Low incidence of anti-interferon-alpha antibodies in patients treated with interferon-alpha-2a for AIDS-associated Kaposi's sarcoma

Anti-interferon (IFN)-alpha antibodies were determined in the serum of 28 patients treated with high-dose human recombinant IFN-alpha-2a for AIDS-associated Kaposi's sarcoma. After a median treatment duration of 3 months, 3 patients developed anti-IFN-alpha antibodies, of whom 2 showed a long lasting tumour response despite the development of these antibodies. None of 3 patients with tumour progression after an initial treatment response had developed IFN-alpha neutralizing antibodies. In conclusion, a low incidence of anti-IFN-alpha antibodies during treatment with high dose IFN-alpha was found, but the appearance had no detrimental effect on the duration of tumour responses in a small number of patients.