Background/aims: Host-related immune factors in childhood chronic hepatitis B and change in the initial profile with interferon (IFN)-alpha treatment need to be clarified. Methods: Sixteen patients were included in the study, and 10 million units of IFN-alpha treatment 3 times per week for 6 months was initiated. Pre- and post-treatment percentages of interleukin (IL)-2 and IFN-gamma in CD4+ T cells were assessed to determine intracellular T helper cell 1 (Thl) type cytokine expression. Similarly, percentages of intracellular IL-2 and IFN-gamma were detected to verify cytotoxic T cell 1 (Tc1) type cytokine expression in CD8+ T cells. Percentages of Th2 and Tc2 type cytokine expression (IL-4 and IL-13) were determined in CD4+ and CD8+ T cells, respectively. Resuts: Six (50%) of these were evaluated as having no response and the other half with partial complete response. All patients had higher percentages of Th2 cells with respect to healthy controls pre-treatment. Tc percentages, both Tc1 and Tc2, were significantly different between these groups, being higher in the patient group. When values of the nonresponder group were compared with healthy controls, IL-4 expression was higher and the percentages of Th1 type cells were significantly low. IL-13 expression in Th2 and Tc2 cells decreased after 6 months of treatment in the unresponsive group. The decrease we observed in Th1 percentages with treatment, in the responsive group, may be due to Thl deposition shifting from the periphery to liver tissue, as reported before. Intracellular cytokine profiles of treatment responders and normal controls were not different. Results: This is the first study in children comparing baseline and post-treatment intracellular cytokine profiles with values in healthy controls.