In all but four cases of CLL with or without monoclonal serum Ig, intracytoplasmic
Ig could not be demonstrated in those lymphocytes carrying 5.1g.
This negative finding is probably due to the lack of sensitivity of the immunofluorescence
technique on fixed cells, this procedure being less sensitive than
the surface staining because of its unavoidable background. Exceptions to
this rule were observed in a patient with a high level of monoclonal serum
IgG in whom the cytoplasm of numerous lymphocytes was stained and in
the three patients with intracytoplasmic crystalline inclusions.