Citation: British Journal of Haematology. 2019, 185, 202
Author: Bolaji M.; Knight K.; Patel A.
Abstract: We present a 60 year-old male with chronic myeloid leukaemia (CML) recurrence 32 years after allogeneic bone marrow transplantation. Our case seems to be the longest late relapse post allogeneic transplantation described in the literature. This raises fundamental questions in relation to the biology of CML with major implications relating to monitoring strategies for patients with treatment-free remission. The patient initially presented in 1986 at the age of 28 years age, and was treated for five months with bulsuphan and thioguanine. In October 1986, the patient received a myeloablative conditioned (MAC) sibling donor allogeneic bone marrow transplant after high dose cyclophosphamide and total body irradiation (TBI). He subsequently experienced minimal skin acute graft versus host disease (GvHD) that did not require systemic treatment. Cyclosporin was discontinued after six months. His last in-patient episode was February 1987. He was in complete remission which was maintained with annual bone marrow assessments for a further five years. The patient received a revaccination schedule and was discharged from our haematology service in 2014, and remained in clinical remission. He re-presented at the age of 60 years, with a mildly elevated white blood cell count discovered during routine blood testing, with no other associated symptoms at a 'well man' clinic. He had basophilia of 0.9x 10<sup>9</sup>/l and a total white blood cell count (WBC) of 13.7 9 109/l; haemoglobin and platelet parameters were normal. The patient was otherwise asymptomatic with no features of splenic enlargement. Peripheral blood BCR-ABL1 PCR was 30.638%, confirming CML. His blood film and bone marrow assessments confirmed chronic phase disease. Donor chimerism (mixed whole blood and myeloid chimerism of 20% with 100% T cell chimerism) confirmed the recurrence of patient-derived CML rather than de novo donor-derived CML. He was treated with imatinib 400 mg daily. The patient responded well with a 3 month BCR-ABL1 PCR of 0.980%. At 6 months this was 0.109%. The patient tolerated this treatment well with minimal side effects. He now has full donor chimerism (whole blood, myeloid, T cell) and continues to be monitored every three months. This case challenges the current perception of the mechanisms surrounding control and cure of CML. Long-term, life-long, follow up of patients in TFR may be necessary to detect very late disease recurrence of CML.
