Early Lyme disease: Humoral immune status and treatment.

OBJECTIVE: To investigate the humoral immune status and the effect of antibiotic treatment in Bulgarian patients with early Lyme disease. METHODS: A total of 34 early Lyme disease patients was examined, 16 with erythema migrans and 18 with non-specific systemic symptoms. Serum samples from all patients and from 12 healthy controls were tested for total immunoglobulins (IgG, IgA and IgM), hemolytic activity of complement (CH50) and immune complexes (ICs). The patients were treated with doxycycline (100 mg orally, twice daily for 10 to 15 days, in one or two courses). RESULTS: The patients showed significantly increased IC levels (P<0.01 for patients with erythema migrans and P<0.001 for patients with non-specific symptoms). There were no significant changes in the levels of total hemolytic complement and total immunoglobulins (IgG, IgA and IgM). The clinical outcome was satisfactory in 21 of the 34 patients (61.8%) after treatment with doxycycline for 10 to 15 days. The rest of the patients (38.2%) failed to respond to the therapy, and continued to report various complaints, such as arthralgia, myalgia, paresthesia, headache, fatigue or recurrent rash. All of these had elevated levels of IC. After a second course of treatment with the same antibiotic regimen these patients had resolution of symptoms (12 patients) or improvement (1 patient). CONCLUSIONS: Immunologic investigation may be useful in determining treatment strategy in Lyme disease. Elevated IC levels may indicate a need for more prolonged antibiotic therapy.