Intrauterine transfusion in 103 fetuses with severe anemia caused by parvovirus infection. A multicenter retrospective study

PURPOSE

Evaluating procedure-related complications and perinatal outcomes after intrauterine transfusion (IUT) before or after 20⁺⁰ weeks of gestation in fetuses with severe anemia due to intrauterine human parvovirus B19 infection.

METHODS

A retrospective study investigating fetuses requiring IUT for fetal Parvo B19 infection in two tertiary referral centers between December 2002 and December 2021. Procedure-related complications, intrauterine fetal death (IUFD), and perinatal outcome were correlated to gestational age (GA) at first IUT, the presence of hydrops and fetal blood sampling results.

RESULTS

A total of 186 IUTs were performed in 103 fetuses. The median GA at first IUT was 19⁺³ (13⁺⁰-31⁺⁴) weeks of gestation. IUFD occurred in 16/103 fetuses (15.5%). Overall survival was 84.5% (87/103). Hydrops (p = 0.001), lower mean hemoglobin at first IUT (p = 0.001) and low platelets (p = 0.002) were strongly associated with IUFD. There was no difference observed in fetuses transfused before or after 20⁺⁰ weeks of gestation.

CONCLUSION

IUT is a successful treatment option in fetuses affected by severe anemia due to parvovirus B19 infection in specialized centers. In experienced hands, IUT before 20 weeks is not related to worse perinatal outcome.

Updated DEGUM Quality Requirements for the Basic Prenatal Screening Ultrasound Examination (DEGUM Level I) between 18 + 0 and 21 + 6 weeks of gestation

A precondition for the early detection of fetal abnormalities is the high quality of prenatal basic ultrasound (screening examination). The objective of ultrasound screening is the recognition of abnormal fetal growth and fetal anatomical anomalies. The prenatal detection of fetal abnormalities enables detailed prenatal counselling of parents, improved care at birth and potentially a reduction in morbidity and mortality. In the guidelines for maternity care in Germany ("Mutterschaftsrichtlinien"), the performance of basic ultrasound in pregnancy is not clearly defined. The required image documentation includes a few biometric measurements only. Therefore, adherence to a standard technique and the possibility of audit are limited, thus not necessarily resulting in high screening quality. In this update of the DEGUM quality requirements for level I screening ultrasound examination between 18 + 0 and 21 + 6 weeks of gestation, the required parameters, standard planes and required documentation are described in detail. The greater experience of gynecologists in the field of sonographic screening examinations and the use of a modern ultrasound technique allow improvement of the screening quality. This will improve the standard of basic ultrasound screening. Due to the enhanced standard of the DEGUM I examination, more pregnant women may benefit from a detailed ultrasound examination and specialized therapy in DEGUM level II and III centers. The required fetal structures are described in detail. This update of the requirements for level I DEGUM basic ultrasound examination between 18 + 0 and 21 + 6 weeks of gestation goes far beyond the guidelines for maternity care in Germany (the "Mutterschaftsrichtlinien") thereby elevating standards.

Smith-Lemli-Opitz syndrome - Fetal phenotypes with special reference to the syndrome-specific internal malformation pattern

Background

Autosomal‐recessive SLOS is caused by mutations in the DHCR7 gene. It is defined as a highly variable complex of microcephaly with intellectual disability, characteristic facies, hypospadias, and polysyndactyly. Syndrome diagnosis is often missed at prenatal ultrasound and fetal autopsy

Methods

We performed autopsies and DHCR7 gene analyses in eight fetuses suspected of having SLOS and measured cholesterol values in long‐term formalin‐fixed tissues of an additional museum exhibit

Results

Five of the nine fetuses presented classical features of SLOS, including four cases with atrial/atrioventricular septal defects and renal anomalies, and one with additional bilateral renal agenesis and a Dandy‐Walker cyst. These cases allowed for diagnosis at autopsy and subsequent SLOS diagnosis in two siblings. Two fetuses were mildly affected and two fetuses showed additional holoprosencephaly. These four cases and the exhibit had escaped diagnosis at autopsy. The case with bilateral renal agenesis presented a novel combination of a null allele and a putative C‐terminus missense mutation in the DHCR7 gene

Conclusions

In view of the discrepancy between the prevalence of SLOS among newborns and the carrier frequency of a heterozygous DHCR7 gene mutation, the syndrome‐specific internal malformation pattern may be helpful not to miss SLOS diagnosis in fetuses at prenatal ultrasound and fetal autopsy

Piepkorn type of osteochondrodysplasia: Defining the severe end of FLNB-related skeletal disorders in three fetuses and a 106-year-old exhibit

The Piepkorn type of lethal osteochondrodysplasia (POCD) is a rare and lethal dwarfing condition. Four cases have been reported to date. The characteristic features are distinctly shortened "flipper-like" limbs, polysyndactyly, excessive underossification, especially of the limb bones and vertebrae, and large (giant) chondrocytes in the cartilaginous bone primordia. These characteristics allowed the diagnosis of Piepkorn type of osteochondrodysplasia in four new cases, three fetuses of 15 to 22 weeks and one 106-year-old museum exhibit. Piepkorn type of osteochondrodysplasia has been assigned to the giant cell chondrodysplasias such as atelosteogenesis type 1 (AO1) and boomerang dysplasia (BD). Analysis of the Filamin B gene in 3p14.3, which is associated with these disorders, allowed the identification of the first FLNB mutations in Piepkorn type of osteochondrodysplasia. The heterozygous missense mutations, found in the three fetuses, were located in exons 28 and 29, encoding the immunoglobulin-like repeat region R15, one of three mutational hot spots in dominant FLNB-related skeletal disorders. Direct preparations and alcian blue staining revealed single upper and lower arm and leg bone primordia, preaxial oligodactyly, and polysyndactyly with complete fusion and doubling of the middle and end phalanges II-V to produce eight distal finger rays. Considering the unique clinical features and the extent of underossification, Piepkorn type of osteochondrodysplasia can be regarded as a distinct entity within the AO1-BD-POCD continuum.

Fetal Pathology of Neural Tube Defects - An Overview of 68 Cases

INTRODUCTION

The prevalence of neural tube defects worldwide is 1 - 2 per 1000 neonates. Neural tube defects result from a disturbance of neurulation in the 3rd or 4th week of development and thus represent the earliest manifestation of organ malformation. Neural tube defects (NTD) are classified into cranial dysraphism leading to anencephaly or meningoencephalocele and spinal dysraphism with or without meningomyelocele. In isolated form they have multifactorial causes, and the empirical risk of recurrence in Central Europe is 2%. As associated malformations they tend to occur sporadically, and in monogenic syndromes they follow Mendelian inheritance patterns with a high risk of recurrence.

PATIENTS

Autopsies were performed on 68 fetuses following a prenatal diagnosis of NTD and induced abortion.

RESULTS

The incidence of NTDs in our autopsied fetuses was 8% and 11% in fetuses with malformations. The percentage of fetuses with anencephaly, encephalocele or spina bifida was 24, 18, and 60%*, respectively. Analysis of the sex distribution showed a female preponderance in cranial dysraphisms but the sex distribution of spina bifida cases was equal. The extent and localization of NTDs varied, with lumbosacral cases clearly predominating. The proportion of isolated, associated and syndromic neural tube defects was 56, 23.5 and 20.6% respectively. In the majority of syndromes, the neural tube defect represented a not previously observed syndromic feature.

CONCLUSION

The high proportion of NTDs with monogenic background underlines the importance of a syndrome oriented fetal pathology. At the very least it requires a thourough photographic and radiographic documentation of the fetal phenotype to enable the genetic counsellor to identify a syndromic disorder. This is necessary to determine the risk of recurrence, arrange confirming mutation analyses and offer targeted prenatal diagnosis in subsequent pregnancies.

Mutations in TGDS associated with additional malformations of the middle fingers and halluces: Atypical Catel-Manzke syndrome in a fetus

Pierre-Robin sequence, radial deviation, and ulnar clinodactyly of the index fingers due to an additional phalangeal bone, as well as heart defects are the key features of Catel-Manzke syndrome. Although mutations in TGDS were identified as the cause of this disorder, the pathogenetic mechanism remains unknown. Here, we report on a fetus with severe heart defect, nuchal edema, talipes, Pierre-Robin sequence, and bilateral deviation and clinodactyly of the index and middle fingers. Pregnancy was terminated at the 22nd week of gestation. Postmortem radiographs showed hypoplasia and V-shaped displacement of the second and third proximal phalanges of both hands as well as hypoplasia of the first metatarsals and the phalangeal bones of the halluces. The suggested diagnosis Catel-Manzke syndrome was confirmed by the detection of two compound heterozygous mutations in TGDS: The known variant c.298G>T; p.(Ala100Ser) and the so far undescribed variant c.895G>A; p.(Asp299Asn), located in the predicted substrate binding site of TGDS. This is the first report on the association of mutations in TGDS with additional anomalies of the middle fingers and halluces. We provide a detailed phenotypic characterization of the only fetus with molecularly confirmed Catel-Manzke syndrome, which is relevant for prenatal diagnosis. Our findings widen the phenotype spectrum caused by TGDS mutations and underline the phenotypic overlap with Temtamy preaxial brachydactyly syndrome. This improves our understanding of the prenatal development and the pathogenetic mechanism of Catel-Manzke syndrome.

Prenatal diagnosis of congenital cytomegalovirus infection in 115 cases: a 5 years' single center experience

OBJECTIVE

The objective of this study is to investigate the diagnostic value of invasive prenatal diagnosis (PD) of congenital cytomegalovirus (CMV) infection from amniotic fluid (AF) and fetal blood (FB).

METHODS

A retrospective study was conducted on 115 pregnancies with CMV primary infection. A total of 111 AF and 106 FB samples were investigated for various virological and non-virological markers. Detailed ultrasound examinations were performed at time of PD.

RESULTS

Overall sensitivity of CMV PCR in FB (75.6%; 95%CI 60-87) and AF (72.7%; 95%CI 57-85) was comparable. In women with amniocentesis >8 weeks between seroconversion and PD, we did not observe significant differences between amniocentesis performed ≥17 + 0 (sensitivity 90.9%; 95%CI 71-99) and ≥20 + 0 gestational weeks (sensitivity 90.0%; 95%CI 68-99). Virological markers in FB were higher in symptomatic compared with asymptomatic fetuses (p < 0.05). No significant differences were observed for non-virological markers. However, platelet counts <120 × 10e9/L and beta-2 microglobulin values >14 mg/L were more frequently found in fetuses with severe ultrasound abnormalities compared with fetuses with no or mild abnormalities (p < 0.001).

CONCLUSION

Optimal timing of amniocentesis in women with primary infection in early gestation should be reevaluated in a prospective study. Analysis of FB markers may be beneficial in the individual management of pregnant women with confirmed congenital CMV infection. © 2017 John Wiley & Sons, Ltd.

Successful treatment of an infant with CDA type II by intrauterine transfusions and postnatal stem cell transplantation

Congenital dyserythropoietic anemias are rare hematological disorders leading to ineffective erythropoiesis with chronic anemia, complicated by iron overload. Here we present a remarkable clinical course of an infant with CDA type II who first presented as a severe fetal hydrops, requiring serial intrauterine red cell transfusions. While postnatal transfusion dependency persisted, the patient was successfully transplanted with a myeloablative conditioning regimen and peripheral blood stem cells of a matched donor. We believe that allogeneic HSCT is a reasonable therapeutic approach for patients with very severe CDA, even if only a matched unrelated donor is available.

Deletions in PITX1 cause a spectrum of lower-limb malformations including mirror-image polydactyly

PITX1 is a bicoid-related homeodomain transcription factor implicated in vertebrate hindlimb development. Recently, mutations in PITX1 have been associated with autosomal-dominant clubfoot. In addition, one affected individual showed a polydactyly and right-sided tibial hemimelia. We now report on PITX1 deletions in two fetuses with a high-degree polydactyly, that is, mirror-image polydactyly. Analysis of DNA from additional individuals with isolated lower-limb malformations and higher-degree polydactyly identified a third individual with long-bone deficiency and preaxial polydactyly harboring a heterozygous 35 bp deletion in PITX1. The findings demonstrate that mutations in PITX1 can cause a broad spectrum of isolated lower-limb malformations including clubfoot, deficiency of long bones, and mirror-image polydactyly.

Multiple hepatic mesenchymal hamartomas in a premature associated with placental mesenchymal dysplasia

Placental mesenchymal dysplasia (PMD) is an uncommon disorder that has to be differentiated histologically from a partial mole. In contrast to a hydatitiform mole, PMD can coexist with a viable fetus. Placental mesenchymal dysplasia is characterized by placentomegaly and dilatation of the chorionic vessels. In our case, multiple hepatic mesenchymal hamartomas in a preterm were associated with PMD. This association is an extremely rare anomaly. Mesenchymal hamartomas occur in 5% of all primary liver tumors in children and are generally benign lesions.

A new platelet alloantigen, Swi(a) , located on glycoprotein Ia identified in a family with fetal and neonatal alloimmune thrombocytopenia

BACKGROUND

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a bleeding disorder caused by transplacental passage of maternal antibodies to fetuses whose platelets (PLTs) express the corresponding human PLT antigen (HPA).

STUDY DESIGNS AND METHODS

We observed a fetus with FNAIT who died from a severe intracranial hemorrhage. Analysis of maternal serum in antigen capture assay with paternal PLTs showed reactivity with PLT glycoprotein (GP)IIb/IIIa (α(IIb) β(3) ) and GPIa/IIa (α(2) β(1) integrin), indicating the presence of anti-HPA-1a and an additional alloantibody against GPIa (termed anti-Swi(a) ).

RESULTS

By immunochemical studies, the localization of the Swi(a) antigen on GPIa/IIa could be confirmed. Analysis of paternal GPIa full-length cDNA showed a single-nucleotide substitution C(3347) T in Exon 28 resulting in a Thr(1087) Met amino acid substitution. Testing of family members by polymerase chain reaction-restriction fragment length polymorphism using MslI endonuclease showed perfect correlation with phenotyping. Extended family and population studies showed that 4 of 10 members of the paternal family but none of 500 unrelated blood donors were Swi(a) carriers. Expression studies on allele-specific transfected Chinese hamster ovary (CHO) cells confirmed that the single-amino-acid substitution Thr(1087) Met was responsible for the formation of the Swi(a) epitope. Adhesion of CHO cells expressing the Swi(a) alloantigen to immobilized collagens was not impaired compared to the wild-type control and was not inhibited by anti-Swi(a) alloantibodies.

CONCLUSION

In this study we defined a new PLT alloantigen Swi(a) that was involved in a case of additional immunization against HPA-1a. Our observations demonstrate that combinations of PLT-specific alloantibodies may comprise low-frequency alloantigens.

[Chemotherapy-induced fetal anemia in maternal acute myelocytic leukemia]

This article discusses the management of a pregnancy of a 32-year-old primigravida with acute myelocytic leukemia treated with induction chemotherapy starting in the 20 + 5 week of gestation. Sonographic monitoring showed evidence of fetal ascites and anemia that could be treated with an intrauterine fetal transfusion. After maternal recovery, a caesarean section was performed in the 27 + 5 week of gestation. We delivered a vivid eutrophic female prematurely. The infant showed persisting signs of myelosuppression. Two further transfusions had to be performed. The present report describes the interdisciplinary therapeutic management when polychemotherapy during pregnancy is necessary for the mother. Cases of acute leukemia in pregnancy are complicated by severe prenatal risks caused by the hematologic illness and by the immediate beginning of chemotherapy. In the third trimester premature delivery is preferable to intrauterine exposition to cytostatic agents. In the second trimester the pregnancy has to be monitored for the typical risks and complications of chemotherapy. Fetal cytotoxic myelosuppression is detectable by prenatal observation so that interventional strategies are feasible.

Fetal manifestation of the Fine-Lubinsky syndrome. Brachycephaly, deafness, cataract, microstomia and mental retardation syndrome complicated by Pierre-Robin anomaly and polyhydramnios

OBJECTIVES

We report on a female fetus of 24 weeks gestational age with Fine-Lubinsky syndrome (FLS), representing the 7th case published so far.

METHODS

Prenatal ultrasound was performed at 22+1 weeks of gestation and thorough postmortem examination was made after termination of pregnancy.

RESULTS

The diagnosis of FLS in the fetus was based on characteristic features that were already apparent in early prenatal life, such as growth deficiency, brachycephaly, flat face with associated dysmorphic signs, microstomia and cataract, while deafness and mental retardation, which are syndrome-specific functional disorders and evident only postnatally, could not be taken into account.

CONCLUSIONS

This case demonstrates the diagnostic problems in fetal syndromology if syndrome-specific features are not yet recognizable and additional complications occur that had not been observed in this disorder.

Segmental arterial mediolysis in a preterm

We firstly report on a dystrophic preterm infant with segmental arterial mediolysis (SAM) found in arteries of placental, umbilical and cerebral tissues. These arterial lesions of unknown etiology developing in the elderly are characterized by segmental lysis of the abdominal splanchnic arteries followed by aneurysms and acute bleeding. Typically, the lesions occur in a skip pattern. We could find a small number of SAM in the spleen but much more in placental and umbilical tissues. Rarely, a vascular elastosis and splitting of individual vessels in the spleen and lung could be detected. The histological findings are similar to that of adult patients.

Monozygotic triplets and monozygotic twins after ICSI and transfer of two blastocysts: case report

There are data regarding the possible influences of extended embryo culture to the blastocyst stage as well as zona pellucida manipulation on the incidence of monozygotic multiples. This is interesting, as one aim of extended culture with embryo selection is to minimize the multiple pregnancy rate. We report, to our knowledge, on the first case of monozygotic twins and monozygotic triplets after ICSI and the transfer of two blastocysts. Monozygotic multiples after ICSI and blastocyst transfer and the resulting problems are another reason to encourage the transfer of only one blastocyst. Theories about risk factors and the pathophysiology of monozygotic multiples will be discussed both in terms of this case report and of the literature. In our opinion, the incidence of 5.9-8.9% monozygotic multiple occurrence after ICSI and blastocyst transfer reported in the literature requires that patients are informed of the uncertainties until this phenomenon and its risk factors are better understood.

Longitudinal thrombopoietin plasma concentrations in fetuses with alloimmune thrombocytopenia treated with intrauterine PLT transfusions

BACKGROUND

The purpose of this study was to describe longitudinal thrombopoietin (TPO) plasma concentrations in fetuses with fetomaternal alloimmune thrombocytopenia (FMAIT).

STUDY DESIGN AND METHODS

Group 1 was the control group, 8 fetuses with normal hematopoiesis. Group 2 consisted of 4 nonthrombocytopenic fetuses with fetomaternal human PLT antigen incompatibility. Group 3 consisted of 14 fetuses with prenatal-diagnosed severe FMAIT owing to human PLT antigen-1a incompatibility. Fetal PLT counts, MoAb-specific immobilization of PLT antigen score, and TPO plasma concentrations were measured in a total number of 94 serial samples taken by cordocentesis before intrauterine PLT transfusion.

RESULTS

Normal fetal TPO plasma concentrations ranged between 15 and 119 pg per mL (Group 1 median, 67 pg/mL). In fetuses with risk of FMAIT but normal PLT counts, TPO concentrations were normal (Group 2 median, 72 pg/mL; range, <15-158 pg/mL). In FMAIT with thrombocytopenia, the median TPO concentration was significantly higher than in Groups 1 and 2 (Group 3 median, 172 pg/mL; range, 15-623 pg/mL; p < 0.001). In the longitudinal analysis, TPO concentrations remained constant (n = 8), peaked only transiently (n = 3), or increased at the end of gestation (n = 3). Elevated TPO concentrations (592 and 623 pg/mL) were detected in one patient, who already had intracranial hemorrhage in utero.

CONCLUSION

TPO concentrations are normal or slightly elevated in FMAIT. Further clinical information can be provided by the longitudinal analysis of TPO concentrations in severe FMAIT.

Concentrations of thrombopoietin and interleukin-11 in the umbilical cord blood of patients with fetal alloimmune thrombocytopenia

The objective of this study is to determine whether the fetus compensates for fetal alloimmune thrombocytopenia (FAITP) by increasing serum concentrations of thrombopoietin (TPO) and interleukin-11 (IL-11). TPO and IL-11 concentrations were measured in cord blood sera of 12 neonates with FAITP, and 35 preterm and 25 term controls. TPO concentrations in the 12 patients (median 129 pg/mL, range 73 to 325 pg/mL) were similar to those of 35 healthy preterm neonates (median 183 pg/mL, range 71 to 290 pg/mL) and the 25 term controls (median 180 pg/mL, range 93 to 302 pg/mL), although the platelet counts were significantly lower in FAITP. TPO concentrations did not correlate with the platelet counts, platelet nadir after birth, or time to recovery of normal platelet count. IL-11 reached detectable concentrations only in four patients with FAITP (median 54 pg/mL). After birth, these patients had a more rapid recovery of the platelet count. Cord blood serum concentrations of TPO are not significantly elevated in FAITP and do not predict the severity of the thrombocytopenia. Elevated IL-11 may signal a more rapid platelet recovery in FAITP.

Fetal serum concentrations of cystatin C and beta2-microglobulin as predictors of postnatal kidney function

OBJECTIVES

Cystatin C and beta(2)-microglobulin are established serum markers of renal function in children and adults. In contrast to creatinine, diaplacental exchange is minimal. The aim of the study was to establish reference values in fetal serum and to test their efficiency in predicting postnatal kidney function.

STUDY DESIGN

This was a prospective noninterventional study measuring cystatin C and beta(2)-microglobulin by particle-enhanced immunoturbidimetry in excess serum from 129 cordocenteses performed in 84 fetuses. Reference intervals (mean +/- 1.96 SD) were calculated in a subgroup of 54 fetuses without evidence of kidney disease, and these reference values were evaluated in 75 sera from 55 fetuses.

RESULTS

Mean cystatin C was 1.66 +/- 0.202 mg/L (upper limit 2.06), and mean beta(2)-microglobulin was 4.25 +/- 0.734 mg/L. Unlike cystatin C, beta(2)-microglobulin decreased significantly with gestational age so that the upper reference limit was 7.19-0.052 x gestational age in weeks. beta(2)-Microglobulin had higher sensitivity (90.0% vs 63.6%) and cystatin C a higher specificity (91.8% vs. 85.5%) for the prediction of impaired renal function; diagnostic efficiency was equal (87.6% vs. 86.1%). Fetuses with impaired renal function at birth or who were aborted for renal malformations had higher cystatin C concentrations than those in a control group. beta(2)-Microglobulin was increased only in fetuses who were aborted.

CONCLUSION

Fetal serum cystatin C and beta(2)-microglobulin concentrations may be useful predictors of postnatal kidney function.

The specific hydrolysis of HIV-1 TAR RNA element with the anti-TAR hammerhead ribozyme: structural and functional implications

The main transcriptional regulator of the human immunodeficiency virus is the Tat protein, which recognises and binds to a fragment RNA at the 5' end of viral mRNA, named transactivation response element (TAR) RNA. Extensive mutagenesis studies have shown that a region of TAR RNA important for Tat binding involves a set of nucleotides surrounding a characteristic UCU nucleotide bulge. The specific Tat-TAR complex formation enhances the rate of transcription elongation but inhibition of that interaction prevents the human immunodeficiency virus type 1 (HIV-1) replication. If so, a possibility of virus inactivation would be a site specific degradation of the TAR RNA element. To break down and inactivate TAR RNA, we designated the anti-hammerhead (HH) ribozyme to cleave nucleosides within the bulge. We showed for the first time the new type of the AUC hammerhead ribozyme, which hydrolyses specifically the TAR RNA element at C8 nucleotide in the bulge (C24 in the standard TAR RNA numbering). The cleavage reaction has broad magnesium requirements. Mn and particularly Ca are less efficient. Argininamide interferes with the cleavage of TAR RNA induced by the ribozyme. These results have two implications; (i) structural, where the HIV-1 TAR RNA element in solution occurs in equilibrium of only two forms, one of which, a double stranded RNA, meets structural requirements for ribozyme pairing and cleavage, and (ii) functional, the HH ribozyme can be explored for an inactivation of HIV-1 through the TAR RNA element deintegration.

Fetal cord blood as an alternative source of hematopoietic progenitor cells: immunophenotype, maternal cell contamination, and ex vivo expansion

The present study was performed to investigate the character of hematopoietic progenitor cells in fetal cord blood (CB). Thirty blood samples from fetuses at a median of 24 weeks of gestation (range 19-29) and 30 neonatal CB samples were analyzed for their immunophenotype by three-color flow cytometry and examined for the presence of female cells by fluorescence in situ hybridization (FISH). We tested the effects of different cytokine combinations (rhIL-1beta, rhIL-3, rhIL-6, rh erythropoietin [rhEPO], rhGM-CSF plus rhSCF, and rhSCF plus rhflt3-ligand) on the differentiation of 100 CD34+-enriched neonatal CB cells for up to 21 days. Ex vivo expansion of 32 unselected fetal blood samples cells was performed in the presence of rhSCF and rhflt3-ligand. The percentage of CD34+ cells in fetal blood was significantly higher compared with neonatal CB (1.24%+/-0.82% versus 0.33%+/-0.18%, p = 0.0001) and inversely correlated with the age of gestation. The contamination of fetal and neonatal CB with maternal cells was low (1.72%+/-0.89%, range 1.0%-4.0%). By using rhflt3-ligand we were able to expand committed progenitor cells while maintaining cells with stem cell function. The use of expanded fetal immature progenitors might have implications for in utero transplantation and autologous gene therapy.

Intrauterine management of fetal parvovirus B19 infection

OBJECTIVES

The aim of our study was to determine the outcome of pregnancies after intrauterine management of fetal parvovirus B19 infection.

DESIGN

Retrospective study.

SUBJECTS

A total of 37 cases of maternofetal parvovirus B19 infection, 35 of which were associated with hydrops fetalis, were referred to our tertiary level center between 1989 and 1996. With regard to fetal hydrops, no apparent cause other than parvovirus B19 infection was found in any patient.

METHODS

In all patients, cordocentesis was performed to assess the degree of fetal anemia. When anemia was present, cordocentesis was followed by intrauterine transfusion with packed red cells into the umbilical vein. Further management depended on the degree of fetal anemia and gestational age and included follow-up fetal blood sampling/transfusion as well as ultrasound examinations as deemed appropriate.

RESULTS

Packed red cell transfusion was performed in 30 patients with significant fetal anemia (Z-score 1.6-7.8 below the mean for gestational age). The fetal hemoglobin values ranged from 2.1 to 9.6 g/dl. Serum levels of platelets in the transfusion group were 9-228 x 10(9)/l with Z-scores in the range of < 1 to 3.8 below the mean. During treatment and follow-up, there were five intrauterine deaths (13.5%), one neonatal death (2.7%) and 31 live births (83.8%).

CONCLUSIONS

Fetal parvovirus infection can lead to marked anemia and hydrops formation. Cordocentesis allows precise assessment of fetal anemia which can then be corrected by intravenous transfusion. Under this regimen, the outcome proved favorable in the majority of fetuses, even those that were severely anemic.

Crystal structure of domain E of Thermus flavus 5S rRNA: a helical RNA structure including a hairpin loop

The synthetic RNA fragment 5'-CUGGGCGG(GCGA)CCGCCUGG (nucleotides in parentheses indicate the loop region) corresponds to the natural sequence of domain E from nucleotides 79-97 of the Thermus flavus 5S rRNA including a hairpin loop. The RNA structure determined at 3.0 A and refined to an R-value of 24.1% also represents the first X-ray structure GNRA tetraloop. The loop is in distinctly different conformation from other GNRA tetraloops analyzed by NMR. The conformation of the two molecules in the asymmetric unit is influenced and stabilized by specific intermolecular contacts. The structural features presented here give evidence for the ability of RNA molecules to adapt to specific environments.

[Prenatal substitution therapy in fetal alloimmune thrombocytopenia]

Fetal alloimmune thrombocytopenia is caused by maternofetal transfer of platelet antibodies. Since the thrombocytopenic fetus is threatened by intracranial hemorrhage, prenatal observation and, if necessary, treatment is required. However, the benefit of therapeutic options, including intravenous IgG (ivIgG) or platelet transfusions, is still controversial. In this study we have evaluated the effect of maternal ivIgG and intraumbilical platelet transfusions on fetal platelet counts in 7 cases. All patients were multiparous women who were immunized against the Zwa antigen during previous pregnancies and had given birth to at least one severely thrombocytopenic infant. First umbilical blood was sampled at the 26th week of gestation. Maternal treatment of ivIgG was given over 7 weeks, the mean number of intrauterine platelet transfusions was 5.9. In 6 of 7 cases the basal platelet count before transfusion did not rise or even further decreased during maternal ivIgG treatment. In one case the baseline platelet count increased from 18,000/microliter to 60,000/microliter during ivIgG. We conclude that, in general, ivIgG alone has no detectable effect on fetal alloimmune thrombocytopenia. Since platelet counts can be very low as early as 20 weeks of gestation, careful fetal monitoring by umbilical blood sampling is required. Platelet transfusions in short intervals appear to be the only effective regimen to increase platelet counts in extremely thrombocytopenic fetuses.

[Intrauterine transfusion in fetal alloimmunothrombocytopenia: comparison of maternal and fetal weight-adjusted IgG therapy with exclusive fetal thrombocyte transfusion]

Fetal alloimmune thrombocytopenia is caused by maternal immunization against a fetal platelet antigen and transplacental transfer of the antibody into the fetal circulation. Since 10-20% of the fetuses or newborns are threatened by intracranial hemorrhages, early management is required. Fetal blood sampling should be started between the 20th and 22nd week of gestation to assess fetal phenotype and platelet count. Different concepts to elevate the fetal platelet count have been discussed: maternal intravenous immunoglobulins, fetal intravenous immunoglobulins, or only repeated fetal platelet transfusions. Our investigations suggested that platelet transfusions in short intervals appear to be the only effective regimen to increase platelet counts in thrombocytopenic fetuses at risk.

[Fetal plasma erythropoietin concentration during intrauterine transfusion therapy in isoimmunohemolytic anemia due to rhesus incompatibility]

PURPOSE

Prenatal plasma concentrations of erythropoietin in fetuses with Rh disease should contribute information to the clinical course and therapeutic control of this disease.

METHOD

Fetal plasma erythropoietin (Epo) and haemoglobin (Hb) concentrations were measured in 145 umbilical venous blood samples of 30 fetuses with Rh disease at 20 to 38 weeks' gestation.

RESULTS

Both Epo and Hb concentrations were independent of the gestational age in red blood cell-isoimmunised pregnancies. The Hb concentration correlated significantly with Epo concentration without intrauterine transfusion (IUT) (r = -0.519, p = 0.005) and after IUT (i = -0.212, p = 0.01). A haemoglobin deficit of 3 g/dl at 20 weeks' gestation increased to 6 g/dl at 38 weeks' gestation in spite of IUT (p = -0.354, p < 0.001).

CONCLUSION

Even with IUT, Epo concentrations increase with gestational age during these pregnancies. This is due to increasing Hb deficits indicating fetal hypoxia which might be prevented by increasing volumes of transfusion.

Complete identification of nonbridging phosphate oxygens involved in hammerhead cleavage

Phosphorothioate interference analysis is suited for the rapid identification of structurally and functionally important phosphate groups. Previous interference studies, however, have been limited to the analysis of pro-Rp phosphate oxygens. We employed solid-phase oligonucleotide synthesis and modification interference analysis to investigate either of the nonbridging phosphate oxygens within the hammerhead ribozyme. Two novel sites of Sp phosphorothioate interference were identified at positions A6 and U16.1. The results from interference experiments were confirmed by single phosphorothioate substitutions at sites of interest. Metal rescue experiments revealed that direct metal ion coordination occurs in the functional ribozyme only at the site of cleavage and at the pro-Rp oxygen of position Ag. The new approach may be generally useful in rapidly evaluating the functional importance of phosphate groups in nucleic acids.

Fetal Rhesus D genotyping on amniocytes in alloimmunised pregnancies using fluorescence duplex polymerase chain reaction

OBJECTIVE

1. To establish the reliability of fetal amniocyte Rhesus D (RhD) genotyping using fluorescence duplex polymerase chain reaction (PCR) and 2. to assess the potential clinical impact on management of alloimmunised pregnancies.

DESIGN

Multicentre observational study.

SETTING

Four departments of obstetrics and gynaecology in Germany.

METHODS

Fourty-four amniotic fluid samples were obtained by amniocentesis from a retrospective group of 27 RhD alloimmunised pregnancies and 15 samples from 14 women treated prospectively. Two RhD gene specific fragments (exon 7 and 10) were amplified using two separate fluorescence duplex PCR assays, and laser detected in an automated DNA sequence analyser.

RESULTS

Amplification of the Rh gene sequences was successful in all samples. PCR at the two RhD gene regions resulted in complete concordance. Genotyping correctly predicted the RhD status of all fetuses serotyped (n = 41). After intrauterine transfusions, PCR identified the RhD type of two fetuses more accurately than serotyping. Earlier knowledge of a negative RhD status would have rendered unnecessary 12 amniocenteses in four fetuses of the retrospective study group, and prevented further invasive testing in one fetus treated prospectively. In the latter group, women with a positive fetal RhD genotype underwent intensive prenatal care including serial invasive monitoring and intrauterine treatment.

CONCLUSIONS

Fetal RhD genotyping of amniocytes is a reliable technique with the potential to improve routine management of alloimmunised pregnant women.

Mirror-image RNA that binds D-adenosine

A 58-mer L-RNA ligand that binds to naturally occurring D-adenosine with a dissociation constant of 1.7 microM in solution was identified from a combinatorial library employing mirror-design. The corresponding D-RNA ligand shows identical binding affinity to L-adenosine. Reciprocal chiral specificity was also evident from ligand discrimination; the binding affinity of the L-RNA ligand for D-adenosine was 9000-fold greater than its affinity for L-adenosine and vice versa. While the D-RNA ligand was rapidly degraded in human serum, the L-RNA ligand displayed an extraordinary stability. This indicates the potential application of specifically designed L-RNA ligands as stable monoclonal antibody analogues and the development of highly stable L-ribozymes.

Mirror-design of L-oligonucleotide ligands binding to L-arginine

The high affinity and selectivity of nucleic acid ligands have clearly demonstrated that RNA can be targeted to a variety of molecules. In practice, however, the use of unmodified aptamers is impeded by the low stability of RNA in biological fluids. Here we describe the mirror-design of a stable 38-mer L-oligoribonucleotide ligand that binds to L-arginine. This L-RNA ligand was also able to bind to a short peptide containing the basic region of the human immunodeficiency virus type-1 Tat-protein. The L-RNA ligand displayed the expected stability in human serum. These findings may contribute to the identification of novel diagnostics and pharmaceuticals.

Therapy with intravenous immunoglobulin G (ivIgG) during pregnancy for fetal alloimmune (HPA-1a(Zwa)) thrombocytopenic purpura

We have evaluated the effect of maternal intravenous immunoglobulin G (ivIgG) treatment on platelet counts in fetal alloimmune thrombocytopenia. Seven patients were studied. All of them were multiparous women who had been immunized against the HPA-1a antigen during previous pregnancies and had given birth to at least one severely thrombocytopenic infant. In this study, umbilical blood collection was performed first at the 20th week of gestation and repeated 2-13 times (mean 6 times), depending on the degree of fetal thrombocytopenia. Fetal platelet counting was combined with intrauterine transfusion of 20-30 ml of HPA-1a-negative platelet concentrates to prevent bleeding following umbilical cord puncture. Initial fetal platelet counts ranged from 10,000 to 91,000 per microliters. Maternal treatment with ivIgG (1 g per kg body weight; mean dose 70 g) was given once a week over 7 weeks. In five of seven cases, the basal platelet count did not rise and in two of these cases, it decreased during maternal ivIgG treatment. In one fetus, the baseline platelet count increased from 10,000 to 35,000 per microliters during ivIgG, and in another fetus from 23,000 to 64,000 per microliters. Our observations suggest that ivIgG has no definite benefit for fetal alloimmune thrombocytopenia. Since platelet counts can be very low, careful fetal monitoring by umbilical blood sampling is required. Frequent platelet transfusions in short intervals may be necessary to increase platelet counts in extremely thrombocytopenic fetuses.

Initial analysis of 750 MHz NMR spectra of selective 15N-G,U labelled E. coli 5S rRNA

The overall folding of an RNA molecule is reflected in its base pairing pattern. The identification of that pattern provides a first step towards the determination of the structure of an RNA molecule. We show that the application of heteronuclear NMR methods at 750 MHz to E. coli 5S rRNA (120 nucleotides) selectively labelled with 15N in guanine and uridine allows observation of base pairing patterns for a larger RNA molecule. We also present evidence that the fold of the E-domain of the 5S rRNA (nt 79-97) as a contiguous part of the 5S rRNA and as an isolated molecule is virtually the same.

Crystallization and preliminary diffraction studies of the structural domain E of Thermus flavus 5S rRNA

The ribosomal 5S RNA is an essential constituent of the large ribosomal subunit. To overcome the difficulties of crystallizing large RNA molecules such as 5S rRNAs, we decided to divide the 5S rRNA in five domains A through E to determine their structure. Recently we determined the crystal structural of the helical domain A. Here we report the crystallization of the chemically synthesized domain E of the Thermus flavus 5S rRNA. The crystal form is trigonal with unit cell dimensions: a = b = 42.80 A and c = 162.20 A. Diffraction-data to 2.8 A have been recorded and the structure solution is currently underway by means of MIR and MAD techniques.