Reduced natural killer T-cells in B-cell chronic lymphocytic leukaemia identified by three monoclonal antibodies: Leu-11, A10, AB8.28.

The proportion of E-rosette positive T-lymphocytes capable of reacting with three monoclonal antibodies (MoAbs)--Leu-11, A10, AB8.28--which appear to recognize specifically natural killer (NK) cells, was assessed in a series of untreated patients with B-cell chronic lymphocytic leukaemia (B-CLL). Irrespective of the clinical stage of the disease, the capacity of B-CLL T-lymphocytes to react with all three MoAbs was significantly reduced compared with that of normal circulating T-cells (Leu-11: 2.5% +/- 1.9 SD; A10: 2.3% +/- 1.3; AB8.28: 7% +/- 6.6 v Leu-11: 13.5% +/- 4.5; A10: 8.5% +/- 4.6; AB8.28: 12% +/- 5.5). Furthermore, a marked difference was demonstrated between the reactivity with the Leu-11, A10, AB8.28 MoAbs and the proportion of Leu-7 positive T-cells, which in B-CLL is significantly higher than in normal blood (23% +/- 12.1 v 11.9% +/- 5.9). These findings are in agreement with previous evidence of a discrepancy in B-CLL between the phenotypic expression, assessed by Leu-7 positivity, and the true functional activity of NK T-cells, and suggest that the Leu-11, A10 and AB8.28 MoAbs correlate well with the depressed NK function found in this disease.