The invention relates to carbohydrate ligands and moieties, respectively, mimicking glycoepitopes comprised by glycosphingolipids of the nervous system, particularly glycoepitopes comprised by glycosphingolipids of the cerebroside, the globoside-, the ganglioside- and the sulfoglucuronyl paragloboside type, which are bound by anti-glycan antibodies associated with neurological diseases. The invention further relates to the use of these carbohydrate ligands/moieties, in diagnosis as well as for the treatment of neurological diseases associated with anti-glycan antibodies. In particular, the invention relates to compounds of formula (I) and (II) and to therapeutically acceptable polymers comprising a multitude of these compounds, including polymers with loading of one compound of formula (I) or (II) or combinations of several compounds of formula (I), and/or (II). The compounds of formula (I) are defined as: formula (I), wherein R