pathology

Last reviewed 01/2018

The majority of cases of CLL result from malignant transformation of a B cell; less frequently, of a T cell. In any particular case B or T cell clonality can be established using DNA probes. The malignant lymphocyte is indistinguishable morphologically, from a normal small, relatively mature lymphocyte.

Smear cells are common which have:

• weakly fluorescent surface membrane immunoglobulin (SmIg) of IgM or IgD class
• membrane receptors for the Fc fragment of IgG and for C3
• positive for Ia and CD5 antigens

CLL differs from multiple myeloma in that CLL is derived from small, relatively mature lymphocytes whereas multiple myeloma is derived form bone marrow plasma cells and their precursors.