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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.

Background - Maternal anti–human leukocyte antigen (HLA) Class I is commonly detected alongside anti–human platelet antigen (HPA)-1a in fetal and neonatal alloimmune thrombocytopenia (FNAIT). Little is known regarding whether the presence of anti-HLA Class I may exert an additive effect on the risk and severity of FNAIT. Methods and Materials - We reanalyzed samples originally collected as part of a large Norwegian screening study on FNAIT during 1995-2004. This study identified and managed 170 pregnancies where the mother was HPA-1a negative and had detectable anti-HPA-1a during pregnancy. Maternal samples from 166 of these pregnancies were rescreened for anti-HLA Class I, revealing 111 (67%) that were antibody positive. Various regression models were used to assess if and how maternal anti-HLA Class I influenced the neonatal platelet count. Results and Conclusions - Unadjusted neonatal platelet counts and the frequency of neonatal thrombocytopenia was not significantly affected by the presence of anti-HLA Class I alongside anti–HPA-1a, but results from regression analyses revealed a possible increased risk when the mother was nulliparous. These results warrant further investigation.

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.

Alloimmunization against human platelet antigen (HPA)-1a during pregnancy can cause foetal/neonatal alloimmune thrombocytopenia (FNAIT) and severe bleeding in the foetus or newborn and likely depends on several factors. HPA-1a alloimmunization is associated with DRB3*01:01, which is associated with several DR-DQ haplotypes. However, it is not known to what extent these haplotypes contribute to the prevalence of HPA-1a alloimmunization. HPA-1a–alloimmunized women, identified in a prospective study, and random donors were typed for selected DRB3, DRB4, DRB1, DQA1 and DQB1 alleles to determine allele and DR-DQ haplotype frequencies. DRB3*01:01 was carried by 94% HPA-1a–immunized women compared to 27% in the general population. In the first population, the DR3-DQ2 haplotype was overrepresented (P < .003). The prevalence of HPA-1a alloimmunization was estimated to be about twice as frequent with DR3-DQ2 compared to DR13-DQ6, together accounting for about 90% of DRB3*01:01–positive individuals. Further, we examined DQB1*02 and DRB4*01:01 alleles for their reported association with HPA-1a alloimmunization, in the context of DR-DQ haplotypes. Since ~ 80% of DQB1*02 alleles are linked to the DR3-DQ2 haplotype, the association might be coincidental. However, the DQB1*02:02–associated DR7-DQ2 haplotype was also overrepresented in alloimmunized women, suggesting a role for this allele or haplotype in HPA-1a alloimmunization. As DRB4*01:01 is predominantly associated with the DR7-DQ2 haplotype in HPA-1a–alloimmunized individuals, the reported association with FNAIT may be coincidental. Typing for DR-DQ haplotypes revealed important genetic associations with HPA-1a alloimmunization not evident from typing individual alleles, and the presence of different DRB3-associated DR-DQ haplotypes showed different prevalence of HPA-1a alloimmunization.

In Norway, the management strategy for fetal and neonatal alloimmune thrombocytopenia (FNAIT) has for more than two decades differed from most other countries. The focus of this paper is to describe and discuss the Norwegian FNAIT management program. We recommend antenatal IVIg to women who previously have had a child with FNAIT-induced ICH, and usually not to HPA-1a alloimmunized pregnant women where a previous child had FNAIT, but not ICH. When deciding management strategy, we use not only the obstetric history but also the antenatal anti-HPA-1a antibody level as a tool for risk stratification. The Norwegian National Unit for Platelet Immunology (NNUPI) at the University Hospital of North Norway in Tromsø provides diagnostic and consulting service for the clinicians and the blood banks all over the country, and serves as a national reference laboratory for FNAIT investigations.

Source at https://doi.org/10.5114/aoms.2016.63600. Licensed CC BY-NC-ND 4.0. 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.

Opening speech given at UiT Digital Humanities Conference 2017

Publisher's terms of use of "author accepted manuscripts (AAMs)": https://www.palgrave.com/gp/journal-authors/aam-terms-v1 Skilled candidates, research results that are useful both immediately and in a longer time frame, innovation and business creation, and the strengthening of the public sector are among the most important societal impacts of a university. In short, universities provide a survival kit in a changing world. The University of Tromsø–The Arctic University of Norway (UiT) has been instrumental in developing the northernmost part of Norway since its inception 50 years ago, and will continue to be so in the foreseeable future. Knowledge and competence originating at UiT has also contributed decisively to the development of Norwegian national Arctic policy. Similarly, international Arctic policy development will benefit greatly from including the perspectives and experiences developed at universities in the circumpolar North.

Introduction The objective of this study was to investigate serial changes in maternal endothelial function, inflammatory response and uterine artery blood flow in normal pregnancy, and to explore their inter-relation. Material and methods In this prospective longitudinal observational study, 53 women with uncomplicated pregnancies were examined at 4-weekly intervals (248 observations) during 22–40 weeks of gestation. Uterine artery blood flow was measured using Doppler ultrasonography. Maternal endothelial function was assessed by flow-mediated vasodilatation (FMD) of the brachial artery. Circulating endothelial progenitor cells (EPC), defined as CD34+ CD133+ VEGFR2+ cells, were quantified by flow cytometry. Biomarkers of inflammation, such as leptin and high sensitivity C-reactive protein (hsCRP), were measured in plasma samples. Multilevel modeling was used to investigate gestational-age-associated serial changes. Results The EPC increased from 6.5 to 12.3 per million mononuclear cells (p < 0.01) and FMD decreased from 16.3 to 13.4% (p = 0.20). Leptin increased from 18 to 22 ng/mL (p < 0.01), and hsCRP did not change significantly (p = 0.61). There was no significant association between FMD and EPC (p = 0.66). FMD was significantly associated with hsCRP (p = 0.002) and leptin (p = 0.003), but the EPC were not. Neither FMD nor EPC were significantly associated with uterine artery blood flow. Conclusion Changes in FMD were significantly associated with inflammatory biomarkers, suggesting that the reduced nitric oxide-dependent vasodilatation in late gestation is related to maternal inflammatory response. As EPC and FMD did not correlate, mechanisms other than mobilization of EPC to repair endothelial damage must be responsible for the gestational-age-associated increase in EPC.

Published version. Source at http://doi.org/10.1007/s00005-015-0371-9. 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.

BACKGROUND Fetomaternal alloimmune thrombocytopenia (FMAIT) is caused by human platelet (PLT) antigen (HPA) incompatibility. Beads coupled with recombinant β3 integrins, displaying the biallelic HPA-1 epitopes (rHPA-1), have been shown to detect HPA-1a alloantibodies implicated in FMAIT. This report describes a multicenter validation of the beads using the results of well-characterized samples to define the optimum parameters for analysis of a large cohort of 498 clinical samples. STUDY DESIGN AND METHODS Fifty-one blinded quality assurance (QA) samples were tested by six laboratories to standardize the rHPA-1 bead assay and to develop an algorithm for sample classification. Five laboratories retrieved samples from 498 independent FMAIT cases, previously tested by the monoclonal antibody-specific immobilization of PLT antigens (MAIPA) assay, from their local archives for testing with the rHPA-1 beads. The results were evaluated using a mathematical algorithm developed to classify the samples. RESULTS The QA samples gave a mean concordance of 94% between the bead and MAIPA assays, while 97% concordance was observed with the FMAIT samples. Of the 15 discrepant samples, seven were positive by the beads but negative by MAIPA, while the contrary was observed for eight samples. Overall, the bead assay achieved 98% sensitivity for HPA-1a antibody detection in FMAIT and 98.7% specificity compared to the local MAIPA. CONCLUSION The rHPA-1 bead assay is a rapid 3-hour assay for the sensitive detection of HPA-1 antibodies. Its ease of use would enable prompt detection of maternal HPA-1a antibodies in suspected FMAIT cases, which is important supportive evidence for treatment by transfusion with HPA-1b1b PLTs.

Human platelet Ag (HPA)-1a, located on integrin β3, is the main target for alloantibodies responsible for fetal and neonatal alloimmune thrombocytopenia (FNAIT) in the white population. There are ongoing efforts to develop an Ab prophylaxis and therapy to prevent or treat FNAIT. In this study, an mAb specific for HPA-1a, named 26.4, was derived from an immortalized B cell from an alloimmunized woman who had an infant affected by FNAIT. It is the only HPA-1a–specific human mAb with naturally paired H and L chains. Specific binding of mAb 26.4, both native and recombinant forms, to platelets and to purified integrins αIIbβ3 (from platelets) and αVβ3 (from trophoblasts) from HPA-1a+ donors was demonstrated by flow cytometry and surface plasmon resonance technology, respectively. No binding to HPA-1a− platelets or integrins was detected. Moreover, the Ab binds with higher affinity to integrin αVβ3 compared with a second HPA-1a–specific human mAb, B2G1. Further in vitro experimentation demonstrated that mAb 26.4 can opsonize HPA-1a+ platelets for enhanced phagocytosis by monocytes, inhibit binding of maternal polyclonal anti–HPA-1a Abs, and weakly inhibit aggregation of HPA-1a–heterozygous platelets, the latter with no predicted clinical relevance. Thus, mAb 26.4 is highly specific for HPA-1a and could potentially be explored for use as a prophylactic or therapeutic reagent for FNAIT intervention and as a phenotyping reagent to identify women at risk for immunization.

Objectives To assess neonatal platelet counts by comparing alloimmunised pregnancies from a Norwegian screening and intervention study with subsequent pregnancies from the same women. Design Prospective observational follow-up study. Setting A university hospital. Population HPA-1a immunised women from a large Norwegian screening study that gave birth to one or more children after the screening study ended (2004–2012). Methods Follow-up of maternal anti-HPA-1a antibody levels and neonatal platelet counts from the screening pregnancies were compared with subsequent pregnancies. None of the women received antenatal intravenous immunoglobulin (IVIG) treatment and neonatal platelet counts were therefore comparable. Main outcome measures Change in neonatal platelet counts from one HPA-1a incompatible pregnancy to the next. Maternal anti-HPA-a1 antibody levels from one HPA-1a incompatible pregnancy to the next. Results Forty-five incompatible subsequent pregnancies were identified. Overall, the neonatal platelet count in the subsequent pregnancy was improved (18%), unchanged (52%), or worse (30%), compared with the corresponding screening pregnancy. There was one case of fetal intracranial haemorrhage (ICH) identified in the screening (intrauterine fetal death detected at 30 weeks of gestation) and no ICH cases recorded for the subsequent pregnancies. In cases where the platelet count was lower in the subsequent pregnancy, the maternal anti-HPA-1a antibody level was higher compared with the screening pregnancy. In comparison, the maternal antibody level was lower in subsequent pregnancies where the platelet count improved. Conclusions In contrast to what is often stated, we found that the neonatal platelet count was increased or unchanged in the majority of subsequent pregnancies of HPA-1a-immunised women.

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.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.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).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.

Background: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a bleeding disorder caused by maternal antibodies against paternal human platelet antigens (HPAs) on fetal platelets. Antibodies against HPA-1a are accountable for the majority of FNAIT cases. We have previously shown that high levels of maternal anti-HPA-1a antibodies are associated with clinically significant reduced birth weight in newborn boys. Chronic inflammatory placental lesions are associated with increased risk of reduced birth weight and have previously been reported in connection with FNAIT pregnancies. The HPA-1a epitope is located on integrin β 3 that is associated with integrin α IIb (the fibrinogen receptor) on platelets and megakaryocytes. Integrin β 3 is also associated with integrin α V forming the α V β 3 integrin heterodimer, the vitronectin receptor, which is expressed on various cell types, including trophoblast cells. It is therefore thinkable that maternal anti-HPA-1a antibodies present during early pregnancy may affect placenta function through binding to the HPA-1a antigen epitope on invasive throphoblasts. The aim of the study was to examine whether interaction of a human anti-HPA-1a monoclonal antibody (mAb) with HPA-1a on trophoblast cells affect adhesion, migration and invasion of extravillous trophoblast cells. Methods: An in vitro model with human anti-HPA-1a mAb, clone 26.4, and the first trimester extravillous trophoblast cell line HTR8/SVneo was employed. The xCELLigence system was utilized to assess the possible effect of anti-HPA-1a mAb on adhesion and migration of HTR8/SVneo cells. Specially designed chambers precoated with Matrigel were used to assess the effect on the invasive capacity of cells. Results: We found that human anti-HPA-1a mAb 26.4 partia lly inhibits adhesion and migratory capacity of HTR8/SVneo cells. Conclusions: Our findings suggest that anti-HPA-1a antibodies may affect trophoblast functions crucial for normal placental development. Future studies including primary throphoblast cells and polyclonal anti-HPA-1a antibodies are needed to confirm these results.

Alloimmunization to human platelet antigens (HPAs) may occur either during pregnancy, when a HPA‑negative 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 anti‑HPA‑1a antibodies, less frequently to anti‑HPA‑5b, anti‑HPA‑1b, and others. Information on anti‑HPA alloantibodies is crucial for the prevention and treatment of their consequences.

Anti-HLA class I antibodies have been suggested as a possible cause of fetal and neonatal alloimmune thrombocytopenia (FNAIT). The aim of this study was to characterize maternal anti-HLA class I alloantibodies in suspected cases of FNAIT. The study population consisted of all nationwide referrals of neonates with suspected FNAIT to the National Unit for Platelet Immunology in Tromso, Norway, during 1998-2009 (cases), and 250 unselected pregnancies originally included in a prospective study (controls). Inclusion criterion was a positive screening for maternal anti-HLA class I antibodies. Neonates with other identifiable causes of thrombocytopenia, including maternal anti-human platelet antigens (HPA) antibodies, were excluded. Ultimately, 50 cases with suspected FNAIT were compared with 60 controls. The median neonatal platelet count nadir among cases was 24×109/L (range 4-98×109/L). Five children (10%) were reported to have intracranial hemorrhage. Maternal and neonatal HLA class I genotype was available for 33 mother/child pairs (66%). Immunization was not tied to any particular HLA class I antigen. Using epitope mapping, we could demonstrate that the maternal anti-HLA class I antibodies were specific towards mismatched paternally-inherited fetal epitopes, with little reactivity towards any third-party epitopes. Antibody reactivity patterns were similar to those found among controls, although the mean fluorescence intensities (MFI) among cases were significantly higher. This study demonstrates the value of using data on HLA epitope expression, instead of HLA antigens, to examine alloimmune responses in connection with neonatal thrombocytopenia. Our findings support the idea that maternal anti-HLA class I antibodies are involved in FNAIT.

SUMMARY Background and objective: Transfusion-transmitted hepatitis B virus (HBV) infection may originate from hepatitis B surface antigen (HBsAg) false-negative blood donors, HBsAg negative and anti-HBc positive blood donors and blood donors with both tests negative. HBV DNA may be present in all these cases and blood may be infectious. The aim of the study was to estimate the risk of transfusion-transmitted HBV in Vietnam using a stochastic Monte Carlo model. Methods: A cross-sectional study of HBV prevalence in 1200 potential blood donors in rural Vietnam is used as basis for the Monte Carlo model together with expert panel estimates of occult hepatitis B infection (OBI) prevalence in blood donors. Results: With 1 000 000 blood donors running in the model, the potential OBI ranged from 658 to 747 blood units per million at 5 percentile and from 1342 to 2507 blood units per million at 95 percentile resulting in the risk of post-transfusion hepatitis ranging from 66 to 250 blood units per million assuming that risk of post-transfusion from potential OBI is 10%. Using the manufacturer’s HBsAg sensitivity, the mean rate of blood units per million donations having false-negative HBsAg results was 298 (5–95 percentile: 14–893). When the test sensitivity was set lower, false-negative tests was observed at a mean of 1087 per million (5–95 percentile: 762–3220). The fraction of potential OBI donors increased with the increasing age in both genders. Conclusion Current HBsAg screening in Vietnam is insufficient in eliminating the risk of transfusion-transmitted HBV infection. The major risk factors are HBsAg false-negative results and OBI. Increased test sensitivity and locally validated HBsAg assays are recommended.

Alloimmunization to human platelet antigens (HPAs) may occur either during pregnancy, when a HPA‑negative 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 anti‑HPA‑1a antibodies, less frequently to anti‑HPA‑5b, anti‑HPA‑1b, and others. Information on anti‑HPA alloantibodies is crucial for the prevention and treatment of their consequences.

Source at http://dx.doi.org/10.2147/ijwh.s90753 Differences in platelet type between the fetus and the mother can lead to maternal immunization and destruction of the fetal platelets, a condition named fetal and neonatal alloimmune thrombocytopenia (FNAIT). FNAIT is reported to occur in ~1 per 1,000 live born neonates. The major risk is intracranial hemorrhage in the fetus or newborn, which is associated with severe neurological complications or death. Since no countries have yet implemented a screening program to detect pregnancies at risk, the diagnosis is typically established after the birth of a child with symptoms. Reports on broader clinical impact have increased clinical concern and awareness. Along with new treatment options for FNAIT, the debate around antenatal screening to detect pregnancies at risk of FNAIT has been revitalized.

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a pregnancy-related condition caused by maternal antibodies binding an alloantigen on fetal platelets. In most cases the alloantigen is formed by a single amino acid, integrin β3 Leu33, referred to as human platelet antigen-1a (HPA-1a). Production of anti-HPA-1a antibodies likely depends on CD4+ T cells that recognize the same alloantigen in complex with the HLA-DRA/DRB3*01:01 molecule. While this complex is well characterized, T cell recognition of it is not. Here, to examine the nature of antigen recognition by HPA-1a-specific T cells, we assayed native and synthetic variants of the integrin β3 peptide antigen for binding to DRA/DRB3*01:01-positive antigen-presenting cells and for T cell activation. We found that HPA-1a-specific T cells recognize non-allogeneic integrin β3 residues anchored to DRA/DRB3*01:01 by the allogeneic Leu33, which itself is not directly recognized by these T cells. Furthermore, these T cell responses are diverse, with different T cells depending on different residues for recognition. This represents a unique form of indirect allorecognition in which a non-allogeneic peptide sequence becomes immunogenic by stable anchoring to MHC by an allogeneic residue.

Endothelial cells (EC) are crucial for normal angiogenesis and important for patients with leukemia, myeloma, and lymphoma during and after hematopoietic stem cell transplantation (HSCT). Knowledge of endothelial dysfunction in hematologic malignancies is provided by translational studies analyzing soluble endothelial markers, morphologic and functional changes of EC cultured in patients' sera or enumeration of circulating EC or endothelial progenitor cells (EPC). EC are important for stem cell homing and maintenance. Endothelial activation or damage is a central component in the pathogenesis of several complications after HSCT, like acute and chronic graft-versus-host disease, sinusoidal obstruction syndrome, capillary leak syndrome, engraftment syndrome, diffuse alveolar syndrome, idiopathic pneumonia syndrome, and transplant-associated microangiopathy. Finally, EC or EPC may facilitate tumor cell survival thus representing potential factors for both disease progression and relapse in hematologic malignancies.

Background and objectives Foetal and neonatal alloimmune thrombocytopenia (FNAIT) is studied mainly in Caucasian populations. Severe thrombocytopenia ( 9 /L) gives risk of haemorrhage and the most feared complication is intracranial haemorrhage (ICH). In Caucasian populations anti-human platelet antigen (HPA)-1a antibodies are the cause of FNAIT in >80% of the cases. The aims of this project were to study the gene frequencies of HPA-1-5 and 15 alleles in an Egyptian population (Arabic), and to determine the frequency of HPA-1a and -5b immunisations in a cohort of Egyptian pregnant women. Materials and methods Altogether 6974 pregnant women were included in the study. Genotyping was performed by polymerase chain reaction and antibodies were detected by flow cytometry and enzyme-linked immunosorbent assay. HPA-1-5 and 15 alleles were studied in 367 individuals. Results The HPA genotypes differed from genotypes published from different Caucasian and Chinese (Han) populations in HPA-1, -2, -3, and -5 systems with significant higher frequency of HPA-1b, -2b and -5b. The rate of HPA-1a alloimmunisation was found comparable to Caucasian populations. Severe thrombocytopenia was found in two newborns. No bleeding complication was reported. Anti-HPA-5b antibodies were detected in 4.4% of the pregnant women. Clinical consequences of these antibodies were not studied. Conclusion The HPA-1bb and -5bb genotypes are more frequent in the Egyptian Arabic population studied compared to Caucasian populations. FNAIT due to anti-HPA-1a and -5b antibodies must be suspected in cases of neonatal thrombocytopenia. Further large prospective studies are needed to increase the knowledge of clinical complications related to HPA alloantibodies in populations with different genetic backgrounds.

BACKGROUND: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a severe bleeding disorder caused by maternal antibody–mediated destruction of fetal or neonatal platelets (PLTs). Results from our recent large screening study suggest that the pathophysiology of FNAIT is more similar to hemolytic disease of the fetus and newborn (HDFN) than previously thought. Immunization against HPA-1a might therefore be preventable by a prophylactic regimen of inducing antibody-mediated immune suppression (AMIS), which has been documented to be a useful prophylaxis against HDFN. This preclinical proof-of-concept study investigated whether passive administration of anti-β3 integrin could induce AMIS and thereby prevent clinical complications of FNAIT. STUDY DESIGN AND METHODS: A murine model of FNAIT using β3 integrin (GPIIIa)-deficient (β3−/−) mice was employed for this study. AMIS in β3−/− mice was induced by intravenous administration of human anti-HPA-1a immunoglobulin G or murine anti-β3 antisera given as prophylaxis after transfusion of HPA-1a–positive human PLTs or murine wild-type PLTs, respectively. RESULTS: AMIS against both human and murine PLT antigens was induced using this prophylactic approach, reducing the amount of maternal PLT antibodies by up to 90%. Neonatal PLT counts were significantly increased and pregnancy outcome was improved in a dose-dependent manner. The incidence of intracranial hemorrhage, miscarriage, and dead-born pups in mice receiving high-dose prophylaxis was reduced to that of normal controls. We also observed that the severity of thrombocytopenia inversely correlated with birth weight. CONCLUSION: This work conceptually proves that prophylactic administration of PLT antibodies induces AMIS and prevents poor pregnancy outcome in FNAIT.

Thrombocytopenia is detected in around one percent of newborns. In otherwise healthy term newborns, thrombocytopenia is most often caused by alloantibodies transferred from the mother to the foetus. In the Caucasian populations human platelet antigen (HPA)-1a is the most immunogenic HPA. In Japan and China antibodies in the HPA-4 system are the most frequent cause of FNAIT. The immune response against the HPA must be understood in order to avoid immunization or prevent induction of FNAIT where mothers are already immunized.

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is caused by maternal antibodies that cross the placenta in connection with pregnancy and destroy fetal platelets. Recently, maternal T cell responses associated with FNAIT have been studied at the clonal level. These T cell clones recognize an integrin β3 epitope, which is anchored to the HLA-DRB3∗0101-encoded MHC molecule DR52a. The same MHC allele is strongly associated with FNAIT. As the production of pathological antibodies reactive with fetal platelets is likely dependent on these T cell responses, there exists a potential for preventing FNAIT by targeting these T cells.

Background We report a case of patient-to-surgeon transmission of hepatitis C virus (HCV), and the subsequent transmission of HCV to surgical patients. Methods In 2007, a cardiac surgeon tested positive for hepatitis C. A complete look-back investigation was initiated that involved screening of all patients on the surgeon's operating lists between September 2004 and April 2007. Genotyping and phylogenetic analyses were performed where HCV RNA was detected. Results Of the 499 patients invited to HCV testing, 431 responded, 13 of whom were found anti-HCV positive. One patient, who had surgery in August 2005, was found most likely to be the source of transmission to the surgeon. Of the 270 patients who had surgery after this incident, 10 became infected, giving an estimated rate of transmission of 3.7%. The HCV polymerase chain reaction positive samples were found to be the same genotype 1a strain by phylogenetic analyses. All the 10 subsequently infected patients had undergone open heart surgery, whereas none of the 103 noncardiac patients became infected, giving an estimated risk of transmission during open heart surgery of 6.0% (95% confidence interval [3.3% to 10.7%]). Conclusions The transmission rate from an HCV positive surgeon to patients in a cardiothoracic setting was higher than previously reported and significantly higher during open heart surgery compared with vascular and pulmonary surgery. These results indicate the need for unequivocal routines for testing and handling of HCV positive health care workers and patients.

Uncertainty regarding the pathophysiology of fetal and neonatal alloimmune thrombocytopenia (FNAIT) has hampered the decision regarding how to identify, follow-up and treat the women and children with this potentially serious condition. Since knowledge of the condition is derived mainly from retrospective studies, understanding of the natural history of this condition remains incomplete. General screening programs for FNAIT have still not been introduced, mainly because of a lack of reliable risk factors and effective treatment. Now, several prospective screening studies involving up to 100,000 pregnant women have been published and the results have changed the understanding of the pathophysiology of FNAIT and, thereby, the approach toward diagnostics, prevention and treatment in a more appropriate way.

Controversies regarding the pathophysiology of neonatal alloimmune thrombocytopenia (NAIT) has hampered the development of consensus about how to identify, follow up and treat the women and children with this serious complication. One reason for this is that knowledge about the condition derived from previous retrospective studies do not necessarily conform with data derived from prospective investigations. The main obstacle to introduction of general screening programs to identify the pregnancies to treat, have been lack of reliable risk factors, and an effective treatment. Now, several recent prospective screening programs including up to 100,000 pregnant women has changed the understanding of the NAIT-pathology, and has shown that we are close to answering these critical questions.

Antibodies are friends and foes in transfusion medicine; friends as diagnostic tools and as naturally occurring antibodies in healthy individuals, foes as alloantibodies or autoantibodies. In order for antibodies to appear, a complex immune response must have taken place. This regularly involves cells and molecules belonging to the innate and adaptive immune systems. The border between the innate and adaptive immune systems is not obvious and the two cannot be regarded as separate systems, but rather as two sequences of the same response. There are few if any immune responses belonging to the field of transfusion medicine that is described in detail from the first contact with the innate immune system all the way to the functional immune response. The most ‘complete’ immune responses are described to infectious agents. Immune responses will be discussed in general and with special focus on responses to foreign human leucocyte antigens (HLA), to RhD – and human platelet antigen (HPA) 1a, which are all strong antigens related to the field of transfusion medicine.

The purpose of the review is to argue for and against introduction of HPA-1 typing of all pregnant women to reduce morbidity and mortality caused by foetal/neonatal alloimmune thrombocytopenia (FNAIT).Several groups have done HPA-1 typing in cohorts of pregnant women. Results from a Norwegian study (100,000 pregnancies) indicate that screening combined with simple intervention decreases morbidity and mortality due to FNAIT and is cost effective in Norway. Results from this study and several other studies show that there is correlation between the level of anti-HPA-1a antibodies in the mother and the severity of thrombocytopenia in the newborn. An important finding is that about 75% of women with antibodies are immunized in connection with delivery. Only 25% of the women are immunized during pregnancy.Screening for FNAIT does not fully meet the criteria presented by the WHO. Nevertheless, the results of the Norwegian study strongly indicate that morbidity and mortality related to FNAIT can be reduced. If the recent attempts to make a vaccine aimed at prevention of immunization and/or tolerizing peptides or neutralizing antibodies for already immunized women are shown to be successful, screening must be implemented.

The implementation of an antenatal screening programme for neonatal alloimmune thrombocytopenia (NAIT) is currently under debate. We evaluated the detection rate for NAIT in a nonscreened population of 661,200 births where NAIT was diagnosed on clinical indication. We did a cross-sectional comparison with a population of 100,448 human platelet antigen 1a (HPA1a)-screened pregnancies from three of the five health regions in Norway. In a nonscreening situation, 7.5 cases of NAIT were detected per year compared with 53 cases when screening was applied. The detection rate of NAIT in Norway was therefore 14% of the expected rate.

The mechanisms of action of infliximab (IFX) in the treatment of ulcerative colitis (UC) are poorly understood. The aim of the study was to investigate the changes in tissue expression of tumor necrosis factor-alpha (TNF-alpha) and other cytokines in UC patients receiving IFX treatment.The levels of TNF-alpha, interleukin (IL)-10, IL-4, and interferon-gamma (IFN-gamma) mRNA in colonic biopsies from 32 UC patients during IFX treatment were measured by real-time polymerase chain reaction (PCR) and compared with those of 19 controls. Immunohistochemistry was performed to characterize the changes of inflammatory cells during treatment.IFX reduced the expression of TNF-alpha and IFN-gamma mRNA, but not that of IL-10 and IL-4 mRNA. Reductions in TNF-alpha mRNA were correlated to clinical and endoscopic improvements, and normalization of TNF-alpha mRNA was obtained in patients with healed mucosa. The numbers of T lymphocytes and macrophages were significantly decreased in patients with healed mucosa after IFX treatment, although compared to normal controls, there were still increased levels of TNF-alpha-positive cells after treatment.IFX induced down-regulation of the mucosal TNF-alpha and IFN-gamma mRNA expression in UC patients. The numbers of T lymphocytes and macrophages were significantly decreased in patients with endoscopically healed mucosa after IFX treatment.

Background: Host factors play an important role in the pathophysiology of Helicobacter pylori infection and development of gastritis and related disease. The established opinion is that the T-cell-mediated immune response to H. pylori infection is of Th1 type. Our earlier immune cell phenotype studies indicate a mixed Th1–Th2 profile of the effector cells. Therefore, an extensive adaptive and regulatory cytokine gene expression profile was conducted by quantitative real-time polymerase chain reaction (qPCR). Materials and Methods: Biopsies from gastric mucosa of 91 patients diagnosed as H. pylori negative, H. pylori positive with gastritis, or H. pylori positive with peptic ulcer were obtained by endoscopy. Gene expressions of nine cytokines and CagA status were measured by qPCR. Results: All cytokine genes showed higher expression levels in the presence of H. pylori when compared to H. pylori-negative samples (fold increase: IL8: × 11.2; IL12A: × 2.4; TNF-α: × 5.2; IFN-γ: × 4.3; IL4: × 3.6; IL6: × 14.7; and IL10: × 6.7). Patients infected with CagA-positive strains had higher expression of IL1-β and IL18 compared to patients infected with CagA-negative strains (× 1.6 for IL1-β and × 2.0 for IL18). Patients with duodenal ulcer had a lower antral Th1/Th2 ratio than other H. pylori-positive patients. Conclusions: The cytokine profile of H. pylori-infected gastric mucosa shows a mixed Th1–Th2 profile. Furthermore, a high IL10 expression may indicate that also regulatory T cells play a role in the chronic phase of H. pylori infection.

BACKGROUND: Maternal plasma and/or serum levels of anti-HPA-1a at delivery were compared to neonatal platelet (PLT) counts. STUDY DESIGN AND METHODS: Samples from HPA-1bb women who gave birth to children with thrombocytopenia or had anamnestic information about a previous child with neonatal alloimmune thrombocytopenia (NAIT) were collected at delivery. A modified monoclonal antibody immobilization of PLT antigen method was used for quantification of anti-HPA-1a. RESULTS: The anti-HPA-1a level in women with severely thrombocytopenic children was higher than the corresponding level in mothers of children born with moderate thrombocytopenia or normal PLT counts. CONCLUSION: Our data show a significant correlation between maternal anti-HPA-1a level and the neonatal PLT count and indicate strongly that this may be a reliable predictive measure for NAIT. Suitable test systems for quantitative measurements of anti-HPA-1a must be developed and evaluated for this particular purpose.

In this comparative cross-sectional study, possible associations between maternal anti-HLA class I antibodies and birth weight in neonatal thrombocytopenia are explored. Although commonly detected in pregnancies and generally regarded as harmless, it has been suggested that such antibodies might be associated with fetal and neonatal alloimmune thrombocytopenia (FNAIT). As a link between FNAIT due to human platelet antigen 1a-specific antibodies and reduced birth weight in boys has previously been demonstrated, we wanted to explore whether maternal anti-HLA class I antibodies might also affect birth weight. To examine this, suspected cases of FNAIT referred to the Norwegian National Unit for Platelet Immunology during the period 1998-2009 were identified. Pregnancies where the only finding was maternal anti-HLA class I antibodies were included. An unselected group of pregnant women participating in a prospective study investigating maternal-fetal hemodynamics at the University Hospital North Norway during the years 2006-2010 served as controls. Twenty-nine percent of controls had anti-HLA class I antibodies. The thrombocytopenic neonates had a significantly lower adjusted birth weight (linear regression, P=0.036) and significantly higher odds of being small for gestational age (OR=6.72, P

Cytokines have been suggested to be key factors in modulating immune response against tumorigenesis in the microenvironment. Therefore, characterization of cytokine expression along the colorectal adenoma-carcinoma sequence may add important information for understanding the immune-related mechanisms of the development of colorectal carcinoma (CRC). In this study, biopsies from 32 patients with colorectal adenoma (CRA), 20 patients with CRC and 18 healthy controls were examined. Cytokine gene expressions of interleukin-4 (IL-4), IL-10, tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma and its upstream inducers (IL-12A and IL-18) were measured at messenger RNA (mRNA) level with quantitative real-time PCR (Q-PCR). Cytokine expressing cells were characterized using immunohistochemistry (IHC). A distinct different cytokine profile between adenoma and CRC was observed: the Th1 cytokines (IFN-gamma, TNF-alpha, IL-12A and IL-18) were increased in local tissues of CRA and decreased in CRC. Consistent with the quantitative cytokine data, IHC examinations revealed slightly increased densities of Th1 cytokine-expressing cells in CRA and a remarkably decreased density of the Th1 cells in CRC. In CRA, the cytokine-expressing cells were highly polarized to the subepithelial stroma while the cells were evenly distributed through the stroma in CRC. In conclusion, distinct changes in the Th1 cytokine profile appear along the colorectal adenoma-carcinoma sequence. This may reflect a change in the host immune regulatory function in the adenoma-carcinoma sequence.

SUMMARY Although antibody-dependent platelet transfusion refractoriness has become less frequent with the introduction of leukocyte filtration of platelet concentrates, it remains a challenge in transfusion medicine. Small transfusion centers do not have easy access to an inventory of human leukocyte antigen (HLA)-typed platelet donors. As flow cytometry has become more common, this technology can easily be introduced in platelet crossmatching, with sensitivity and predictive values comparable to those of other techniques, and with the advantage of automation. An algorithm is presented for use of flow cytometry in the selection of compatible platelets for alloimmunized patients.

Only a fraction of Helicobacter pylori (HP)-infected individuals develop clinical disease. Recent research indicates that immunological mechanisms may be important for understanding the pathophysiology of HP infection. Differences in the individual cellular immune response may reflect the clinical diversity. The aim of the present study was to investigate the cellular immune response against HP in three clinically well-defined patient groups: HP-positive peptic ulcer, HP-positive and HP-negative gastritis. Biopsies from gastric mucosa were processed for analysis by flow cytometry and histology. The number of T lymphocytes (CD3+) was significantly higher in HP-positive peptic ulcer (13.8%) than in HP-positive nonulcer gastritis (6.3%). A nonsignificant increase for B lymphocytes (CD19+) was noted as well. Furthermore, a significant difference was seen in mucosal CD4/CD8 ratio between HP ulcer (2.4) and nonulcer HP gastritis (1.0) patients. Thus, B cells (CD19+) and T-helper cells (CD4+) were dominant in gastric mucosa from peptic ulcer patients, and cytotoxic T cells (CD8+) were relatively dominant in gastric mucosa from nonulcer patients. In conclusion, distinct differences in the T-cell subset distribution of mucosal lymphocytes were detected in patients with HP infection, strongly correlated with the presence or absence of peptic ulcer.