Combined T and B lymphocyte marker test in lymphoproliferative disorders.

The combined T and B lymphocyte marker test of Mendes et al (1974) has been developed to provide an easy, reproducible test for clinical practice. It has been used to study subpopulations of peripheral lymphocytes in patients with lymphoid malignancies. Significant increases in the numbers of lymphocytes which bind both sheep erythrocytes (E) and the fixed, third component of complement (C3) have been found using this test, in the peripheral blood of all untreated lymphosarcoma (L/SA) patients and T cell acute lymphoblastic leukaemia (ALL) patients. Such increases were not found in blood from patients with chronic lymphatic leukaemia (CLL), other non-lymphoid malignancies, null-cell ALL or normal individuals. These mixed E and C3 receptor bearing cells may be Fc receptor positive and represent a separate subpopulation of lymphocytes.