Are activation markers (CD25, CD38 and CD103) predictive of sensitivity to purine analogues in patients with T-cell prolymphocytic leukemia and other lymphoproliferative disorders?

T-cell prolymphocytic leukemia (T-PLL) is a rare lymphoproliferative disorder with distinctive clinical and laboratory features. It is often resistant to conventional chemotherapy, but complete or partial responses have been documented with the use of purine analogues. We report on two cases of T-PLL with a slightly different immunophenotype but a remarkably different response to pentostatin. We discuss the possible therapeutic implications of this finding and establish a comparison between immunophenotype and sensitivity to purine analogues in patients with T-PLL and other chronic lymphoproliferative disorders.