Constitutional pericentric inversion of chromosome 9 and acute leukemia.

In view of the recent reports demonstrating delayed engraftment after autologous and allogeneic transplantation from donors with constitutional pericentric inversion of chromosome 9, [inv(9)], we conducted a retrospective study on six patients with acute leukemia and inv(9) to investigate if there is an impaired engraftment potential of the inv(9) hematopoietic stem cells. All but one of our patients had poor outcome. The hematopoietic recovery after induction chemotherapy was not prolonged. It is possible that the hematopoietic defects of inv(9) become more apparent after repeated courses of chemotherapy. Alternatively, the number of patients in our series may have been too small to detect a partial hematopoietic defect in patients with constitutional inv(9). Larger studies are required to confirm our findings.