DIFFERENTIATION OF SARCOIDOSIS FROM TUBERCULOSIS BY USE OF ELECTRON-CAPTURE GAS-LIQUID-CHROMATOGRAPHY

To explore further the possible etiologic role of mycobacteria in the development of sarcoidosis, we measured free, nonbound tuberculosteari c acid (TSA, 10-methyloctadecanoic), a component of mycobacteria, in t he sera of subjects with sarcoidosis or active untreated pulmonary tub erculosis and in healthy controls by use of frequency-pulsed electron capture gas-liquid chromatography (FPEC-GLC), The selective analytic s ystem is capable of measuring as little as 15-fmol quantities of free, nonbound TSA in serum and cerebral spinal fluid. We found that TSA wa s present in the sera of all subjects with Mycobacterium tuberculosis (n = 10) but was undetectable in subjects with sarcoidosis (n = 15) an d in healthy controls (n = 15), thereby suggesting that if sarcoidosis is caused by a mycobacterial organism, TSA is not produced or does no t gain access to the systemic circulation in quantities sufficient for measurement, However, in the course of the studies we found that a pe ak, designated pll, was elevated in the sera of all subjects with acut e sarcoidosis (n = 4). Also, a peak designated p3 was reduced signific antly in all subjects with acute and chronic sarcoidosis and absent in subjects with M. tuberculosis compared with healthy controls. Both pe aks were later shown by chemical analysis and mass spectral studies to be carboxylic acids not previously associated with specific disease e ntities, Follow-up detailed studies will be needed to determine if qua ntitation of these unique carboxylic acids will be useful in different iating sarcoidosis from other disorders.