Detection of Trisomy 8 in Donor-Derived Ph−Cells in a Patient with Ph+Chronic Myeloid Leukemia Successfully Treated with Imatinib (STI571) in Relapse after Allogeneic Transplantation

Systematic scoping review of studies reporting unexpected donor-derived abnormalities from recipients of allogeneic hematopoietic cell transplantation: a proposed framework for donor disclosure: donor-derived abnormalities in allogeneic HCT

BACKGROUND

Allogeneic hematopoietic cell transplantation (HCT) is used increasingly to treat blood and immune-based disorders. Post-transplant testing of HCT recipients can lead to unexpected molecular, cytogenetic and other information in donor-derived cells, evoking questions regarding the potential impact on donor health.

OBJECTIVE

To identify the breadth of donor-derived abnormalities identified by testing HCT recipients and the extent to which disclosure and donor follow up are described.

METHODS

A systematic search and scoping review were conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews in OVID MEDLINE and EMBASE (1947 to May 24, 2021).

RESULTS

We identified 38 studies (63 donor-recipient pairs) addressing non-leukemic abnormalities, to complement existing literature describing donor cell leukemia and donor-derived myelodysplasia. Donors were unrelated adults (n=20), related family members (n=28), cord blood donors (n=6) or were not reported (n=9). Acquired cytogenetic, molecular, and morphologic abnormalities were reported. Donor origin was confirmed by cytogenetic analysis via karyotyping, FISH, STR-PCR, and other techniques. A disease in donor-derived cells was described in 35 recipients (56.5%). Despite the relevance for testing and disclosure to donors, only 22 cases (32%) mentioned donor follow-up, and 5 cases confirmed that the donor developed a disease associated with the identified abnormality. Unrelated donor disclosure was mentioned in 3 of 26 cases (12%), where the findings were reported back to the registry.

CONCLUSION

Incidental abnormalities identified in transplanted donor cells may contribute to post-transplant risk of illness in the recipient and may be relevant to donor health. A framework for donor disclosure is proposed that incorporates consideration of analytic validity of the testing, potential significance of the finding, and the extent to which the abnormality is actionable. Adoption of effective processes to safeguard both donor and recipient health outcomes related to this issue is needed. [295].

Update on cytogenetic and molecular changes in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis and a high propensity to transform to acute myeloid leukemia (AML). In the pathogenesis of the disease, both gene mutations and cytogenetic changes play an important role. The latter have been integrated into prognostic scoring systems including the IPSS (International Prognostic Scoring System) and WPSS (World Health Organization [WHO] classification-based Prognostic Scoring System). In these systems and in multivariate analyses comparing clinical and genetic data, complex karyotypes are associated with a particularly poor prognosis. del(5q) plays a distinct role by classifying the only genetically defined WHO subtype. Also, due to advancement in technology such as whole genome sequencing, the number of known mutations occurring in MDS is steadily increasing. Important recent discoveries include mutations in EZH2, DNMT3A, ASXL1 and IDH1/2. Like TET2, the most commonly mutated gene in MDS, all are involved in epigenetic regulation. Mutations such as ASXL1, RUNX1, EZH2, ETV6/TEL and TP53 have an adverse impact on patient overall survival. Early evidence suggests that some mutations might influence treatment response, necessitating reassessment of the prognostic effect of genetic alterations in the light of every new treatment. This review discusses clinical and biological effects of the most common cytogenetic and molecular aberrations in patients with MDS.

Long-term persistence of nonpathogenic clonal chromosome abnormalities in donor hematopoietic cells after allogeneic stem cell transplantation

We describe the cases of two unrelated patients who exhibited multiple chromosomal abnormalities in donor cells after allogeneic peripheral blood stem cell transplantation (PBSCT). The patients were diagnosed with chronic myeloid leukemia and chronic lymphocytic leukemia, respectively, and both underwent nonmyeloablative conditioning with cyclophosphamide and fludarabine followed by PBSCT from their HLA-matched opposite-sex siblings. Post-transplant bone marrow cytogenetics showed full engraftment, and the early post-transplant studies demonstrated only normal donor metaphases. Subsequent studies of both patients, however, revealed a population of metaphase cells with abnormal, but apparently balanced, donor karyotypes. Chromosome studies performed on peripheral blood cells collected from both donors after transplantation were normal. Both patients remained in clinical remission during follow-up of approximately 8 years in one case, and 6 years in the other case, despite the persistence of the abnormal clones. Chromosomal abnormalities in residual recipient cells after bone marrow or PBSCT are not unusual. In contrast, only rare reports of chromosome abnormalities in donor cells exist, all of which have been associated with post-bone marrow transplant myelodysplastic syndrome or acute leukemias. The present cases demonstrate the rare phenomenon of persistent clonal nonpathogenic chromosome aberrations in cells of donor origin.

Emerging stem cell concepts for imatinib-resistant chronic myeloid leukaemia: implications for the biology, management, and therapy of the disease

Chronic myeloid leukaemia (CML) is a myeloid neoplasm defined by the BCR/ABL oncoprotein that is considered essential for leukaemogenesis and accumulation of neoplastic cells. The BCR/ABL kinase inhibitor imatinib is an effective agent in most patients and can now be regarded as front-line therapy. Hence, intrinsic and acquired resistance to imatinib has been described and is an emerging challenge in clinical practice. While CML stem cells display primary resistance, stem cell subclones may, in addition, acquire imatinib-resistant mutants of BCR/ABL. Other factors that are considered to contribute to stem cell resistance include the genetic background, clonal evolution, additional biological features of subclones, gene amplifications, silencing of tumour suppressor genes and specific pharmacological aspects. In this article, mechanisms of resistance of CML (stem) cells against imatinib and other BCR/ABL inhibitors are discussed, together with strategies to overcome and/or to prevent resistance with available drugs or novel anti-leukaemic approaches.

Inv (11)(p15q21) in donor-derived Ph-negative cells in a patient with chronic myeloid leukemia in relapse successfully treated with imatinib mesylate post allogeneic stem cell transplantation

Imatinib mesylate (IM) is the standard first-line treatment for patients with chronic myeloid leukemia (CML). Surprisingly, 2-15% of patients achieving a complete cytogenetic response develop cytogenetic abnormalities in Philadelphia (Ph)-negative cells. Following hematopoietic stem cell transplantation (HSCT), IM induces complete molecular responses (CMR) in approximately 70% patients with relapsed CML, and no IM-related cytogenetic abnormalities in Ph-negative donor-derived cells have been described after HSCT. We report a 56-year-old female who presented with a relapse from CML in September 2002. She had received a matched related HSCT for CML in chronic phase. Donor lymphocyte infusion was given 3 years post-HSCT for a relapse. Sustained CMR was achieved within 3 months of initiation of IM. In October 2005, routine evaluation demonstrated continuous CMR, full male donor engraftment and an inv (11) on donor cells. Evaluation of the donor demonstrated no dysplasia or cytogenetic abnormalities. This observation reinforces the possibility that IM therapy may be casually linked to the phenomenon of secondary cytogenetic changes in diploid cells.