Apoptosis and immune response in peripheral blood cells after stimulation with myelin basic protein in HIV+ patients with Leukoencephalopathy

INTRODUCTION: The most consistent hypothesis to explain the slow progression of PML observed in HAART treated patients is that the reconstitution of the immune system may restore immune defenses against JCV leading these patients to a longer survival time. Conversely it has also been observed that in a very limited number of cases the introduction of HAART can contribute, to induce new demyelinating lesions and to their increase in size in already diagnosed PML and in NDLE, a PML-like JCV negative disorders, patients. A possible explanation of controversial effect of immune reconstitution could be immune competent cells switch this activity, probably through molecular mimicry with cross-reacting JCV epitopes, also against self-component like Myelin Basic Protein (MBP). A disregulation of apoptosis could play a key role in inducing or maintaining auto-reactive immune phenomenon. In NDLE and in PML patients, an imbalance of apoptosis could lead to autoimmune demyelination mechanism. METHODS: In our study we analyzed by flow cytometry CD4+ CD8+ apoptotic cells after MBP stimulation in 8 PML, 14 NDLE, 20 Relapsing-remitting (RR) MS groups and 14 Healthy Control (HC). RESULTS: We observed a significant increase of CD8+ apoptotic cell in HC in comparison to MS, NDLE and PML patients (p<0.05). DISCUSSION: These data evidence an activation of immune system against self antigen like MBP in patients with leukoencephalopathy and MS with a decrease of CD8+ apoptotic MBP specific T cells in the same patients. On the whole they suggest that these auto-reactive immune phenomenons could play a relevant role in PML, NDLE and MS.