Russell bodies

Russell bodies are eosinophilic, large, homogenous immunoglobulin-containing inclusions usually found in a plasma cell undergoing excessive synthesis of immunoglobulin; the Russell body is characteristic of the distended endoplasmic reticulum. They are found in the peripheral areas of tumors. Russell bodies are thought to have originated as an SOS compartment, where abnormal proteins that are not secreted, but have fled intracellular degradation, can gather without blocking normal secretory pathways. The excess immunoglobulin builds up and forms intracytoplasmic globules, which is thought to be a result of insufficient protein transport within the cell. This causes the proteins to neither be degraded or secreted and stay stored in dilated cisternae. In 1949, Pearse discovered that Russell bodies also contain mucoproteins that are secreted by plasma cells. Russell bodies are not tissue specific; during research they were induced in rat glioma cells. Russell bodies were found to have positive reactions to PAS stain, CD 38 and CD 138 stains. Plasma cells that contain Russell bodies and are stained with H&E stain are found to be autofluorescent, while those without Russell bodies are not autofluorescent. Russell bodies tend to be found in places with chronic inflammation. Multiple aggregrates of Russell bodies create what are known as Mott cells.