Borrelia burgdorferi DNA in biological samples from patients with sarcoidosis using the polymerase chain reaction technique.

Polymerase chain reaction (PCR) was used to detect the presence of Borrelia 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 10(4)-fold excess of human eukaryotic DNA, and was also specific to different B. burgdorferi strains tested. Sera serologically positive to B. burgdorferi (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. burgdorferi may 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.