Purpose: To evaluate the use of a combined reverse-transcriptase polymerase chain reaction (RT-PCR) and metaphase fluorescent in situ hybridization (FISH) approach post-allogcneic marrow transplant in the detection of relapse in pediatric patients with chronic myeloid leukemia (CML).
Patients and Methods: Five pediatric patients with CML were monitored post-allogeneic transplant (two of them also had received donor lymphocyte infusions) using the combined approach of RT-PCR and metaphase FISH. Both the transplants and the follow-up were carried out in a single institution setting.
Results: During the posttransplant evaluation, a transiently positive signal for the Philadelphia chromosome but no transcription of the bcr/abl-fusion message was detected in one patient currently in remission. A posttransplant relapse was detected in two patients who demonstrated the Philadelphia chromosome and the bcr/abl-fusion transcript; one was successfully treated with donor lymphocyte infusions. The two patients consistently negative for both the Philadelphia chromosome and the bcr/abl-fusion transcript are currently in remission.
Conclusion: Pediatric patients with CML may transiently demonstrate cells positive for the Philadelphia chromosome but not actively transcribing the bcr/abl-fusion message in their marrow during their posttransplant evaluation but remain in remission. Recurrence is highly likely in patients demonstrating positivity for both: these patients may be considered candidates for donor lymphocyte transfusion therapy.