Blood group antigens
The final aim of this research line is to develop an affordable blood group genotyping platform to comprehensively genotype all donors for blood group, platelet and HLA antigens. In the latter years we have made progress in reaching this target by close collaboration with the University of Cambridge, the NHSBT and Thermo Fisher (formerly Affymetrix) and expect that within one year the Blood Typing Array will be launched. Our input has been the selection of SNP targets, the rare donor samples and the development of typing algorithms.
With the dept. of Donor studies we are developing models for preventive matching in relation to the size of blood stocks, once the donor population is fully typed. Within the BloodMatch project the cost and health effects of matching on prevention of alloimmunization will be estimated. Altogether, these results will pave the way to a change in blood transfusion practices, from preventing transfusion reactions by screening patients for alloimmunisation to preventing alloimmunisation by preventive matching.
Blood group polymorphisms in European populations are nowadays well characterized. In collaboration with visiting Chinese scientists, we have now switched our focus to Asian populations and characterized several novel alleles and adapted genotyping assays for these populations. Within the BloodMatch project we inventorized the blood group polymorphisms in the main immigrant groups in the Netherlands.
In a previous project we elucidated the molecular basis of the Vel blood group antigens and we are now investigating the role of this protein in erythropoiesis, as we previously found that the SNP determining the level of Vel-expression was significantly related to Hb concentration in RBCs (MCHC) in blood donors.
HDFN and FNAIT
Our previous research has led to the implementation of nationwide fetal RhD screening to guide antenatal anti-D immunoprophylaxis. In the last years we have carefully evaluated the results of this program.
To understand the preventive mechanism of anti-D immunoprophylaxis, we continued our attempts to express the RhD antigen in murine erythroid cells, in order to set up a murine model. Although still not successful, we obtained more insight in the interactions in the trimeric complex, especially between RhAG and RhD.
By analyzing data from alloimmunised pregnant women we have been able to show that anti-D immunoglobulin does not only protect against immunization against RhD antigen but also to non-Rh-antigens. This has direct consequences for understanding the working mechanisms, and show that it is might be possible to prevent pregnancy induced alloimmunisation with a universal anti-fetal RBC immunoglobulin.
The HIP study (http://hipstudie.nl/) has been started in March 2017, in this study we screen 1/3 of all pregnant women for the presence of anti-HPA 1a antibodies, and we will correlate the laboratory results with the clinical data. The aim of this project is to provide a scientific basis for the implementation of a screening program for FNAIT, and to develop assays predicting which pregnancies with anti-HPA 1a antibodies are at risk for disease and should be treated with IVIg.
Minimal residual disease (MRD) in Childhood cancers
Development of MRD assays
For ALL we were among the first to develop and evaluate patient specific antigen-receptor PCRs to detect MRD. Our diagnostic laboratory is now routinely performing this test together with the ErasmusMC for all ALL patients in the Netherlands. Based on expression profiles from neuroblastoma tumors we have identified Phox2B, as the so far only NBL specific MRD target. This marker is now generally applied as MRD marker in NBL patients. At present we are developing digital PCR and NGS-based assay for the detection of minimal residual disease, not only in cells but also in body fluids (plasma, cerebrospinal fluid)
Testing clinical relevance of MRD assays
Because of the great predictive value of therapy response, at present the treatment of children with ALL is stratified according to the response on therapy as measured with these PCRs, and we are currently evaluating whether MRD testing should also be used for therapy stratification for adult ALL. Based on the knowledge obtained in MRD testing in ALL, we started a research line on the detection of MRD in neuroblastoma, the most common extracranial solid tumor in children. In collaboration with our clinical partners we are currently evaluating the value of MRD testing to stage NBL patients at diagnosis and during treatment.
The evaluation of the first clinical protocol in acute lymphoid leukemia showed that guiding treatment, including reduction of chemotherapy and the indication of stem cell transplantation, on the basis of therapy response as measured by PCR, resulted in improved outcome with less side effects of therapy. Our recent results in a prospective neuroblastoma trial on > 300 German and Dutch patients, for which we developed and conducted the MRD measurements, indicate that also for this disease PCR based MRD measurements during treatment is highly predictive for event free survival.
- Zwiers C KJ, Vermij L, van Sambeeck J, Oepkes D, de Haas M, van der Schoot CE. ABO incompatibility and RhIg immunoprophylaxis protect against non-D alloimmunization by pregnancy. Transfusion. 2018 Apr 6
- Stegmann TC, Veldhuisen B, Nagelkerke SQ, Winkelhorst D, Schonewille H, Verduin EP, Kuijpers TW, de Haas M., Vidarsson G. and van der Schoot CE.l. RhIg-prophylaxis is not influenced by FCGR2/3 polymorphisms involved in red blood cell clearance. Blood 2017;129(8):1045-8.
- van der Schoot CE, de Haas M, Clausen FB. Genotyping to prevent Rh disease: has the time come? Curr Opin Hematol. 2017;24(6):544-50.
- de Haas M, Thurik FF, van der Ploeg CP, Veldhuisen B, Hirschberg H, Soussan AA, Woortmeijer H., Abbink F., Page-Christiaens GC., Scheffer PG. and van der Schoot CE . Sensitivity of fetal RHD screening for safe guidance of targeted anti-D immunoglobulin prophylaxis: prospective cohort study of a nationwide programme in the Netherlands. BMJ . 2016;355:i5789.
- Pieters R, de Groot-Kruseman H, Van der Velden V, Fiocco M, van den Berg H, de Bont E, Egeler RM, Hoogerbrugge P, Kaspers G, Van der Schoot E, De Haas V, Van Dongen J. Successful Therapy Reduction and Intensification for Childhood Acute Lymphoblastic Leukemia Based on Minimal Residual Disease Monitoring: Study ALL10 From the Dutch Childhood Oncology Group J Clin Oncol. 2016 Aug 1;34(22):2591-601