Ultrastructural, Immunologic, and Functional Studies on Sézary Cells: A Neoplastic Variant of Thymus-Derived (T) Lymphocytes

Abstract

The vast majority of human lymphoid neoplasms examined to date have been associated with a proliferation of bone marrow-dependent (B) lymphocytes. In an effort to delineate human tumors of T-cell (thymusdependent) lineage, use was made of the peripheral blood leukocytes of sixteen subjects with various forms of mycosis fungoides. The abnormal cells in the circulation of these patients are morphologically identical to those that infiltrate their nodes and skin. On electron microscopy, such neoplastic lymphocytes (S6zary cells) had "cerebriform" nuclei and an abundance of cytoplasmic fibrils not described heretofore. S6zary cells were nonadherent and nonphagocytic and usually responded to stimulation with phytohemagglutinin, refuting earlier suggestions that the cells represent monocytes or histiocytes. In contrast to chronic lymphocytic leukemia lymphocytes, the Szary cells lacked surface immunoglobulin and receptors for complement. Ultrastructural analysis identified S6zary cells in the center of directly formed rosettes (E-rosettes) characterizing the behavior of T lymphocytes in this test.Though some S6zary cells lacked both T and B cell-surface properties, in general, these observations support the view that the S6zary cell is a neoplastic variant of a thymusderived lymphocyte.

Surface Features of Cells in Human Lymphoproliferative Disorders. An Immunoelectron Microscopy Study

“…Sezary cells have been shown to have membrane properties common to T lymphocytes (21,22). In this study they were found to lack detectable s.Ig including at the level of their Segment of villous membrane.…”

The Sézary Syndrome Cell: Surface Ultrastructural Characteristics

“…A third report contains two fig ures, with low-power magnification, of Sezary cells from each of two pa tients. The cells from one are smooth, whereas those from the other pa tient have what appears to be an intermediate number of cytoplasmic projections [22], A study of preferential cutaneous infiltration by neo plastic thymus-derived lymphocytes showed a circulating Sezary cell from each of two patients. One cell was smooth while the other was very villous [7|.…”

The surface morphology of human B lymphocytes as revealed by immunoelectron microscopy.

“…S6zary's syndrome is characterized by a generalized erythrodermia, lymphadenopathies, and an infiltration of skin by these abnormal cells which also circulate in blood . By several immunological assays it has recently been shown that S6zary cells have membrane properties of T lymphocytes (55,56) . However, the lack of sIg reported here also concerned the segments of villous membrane exhibited by these lymphocytes .…”