What is the role of giant cells in AL-amyloidosis?

AL-amyloidosis is one of the most common amyloidoses and can be found in a localized and a systemic form. The precursor protein is an immunoglobulin l ight chain which as AL-protein in both localized and systemic AL-amyloidosi s shows the same pattern of fragmentation and changes of primary structure. In this work it is shown that that there is a difference between localized and systemic amyloidosis in respect to accompanying giant cells which cons tantly are found associated with amyloid deposits in localized AL-amyloidos is. In addition, giant cells were found together with amyloid deposits in l ymph nodes of some cases of systemic AL-amyloidosis. Based on these finding s and electron microscopic studies, it is discussed whether the giant cells actively participate in amyloid fibril formation by uptake and modificatio n of the precursor protein or the giant cells are part of a foreign body re action. Included in this work are two new cases of localized lung (lambda I ) and ureteric (rd) AL-amyloidosis.