Clinical Relevance of Different IgG and IgM Serum Antibody Responses to Borrelia burgdorfer/ After Antibiotic Therapy for Erythema Migrans

To investigate the kinetics of anti-Borrelia burgdorferi antibodies for a minimum of 1 year after antibiotic therapy in patients with erythema migrans (EM) and to correlate antibody titer kinetics with clinical variables. Retrospective study of serial anti-B burgdorfer/antibodies in correlation to clinical variables. University-based hospital. One hundred thirteen patients with EM. Pretreatment and a median of 4 consecutive posttreatment serum samples from median follow-up of more than 400 days were simultaneously investigated for anti-B burgdorferi lgG and 1gM antibodies. Semiquantitative titers were plotted to identify different groups of antibody kinetics. Individual patients were then stratified to those groups according to their antibody development. A statistical comparison of clinical and therapy-related characteristics among the serologic groups was performed. Anti-B burgdorferi lgG and 1gM antibody titers developed in 3 distinct courses: persistent positivity across follow-up (lgG: 12 patients, 11%; 1gM: 14, 12%), persistent negativity (lgG: 63, 56%; 1gM: 47, 42%), and decrease of a positive pretreatment titer to a negative titer approximately 5 months after therapy (lgG: 34, 30%; 1gM: 49, 43%). Statistics revealed significant correlations only between persistent positive lgG titers and long disease duration or large EM lesions before therapy. Long duration or large size of EM before therapy correlates with persistence of a positive anti- B burgdorferi lgG antibody titer after therapy. Serologic profiles do not depend on the type or duration of therapy or the clinical course thereafter. Thus, antibody testing in the follow-up of patients with EM is inappropriate for the assessment of therapeutic response.