Changes in immune parameters seen in Gulf War veterans but not in civilians with chronic fatigue syndrome

The purpose of this study was to evaluate immune function through the asses sment of lymphocyte subpopulations (total T cells, major histocompatibility complex [MWC] I- and II-restricted T cells, B cells, NK cells, MHC II-rest ricted T-cell-derived naive and memory cells, and several MWC I-restricted T-cell activation markers) and the measurement of cytokine gene expression (interleukin 2 [IL-2], IL-4, IL-6, IL-10, IL-12, gamma interferon [IFN-gamm a] and tumor necrosis factor alpha [TNF-alpha]) from peripheral blood lymph ocytes, Subjects included two groups of patients meeting published case def initions for chronic fatigue syndrome (CFS)-a group of veterans who develop ed their illness following their return home from participating in the Gulf War and a group of nonveterans who developed the illness sporadically. Cas e control comparison groups were comprised of healthy Gulf War veterans and nonveterans, respectively. We found no significant difference for any of t he immune variables in the nonveteran population. In contrast, veterans wit h CFS had significantly more total T cells and MHC II+ T cells and a signif icantly higher percentage of these lymphocyte subpopulations, as well as a significantly lower percentage of NK cells, than the respective controls. I n addition, veterans with CFS had significantly higher levels of IL-2, IL-1 0, IFN-gamma, and TNF-alpha than the controls. These data do not support th e hypothesis of immune dysfunction in the genesis of CFS for sporadic cases of CFS but do suggest that service in the Persian Gulf is associated with an altered immune status in veterans who returned with severe fatiguing ill ness.