Do chorionic villus samplings (CVS) or amniocenteses (AC) induce RhD immunisation? An evaluation of a large Danish cohort with no routine administration of anti-D after invasive prenatal testing.

OBJECTIVE: To evaluate the risk of inducing RhD immunisation in pregnancies of RhD-negative mothers with an RhD-positive fetus undergoing chorionic villus samplings (CVS) or amniocenteses (AC). DESIGN, SETTING AND POPULATION: Registry-based study in a Danish cohort which has not been given rhesus prophylaxis. METHODS: Data were retrieved from the Department of Clinical Immunology at Rigshospitalet. All RhD-negative women carrying an RhD-positive fetus with screen test results from weeks 8-12 and weeks 25-29 were linked to data from the Danish Fetal Medicine Database. Data were divided into cases where no invasive prenatal diagnostic procedure was performed, cases that had AC performed, and cases that had CVS performed. MAIN OUTCOME MEASURES: A comparison of the proportion of women who developed RhD immunisation between the two screen tests. RESULTS: The cohort consisted of 10 085 women: 9353 had no invasive procedures performed, 189 had AC and 543 had CVS performed. No women were immunised spontaneously or due to the procedure between the first and second screen test in the group with no procedure performed, or in the AC group. One woman was immunised in the CVS group. When comparing the proportion of women who was immunised in the CVS group with the no invasive test group a non-significant difference was found (P = 0.055). CONCLUSION: The RhD immunisation rate before gestational weeks 25-29 in RhD-negative women carrying an RhD-positive fetus is very low, even in women undergoing prenatal invasive testing without rhesus prophylaxis. TWEETABLE ABSTRACT: The RhD immunisation rate during pregnancy is very low even in women undergoing prenatal invasive testing.

Blood Chimerism in Dizygotic Monochorionic Twins During 5 Years Observation.

Dizygotic monochorionic twin pregnancies can result in blood chimerism due to in utero twin-to-twin exchange of stem cells. In this case, we examined the proportion of allogeneic red blood cells by flow cytometry and the proportion of allogeneic nucleated cells by digital polymerase chain reaction at 7 months and again at 5 years. We found an increase in the proportion of allogeneic cells from 63% to 89% in one twin, and a similar increase in autologous cells in the other twin from 57% to 84%. A paradigm for stem cell therapy could be modeled on this case: induction of tolerance and chimerism by antenatal transfusion of donor stem cells. The procedure would hold the promise of transplantation and tolerance induction without myeloablative conditioning for inheritable benign hematological diseases such as sickle cell disease and thalassemia.

Routine noninvasive prenatal screening for fetal RHD in plasma of RhD-negative pregnant women-2 years of screening experience from Denmark.

OBJECTIVE: Prenatal and postnatal RhD prophylaxis reduces the risk of RhD immunization in pregnancies of RhD-negative women. Based on the result from prenatal screening for the fetal RHD gene, prenatal RhD prophylaxis in Denmark is targeted to RhD-negative women who carry an RhD-positive fetus. Here, we present a 2-year evaluation of a nationwide prenatal RHD screening. METHODS: Blood samples were drawn from RhD-negative women in gestational week 25. DNA was extracted from maternal plasma and analyzed for the RHD gene. The prenatal RHD results were compared with the serological typing of newborns in 12,668 pregnancies. Early compliance was assessed for 690 pregnancies. RESULTS: The sensitivity for the detection of fetal RHD was 99.9% (95% CI: 99.7-99.9%). Unnecessary recommendation of prenatal RhD prophylaxis was avoided in 97.3% of the women carrying an RhD-negative fetus. Fetuses that were seropositive for RhD were not detected in 11 pregnancies (0.087%). The sample uptake percentage was 84.2%, and the compliance for prenatal anti-D administration was 93.2%. CONCLUSION: The high sensitivity, maintained over 2 years, underlines the reliability of routine prenatal fetal RHD screening in RhD-negative pregnant women, specifically at 25 weeks of gestation. The remaining challenges are logistical and are related to program compliance.

Study of compliance with a new, targeted antenatal D immunization prevention programme in Denmark.

BACKGROUND AND OBJECTIVES: A targeted routine antenatal anti-D prophylaxis programme was implemented in Denmark where anti-D immunoglobulin is given based on the result from noninvasive antenatal screening for fetal RHD. Our objective was to evaluate compliance with this new programme right after its initiation. MATERIALS AND METHODS: We examined the treatment outcome of 239 D-negative pregnant women who gave birth at our hospital between June and September 2010. RESULTS: The majority of these women (90%) underwent antenatal RHD screening, 86% of the women who were recommended antenatal prophylaxis received anti-D, and 99% of the women who delivered RhD-positive infants received postnatal anti-D. CONCLUSION: These compliance results are acceptable as they were obtained only a few months after the initiation of the new prophylaxis regime. However, suggestions to further improve compliance are presented.

High-affinity human leucocyte antigen class I binding variola-derived peptides induce CD4+ T cell responses more than 30 years post-vaccinia virus vaccination.

Interferon-gamma secreting T lymphocytes against pox virus-derived synthetic 9-mer peptides were tested by enzyme-linked immunospot in peripheral blood of individuals vaccinated with vaccinia virus more than 30 years ago. The peptides were characterized biochemically as high-affinity human leucocyte antigen (HLA) class I binders (K(D)

Screening for autologous blood transfusions.

The ratio between the amount of hemoglobin in the mature erythrocyte population and the reticulocytes (RBCHb:RetHb ratio) has previously been suggested as a marker to screen for EPO-abuse. We speculated that the reinfusion of blood would lead to a marked increase in this ratio, making it a valuable parameter in the screening for autologous blood doping. Three bags of blood (approximately 201+/-11 g of Hb) were withdrawn from 16 males and stored at either -80 degrees C (-80 T, n=8) or +4 degrees C (+4 T, n=8) and reinfused 10 weeks or 4 weeks later, respectively. Seven subjects served as controls. Different erythrocyte parameters were measured on a hematological analyzer serially throughout and during a 4 week wash-out period. By using RBCHb:RetHb ratio cut-off limits of 145.7 (1:100) ('suspicious') and 182.9 (1:1000) ('positive'), 35.4% (-80 T) and 19.6% (+4 T) of all samples obtained during a 4 week wash-out period were identified as 'suspicious', and 18.8% (-80 T) and 4.3% (+4 T) as 'positive'. In total, 7 out of 16 (43.8%) subjects had at least one sample exceeding 182.9. Compared to the currently used indirect parameters, the RBCHb:RetHb ratio is the best indicator of autologous blood doping after reinfusion, and the parameter could be used in a testing setting, once stability validation has been performed.

MHC-I-restricted epitopes conserved among variola and other related orthopoxviruses are recognized by T cells 30 years after vaccination.

It is many years since the general population has been vaccinated against smallpox virus. Here, we report that human leukocyte antigen (HLA) class I restricted T cell epitopes can be recognized more than 30 years after vaccination. Using bioinformatic methods, we predicted 177 potential cytotoxic T lymphocyte epitopes. Eight epitopes were confirmed to stimulate IFN-gamma release by T cells in smallpox-vaccinated subjects. The epitopes were restricted by five supertypes (HLA-A1, -A2, -A24 -A26 and -B44). Significant T cell responses were detected against 8 of 45 peptides with an HLA class I affinity of K(D) less than or equal to 5 nM, whereas no T cell responses were detected against 60 peptides with an HLA affinity of K(D) more than 5 nM. All epitopes were fully conserved in seven variola, vaccinia and cowpox strains. Knowledge of the long-term response to smallpox vaccination may lead to a better understanding of poxvirus immunity and may aid in the development of new improved vaccines and diagnostic tools.

Dizygotic monochorionic twin pregnancy conceived following intracytoplasmic sperm injection treatment and complicated by twin-twin transfusion syndrome and blood chimerism.

We report a case of a dizygotic monochorionic twin pregnancy preceded by intracytoplasmic sperm injection treatment including assisted hatching. On ultrasound examination at 25 weeks' gestation the twins, which had been assumed to be monochorionic, were found to be of different sexes. Karyotyping and zygocity determination were performed on amniotic fluid and showed the twins to be dizygotic with normal female and male karyotypes. There were clinical and sonographic signs of twin-twin transfusion syndrome (TTTS), and Cesarean delivery was performed at 32 weeks' gestation. At birth the twins were phenotypically a normal male and a normal female. Histology of the placenta showed it to be monochorionic diamniotic. Blood chimerism was found postnatally as both infants had the karyotypes 46,XX[13]/46,XY[17]. Chimerism was not found in cells from a buccal swab at 6 months of age. This is one of only a few reported cases of dizygotic monochorionic twins. Nearly all of these cases have been conceived after assisted reproductive technology procedures. It is of clinical importance to be aware of this rare phenomenon in relation to TTTS, prenatal screening and parental counseling.

Estrogen directly attenuates human osteoclastogenesis, but has no effect on resorption by mature osteoclasts.

Estrogen deficiency arising with the menopause promotes marked acceleration of bone resorption, which can be restored by hormone replacement therapy. The inhibitory effects of estrogen seem to involve indirect cytokine- mediated effects via supporting bone marrow cells, but direct estrogen-receptor mediated effects on the bone-resorbing osteoclasts have also been proposed. Little information is available on whether estrogens modulate human osteoclastogenesis or merely inhibit the functional activity of osteoclasts. To clarify whether estrogens directly modulate osteoclastic activities human CD14+ monocytes were cultured in the presence of M-CSF and RANKL to induce osteoclast differentiation. Addition of 0.1-10 nM 17beta-estradiol to differentiating osteoclasts resulted in a dose-dependent reduction in tartrate resistant acid phosphatase (TRACP) activity reaching 60% at 0.1 nM. In addition, 17beta-estradiol inhibited bone resorption, as measured by the release of the C-terminal crosslinked telopeptide (CTX), by 60% at 0.1 nM, but had no effect on the overall cell viability. In contrast to the results obtained with differentiating osteoclasts, addition of 17beta-estradiol (0.001-10 nM) to mature osteoclasts did not affect bone resorption or TRACP activity. We investigated expression of the estrogen receptors, using immunocytochemistry and Western blotting. We found that ER-alpha is expressed in osteoclast precursors, whereas ER- beta is expressed at all stages, indicating that the inhibitory effect of estrogen on osteoclastogenesis is mediated by ER-alpha for the major part. In conclusion, these results suggest that the in vivo effects of estrogen are mediated by reduction of osteoclastogenesis rather than direct inhibition of the resorptive activity of mature osteoclasts.

The development and characterization of an ELISA specifically detecting the active form of cathepsin K.

OBJECTIVE: Cathepsin K plays essential roles in bone resorption and is intensely investigated as a therapeutic target for the treatment of osteoporosis. Hence an assessment of the active form of cathepsin K may provide important biological information in metabolic bone diseases, such as osteoporosis or ankylosing spondylitis. METHODS: Presently there are no robust assays for the assessment of active cathepsin K in serum, and therefore an ELISA specifically detecting the N-terminal of the active form of cathepsin K was developed. RESULTS: The assay was technically robust, with a lowest limit of detection (LOD) of 0.085 ng/mL. The average intra- and inter-assay CV% were 6.60% and 8.56% respectively. The dilution recovery and spike recovery tests in human serum were within 100±20% within the range of the assay. A comparison of latent and active cathepsin K confirmed specificity towards the active form. Quantification of the levels of active cathepsin K in supernatants of purified human osteoclasts compared to corresponding macrophages showed a 30-fold induction (p<0.001). In contrast, in serum samples from osteoporotic women on estrogen or bisphosphonate therapy and from ankylosing spondylitis patients no clinically relevant differences were observed. CONCLUSION: In summary, we have developed a robust and sensitive assay specifically detecting the active form of cathepsin K; however, while it monitors osteoclasts with high specificity in vitro, it appears that circulating levels of active cathepsin K do not reflect bone changes under these circumstances.

Osteoclasts prefer aged bone.

UNLABELLED: We investigated whether the age of the bones endogenously exerts control over the bone resorption ability of the osteoclasts, and found that osteoclasts preferentially develop and resorb bone on aged bone. These findings indicate that the bone matrix itself plays a role in targeted remodeling of aged bones. INTRODUCTION: Osteoclasts resorb aging bone in order to repair damage and maintain the quality of bone. The mechanism behind the targeting of aged bone for remodeling is not clear. We investigated whether bones endogenously possess the ability to control osteoclastic resorption. METHODS: To biochemically distinguish aged and young bones; we measured the ratio between the age-isomerized betaCTX fragment and the non-isomerized alphaCTX fragment. By measurement of TRACP activity, CTX release, number of TRACP positive cells and pit area/pit number, we evaluated osteoclastogenesis as well as osteoclast resorption on aged and young bones. RESULTS: We found that the alphaCTX/betaCTX ratio is 3:1 in young compared to aged bones, and we found that both alpha and betaCTX are released by osteoclasts during resorption. Osteoclastogenesis was augmented on aged compared to young bones, and the difference was enhanced under low serum conditions. We found that mature osteoclasts resorb more on aged than on young bone, despite unchanged adhesion and morphology. CONCLUSIONS: These data indicate that the age of the bone plays an important role in controlling osteoclast-mediated resorption, with significantly higher levels of osteoclast differentiation and resorption on aged bones when compared to young bones.