This thesis describes the clinical significance of thebiomarker C4d, a split product of the complement system, in several manifestations of systemic autoimmunediseases such as SLE and... Show moreThis thesis describes the clinical significance of thebiomarker C4d, a split product of the complement system, in several manifestations of systemic autoimmunediseases such as SLE and antiphospholipid syndrome. The findings in this thesis suggest that this biomarker might be of use in unraveling disease mechanisms where complement activation is involved, as well as serving as a diagnostic tool to detect patients at risk of antibody mediated tissue injury Show less