Serum cytokine responses during acute human granulocytic ehrlichiosis

Human granulocytic ehrlichiosis (HGE) is caused by obligate intracellular b acteria in the Ehrlichia phagocytophila group. The disease ranges from subc linical to fatal. We speculated that cell-mediated immunity would be import ant for recovery from and potentially in the clinical manifestations of HGE ; thus, serum tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta ( IL-1 beta), gamma interferon (IFN-gamma), IL-10, and IL-4 concentrations we re studied, IFN-gamma (1,035 +/- 235 pg/ml [mean +/- standard error of the mean]) and IL-10 (118 +/- 46 pg/ml) concentrations were elevated in acute-p hase sera versus convalescent sera and normal subjects (P less than or equa l to 0.013 and P less than or equal to 0.018, respectively). TNF-alpha, IL- 1 beta, and IL-4 levels were not elevated. Cytokine Levels in severely and mildly affected patients were not different. HGE leads to induction of IFN- gamma-dominated cell-mediated immunity associated with clinical manifestati ons, recovery from infection, or both.