Objectives and methods: Brucellosis is characterized by chronicity and relapses despite efficacious treatment. Cytokines and especially the Th1/Th2 balance may be involved in the susceptibility or resistance to the Brucella species. In order to identify predictors of treatment outcome, we measured the pre and posttreatment levels of serum interleukin-2 (IL-2) and soluble IL-2 receptor alpha (sIL-2Ralpha) in 20 children with brucellosis. All children were treated for 6 weeks and three of them (15%) presented with a relapse at 2, 3 and 8 months after treatment had ended.
Results: Serum IL-2 levels, both pretreatment and posttreatment, did not significantly differ between patients and controls. By contrast, pretreatment sIL-2Ralpha levels were significantly higher in patients (P< or =0.0001) than in controls. sIL-2Ralpha levels significantly declined (P<0.001) after the 6-week antibiotic regimen in the 17 children who subsequently had a good outcome without relapses, but not in the three patients who relapsed.
Conclusions: A decline in serum sIL-2Ralpha levels might be used as a marker of treatment efficacy in brucellosis.