Formation of mouse red cell rosettes by lymphocytes from patients with chronic lymphatic leukemia and assessment of T cell function

Abstract

Peripheral-blood lymphocytes from 16 patients with chronic lymphatic leukemia (CLL) were studied for B cell markers by the mouse red blood cell (MRBC) rosette formation test and for T cell markers by the sheep red blood cell (SRBD) rosette formation test. In 14 of the 16 CLL patients there was a high percentage of mouse red blood rosette formation (mean value, 59 ± 16.7%). In all 16 patients the percentage of T cells was very low (mean value, 9.7 ± 5.3%). There seems to be a correlation between the percentage of MRBC rosette formation and the clinical condition of the patients; the two patients with the highest and the two with the lowest percentages were in the worst clinical condition and refractory to therapy. Peripheral-blood lymphocytes from 10 normal control donors demonstrated a low percentage of MRBC rosette formation (mean value, 8 ± 4%) and a high percentage of SRBC rosette formation (60 ± 10%). The local graft versus host reaction (GVHR), which measures the functional capacity of the T lymphocytes, resulted in a positive reaction for all the normal donors when it was performed with 20 × 10 6 lymphocytes, whereas the lymphocytes of 13 of the 16 patients mounted a negative reaction. When the test was repeated with 100 × 10 6 lymphocytes in 9 of these 13 patients the reaction became positive. It would seem that the negative GVHR of the CLL patients' lymphocytes is primarily due to the overwhelming numerical superiority of B cells and the consequent small percentage of T cells in the inoculum used. These findings demonstrate that the MRBC rosette formation test can be used as a B cell marker for diagnostic purposes in CLL and supports our previous finding that in CLL the T lymphocyte defect is not a functional but rather a quantitative one.