Effect of Probiotics on Serum Cytokines in Irritable Bowel Syndrome With Gulf War Illness

Introduction: Gulf war illness (GWI) is a multisystem disorder of unknown etiology. There is high prevalence of IBS among Veterans with GWI. There is inconsistent evidence that low grade chronic gastrointestinal (GI) inflammation may play a part in the pathogenesis of IBS and GWI. We examined the blood cytokines profile of Veterans with IBS and GW illness before and after treatment with probiotics. Methods: In a randomized double-blind placebo controlled trial we enrolled Veterans with IBS (Rome III criteria) and two or more symptoms of GWI. Veterans were randomized to receive probiotic (De Simone Formulation; formally known as VSL#3) or identical placebo. Blood was collected at enrollment and after 8-week treatment with probiotics. A multiplexed immunoassay was used to assess the serum concentration of 13 cytokines/inflammatory markers: interferon (IFN)-γ; interleukins (ILs)-1β, 2, 4, 5, 6, 8, 10, 12, 13, and 17; tumor necrosis factor (TNF-α, IL-2 receptor. The cytokine levels were compared to reference intervals established on 120 healthy controls. Results: Data was analyzed from 42 Veterans who provided baseline and 11 Veterans who provided both pre and post treatment blood samples for cytokine analysis. The serum pro- and anti-inflammatory cytokines levels were no different between IBS with GWI and healthy controls. There was no change in pro- or anti-inflammatory cytokines after treatment with probiotics (Figure). Conclusion: The level of pro- and anti-inflammatory cytokines were no different in Veterans with IBS and GWI compared with healthy controls and the levels do not alter after treatment with probiotics. The role of cytokines in pathophysiology, and as a biomarker of treatment of IBS and GWI is likely complex and remains unknown.Figure 1.: Comparison of Pre and Post treatment with probiotics cytokines (mean±SE)