Neopterin and oxidative stress markers in the diagnosis of extrapulmonary tuberculosis.

BACKGROUND: Extrapulmonary tuberculosis (EPTB) often presents with nonspecific signs and symptoms. Further the paucibacillary nature of extrapulmonary specimens and irregular distribution of bacilli lower the sensitivity of conventional diagnostic methods making EPTB, a diagnostic dilemma.

OBJECTIVE: To study neopterin, protein carbonyl and malondialdehyde (MDA) in EPTB.

METHODS: Sixty nine clinically confirmed cases with an equal number of age and sex matched healthy controls were enrolled. Ziehl-Neelsen staining for acid fast bacilli and culture on Lowenstein-Jensen medium were performed on all the extrapulmonary specimens. Serum neopterin and protein carbonyl levels were estimated using commercial ELISA kits. Malondialdehyde was determined by measuring thiobarbituric acid reactive substances.

RESULTS: Serum neopterin, protein carbonyl and MDA levels were significantly discriminative for cases of EPTB from healthy controls (p < 0.05). Levels of all the three biomarkers under study significantly differed between culture as well as smear positive and negative cases. A positive correlation between neopterin and protein carbonyl was seen among the cases.

CONCLUSIONS: So far few studies have integrated combination of validated host biomarkers for active disease in EPTB. Our study suggests the potential diagnostic role of neopterin, protein carbonyl and MDA in EPTB.