Rickettsia infection could be the missing piece of the Buerger's disease puzzle

BACKGROUND: Rickettsia was suggested as a possible etiology of Buerger's disease (BD) in the 1980s but this suggestion was never ruled out or proven. Recently, we found evidence of Rickettsia by polymerase chain reaction in 3 out of 25 biopsy samples from the amputated limb of a young man diagnosed with BD. The aim of this paper was to investigate the presence of anti-rickettsial antibodies in the sera of BD patients. METHODS: To detect the IgG class antibody against Rickettsia rickettsii, which has cross reactions with the spotted fever group (RSFG), and Rickettsia typhi, which has cross reactions with typhus fever group, the sera of patients and controls were diluted to 1:64 and analyzed by indirect micro fluorescence immunoassay (MIF). RESULTS: The MIF study showed that 26 of the 28 patients were positive for Rickettsia rickettsii antibodies and MIF had the same appearance as the positive control, which was provided with the kit. In all members of the healthy control group, Rickettsia rickettsii was negative and had the appearance of the negative control. Rickettsia typhi was negative for all patients and members of the control group. CONCLUSIONS: A species of Rickettsia associated with the RSFG, which might not be pathogenic for the entire population, may induce BD in the context of a specific genetic or environmental background. RSFG infection could explain key questions about BD, including its gender and geographical distribution, clinical manifestation, angiography pattern, and pathological findings. Evaluating antibodies against RSFG in BD patients from different countries is now highly recommended.