The spontaneous and stimulated nitroblue tetrazolium (NBT) tests in mononuclear cells of patients with tuberculosis
Dubaniewicz A, Dubaniewicz A, Hoppe A

Purpose: The aim of this study was to evaluate the ability of the NBT reduction by non- and BCG-stimulated monocytes isolated from peripheral blood persons with pulmonary tuberculosis (TB) before treatment, after two-month antituberculosis therapy and in an inactive stage of this disease. 
Material and methods: The spontaneous and induced NBT tests were done in 24 healthy individuals and 59 patients with pulmonary tuberculosis: 33 before antituberculosis treatment and 26 with inactive stage of TB. Mononuclear cells were isolated from peripheral blood by the Břyum method and indentified by histochemical assay. The abilities of non- and BCG-stimulated monocytes of NBT reduction were estimated by the method according to Park with Szczylik modification. 
Results: In an active state of TB and after 2 months treatment, the non- and BCG-stimulated monocytes capacity to reduce NBT was found to be significantly increased in comparison to controls. The NBT test parameters in the absence of cell stimulation and after administration of BCG were comparable in active TB and after two-month treatment. In an inactive TB, the ability of NBT reduction by non- and BCG-stimulated monocytes was comparable to the controls. The stimulation of mononuclear cells accompanied by the significantly higher capacity of monocytes to reduce NBT in controls and in TB patients with post-tuberculous changes in the lungs.
Conclusions: These results of the spontaneous and induced NBT tests adequately reflect the status of the host’s specific reactivity during tuberculosis and can be simple, cheep and useful for a monitoring antituberculosis treatment. 

Key words:   NBT test, monocytes, tuberculosis.