Evolution of a Lymphoma With Helper T Cell Characteristics in S # { 235 } zarySyndrome

A patient with S#{233}zary syndrome presented with disease limited to the skin and circulating abnormal lymphocytes but subsequently developed a diffuse undifferentiated lymphoma. Malignant cells from a lymph node effaced with the morphologically undifferentiated lymphoma were characterized as being of thymus-derived (T cell) origin. We have previously shown that circulating malignant lymphocytes from some patients with S#{233}zary syndrome are malignant cells that function as helper cells for Ig biosynthesis by normal B lymphocytes. In the present case, either peripheral blood lymphocytes, comprised mainly of S#{233}zary cells, or cells from the malignant lymph node, containing morphologically undifferentiated lymphomatous cells, greatly augmented pokeweed m itogen-driven 1gM synthesis by purified normal B lymphocytes. Thus both the peripheral blood lymphocytes and lymphoma cells from this patient could perform a helper function for Ig biosynthesis in vitro. The undifferentiated lymphoma in this case probably represented an extension of the original malignant clone of helper T cells rather than an unrelated lymphoma that developed de novo. This case illustrates that a T cell malignancy may be morphologically either relatively well differentiated, as in the circulating S#{233}zary cells, or relatively undifferentiated, as in the lymphomatous node, and still express a residual helper T cell function. Furthermore, this case supports the view that it may be possible to classify certain morphologically undifferentiated lymphomas (or immunoblastic sarcomas) according to their immunoregulatory capacity in vitro.