NEOPTERIN AS A MARKER FOR CELL-MEDIATED-IMMUNITY IN PATIENTS WITH PULMONARY TUBERCULOSIS

SETTING: Cell-mediated immunity (CMI) involves macrophage activation a nd T cell proliferation. These two parameters are compared in this stu dy. OBJECTIVE: To ascertain the role of neopterin as a biochemical mar ker for CMI in patients with pulmonary tuberculosis. DESIGN: We measur ed neopterin levels in serum and the culture supernatants of periphera l blood mononuclear cells (MNC) after stimulation with purified protei n derivative (PPD) in 11 patients with pulmonary tuberculosis and 10 h ealthy individuals. Lymphocyte proliferative response to PPD was carri ed out in these two groups. RESULTS: The mean concentration of serum n eopterin was significantly higher in patients than in controls (P < 0. 01). The spontaneous release of neopterin was significantly higher in culture supernatants of MNC from patients when compared with those of healthy controls (P < 0.05). Release of neopterin from MNC stimulated with PPD, however, was similar in both groups. The neopterin release a nd the stimulation index (SI) in lymphocyte proliferation assay were n ot comparable, suggesting that these two parameters do not run in para llel for measuring the status of CMI. However, serum concentration of neopterin was inversely related to the SI in a large proportion of sub jects (66%). CONCLUSION: Measurement of neopterin, a soluble product o f immune cells (macrophage), may provide information on the state of C MI.