Electron-capture gas chromatographic-chemical ionization mass spectrometric study of sera from people vaccinated with bacille Calmette-Guerin for characteristic metabolites.

Serum samples from 26 individuals vaccinated with bacille Calmette-Guerin (BCG) and from 26 controls (10 patients with pulmonary tuberculosis and 16 non BCG-vaccinated healthy individuals) were analyzed by frequency-pulsed electron-capture gas chromatography (FPEC-GC) and chemical ionization gas chromatography-mass spectrometry (CIGC-MS) for the presence of characteristic metabolites. A distinct pattern consisted of tuberculostearic acid (TSA) and a peak, labeled peak 1, was observed in all BCG-vaccinated individuals, whereas only three of 26 controls generated this chromatography profile. TSA was detected in all patients with pulmonary tuberculosis but peak 1 was absent. Sera drawn from 12 individuals 11 to 14 days after BCG vaccination yielded three transitional FPEC-GC profiles. A permanent FPEC-GC profile consisting of TSA and of a full scale peak 1 appeared 28 days to a few months after BCG vaccination. Peak 1 was tentatively identified by CIGC-MS as 9-methyl-hexacosanol. The findings suggest that peak 1 may serve as a marker to detect Mycobacterium bovis BCG and to distinguish individuals infected with M. tuberculosis from individuals vaccinated with BCG.