Excess m chains are present in the peripheral blood and k light chains sometimes found in the urine. Amyloidosis Amyloidosis is a syndrome in which proteins with a b pleated sheet secondary structure accumulate in tissues. The b pleated sheet structure causes a green birefringence when Congo red stained material is polarized. Amyloid fibrils consist of two paired filaments,creating a parallel array. This imposes a regular parallel order to the molecules of Congo red dye,causing polarization of light and the birefringentproperties characteristic of amyloid.
Amyloid infiltrates cause organ damage resulting in failure as in the nephrotic renal syndrome.
Heart failure can be seen secondary to amyloid deposition in the cardiac conduction system. GI tract infiltration can cause macroglossia, hemorrhage, malabsorption, diarrhea, and obstruction. Summary In summary, plasma cell disorders are malignant proliferations of B lymphocyte origin. Although the terminally differentiated cell is the cell we observe, immunologic and molecular genetic studies indicate that the disorders arise in genetic events at an early stage in B cell development. The infiltrating cells are lymphocytes, plasmacytoid lymphocytes, and plasma cells producing monoclonal immunoglobulin proteins.