Introduction:
Advanced glycation end-products (AGE) are involved in the pathogenesis of many diseases, including neurodegenerative diseases such as multiple sclerosis (MS). The aim of the study was to evaluate the intensity of the protein glycation process in patients with multiple sclerosis and its possible involvement in disease activity.

Material and methods:
The study group (n = 45) consisted of patients suffering from MS, and the control group (n = 31) consisted of healthy adults. Concentrations of selected glycation markers such as carboxymethyllysine (CML) and carboxyethyllysine (CEL) in sera of patients with MS and healthy volunteers were determined by enzyme-linked immunosorbent assay (ELISA).

Results:
Serum CML and CEL concentrations in patients with MS were higher than in healthy volunteers but only for CML the difference was statistically significant. CML concentrations positively correlated with CEL concentrations only in the healthy persons. In MS patients the serum CML and CEL concentrations did not differ significantly depending on the duration of the disease and depending on the EDSS (Expanded Disability Status Scale) score.

Conclusions:
Multiple sclerosis is accompanied by an intensification of protein glycation processes, especially within the pathways leading to the formation of carboxymethyllysine. The duration of the disease and the degree of motor impairment do not appear to affect the progression of the glycation processes. However, the disease process associated with multiple sclerosis may affect the relationship between CML and CEL concentrations.