FLT3-TKD Measurable Residual Disease Detection Using Droplet Digital PCR and Clinical Applications in Acute Myeloid Leukemia.

The tyrosine kinase domain of the FMS-Like tyrosine kinase 3 (FLT3-TKD) is recurrently mutated in acute myeloid leukemia (AML). Common molecular techniques used in its detection include PCR and capillary electrophoresis, Sanger sequencing and next-generation sequencing with recognized sensitivity limitations. This study aims to validate the use of droplet digital PCR (ddPCR) in the detection of measurable residual disease (MRD) involving the common FLT3-TKD mutations (D835Y, D835H, D835V, D835E). Twenty-two diagnostic samples, six donor controls, and a commercial D835Y positive control were tested using a commercial Bio-rad® ddPCR assay. All known variants were identified, and no false positives were detected in the wild-type control (100% specificity and sensitivity). The assays achieved a limit of detection suitable for MRD testing at 0.01% variant allelic fraction. Serial samples from seven intensively-treated patients with FLT3-TKD variants at diagnosis were tested. Five patients demonstrated clearance of FLT3-TKD clones, but two patients had FLT3-TKD persistence in the context of primary refractory disease. In conclusion, ddPCR is suitable for the detection and quantification of FLT3-TKD mutations in the MRD setting; however, the clinical significance and optimal management of MRD positivity require further exploration.

Applying molecular measurable residual disease testing in acute myeloid leukaemia.

Molecular testing in acute myeloid leukaemia (AML) has continued to dramatically advance in recent years, facilitating the ability to detect residual disease at exponentially lower levels. With the advent of the recently updated ELN consensus recommendations, there is increasing complexity to ordering and interpreting measurable residual disease (MRD) assays in AML. We outline the technology itself in conjunction with the relevant testing timepoints, clinically significant thresholds and potential prognostic and therapeutic significance of MRD testing for the major molecular targets in AML. This practical overview should assist haematologists in incorporating molecular MRD assays routinely into their personalised AML clinical management.

Navigating the challenges of Bombay phenotype (Oh ) and twin pregnancy; a case report and literature review.

BACKGROUND: Bombay phenotype (Oh ) is a rare blood group and poses unique challenges during pregnancy, including an adequate supply of blood products in case of postpartum hemorrhage (PPH) and the risk of hemolytic disease of the fetus and newborn (HDFN). Case reports of antenatal care in this cohort are scarce. Herein, we present a case of twin pregnancy in an Oh woman and outline her multidisciplinary management. We summarize the literature to better inform decision-making and patient blood management in the antenatal care of Oh women. CASE DESCRIPTION: A 22-year-old G1P0 presented at 15 weeks gestation with dichorionic diamniotic twins and known Oh phenotype. Hematinics were optimized to minimize anemia. Anti-H titers were tracked and were 1:256 at both 28 and 36 weeks gestation. Regular middle cerebral artery dopplers were performed to assess for fetal anemia. There was constant communication with obstetrics and anesthetics teams. Both autologous frozen and directly donated fresh red cells were available as part of a clear, detailed transfusion plan. Transfusion was not required and neither child was affected by HDFN. The neonates were group O, DAT negative, and group A, DAT positive. Maternal anti-A was detected in the neonatal eluate. CONCLUSION: To our knowledge, this is only the second report of twin pregnancy in an Oh female and the first time a detailed transfusion plan has been published. Through employing patient blood management strategies, engaging a collaborative multidisciplinary approach, and establishing a clear delivery plan, the antenatal challenges of Bombay phenotype are surmountable.