Introduction of Noninvasive Prenatal Testing for Blood Group and Platelet Antigens from Cell-Free Plasma DNA Using Digital PCR

Pooled human bone marrow-derived mesenchymal stromal cells with defined trophic factors cargo promote dermal wound healing in diabetic rats by improved vascularization and dynamic recruitment of M2-like macrophages

Human Mesenchymal Stromal Cells (hMSCs) are a promising source for cell-based therapies. Yet, transition to phase III and IV clinical trials is remarkably slow. To mitigate donor variabilities and to obtain robust and valid clinical data, we aimed first to develop a manufacturing concept balancing large-scale production of pooled hMSCs in a minimal expansion period, and second to test them for key manufacture and efficacy indicators in the clinically highly relevant indication wound healing. Our novel clinical-scale manufacturing concept is comprised of six single donor hMSCs master cell banks that are pooled to a working cell bank from which an extrapolated number of 70,000 clinical doses of 1x10⁶ hMSCs/cm² wound size can be manufactured within only three passages. The pooled hMSC batches showed high stability of key manufacture indicators such as morphology, immune phenotype, proliferation, scratch wound healing, chemotactic migration and angiogenic support. Repeated topical hMSCs administration significantly accelerated the wound healing in a diabetic rat model by delivering a defined growth factor cargo (specifically BDNF, EGF, G-CSF, HGF, IL-1α, IL-6, LIF, osteopontin, VEGF-A, FGF-2, TGF-β, PGE-2 and IDO after priming) at the specific stages of wound repair, namely inflammation, proliferation and remodeling. Specifically, the hMSCs mediated epidermal and dermal maturation and collagen formation, improved vascularization, and promoted cell infiltration. Kinetic analyses revealed transient presence of hMSCs until day (d)4, and the dynamic recruitment of macrophages infiltrating from the wound edges (d3) and basis (d9), eventually progressing to the apical wound on d11. In the wounds, the hMSCs mediated M2-like macrophage polarization starting at d4, peaking at d9 and then decreasing to d11. Our study establishes a standardized, scalable and pooled hMSC therapeutic, delivering a defined cargo of trophic factors, which is efficacious in diabetic wound healing by improving vascularization and dynamic recruitment of M2-like macrophages. This decision-making study now enables the validation of pooled hMSCs as treatment for impaired wound healing in large randomized clinical trials.

Noninvasive Prenatal Testing in Immunohematology-Clinical, Technical and Ethical Considerations

Hemolytic disease of the fetus and newborn (HDFN), as well as fetal and neonatal alloimmune thrombocytopenia (FNAIT), represent two important disease entities that are caused by maternal IgG antibodies directed against nonmaternally inherited antigens on the fetal blood cells. These antibodies are most frequently directed against the RhD antigen on red blood cells (RBCs) or the human platelet antigen 1a (HPA-1a) on platelets. For optimal management of pregnancies where HDFN or FNAIT is suspected, it is essential to determine the RhD or the HPA-1a type of the fetus. Noninvasive fetal RhD typing is also relevant for identifying which RhD-negative pregnant women should receive antenatal RhD prophylaxis. In this review, we will give an overview of the clinical indications and technical challenges related to the noninvasive analysis of fetal RBCs or platelet types. In addition, we will discuss the ethical implications associated with the routine administration of antenatal RhD to all pregnant RhD-negative women and likewise the ethical challenges related to making clinical decisions concerning the mother that have been based on samples collected from the (presumptive) father, which is a common practice when determining the risk of FNAIT.

Confirmed non-invasive prenatal testing for foetal Rh blood group genotyping along with bi-allelic short insertion/deletion polymorphisms as a positive internal control

BACKGROUND

Determination of foetus rhesus blood group at risk of hemolytic disease has potential application for early non-invasive prenatal testing (NIPT). There are several challenges in developing NIPT rhesus blood group genotyping assays by using cell-free foetal DNA (cff-DNA) in plasma of RhD-negative pregnant women. So, the aim of this study was optimization of Real-time PCR assay for NIPT rhesus genotyping and development of Bi-allelic short insertion/deletion polymorphisms (INDELs) as internal control to optimise and validate rhesus genotyping based on Real-time PCR to avoid false or negative results.

MATERIAL AND METHODS

NIPT Rhesus genotyping including RHD (exon 7), RHCc, and RHEe genes were performed by TaqMan Real-time PCR on 104 maternal samples at different gestation ages (12 to ≥40 weeks) from 51 alloimmunized pregnant women. The sensitivity protocol was confirmed with standard DNA samples. Eight selected INDELs were designed and used to detectable cff-DNA in maternal plasma. INDELs frequency and inheritance were determined on 6 family and 61 unrelated individuals. Finally, multiplex Real-time PCR was performed for each sample with INDELs pairs and Rh probes.

RESULTS

The results showed 100% accuracy rhesus typing for RHD, RHC and RHE assays and 95.7% accuracy for RHc. Also, eight selected INDELs as internal control for NIPT were 100% concordance for typed samples.

CONCLUSION

The Real-time PCR assay is a suitable method with high sensitivity and specificity for rhesus typing as NIPT for prediction of hemolytic disease in foetuses. The INDELs described here are suitable internal control for confirmation of NIPT on cff-DNA.

Noninvasive diagnostics of fetal KEL*01.01 allele from maternal plasma of immunized women using digital PCR protocols

Allo-antibodies produced by K-negative pregnant women against a fetal K antigen from the Kell blood group system may cause hemolytic disease of the fetus and newborn (HDFN). Predicting the fetal K antigen using noninvasive prenatal testing (NIPT) is important for decisions concerning management of pregnancies. Digital and droplet digital PCR techniques permit the detection of fetal single nucleotide variant with a higher specificity and sensitivity than real-time polymerase chain reaction (PCR).

AIM

The aim was to evaluate and compare protocols for fetal KEL*01.01 genotyping using different assays and digital PCR platforms.

METHODS

DNA isolated from 59 pregnant women (9-39 weeks of gestation, 49 with anti-K) was tested using home-made and custom-ordered KEL*01.01/KEL*02 assays with Droplet Digital™ and QuantStudio™3D. The results were compared with fetal/neonatal genotypes/phenotypes.

RESULTS

Fetal KEL*01.01 results using all tested protocols were concordant with fetal/neonatal KEL*01.01 genotypes/phenotypes. None of the tested combinations of assays or digital PCR platforms gave false KEL*01.01-negative results, but inconclusive KEL*01.01 reads were observed in all tested protocols. For 36 cases compared using two digital PCR platforms and assays, there were not statistically significant differences in a level of fetal KEL*01.01 fraction (p < .72).

CONCLUSION

Independent of the applied dPCR and ddPCR platforms and KEL*01.01 assays, prediction of the fetal KEL*01.01 is highly reliable. Before implementation in routine practice further validation of the KEL*01.01 protocol with a larger group of pregnant women should be performed.

Non-invasive prenatal testing for management of haemolytic disease of the fetus and newborn induced by maternal alloimmunisation

Anti-D immunoglobulin prophylaxis reduces the risk of RhD negative women becoming alloimmunised to the RhD antigen and is a major preventative strategy in reducing the burden of haemolytic disease of the fetus and newborn (HDFN). HDFN also arises from other maternal red cell antibodies, with the most clinically significant, after anti-D, being anti-K, anti-c and anti-E. Among the 39 human blood group systems advanced genomic technologies are still revealing novel or rare antigens involved in maternal alloimmunisation. Where clinically significant maternal antibodies are detected in pregnancy, non-invasive prenatal testing (NIPT) of cell-free fetal DNA provides a safe way to assess the fetal blood group antigen status. This provides information as to the risk for HDFN and thus guides management strategies. In many countries, NIPT fetal RHD genotyping as a diagnostic test using real-time PCR has already been integrated into routine clinical care for the management of women with allo-anti-D to assess the risk for HDFN. In addition, screening programs have been established to provide antenatal assessment of the fetal RHD genotype in non-alloimmunised RhD negative pregnant women to target anti-D prophylaxis to those predicted to be carrying an RhD positive baby. Both diagnostic and screening assays exhibit high accuracy (over 99 %). NIPT fetal genotyping for atypical (other than RhD) blood group antigens presents more challenges as most arise from a single nucleotide variant. Recent studies show potential for genomic and digital technologies to provide a personalised medicine approach with NIPT to assess fetal blood group status for women with other (non-D) red cell antibodies to manage the risk for HDFN.