Increase in Ty Lymphocytes in B-Cell Chronic Lymphocytic Leukaemia

S ummary . The proportion of Tγ and Tμ lymphocytes was studied in 40 cases of B-chronic lymphocytic leukaemia (B-CLL) and six of B-prolymphocytic leukaemia (B-PLL). The significant increase in Ty cells, previously reported in two small B-CLL series, was confirmed and shown to be directly correlated with the clinical stages of the disease (P < 0.01 to < 0.001). The normal Tμ: Tγ ratio (2.3:1) was reversed in B-CLL (1:1.4) and B-PLL (1:1.9). The proportion of Tμ cells was decreased but was not related to stage.
Our findings suggest that the increase in Ty cells may be responsible for the hypogammaglobulinaemia of B-CLL. This is supported by two sets of observations. First, serum Ig levels were more often normal in cases in Stages 0 and 1 than in Stages II-IV (P < 0.05), while the levels of two or three Ig classes were below normal in Stages II-IV twice as frequently. Secondly, splenic irradiation in one case was followed by a fall in the absolute number of Ty lymphocytes, a reversion to normal of the TμW: Tγ ratio and an improvement in serum Ig levels. Thus, the imbalance in the regulatory T-cell subsets may provide an important clue to understand the pathogenic mechanism of the immunodeficiency in the chronic B-cell leukaemias.