Evidence for the presence of a receptor for IgM on the pathological cells of Sézary's syndrome.

It has been demonstrated that in two patients with T-cell Sézary syndrome the pathological cells express a receptor for EA(IgM) when cultured in a medium with foetal calf or autologous serum. A study of the time-course of this rosette formation revealed that a large proportion, but not all, of E-rosetting cells progressively expressed this receptor. In agreement with previous reports by others on the normal T-cell population bearing the IgM receptor, incubation at 37 degrees C in the presence of serum was shown to be a necessary condition. The implications of this pathological subpopulation of T-cells are discussed.