Hey Mahdi. I suggest you look here https://www.1177.se/Varmland/Regler-och-rattigheter/Var-for-personer-fran-andra-lander/ (Swedish)
In the information you can read that you need to have the European insurance card with you or a attestation/certification from the Swedish Insurance agency that you have the right to get medical treatment in Sweden (EU-member). If you cannot provide that card or certificate you have to pay the full amount for doctor and medication. Contact the insurance agency where you live to get the documents you need before going to Sweden.

I would recommend that you contact the hospital in the city where you will study to inform them that you will need Tysabri treatment during your stay in Sweden, so you have eveything prepared. Also bring your medical journal from your doctors at home (in English or Swedish). Good luck!