Erythema chronicum migrans in Sweden: clinical manifestations and antibodies to Ixodes ricinus spirochete measured by indirect immunofluorescence and enzyme-linked immunosorbent assay.

26 Swedish patients with erythema chronicum migrans (ECM) were studied regarding associated clinical symptoms and antibodies to Swedish Ixodes ricinus spirochete. 11/26 (42%) of the patients had associated symptoms, compared to more than 90% of 314 American patients with ECM, as described by Steere et al. Only 2/26 (8%) had multiple skin lesions, compared to 48% of the American patients. Elevated erythrocyte sedimentation rate and circulating immune complexes were demonstrated in 6/25 (24%) and 8/25 patients (32%), respectively, as against in 53% and 84%, respectively, of the American patients. The antibody response to Ixodes ricinus spirochete was measured by indirect immunofluorescence (IFA) and enzyme-linked immunosorbent assay (ELISA). Compared to the 95% percentile of controls, significantly high antibody titers were demonstrated in 3/25 (12%) by IFA, and 7/25 (28%) by ELISA. The ELISA antibody titers differed significantly (p less than 0.05) between ECM-patients and controls. The spirochetal antibody response in ECM was also compared with that in spirochete-associated disease of the central nervous system.