Spontaneous and anti-Fas-induced apoptosis in lymphocytes from HIV-infected patients undergoing highly active anti-retroviral therapy Sandro Grelli a , Selenia Campagna a,b , Miriam Lichtner c , Giovanni Ricci d , Stefano Vella e , Vincenzo Vullo c , Francesco Montella d , Simonetta Di Fabio e , Cartesio Favalli a , Antonio Mastino f,g and Beatrice Macchi b,g Objective: The aim of this study was to investigate susceptibility to spontaneous or anti-Fas-induced apoptosis in peripheral blood mononuclear cells (PBMC) from HIV- positive patients before and during highly active anti-retroviral therapy (HAART). Design: A longitudinal study was performed on 12 evaluable patients on HAART. This cohort was analysed prior to and at week 2, 4, 8, 16 and 24 after beginning HAART. Variations in CD4 and CD8 cells, viral load, susceptibility to spontaneous or anti-Fas- induced apoptosis in the presence of IL-2, IL-4 or IL-12 were studied. Expression of Fas and Bcl-2 were also assessed. Methods: Levels of HIV RNA were determined by a quantitative reverse transcrip- tion±PCR assay. Apoptosis was evaluated by staining isolated nuclei with propidium iodide followed by multiparameter ¯ow cytometry analysis. Results: Spontaneous apoptosis of PBMC was promptly inhibited after the start of treatment. Similarly, anti-Fas-induced apoptosis diminished greatly during treatment. Expression of Fas decreased signi®cantly, while that of Bcl-2 remained statistically unchanged during the ®rst 24 weeks of therapy. Levels of apoptosis correlated inversely to CD4 cell counts and directly to viral load in a highly signi®cant way. Expression of Fas was directly correlated to apoptosis. Interleukin (IL)-2, but not IL-4 or IL-12, protected PBMC of HIV-positive individuals from spontaneous or anti-Fas- induced apoptosis before and during HAART. Conclusion: These results suggest that regulation of apoptosis and of Fas expression are involved in immunoreconstitution during HAART. & 2000 Lippincott Williams & Wilkins AIDS 2000, 14:939±949 Keywords: AIDS, programmed cell death, apoptosis, immunoreconstitution, Fas, Bcl-2 From the a Department of Experimental Medicine and Biochemical Sciences, University of Rome 'Tor Vergata', b IRCCS, S. Lucia, c Department of Infectious and Tropical Disease, University of Rome 'La Sapienza', d S. Giovanni Hospital, e Istituto Superiore di Sanita Á, Rome, f Institute of Microbiology, Faculty of Sciences, University of Messina, Messina, g Department of Neuroscience, Universityof Rome 'Tor Vergata', Rome, Italy. Sponsorship: Supported by I.S.S., Program AIDS to Beatrice Macchi and by MURST, National Research Program to Antonio Mastino. Requests for reprints to: B. Macchi, Department of Neuroscience, University of Rome 'Tor Vergata', Via di Tor Vergata 135, 00133 Rome, Italy. Note: A. Mastino and B. Macchi contributed equally to this work. Received: 14 September 1999; revised: 2 February 2000; accepted: 9 February 2000. ISSN 0269-9370 & 2000 Lippincott Williams & Wilkins 939