Background: Lyme borreliosis is a tick-transmitted, chronic, zoogenous disease caused by Borrelia burgdorferi spirochete. The clinical picture of Lyme disease is characterized by the variety of tissue and organ involvement and differing severity of symptoms. One of the pathogenic symptoms of early Lyme disease is a skin lesion called erythema migrans.
Material and methods: The purpose of our research was to estimate the parameters of the antioxidant system and the concentration of lipid peroxidation products in the plasma of patients with erythema migrans (EM). The parameters measured included the activity levels of superoxide dismutase (SOD) according to Sykes, gluthatione reductase (GSSG-R) according to Mize and Langdon, glutathione peroxidase (GSH-Px) according to Paglia and Valentine; the concentrations of malondialdehyde (MDA) were examined by means of a Bioxytech LPO-586 kit. The total sulphydryl groups (-SH) according to Ellman and reduced glutathione (GSH) were measured using a Bioxytech GSH-400 test in plasma samples collected from 20 patients with EM aged from 19 to 50, taken before (examination 1) and after (examination 2) therapy with amoxycycline. The control group consisted of 8 healthy people.
Results: The results of our examinations prove that beta-lactamase antibiotic therapy brings non-enzymatic antioxidant parameters to control values, though the treatment causes no change in enzymatic antioxidant parameters, resulting in the further activation of free radicals.
Conclusions: In patients with Erythema migrans, the decreased capability to reduce lipid superoxidants leads to maintaining a high concentration of membrane lipid peroxidation products.

Keywords: Lyme borreliosis, erythema migrans