Detection of an interferon inhibitor (II) in patients (Pts) with a spectrum of HIV disease

Introduction AIDS pts have an inhibitor of interferon in their serum that can block the antiviral activity of all three types of interferons and reduce the synthesis of interferon alpha. Healthy, HIV seronegative persons lack II and interferon activity (IA) in their scrum. Prior to this pilot study, n was not studied in pts with a spectrum of HIV disease or known if II activity would change with a change in antiretroviral therapy. Methods After informed consent, 5ml of serum was collected from HIV+ pts, along with CD4 cell counts and in some pts, HIV-RNA, at three different visits. Most pts had a change in their antiretroviral (ARV) therapy at the first visit. II and IA assays were done with previously published methods. Results 29 pts (23 men, 6 women) were studied for 42 to 398 days. The mean age was 37 yr (range 26-51), the mean CD4 cell count was 271 (range 1-1149). II was detected in all baseline samples, mean 11.8 IU (range 4-23) whereas IA was detected in 25/29 (86.2%), mean 7.4 IU (range 2-25). 25 pts underwent a change in ARV. 19 (76%) pts were receiving a protease inhibitor (PI) in a combination regimen at the final visit. 13 (52%) had a ≥ 50% reduction in II; 11 (44%) had a ≥ 50% reduction in IA. Correlation coefficients (R) for II; vs CD4 cell ct, -.51, p=0.031; vs HIV-RNA, .56, p=0.018, R for IA: vs CD4 cell ct, -.66, p=0.003; vs HIV-RNA, .89, p<0.001. Conclusions Most if not all HIV+ pts have an II in their serum. The activity of u was lowered in half of the pts who underwent a change in ARV. II could be an important host immunologic factor in the pathogenesis of HIV infection; further study is needed.