Intracellular immunoglobulin in lymphocytes from patients with chronic lymphocytic leukemia: an immunoelectron microscopic study.

The presence of ultrastructural distribution of intracellular immunoglobulin (Ig) in leukemic cells from patients with chronic lymphocytic leukemia (CLL) and in normal B cells were investigated by an immunoelectron microscopic technique. Most normal B cells had no intracellular Ig in spite of the presence of surface Ig. However, leukemic cells from 10 to 11 patients with CLL contained intracellular Ig and showed various staining patterns. In eight patients, Ig was present in the perinuclear space (PN), the endoplasmic reticulum (ER) and, if identified, the Golgi complexes. In four patients, most cells had diffuse staining of the cytoplasm. In five patients, Ig was detected in the ER-associated structures or the vesicles, in addition to the PN and ER. These findings suggest that CLL cells have a greater capacity to produce Ig than those of normal B cells and include various clones with distinct staining patterns of intracellular Ig.