In vitro immunological studies on East African cancer patients. II. Increased sensitivity of blood lymphocytes from untreated Burkitt lymphoma patients to inhibition of spontaneous rosette formation.

Frozen aliquots of peripheral blood mononuclear cells from patients with Burkitt's lymphoma (BL) at various stages of the disease have been compared with samples from East African children who were healthy or who suffered from non-malinant disorders. Using the sheep-cell rosette test (which is believed to identify T-lymphocytes), we found a significant reduction in the proportion of rosette-forming cells (RFC) in the samples from untreated BL patients. After reduction of remission the difference between BL patients and controls was abolished. Rosette formation was more readily inhibited by anti-lymphocyte globulin (ALG) in samples from untreated BL patients than in controls. On induction of remission the rosette inhibition curve shifted towards the control values. The findings are compatible with the presence, in untreated BL, of a circulating factor which impairs the capacity of T-lymphocytes to form rosettes with sheep erythrocytes. It remains to be established whether the functional capacity of T-cells to protect the host against tumour proliferation is also impaired.