An output-feedback MPC-based scheduling method for enhancing immune response to HIV

Recently developed models of the interaction of the human immune system and the human immunodeficiency virus (HIV) suggest the possibility of using interruptions of highly active anti-retroviral therapy (HAART) to simulate a theraputic vaccine and induce cytotoxic lymphocyte (CTL) mediated control of HIV infection. In previous work we have developed a model predictive control (MPC) based method for determining optimal treatment interruption schedules for this purpose. In this paper, we introduce a nonlinear observer for the HIV-immune response system and an integrated output-feedback MPC approach for implementing the treatment interruption scheduling algorithm using the easily available viral load measurements. We explore the robustness of this method to inevitable variations in the patient model, and discuss the implications of the results