High prevalence of 'Borrelia-like' organisms in skin biopsies of sarcoidosis patients from Western Austria

Background Sarcoidosis is a multisystem granulomatous disorder of unknown aetiology with frequent skin involvement. Objective To investigate the frequency of 'Borrelia-like' organisms in cutaneous sarcoidosis (CS) by focus-floating microscopy (FFM). Methods Retrospective analysis of 38 CS specimens by immunohistochemistry with polyclonal anti-Borrelia antibody and assessment by FFM. Results Specimens of 34.2% CS were positive for 'Borrelia-like' organisms by FFM. Usually single spirochetes, rarely pairs or small clusters of bacteria were observed between collagen bundles or at the periphery of granulomas. Polymerase chain reaction (PCR) was performed in addition in 11 cases and was negative in all biopsies. Samples of erythema migrans served as positive controls: 92.3% of 39 samples were positive by FFM, but only 46.6% gave positive results by PCR. Of 61 negative controls only one specimen was falsely positive by immunohistochemistry. Conclusion Detection of 'Borrelia-like' organisms by FFM in tissue sections of CS underlines the possibility that such microorganism may be involved in the pathogenesis of some cases of CS. Derler AM, Eisendle K, Baltaci M, Obermoser G, Zelger B. High prevalence of 'Borrelia-like' organisms in skin biopsies of sarcoidosis patients from Western Austria.