Polymerase chain reaction （PCR） was used to detect the presence of Barrelia burgdoferi DNA in biological samples from patients with sarcoidosis. The target DNA sequence was of chromosomal origin. The amplified DNA sequence was analyzed by agarose gel electrophoresis

PAGE with silver staining

and the identity of amplified DNA was confirmed by restriction enzyme cleavage and DNA-DNA hybridization with a 32P-labelled probe. The assay was sensitive to fewer than two copies of B. burgdorferi genome

even in the presence of a 104-fold excess of human eukaryotic DNA

and was also specific to different B. burgdorferi strains tested. Sera serologically positive to B. burgdcrferi （n=26）

bronchoalveolar lavage fluid and supernatant of BALF （n=26） and peripheral blood （n=9） from sarcoidosis patients were tested. The positive rate was low （4/26

2/26. and 0/9

respectively）. It was considered that DNA from B. burgdor ferimay be identified in a minority of patients with sarcoidosis

and it may play a pathogenetic role in such cases. More studies need to be done before advancing the hypothesis of an etiologic role of B. burgdorferi in sarcoidosis.