Angioimmunoblastic lymphadenopathy with dysproteinemia. Immunohistologic and ultrastructural studies.

Immunoblasts of the B-cell line and immunoblasts of the T-cell line have very similar light-microscopic appearances but different immunologic compositions. The immunoblasts of a patient with angioimmunoblastic lymphadenopathy with dysproteinemia were found to bear surface immunoglobulin and complement receptor. They lacked receptor for cytophilic antibody. Surface villous projections were demonstrated by scanning electron microscopy. These features strongly indicate their B-cell origin.