Long-term serological follow-up of patients treated for chronic cutaneous borreliosis or culture-positive erythema migrans.

The kinetics of antibodies to Borrelia burgdorferi following successful treatment of early and late cutaneous borreliosis were analysed in consecutive serum samples by an enzyme-linked immunosorbent assay (ELISA) technique. Twenty-three patients with culture positive erythema migrans were followed for 23+/-14 months: 41% stayed seronegative, 35% showed an isolated immunoglobulin M (IgM) response, 8% an isolated IgG response and 16% a combined IgM and IgG responses. In general, antibody levels peaked within the first 3 months of symptom onset, whereafter a gradual decline was observed within 1 year. Twenty-two patients with chronic cutaneous borreliosis were followed for 23+/-11 months and all patients stayed IgG positive. Nearly three-quarters showed a clear decline in IgG levels over the years, while the rest did not. After 9+/-1 years 88% of 16 patients examined were still IgG positive. In conclusion, treatment of erythema migrans should be initiated on clinical appearance as a substantial number of patients stayed seronegative. Treatment success may in part be monitored serologically for both seropositive erythema migrans and chronic cutaneous borreliosis as most patients show declining titres after successful treatment. However, continuously high titres do not necessarily indicate treatment failure.