Serial evaluation of serum neopterin in HIV seronegative patients treated for tuberculosis.
OBJECTIVE: To delineate the course of serum neopterin (s-neo) concentrations in patients with pulmonary tuberculosis who are on anti-tuberculosis therapy. DESIGN: S-neo concentrations were measured by high performance liquid chromatography (HPLC) in 39 patients treated for pulmonary tuberculosis at pretreatment, at one month and at end of treatment. It was also measured in 11 relapse cases and their matched controls at the above time points and at the time of relapse. The results were correlated with bacteriological and radiological findings. RESULTS: All patients had elevated levels of s-neo at pretreatment which had declined at 1 month and were near normal at the end of treatment. The decline was more significant in patients with moderate lesions, suggesting that immune activation is maximum in this group of patients. The mean decrease was 37% at one month and 66% at the end of treatment. The corresponding decreases were 11% and 56% in patients with limited lesions and 11% and 45% in those with extensive lesions. It continued to fall after completion of therapy in patients who did not relapse, whereas an increase after completion of therapy was associated with bacteriologically proven relapse. CONCLUSIONS: The measurement of s-neo concentration could be of help in evaluating response to therapy. This study provides a rational basis for the association between s-neo concentration and relapse.