A MODEL OF THE ROLE OF COFACTORS
IN THE INITIATION AND DEVELOPMENT OF AIDS

STEPHEN J. MERRILL AND ROBERT S. ROOT-BERNSTEIN

Abstract. Understanding the process by which the Human Immunodeficiency Virus (HIV) infects cells in a new host and initiates the steps leading to AIDS requires that both the nature of the initial infection and interactions of the virus and the host be delineated. Factors which must be considered include the nature of the strain of the infecting virus, the state of the host at the time of infection, and the immune response of the host to the virus. The state of the host certainly includes the general "health" and immunological status. In this paper, the role of "cofactors" as seen through antigen load at the time of infection is explored. The motivation for construction of a mathematical model is given by epidemiological observations and laboratory findings suggesting that chronic infections of particular types may make a host more suscep tible to an HIV infection. In addition, these "cofactors" may also modulate the rate of disease progression and the clinical nature of the disease itself. What might modulate the susceptibility of the host to HIV infection is a primary question here. The behavior of model solutions suggest that certain individuals may not be susceptible to an HIV infection if exposed to a small dose. And, that an early infection may be aborted by an appropriate change in host parameters. This suggests that identifying and treating the underlying cofactors may be of therapeutic value in early stages of HIV infection.