[Longitudinal assessment of IFN-gamma production in patients with pulmonary tuberculosis complicated with diabetes mellitus].

ABSTRACT

Patients with diabetes mellitus (DM) are more susceptible to bacterial infection including pulmonary tuberculosis. To define the immunopathologic mechanisms underlying pulmonary tuberculosis in patients with DM, the production of IFN-gamma by CD4+ T cells or PBMC were followed up longitudinally during antituberculous chemotherapy. At the time of diagnosis, IFN-gamma production by CD4+ T cells in either tuberculosis patients without DM (TB) or with DM was significantly lower than that in the healthy control. CD4+ T cells in tuberculosis patients with DM under poor control (DM(p)TB) produced significantly less IFN-gamma than did patients with DM under good control (DM(g)TB). In longitudinal studies, IFN-gamma production in both TB and DM(g)TB patients returned to the control level by 6 months, whereas the production in DM(p)TB patients remained depressed. There was no significant relation between regimens of antituberculous chemotherapy and the production of IFN-gamma by PBMC in all subject groups. IFN-gamma production was depressed in DM(p)TB patients treated with HREZ for 6 months. These results indicate that depressed production of IFN-gamma in DM(p)TB patients is prolonged not due to tuberculous infection but intrinsic defect presumably induced by poorly controlled DM.