Intracellular IgA immunoglobulin crystals in chronic lymphocytic leukaemia

Abstract

Lymphocytes from a case of chronic lymphocytic leukaemia were found to contain crystalline protein inclusions within cisternae of rough endoplasmic reticulum. These inclusions were characterized as IgA λ immunoglobulin and differed from the immunoglobulins found at the surface of the cells containing the inclusions. No serum paraprotein was detected in the serum of the patient, although small amounts of λ light chain protein were present in the urine. These observations suggest that the crystalline immunoglobulin was not excreted in significant amounts by the lymphocytes.