The effect of stress on the transcriptomes of circulating immune cells in patients with Gulf War Illness

Aims: In an effort to gain further insight into the underlying mechanisms tied to disease onset and progression of Gulf War Illness (GWI), our team evaluated GWI patient response to stress utilizing RNA-Seq. Main Methods: The protocol included blood collection before (baseline), during (peak of exercise, measured by VO2 max), and after exercise challenge (recovery – four hours post-exercise challenge). Peripheral blood mononuclear cell (PBMC) transcriptomics data were analyzed using DESeq2 and DEXseq software to understand why GWI patients process stressors differently from their healthy counterparts. Key findings: Our findings validate previously identified dysregulation of immune and inflammatory pathways among GWI patients as well as highlight novel immune and inflammatory markers of disease activity. These results provide a foundation for future research efforts in understanding GWI pathophysiology and creating targeted treatments. Significance: Gulf War Illness is a complex, chronic, and debilitating multi-system illness impacting 25%-30% of the U.S. troops deployed to the 1990-1991 Gulf War. The condition is characterized by medically unexplained fatigue and affects multiple organ systems. Because the underlying mechanisms are largely unknown, patients receive symptom-based treatment, rather than targeting fundamental biological processes. To the best of our knowledge, this is the first study that applies RNA-Seq to analyze the effect of GWI, and the response to stressors in GWI, on the transcriptomic changes in circulating immune cells. RNA-seq of total RNA from peripheral blood mononuclear cells of GWI patients and matched healthy controls that underwent the exercise challenge. Blood was drawn at T0 (baseline, before exercise), T1 (VO2max, peak of exercise) and T2 (recovery, four hours after T1) time points.