Modeling of HIV mediated derangement of immune system dynamics

Acquired Immuno-Deficiency Syndrome (AIDS) is a dreaded outcome of HIV (Human Immunodeficiency Virus) attack on the human immune system. The application of mathematical models to HIV data is resulting in a steady stream of studies, which are leading to better understanding and prediction of the behavior of the virus and the immune system, and are helping clinicians in making the very complex choices involved in treating HIV-infected patients. The aim of the present study is primarily focused on two aspects: (i) how does this complex mechanism work when there is a foreign particle (HIV antigen) inside the body and, (ii) what could happen if one or more components of the immune system do not function properly. Our model shows that HIV antigen triggers off the unstable state. However, since HIV itself is attaching to the CD4 cells, instead of a steady rise, there is actually a steady decline of CD4 cell count, moving the dynamics of the system towards the immunodeficient steady state. Our model is also capable of predicting the dynamics in abnormal performance of the system. HIV as an antigen stimulates more formation of CD4 cells. But, further rise in HIV count actually suppresses CD4, leading to progress of the diseased state to full blown AIDS. From our preliminary findings, we can justifiably look ahead in the following manner. There is a slow decline of CD4 cells in the latent infection stage. This can now be modeled by altering our parameters suitably to purvey insight into the factors responsible. These factors can then be taken care of by new groups of anti-HIV drugs, which may reduce the severity and speed of disease progression