Case report: Long-term voluntary Tyrosine Kinase Inhibitor (TKI) discontinuation in chronic myeloid leukemia (CML): Molecular evidence of an immune surveillance.

The classical natural history of chronic myeloid leukemia (CML) has been drastically modified by the introduction of tyrosine kinase inhibitor (TKI) therapies. TKI discontinuation is currently possible in patients in deep molecular responses, using strict recommendations of molecular follow-up due to risk of molecular relapse, especially during the first 6 months. We report here the case of a patient who voluntarily interrupted her TKI therapy. She remained in deep molecular remission (MR4) for 18 months followed by detection of a molecular relapse at +20 months. Despite this relapse, she declined therapy until the occurrence of the hematological relapse (+ 4 years and 10 months). Retrospective sequential transcriptome experiments and a single-cell transcriptome RNA-seq analysis were performed. They revealed a molecular network focusing on several genes involved in both activation and inhibition of NK-T cell activity. Interestingly, the single-cell transcriptome analysis showed the presence of cells expressing NKG7, a gene involved in granule exocytosis and highly involved in anti-tumor immunity. Single cells expressing as granzyme H, cathepsin-W, and granulysin were also identified. The study of this case suggests that CML was controlled for a long period of time, potentially via an immune surveillance phenomenon. The role of NKG7 expression in the occurrence of treatment-free remissions (TFR) should be evaluated in future studies.

Cartridge-based automated BCR-ABL1 mRNA quantification: solving the issues of standardization, at what cost?

BACKGROUND: Molecular monitoring of chronic myeloid leukemia patients treated with tyrosine kinase inhibitors is essential for therapeutic stratification. Inter-laboratory reproducibility is, therefore, a crucial issue which requires standardization and strict alignment of BCR-ABL1 values to the international scale. An automated cartridge-based assay (Xpert BCR-ABL Monitor(™), Cepheid) had been proposed as a robust alternative to non-automated assays. This study aimed to compare inter-laboratory reproducibility of automated and non-automated quantification, the possibility of converting automated results to the international scale, and the potential economic impact of automation. DESIGN AND METHODS: One hundred and eighteen blood samples from chronic myeloid leukemia patients treated with tyrosine kinase inhibitors were prospectively analyzed in two laboratories using both automated and non-automated assays. The economic evaluation involved a micro-costing study and average costs were assessed as a function of sample throughput. RESULTS: Automated assays achieved similar inter-laboratory reproducibility to highly standardized non-automated assays and a short delay (≤6 h) between sampling and blood lysis had a positive impact on inter-laboratory reproducibility. Reporting automated BCR-ABL1 ratios on the international scale was possible using a specific conversion factor which may vary with batches. Cost assessment showed that automated assays could be relevant for annual activity levels below 300 since average costs were lower than those of the non-automated assays. CONCLUSIONS: The Xpert BCR-ABL Monitor(™) assay could be appropriately used in a near-patient setting for routine quantification of e13/e14-a2 transcripts, preferably in partnership with a regional reference laboratory. However, its prognostic impact relative to non-automated quantification remains to be tested prospectively within appropriate clinical trials.

Endothelin receptor expression in human lungs of newborns with congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) is a major cause of refractory respiratory failure in the neonatal period and is characterized by persistent pulmonary hypertension of the newborn (PPHN) and pulmonary hypoplasia. Endothelin-1 (ET-1) dysregulation may play a significant role in the pathophysiology of PPHN and ET-1 acts through binding to type A (ETA) and type B (ETB) receptors. Therefore, ETA and ETB receptor protein expression was studied using immunohistochemistry in 10 lung specimens obtained from newborns with CDH, and 4 normal lung specimens, in order to explore whether dysregulation of ETA and ETB expression contributes to PPHN. ETA and ETB mRNAs were then quantified using real-time RT-PCR in laser-microdissected pulmonary resistive arteries. In the lungs of newborns with CDH, immunohistochemistry of both ETA and ETB receptors demonstrated over-expression in the thickened media of pulmonary arteries. Using laser microdissection and real-time RT-PCR, higher levels of ETA and ETB mRNA were found in CDH pulmonary arteries than in controls: this increase was more pronounced for ETA mRNA. This study provides the first demonstration of ET-1 receptor dysregulation in association with structural alteration of pulmonary arteries in newborns with CDH and PPHN. This dysregulation preferentially affects the ETA receptor. These results suggest that dysregulation of ET-1 receptors may contribute to PPHN associated with CDH.