Immunological and chromosomal studies in a patient with Sézary syndrome.

A patient with the small-cell variant of Sézary syndrome was studied before and during treatment with low-dose chlorambucil. He had depressed responses to phytohemagglutinin (PHA) and concanavalin A that returned to normal with clinical improvement. Spontaneously dividing cells were found in the peripheral blood by culturing lymphocytes without PHA for 24 hours. Seventy-two-hour PHA-stimulated lymphocyte cultures revealed predominantly hypodiploid chromosome numbers. Both abnormalities improved during treatment. Lymphocytes that were studied for sister chromatid exchanges had an increased number of exchanges per metaphase. Immunofluorescence studies revealed immunoglobulins and C at the dermoepidermal junction and in the dermal vessel walls. Our findings demonstrate that the depression of mitogen responsiveness that is sometimes seen in Sézary syndrome can be favorably affected by chemotherapy. Likewise, some chromosomal abnormalities may regress during successful therapy. These findings may provide a way of measuring the response to therapy.