Feedback Regulation of Immune Response to Maximum Exercise in Gulf War Illness

Gulf War Illness is a disease that affects about a third of the veterans that served in the 1990-91 Persian Gulf War. The symptoms are varied, the cause is unknown, and there is no known treatment. In this paper we compare the dynamic characteristics of cytokines feedback response to exercise in n=12 veterans diagnosed with Gulf War Illness (GWI) and n=12 healthy veterans deployed to the same theatre of operations. A third-order transfer function is used to model the process dynamics of 18 cytokines projected onto principal components with a Proportional Integral Derivative (PID) controller enforcing the homeostatic regulation of these co-expression patterns. Transfer functions were fit to each subject for each principal component and the dynamic response parameters compared between the veteran control and GWI subject groups. Results of this analysis indicate that while much of the regulatory response dynamics are shared by both groups, there is a significant difference in the damping of the Th1:Th2 cytokine response to exercise in Gulf War Illness.