Unusual T‐Cell Phenotype in Advanced B‐Chronic Lymphocytic Leukaemia

Abstract

T lymphocytes isolated by E[sheep erythrocyte]-rosetting from 22 patients with B cell chronic lymphocytic leukemia (B-CLL) showed membrane phenotype features distinct from those of normal T lymphocytes. These changes were particularly marked in advanced disease (Rai stages II, III, IV and WBC [white blood cells] over 100 .times. 109/l). The most significant finding was the demonstration, in 10 cases, of a major population of E-rosette positive cells (40-80%) unreactive with the [mouse] OKT monoclonal antibodies against mature or immature T cells; 15-30% of the cells were unreactive in 7 other cases. A significant reduction in OKT4 positive (helper) lymphocytes was seen in 18 cases. The proportion of OKT8 positive cells was increased in 2 and normal or low in the rest. Only 4 patients with early disease (stages 0 and 1) had a normal T cell phenotype. These findings could explain abnormalities previously described in the T lymphocytes to B-CLL and provide new insights into the pathogenesis of the disease.