Detection of spirochaetal microorganisms by focus floating microscopy in necrobiosis lipoidica in patients from central Europe.

AIMS: Necrobiosis lipoidica (NL) is a chronic inflammatory skin disease with unknown aetiology. The aim was to determine the presence of spirochaetal microorganisms in NL.

METHODS AND

RESULTS

Focus-floating microscopy (FFM) is a modified immunohistochemical technique that was developed to detect borrelial spirochaetes within tissue sections. It has proven to be more sensitive for the detection of spirochaetes than polymerase chain reaction (PCR). Fifty-six cases of NL as well as 44 negative and 33 positive controls were investigated for the presence of Borrelia within tissue specimens. Using FFM, Borrelia could be detected in 42 cases (75.0%) and were seen significantly more often in histologically active inflammatory-rich (38/41, 92.7%) than in inflammatory-poor (4/15, 26.7%) cases of NL (P < 0.001). Seven cases investigated with a Borrelia-specific PCR (23s-RNA) remained negative. In contrast, FFM was positive in 30 of 33 (90.9%) positive controls of acrodermatitis chronica atrophicans and 15 of the positive controls (45.5%) were also positive with PCR, whereas no negative controls revealed any microorganisms.

CONCLUSIONS

Detection of spirochaetes in NL points to a specific involvement of B. burgdorferi or other similar strains in the development of or trigger for this disease.