A induced the production of specific anti-idiotypes, that might have been of clinical benefit.(ABSTRACT TRUNCATED AT 250 WORDS)