Tuberculostearic acid in lymph nodes from patients with sarcoidosis.

It has earlier been suggested that mycobacteria may play an aetiological role in the development of sarcoidosis. To investigate this further we analyzed the presence of a characteristic mycobacterial constituent, tuberculostearic acid (TS, 10-methyloctadecanoic acid), in lymph nodes from 22 patients with sarcoidosis and in eleven children and three adult controls. To detect TS gas chromatography/mass spectrometry was used. These findings were compared with the results from conventional mycobacterial culture and radiometric respirometry. Although the latter techniques failed to detect mycobacteria in all the tested tissue samples, TS was found in various amounts. Thus, 0-3 micrograms TS/g freeze-dried tissue was noted in eight sarcoid patients, 3-50 micrograms TS/g in eight and 51-400 micrograms TS/g in the remaining six patients. Among the controls only 1/14 had detectable TS. In one patient with lymph node tuberculosis TS was in the range 51-400 micrograms/g. We conclude that the findings could be explained by the presence of mycobacteria not cultivable with the studied techniques or with the presence of remnants after an earlier colonisation with mycobacteria, e.g. BCG-vaccination. Mycobacteria or mycobacterial cell-envelope in sarcoid tissue may possibly act as cofactors in the development of the disease, i.e. they might function as triggering agents (adjuvans) of the immune response. On the other hand the findings may be without any aetiological significance. In that latter case a hitherto unknown lack of wax decomposition during several decades has to be considered.