Impaired recirculation of b lymphocytes in chronic lymphocytic leukemia

Lymphocytes of the peripheral blood and thoracic duct lymph were studied in 4 patients with chronic lymphocytic leukemia (CLL),1 patient with lymphosarcoma (LSA) and 3 patients with nonhematolo‐gical diseases (controls). When stimulated in vitro with phytohemagglu‐tinin (PHA) lymph lymphocytes of CLL patients responded markedly as determined by 14 [C]thymidine incorporation, whereas blood lymphocytes showed a delayed and diminished response. The response of blood and lymph lymphocytes of the LSA and control patients was equal. Purified rabbit antisera against κ,λ, μ and γ‐chains were labeled with 25 I and the labeled cells assessed by autoradiography. In CLL patients, the percentage of lymphocytes bearing κ and μ determinants was higher in the blood than in the lymph. Controls showed a much lower percentage of lymphocytes with immunoglobulins, which was equal in blood and lymph. Furthermore, the membrane dynamics of HL‐A‐anti‐HL‐A complexes on the surface of blood and lymph lymphocytes were studied by means of membrane fluorescence. In CLL, the percentage of lymph lymphocytes showing “cap formation” within 2 h was higher in the lymph than in the blood. Using autotransfusion of [ 3 H‐]cytidine‐labeled blood lymphocytes, it is shown that the recovery of labeled cells in the lymph of CLL patients within 48 h is diminished compared to controls. It is concluded that in CLL, the leukemic cells are B cells whose capacity to recirculate from blood to lymph through the postcapillary venules is impaired. Only a minor population of PHA‐responsive T cells appears to recirculate normally. Consequently, the concentration of T cells is higher in the lymph than in the blood and the leukemic B lymphocytes accumulate in the vascular pool. The impaired ability for recirculation and “cap formation” suggests a membrane abnormality of the CLL cell.