The PPMS patients have the highest mean age in our cohort and this corresponds well with the age-dependent increase of iron release in the white matter seen in the above mentioned study [39].The elevated levels of sCD163 could be a mechanism of tissue homeostasis and repair and thus CD163 could be a marker of immune modulatory functions regarding not only degeneration and anti-inflammation but also tissue repair [40], [41]. Here, CD163 is linked to primary progressive multiple sclerosis.