Cell Membrane Enzymes II.

The distribution of two cell membrane enzymes, alkaline phosphatase and alkaline phosphodiesterase I has been studied in normal and leukaemic lymphocytes. No reduction in the level of activity of either enzyme was found in the chronic or acute B- and T-cell leukaemias. Alkaline phosphatase activity was elevated in the lymphocytes from T-CLL, cord blood and tonsils and the blast cells from Null-ALL. Alkaline phosphodiesterase was elevated in lymphocytes from cord blood and tonsils and the blast cells from Null-ALL. As findings in Null-ALL were based on only two cases, they need confirmation in a larger series. The significance of these results is discussed in relation to current theories of maturation and differentiation in the lymphoproliferative disorders.