Mentype® DIPquant

High sensitivity chimerism monitoring

Features

Early detection of imminent relapse
Detection of minor target ratios down to 0.05 % up to 12.5 % chimerism
Performed on standard qPCR systems

Following initial genotyping, Mentype^® DIPquant provides a sensitive chimerism diagnostics suitable for detecting small changes in a patient’s chimerism status. Thus, it can indicate relapse earlier than less sensitive methods. Mentype^® DIPquant allows highly sensitive chimerism quantification in cases where DNA input is not a limiting factor. If the DNA quantity is limited, semi-quantitative engraftment detection with Mentype^® DIPscreen for wide chimeric ratios is possible. The combination of Mentype^® DIPscreen and Mentype® DIPquant therefore covers all demands for routine chimerism analysis.

Biomarkers

Insertion-deletion polymorphism (DIPs or INDELs), Reference gene

Product Specifications

Panel
56 allele specific singleplex assays, 1 Reference assay

Reactions
3 allele specific assays + Reference assay in duplicates (8 reactions per sample)

PCR controls
2 (PC via existing samples, NTC)

Sample input
250 ng gDNA from peripheral blood

Sensitivity
≥ 0.05 %

Turnaround time
~ 1.5 h after nucleic acid preparation

Detection
Relative quantification

To be used with
Standard qPCR cycler (FAM)

Data analysis
ChimerisMonitor (RUO), Cycler specific software, ∆∆Ct calculation

Scientific Background

It is crucial to analyze molecular chimerism after allogeneic bone marrow and blood stem cell transplantation to monitor the transplant engraftment or to detect an imminent rejection of the graft at an early stage. Molecular chimerism analysis is carried out by the detection of deletion/insertion polymorphisms, which are extremely suitable for analysis by allele-specific qPCR technology as compared to other DN detecting deletion/insertion polymorphisms, which are extremely suitable for analysis by allele-specific qPCR technology A-sequence motifs.

Following the identification of patient and donor informative DIP loci using the Mentype^® DIPscreen application, quantitative chimerism analysis can be performed by using the corresponding Mentype^® DIPquant singleplex assays. The flexible assay format allows the analysis of individual samples and large sample quantities with minimal material expenditure. Since the high sensitivity of the qPCR method is associated with limited accuracy in the field of mixed chimerism, it is advisable to analyze samples with mixed chimerism by using the Mentype^® DIPscreen kit (Guideline on Allogeneic Stem Cell Transplantation of the German Association for Bone Marrow and Blood Cell Transplantation, Bader et al., 2016).

Product References

Ferreras, C. et al. Results of phase 2 randomized multi-center study to evaluate the safety and efficacy of infusion of memory T cells as adoptive therapy in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia and/or lymphopenia (RELEASE NCT04578210). Cytotherapy 26, 25-35, https://doi.org/10.1016/j.jcyt.2023.10.002 (2024)
Al-Akioui Sanz, K. et al. Familial CD45RA– T cells to treat severe refractory infections in immunocompromised patients. Front. Med. 10. https://doi.org/10.3389/fmed.2023.1083215 (2023)
Huyveneers, L. E. P. et al. Autopsy Study Defines Composition and Dynamics of the HIV-1 Reservoir after Allogeneic Hematopoietic Stem Cell Transplantation with CCR5D32/D32 Donor Cells. Viruses 14. https://doi.org/10.3390/v14092069 (2022)
Pérez-Martínes, A. et al. Phase I dose-escalation single centre clinical trial to evaluate the safety of infusion of memory T cells as adoptive therapy in COVID-19 (RELEASE). EClinicalMedicine 39. https://doi.org/10.1016/j.eclinm.2021.101086 (2021)
Gómez-García, L. M. et al. A phase II clinical trial of infusing haploidentical K562-mb-IL15-41BBL activated and expanded Natural Killer cells as consolidation therapy for pediatric acute myeloblastic leukemia. ESS Open Archive. DOI: 10.22541/au.160192968.85891275/v1 (2020)
Navarro-Bailón, A et al. Short Tandem Repeats (STRs) as Biomarkers for the Quantitative Follow-Up of Chimerism after Stem Cell Transplantation: Methodological Considerations and Clinical Application. Genes 11, 993. https://doi.org/10.3390/genes11090993 (2020)
Salgado, M. et al. Mechanisms That Contribute to a Profound Reduction of the HIV-1 Reservoir After Allogeneic Stem Cell Transplant. Annals of Internal Medicine 169, 674-683. https://doi.org/10.7326/M18-0759 (2018)
Sellmann, L. et al. Diagnostic value of highly-sensitive chimerism analysis after allogeneic stem cell transplantation. Bone Marrow Transplant 53, 1457-1465. https://doi.org/10.1038/s41409-018-0176-7 (2018)
Navarro-Bailón, A. et al. A Novel Quantitative PCR Approach Targeting Insertion/Deletion Polymorphisms (Indel-PCR) for Chimerism Quantification: Finally High Sensitivity and Quantification Capacity Together. Blood 126, 4227. https://doi.org/10.1182/blood.V126.23.4277.4277 (2015)
Stahl, T. et al. Digital PCR to assess hematopoietic chimerism after allogeneic stem cell transplantation. Experimental Hematology 43, 462-468. https://doi.org/10.1016/j.exphem.2015.02.006 (2015)
Willasch, A. M. et al. Monitoring of Hematopoietic Chimerism after Transplantation for Pediatric Myelodysplastic Syndrome: Real-Time or Conventional Short Tandem Repeat PCR in Peripheral Blood or Bone Marrow? Biol Blood Marrow Transplant 20, 1918-1925. https://doi.org/10.1016/j.bbmt.2014.07.030 (2014)