The production of cytokines (MIG, IFN-gamma, TNF-alpha, IL-4, IL-5, and IL-10) was studied in 39 individuals, including 28 with chagasic esophagopathy and 11 nonchagasic patients with gastroesophageal reflux disease. A sandwich enzyme immunoassay employing monoclonal antibody pairs specific for each cytokine was used. IFN-gamma and MIG production was significantly higher in patients with megaesophagus compared to control. Furthermore, in the absence of stimulation TNF-alpha levels were lower in the chagasic group than in the control group. In addition, significantly lower TNF-alpha levels were observed for the advanced form of the disease compared to the nonadvanced form. These results support the hypothesis that, although patients with advanced phase of megaesophagus present low number of CD4+ T lymphocytes, PBMC from this patients are able to respond up specific antigen stimulation.