What's with the boys? Lower birth weight in boys from HPA-1a alloimmunized pregnancies - New insights from a large prospective screening study in Poland.

Fetomaternal incompatibility in human platelet antigens (HPAs) can cause maternal alloimmunization, which in turn may lead to thrombocytopenia with or without intracranial hemorrhage (ICH) in the fetus or newborn. Retrospective studies suggest that boys from alloimmunized mothers may have higher risk of ICH and lower birth weight than girls. The objective of this study was to assess how maternal HPA-1a alloimmunization, sex of the neonate and birth weight relates in a large prospective cohort. Through a national screening study in Poland (PREVFNAIT) involving HPA-1 typing of 24,259 pregnant women during 2013-2017, 606 HPA-1a negative pregnant women and their offspring were identified and included. Various multivariate models were used to assess if and how maternal HPA-1a alloimmunization status was associated with birth weight and risk of having a small for gestational age (SGA) neonate, and if and how sex of the neonate mattered. Most immunized pregnancies had male fetuses (69 %). Women carrying a male fetus had increased likelihood of having an SGA newborn if they were HPA-1a alloimmunized compared to non-immunized mothers. Increasing maternal anti-HPA-1a antibody levels were significantly associated with reduced birth weight and SGA risk among male-fetus pregnancies, but not if the fetus was female. In conclusion, anti-HPA-1a antibodies in a male fetus pregnancy is associated with increased risk of SGA and lower birth weight, especially if the antibody level is high. Sex of the fetus may therefore be considered as a new clinical predictor of more severe FNAIT neonatal outcome.

Platelet alloimmunization is associated with low grade chronic histiocytic intervillositis - A new link to a rare placental lesion?

INTRODUCTION: Maternal alloimmunization against human platelet antigen (HPA)-1a has been implied to mediate both reduced birth weight and chronic placental inflammation. Fetal growth restriction is associated with different types of chronic inflammation in the placenta, mainly chronic histiocytic intervillositis and chronic villitis. The aim of this prospective study was to do a systematic examination of placentas from HPA-1a alloimmunized pregnancies, with focus on the histopathological and immunohistochemical diagnosis of variants of chronic inflammation. MATERIAL AND METHODS: In a Polish-Norwegian study, 48 placentas were examined. The histopathology of placentas from 27 HPA-1a immunized women was compared with 21 placentas from non-immunized HPA-1a negative women (controls). In the group of alloimmunized women, ten received antenatal intravenous immunoglobulin G (IVIg). Tissue sections from formalin fixed paraffin embedded placental tissue were stained with hematoxylin and eosin and microscopically examined with focus on various types of chronic placental inflammations. RESULTS: Chronic histiocytic intervillositis was observed in 40.7% of placentas from HPA-1a alloimmunized pregnancies, compared to none in the control group (p = 0.001). Chronic villitis of unknown etiology was more frequently found in the alloimmunized group, however this difference was not statistically significant. Maternal administration of IVIg did not seem to protect against chronic inflammatory lesions. DISCUSSION: Placentas with detectable maternal anti-HPA-1a antibodies are associated with highly increased risk of low-grade chronic histiocytic intervillositis.

Prediction of fetal blood group and platelet antigens from maternal plasma using next-generation sequencing.

BACKGROUND: Fetuses whose mothers have produced antibodies to red blood cell (RBC) or platelet antigens are at risk of being affected by hemolytic disease or alloimmune thrombocytopenia, respectively, only if they inherit the incompatible antigen. Noninvasive diagnosis of the fetal antigen is employed for management of immunized pregnancies, but the specific detection of SNPs, encoding the majority of antigens, in maternal plasma is still a challenge. We applied targeted next-generation sequencing (NGS) to predict the fetal antigen based on the detection of fetomaternal chimerism. METHODS AND MATERIALS: The DNA of 13 pregnant women (with anti-K [3] anti-k [1], anti-Fya [1], anti-D + C + Jka [1], anti-D + E + K [1], anti-HPA-1a [1], anti-HPA-3b [1], anti-HPA-5b [1], and nonimmunized [3]) was sequenced using primers for regions encoding RhD, RhC, Rhc, RhE/e, K/k, Fya/b, Jka/b, MN, Ss, and HPA-1, 2, 3, 5, 15, 4 X-polymorphisms on the Ion Torrent Personal Genome Machine (PGM) System (Thermo Fisher Scientific, Inc., Waltham, MA, USA). RESULTS: NGS results were in agreement with the phenotype/genotype of women and their neonates (except for the unsuccessful detection of MN and RhC). NGS determined fetal allele chimerism for K, k, Fya, Fyb, Jka, Jkb, S, RhE (from 0.42% to 6.08%); RhD, Rhc (100%); HPA-1a, -2b, -3a, 3b, -5b, -15a, 15b (from 0.23% to 4.11%). NGS revealed fetal chimerism for incompatible antigens (from 0.7% to 4.8%) in 7 immunized cases, excluded in 3 (with anti-K, anti-Fya , anti-HPA-3b). CONCLUSION: The designed NGS predicts the fetal RBC and platelet antigen status universally in cases with various clinically significant antibodies as well as providing confirmation of the presence of fetal DNA. However, some improvement of the unsuccessful primers is required.

Noninvasive prenatal HPA-1 typing in HPA-1a negative pregnancies selected in the Polish PREVFNAIT screening program.

BACKGROUND: Anti-HPA-1a alloantibodies in HPA-1a negative mothers can lead to fetal/neonatal alloimmune thrombocytopenia (FNAIT). Noninvasive prenatal testing (NIPT) of HPA-1a determines fetuses at risk and the course of maternal antenatal treatment. STUDY DESIGN AND METHODS: The aim was to develop and validate HPA-1a NIPT by real-time polymerase chain reaction (PCR) or next-generation sequencing (NGS) for a high-throughput screening setting. DNA from 328 plasma samples of 299 HPA-1a negative pregnant women was examined for HPA-1a by real-time PCR and in two cases also by NGS (Ion Torrent). The results were compared with neonatal HPA-1a genotyping in 281 cases. RESULTS: HPA-1a NIPT was negative in 44 of 51 HPA-1a negative fetuses, inconclusive in five, and false positive in two. In 228 of 229 HPA-1a positive fetuses, the NIPT results were positive (mean threshold cycle 36.0 ± 1.7) and inconclusive in one. In 22 cases with HPA-1a positive fetuses analyzed twice, the sensitivity of HPA-1a detection was significantly higher at 28 weeks compared with 16 to 20 weeks. NGS efficiently detected the ITGB3 coding HPA-1a/b (1% and 5% fetal HPA-1a reads). CONCLUSION: Real-time PCR is reliable to predict the fetal HPA-1a positive genotype in a screening study, but false-positive results are reported in 4%, with unnecessary prenatal treatment if anti-HPA-1a is detected.

Identification and follow-up of pregnant women with platelet-type human platelet antigen (HPA)-1bb alloimmunized with fetal HPA-1a.

INTRODUCTION: Pregnant women negative for human platelet antigen 1a (HPA-1a) are at risk of alloimmunization with fetal HPA-1a antigen inherited from the father, and their offspring may develop fetal and neonatal alloimmune thrombocytopenia (FNAIT). The aim of this study was to analyze the frequency of HPA-1a alloimmunization in pregnant Polish women, the feasibility of using maternal platelets for intrauterine transfusions in women subjected to diagnostic fetal blood sampling (FBS) and to discuss potential consequences of alloimmunization. MATERIAL AND METHODS: Fifteen thousand two hundred and four pregnant women were typed for HPA-1a; HPA-1a negative were screened for anti-HPA-1a. Alloimmunized women received specialist perinatology care; some of them were subjected to FBS, followed by transfusion of HPA-1a negative platelet concentrates (PC) prepared from maternal blood. RESULTS: Three hundred seventy-three (2.5%) women were HPA-1a negative, and 32 (8.6%) tested positively for anti-HPA-1a. Antibodies were detected in 22 women during pregnancy. Diagnostic FBS followed by PC transfusion was performed in 14 woman, who were platelet donors for their 16 unborn babies. Blood donations were tolerated well by the patients, and also intrauterine platelet transfusions were uneventful. Pharmacotherapy with intravenous immunoglobulins was implemented in 11/22 patients. CONCLUSIONS: HPA-1a negative women (ca. 2.5% of all pregnant patients) are at risk of alloimmunization with HPA-1a antigen and developing FNAIT. Alloimmunized women can be donors of platelets for their offspring providing removal of antibodies from PC. Owing to potential complications, special care should be taken if an alloimmunized woman was qualified as a blood or stem cell recipient.

Single nucleotide polymorphisms in A4GALT spur extra products of the human Gb3/CD77 synthase and underlie the P1PK blood group system.

Contrary to the mainstream blood group systems, P1PK continues to puzzle and generate controversies over its molecular background. The P1PK system comprises three glycosphingolipid antigens: Pk, P1 and NOR, all synthesised by a glycosyltransferase called Gb3/CD77 synthase. The Pk antigen is present in most individuals, whereas P1 frequency is lesser and varies regionally, thus underlying two common phenotypes: P1, if the P1 antigen is present, and P2, when P1 is absent. Null and NOR phenotypes are extremely rare. To date, several single nucleotide polymorphisms (SNPs) have been proposed to predict the P1/P2 status, but it has not been clear how important they are in general and in relation to each other, nor has it been clear how synthesis of NOR affects the P1 phenotype. Here, we quantitatively analysed the phenotypes and A4GALT transcription in relation to the previously proposed SNPs in a sample of 109 individuals, and addressed potential P1 antigen level confounders, most notably the red cell membrane cholesterol content. While all the SNPs were associated with the P1/P2 blood type and rs5751348 was the most reliable, we found large differences in P1 level within groups defined by their genotype and substantial intercohort overlaps, which shows that the P1PK blood group system still eludes full understanding.

A preliminary evaluation of next-generation sequencing as a screening tool for targeted genotyping of erythrocyte and platelet antigens in blood donors.

BACKGROUND: Matching the compatibility of donor blood with the recipient's antigens prevents alloimmunisation. Next-generation sequencing (NGS) technology is a promising method for extensive blood group and platelet antigen genotyping of blood donors. It circumvents the limitations of detecting known alleles based on predefined polymorphisms and enables targeted sequencing on a massive scale. The aim of this study was to evaluate the NGS AmpliSeq application on the Ion Torrent platform as a screening tool for genotyping blood donors' erythrocyte/platelet antigens. MATERIALS AND METHODS: Primers for regions encoding antigens RhD (exons 5, 7), Rhc, RhE/e, Fya/b, Jka/b, M/N, S/s, HPA-1, 2, 3, 5, 15 were designed with Ion AmpliSeq Designer with manual inclusion of RHCE*C primers. DNA libraries of 57 regular blood donors with determined phenotype/genotype (prepared using the Ion AmpliSeq Library Kit and 14 primer pairs) were sequenced on the Ion Torrent PGM using 316v2 chips and 200 bp chemistry. RESULTS: Sequencing was successful in all but the MN and HPA-5 regions. Mean sequencing coverage in one experiment was 4,606 reads, except for the RHCE*C region (mean 568 reads). NGS results agreed with the known phenotype/genotype of donors except in one phenotypically Fy(a+b-) case in whom FY*A/FY*B alleles were found. Reading rates for homozygotes were 97-100%, while they were around 50% for heterozygotes. NGS of RHD regions led to identification of mutations in two RhD negative donors. DISCUSSION: NGS can be performed as a screening test to determine erythrocyte/platelet antigens in blood donors. This method allowed testing of 48 donors for 14 features (200 bp long) with the depth of a few thousand reads simultaneously, and the estimation of natural chimerism or hemi/homozygotic status. NGS screening can be adjusted to the genetic background of a given tested population.

What weighs more-low compliance with self-deferral or minor medical procedures? Explaining the high rate of hepatitis C virus window-period donations in Poland.

BACKGROUND: Since the introduction of nucleic acid testing (NAT) for routine blood donor screening, hepatitis C virus (HCV) RNA-only detection rates reported from Poland have been higher than in most other European countries. STUDY DESIGN AND METHODS: To examine factors that likely contribute to these window-period donations, we conducted a case-control study among 47 recently HCV-infected blood donors (cases), who gave blood between July 2002 and June 2014, and 141 controls matched by age, sex, and donation dates. Firth-corrected, conditional logistic regression models were fitted to estimate adjusted odds ratios and 95% confidence intervals. Adjusted population-attributable fractions were calculated based on the distribution of exposure among the cases. RESULTS: On multivariate analysis, recent exposures in health care environments not routinely ascertained through predonation questionnaires were strongly associated with recently acquired HCV infection. These exposures included minor medical and dental procedures in the preceding 6 months (adjusted odds ratio, 5.77; 95 % confidence interval, 2.01-18.53). However, based on the population-attributable fraction, more important were behavioral deferrable risks that went unreported at the time of donation, such as high-risk sexual behaviors in the preceding 6 months (population-attributable fraction, 34%) or lifetime histories of drug use (population-attributable fraction, 28%). CONCLUSIONS: This study raises questions about the effectiveness of deferral policy in excluding high-risk individuals. In addition, it provides further evidence supporting short, temporal deferrals for small medical procedures and dental treatments in Poland.

Recent advances in understanding the clinical relevance of antiplatelet alloantibodies.

Alloimmunization to human platelet antigens (HPAs) may occur either during pregnancy, when a HPA­negative mother gives birth to a newborn who inherits HPAs from the father, or following blood transfusion or stem cell transplantation. Antiplatelet alloantibodies do not cause thrombocytopenia in a patient, but their detection must always be recorded in medical records because they may induce fetal and neonatal alloimmune thrombocytopenia in present and all subsequent pregnancies, platelet refractoriness, posttransfusion purpura, or prolonged thrombocytopenia with engraftment failure after stem cell transplantation. Passive transfer of platelet alloantibodies through transfused blood components may trigger thrombocytopenia and severe posttransfusion reactions in the recipient. In a Caucasian population, such clinical outcome of platelet alloimmunization is mostly due to anti­HPA­1a antibodies, less frequently to anti­HPA­5b, anti­HPA­1b, and others. Information on anti­HPA alloantibodies is crucial for the prevention and treatment of their consequences.

Compound heterozygosity of two novel RHAG alleles leads to a considerable disruption of the Rh complex.

BACKGROUND: The Rhesus (Rh) complex consists of a core comprising the Rh proteins (RhD/RhCE) and the Rh-associated glycoprotein (RhAG) with accessory chains (GPB, LW, CD47). Molecular defects of the RHAG gene may cause a regulator Rhnull phenotype without Rh antigen expression or a Rhmod phenotype with decreased Rh antigen expression. STUDY DESIGN AND METHODS: Blood samples of a donor with strongly diminished Rh antigens and five family members were analyzed by serological phenotyping, flow cytometry, molecular testing, and gene expression analysis of Rh complex candidate genes. RESULTS: RHAG sequencing identified a missense mutation, c.241G>C (p.Gly81Arg) and a splice site mutation, c.640 + 3del14, among the cohort. Compound heterozygosity of these novel alleles identified in the propositus and two siblings gave rise to a strongly diminished expression of RhAG, Rh, and CD47 antigens on the RBC surface. CONCLUSION: The Rhmod phenotype was caused by a novel RHAG splice site mutation in association with a non-functional allele. The primary depression of RhAG is most likely due to posttranslational events that affect the interaction and processing of the RhAG glycoprotein and gave rise to a secondary depression of RhD, RhCE, and CD47, the major members of the Rh complex.

Fetal/Neonatal Alloimmune Thrombocytopenia: Pathogenesis, Diagnostics and Prevention.

Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is a relatively rare condition (1/1000-1/2000) that was granted orphan status by the European Medicines Agency in 2011. Clinical consequences of FNAIT, however, may be severe. A thrombocytopenic fetus or new-born is at risk of intracranial hemorrhage that may result in lifelong disability or death. Preventing such bleeding is thus vital and requires a solution. Anti-HPA1a antibodies are the most frequent cause of FNAIT in Caucasians. Its pathogenesis is similar to hemolytic disease of the newborn (HDN) due to anti-RhD antibodies, but is characterized by platelet destruction and is more often observed in the first pregnancy. In 75 % of these women, alloimmunization by HPA-1a antigens, however, occurs at delivery, which enables development of antibody-mediated immune suppression to prevent maternal immunization. As for HDN, the recurrence rate of FNAIT is high. For advancing diagnostic efforts and treatment, it is thereby crucial to understand the pathogenesis of FNAIT, including cellular immunity involvement. This review presents the current knowledge on FNAIT. Also described is a program for HPA-1a screening in identifying HPA-1a negative pregnant women at risk of immunization. This program is now performed at the Institute of Hematology and Transfusion Medicine in cooperation with the Department of Obstetrics and Gynecology of the Medical Centre of Postgraduate Education in Warsaw as well as the UiT The Arctic University of Norway.

Real-Time PCR Analysis of Chimerism in T Cell Subsets as an Early Predictor of Graft-Versus-Host Disease Following Allogeneic Stem Cell Transplantation.

BACKGROUND: Graft-versus-host-disease (GvHD) is the major cause of morbidity and mortality after stem cell transplantation. The development of early prediction methods is therefore of importance. Our aim was to analyze the usefulness of early donor chimerism monitoring after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in T cells and in CD4+ and CD8+ (lineage chimerism) for GvHD prediction. MATERIAL AND METHODS: Chimerism was analyzed in 76 consecutive adult patients using RQ-PCR TaqMan technology on DNA extracted from Pan T, CD4+, and CD8+ cell subsets on Day 5, 10, 15 and 30 after allo-HSCT. RESULTS: The threshold of chimerism predictive for GvHD was the same for all tested cell subsets. In acute myeloid leukemia (AML) patients treated with myeloablative conditioning (MAC), the threshold predictive for acute graft versus host disease was 95% and 99% for Day 10 and Day 15, respectively. In patients treated with reduced intensity conditioning (RIC), the threshold predictive for chronic graft versus host disease was 98% on Day 10. The differences were statistically significant. CONCLUSIONS: Chimerism analysis in T cell subsets by RQ-PCR on Day 10 and Day 15 after transplantation is useful for prediction of aGvHD (AML patients after MAC) and cGvHD (patients after RIC). However, there was no difference in the results between chimerism in the T cell subsets. Our RQ-PCR protocol was highly sensitive and proved effective for analysis of lineage chimerism.

Blood donors screening for blood born viruses in Poland.

Blood donor screening of viral markers in Poland is based on serologic testing for anti-HCV, HBsAg, anti-HIV1/2 (chemiluminescence tests) and on nucleic acid testing (NAT) for RNA HCV, RNA HIV-1 and DNA HBV performed in minipools of 6 with real-time PCR (MPX 2.0 test on cobas s201) or with TMA in individual donations (Ultrio Plus or Ultrio Elite). Donors of plasma for anti-D and anti-HBs production are tested for parvovirus B19 DNA. Before implementation tests and equipment are evaluated at the Institute of Hematology and Transfusion Medicine (IHTM). The last 20 years witnessed a decreasing trend for HBsAg in both first time and repeat donors (1%-0.3% and 0.1%-0.02% respectively). Prevalence of anti-HCV repeat reactive results was stable and oscillated around 0.8% for first time donors and 0.2% for repeat donors. Elevated prevalence of seropositive HIV infected donors was recently observed (7.5-9 cases/100,000 donors). Since respective molecular markers implementation HCV RNA was detected on average in 1/119,235 seronegative donations, HIV RNA in 1/783,821 and HBV DNA in 1/61,047. HBV NAT yields were mostly occult hepatitis B (1/80,248); window period cases were less frequent (1/255,146). The efficiency of HBV DNA detection depends on the sensitivity of the HBV DNA screening system.

[Standardization of the quantitative flow cytometric test with anti-D antibodies for fetomaternal hemorrhage in RhD negative women]. / Standaryzacja metody ilosciowej oceny przecieku plodowo-matczynego u kobiet RhD ujemnych przy pomocy cytometrii przeplywowej z uzyciem przeciwcial anty-D.

BACKGROUND: In order to determine the appropriate dose of anti-D immunoglobulin to be administered as a preventive measure against hemolytic disease of the fetus/newborn in the subsequent pregnancy it is necessary to assess the number of fetal red blood cells that infiltrate/penetrate into the maternal circulation as a result of fetomaternal hemorrhage (FMH). One of the quantitative methods of FMH analysis is based on flow cytometry (FACS) which makes use of monoclonal antibodies to RhD antigen (anti-D test). The aim of the study was to further develop the method, evaluate its sensitivity and reproducibility and to compare it with the test based on the detection of fetal hemoglobin (HbF). MATERIAL AND METHODS: The FACS study involved 20 RhD negative pregnant women and 80 RhD negative women after delivery. The following monoclonal antibodies were used: BRAD 3 FITC (anti-RhD antigen), CD45 PerCP (anti leukocyte antigen CD45), and anti-HbF PE. RESULTS: The fluorescence intensity of cells incubated with BRAD 3 FITC was demonstrated to depend on the RhD antigen expression, though the anti-D test also detects the weak D variant. The CD45 PerCP antibodies increased the sensitivity of anti-D test since they eliminated the leukocytes which non-specifically bind anti-D from the analysis. The presence of anti-D antibodies in maternal plasma does not affect the quantitative assessment of the fetal RhD positive fetal cells with BRAD 3 FITC. In case of FMH, the results of the anti-D test were similar to those with anti-HbF antibodies. CONCLUSIONS: The flow cytometric test with anti-D and anti-CD45 is useful in the assessment of the fetomaternal hemorrhage in RhD negative women. The sensitivity of the test is estimated at 0.05%.

Introducing Pathogen Reduction Technology in Poland: A Cost-Utility Analysis.

BACKGROUND: Mirasol® pathogen reduction technology (PRT) uses UV light and riboflavin to chemically inactivate pathogens and white blood cells in blood components. In the EU, Mirasol PRT is CE-marked for both plasma and platelet treatment. In Poland, the decision to introduce PRT treatment of the national supply of fresh frozen plasma has spurred interest in evaluating the cost-effectiveness of this strategy. METHODS: A decision-analytic model evaluated the incremental costs and benefits of introducing PRT to the existing blood safety protocols in Poland. RESULTS: Addition of PRT treatment of plasma to current screening in Poland is estimated to cost 2.595 million PLN per quality-adjusted life year (QALY) (610,000 EUR/QALY); treating both plasma and platelet components in addition to current safety interventions had a lower cost of 1.480 million PLN/QALY (348,000 EUR/QALY). CONCLUSIONS: The results suggest that in Poland the cost per QALY of PRT is high albeit lower than found in previous economic analyses of PRT and nucleic acid testing in North America. Treating both platelets and plasma components is more cost-effective than treating plasma alone. Wide confidence intervals indicate high uncertainty; to improve the precision of the health economic evaluation of PRT, additional hemovigilance data are needed.

Sensitivity of hepatitis C virus core antigen and antibody combination assays in a global panel of window period samples.

BACKGROUND: Hepatitis C virus (HCV) antigen and antibody combination assays have been launched as a cost-effective alternative to nucleic acid testing (NAT) for reducing the antibody-negative window period (WP). Later, a HCV antigen chemiluminescence immunoassay (CLIA) became available. STUDY DESIGN AND METHODS: A panel composed of 337 HCV NAT-yield samples that were characterized for viral load (VL) and genotype was used to compare the sensitivity of two combination enzyme-linked immunosorbent assays (Monolisa, Bio-Rad; and Murex, formerly Abbott) and a HCV antigen CLIA (Abbott). Analytic sensitivity was compared with HCV RNA detection using Ultrio (Grifols) by testing serial dilutions of 10 genotype (gt)1 to gt4 samples. RESULTS: HCV antigen CLIA detected 92.4% of samples, whereas Monolisa and Murex detected 38.3 and 47.5%, respectively. In the HCV RNA VL range of 10(5) to 10(7) IU/mL, Monolisa and Murex detected 38% to 56% of gt1, 85% to 78% of gt2, and 21% to 37% of gt3. The overall geometric mean 50% limit of detection (range) of Ultrio on gt1 to gt4 dilution series was 3.5 (1.2-7.7) copies/mL, compared to 3.3 × 10(6) (4.4 × 10(5) -2.7 × 10(7) ), 3.4 × 10(6) (2.2 × 10(5) -4.2 × 10(7) ), and 2728 (415-7243) copies/mL for Monolisa, Murex, and HCV antigen CLIA, respectively. CONCLUSION: Analytical sensitivity of NAT was on average 1 million- and 780-fold higher than combination assays and HCV antigen CLIA, respectively. Relative sensitivities of combination assays differed for genotypes with Murex being more sensitive for gt1 and gt3 and Monolisa more sensitive for gt2. Although being less sensitive than NAT, combination assays could be considered in resource-limited settings since they detect 38% to 47% of seronegative WP donations.

[PREVFNAIT prevention of foetal/neonatal alloimmune thrombocytopenia (FNAIT) in Polish foetuses and newborns--the PREVFNAIT program]. / Zapobieganie alloimmunologicznej maloplytkowosci plodów i noworodków (AIMPN) w Polsce--program PREVFNAIT.

The scientific goals related to the grant include 1) estimation of FNAIT prevalence in Poland and 2) search for biomarkers to predict the risk of the antibody production and severity of fetal thrombocytopenia. Fetal/Neonatal Alloimmune Thrombocytopenia (FNAIT) is caused by destruction of fetal blood platelets due to maternal antibodies. This condition, which most commonly results from incompatibility between the mother and the fetus for the Human Platelet Antigen-1a (HPA-1a), may lead to intracranial hemorrhage, damage of the central nervous system (CNS) and even death of the fetus or the newborn. It can be the cause of strokes in term newborns. FNAIT is usually attributed to the presence of anti-HPA-1a antibodies. Its incidence rate is estimated at approximately 1/1000-2000 live births. In the absence of a screening program, it is usually diagnosed after birth of a child with symptoms of thrombocytopenia or CNS hemorrhage. Monitoring of antibody production and thrombocytopenia treatment to effectively minimize the risk of stroke are therefore launched only at the next pregnancy. Testing indications are broader to include fetal ultrasound for symptoms of stroke to the CNS, ventricular enlargement or hydrocephalus, and obstetric failure. Diagnostic process is also recommended prior to the planned cordocentesis, in vitro fertilization and in sisters of mothers with children with FNAIT history. HPA-1a testing remains the best method for diagnosing pregnancies at risk. The detection frequency for FNAIT in Poland remains low. Therefore, the Institute of Hematology and Transfusion Medicine (IHTM) will have performed such HPA-1a antigen testing in 30 000 Polish women within the framework of the PREVFNAIT program by March 2016. HPA-1a negative women (2% of the population) are a risk group for production of anti- HPA-1a antibodies responsible for FNAIT therefore all of them will be monitored for the presence and activity of anti-HPA-1a antibodies. Such testing will be performed free of charge for the women.

14 Years of Polish Experience in Non-Invasive Prenatal Blood Group Diagnosis.

BACKGROUND: Blood cell antigens may cause maternal alloimmunization leading to fetal/newborn disorders. Non-invasive prenatal diagnostics (NIPD) of the blood group permits the determination of feto-maternal incompatibility. AIM: To evaluate 14 years of blood group NIPD at the Institute of Hematology and Transfusion Medicine (IHTM) in Warsaw. METHODS: Plasma DNA from 536 RhD-negative, 24 Rhc-negative, 26 RhE-negative, 43 K-negative, and 42 HPA-1a-negative pregnant women was examined by real-time PCR to detect RHD, RHCE*c, RHCE*E, RHCE*C, KEL*01 and HPA*1A, respectively. We tested for CCR5, SRY or bi-allelic polymorphisms and quantified the total or fetal DNA. RESULTS: The results of fetal antigen status prediction by NIPD in all but one case (false-positive result of KEL*01) were correct taking neonate serology as a reference. It was confirmed that all negative results of NIPD contained fetal DNA except for four cases where there was no difference between the parents' polymorphisms. CONCLUSIONS: A fetal genotype compatible with the mother was determined in 25% of all pregnancies tested at the IHTM for the fetal blood group. These cases were not at risk of disease, so it was possible to avoid invasive procedures.