Clinical practices and outcomes of RhD immunoglobulin prophylaxis following large-volume fetomaternal haemorrhage in Queensland, Australia

Background: Guidelines for laboratory assessment of fetomaternal haemorrhage (FMH) was published by the Australian and New Zealand Society of Blood Transfusion (ANZSBT) in 2002. However, data on adherence by practitioners and clinical outcomes are lacking. Aims: The primary objective is to examine the follow-up testing and dosing of additional RhD immunoglobulin in RhD negative women who experienced large-volume FMH for whom additional intravenous RhD immunoglobulin was requested in Queensland, Australia. The secondary objectives are to examine the rate and risk factors of RhD alloimmunisation in these women. Materials and Methods: RhD negative women with FMH >6\ua0mL for whom additional dose(s) of intravenous RhD immunoglobulin was requested through Australian Red Cross Lifeblood from February 2007 to February 2018 were identified. For each patient, the volume of FMH, methods and timing of FMH quantitation, dose of RhD immunoglobulin, maternal and cord blood groups were analysed against the corresponding antibody screen and identification. Results: Following FMH >6\ua0mL, only 15% and 11.5% of cases adhered to current ANZSBT guideline on follow-up testing and supplemental RhD immunoglobulin dosing respectively. Despite the provision of single supplemental RhD immunoglobulin at a ratio of 100\ua0IU to 1\ua0mL fetal red cells, the rate of RhD alloimmunisation in RhD negative women with RhD positive fetus or fetus of unknown RhD status following FMH >6\ua0mL is at least 4%. Conclusions: Poor compliance with guidelines for follow-up and management of large-volume FMH may contribute to increased risk of RhD alloimmunisation. Further analysis of data is warranted

Pretransplant platelet transfusion refractoriness is not associated with platelet nonengraftment in T-replete hematopoietic progenitor cell transplantation for hematologic malignancies

BACKGROUNDCellular engraftment after allogeneic hematopoietic progenitor cell transplantation (HPCT) can be affected by pre-HPCT antibodies against donor human leukocyte antigen (HLA; donor-specific antibodies [DSAs]), which are commonly acquired by either pregnancy or transfusion. Issues regarding high assay sensitivity and variable interpretation limit routine screening for DSAs. Platelet (PLT) transfusion refractoriness (PTR) is relatively common in patients with hematologic malignancies, and anti-HLA alloantibodies can be identified in up to 20% of cases. For patients with PTR undergoing subsequent allogeneic HPCT, however, the effect if any on subsequent PLT nonengraftment is unknown

Fetal/neonatal alloimmune thrombocytopenia : A systematic review of impact of HLA-DRB3∗01:01 on fetal/neonatal outcome

The most common, severe cases of fetal and neonatal alloimmune thrombocytopenia among whites are caused by antibodies against human platelet antigen 1a (HPA-1a). The aims of this systematic review and meta-analysis are to determine the association between maternal HLA-DRB3∗01:01 and: (1) HPA-1a-alloimmunization and (2) neonatal outcome in children born of HPA-1a-immunized women. A systematic literature search identified 4 prospective and 8 retrospective studies. Data were combined across studies to estimate pooled odds ratios (ORs) and the associated 95% confidence intervals (CIs). The population represented by the prospective studies was more than 150 000. In the prospective studies, there were 64 severely thrombocytopenic newborns (platelet count < 50 × 109/L) of whom 3 had intracranial hemorrhage. The mothers of all 64 children were HLA-DRB3∗01:01+. The number of severely thrombocytopenic children born of HPA-1a-alloimmunized women in the retrospective studies was 214; 205 of whom were born of HLA-DRB3∗01:01+ women. For HLA-DRB3∗01:01- women, the OR (95% CI) for alloimmunization was 0.05 (0.00-0.60), and for severe neonatal thrombocytopenia 0.08 (0.02-0.37). This meta-analysis demonstrates that the risk of alloimmunization and of having a child with severe thrombocytopenia are both very low for HPA-1a- women who are HLA-DRB3∗01:01-

Maternal HPA-1a antibody level and its role in predicting the severity of Fetal/Neonatal Alloimmune Thrombocytopenia : a systematic review

Background and Objectives: In Caucasians, fetal/neonatal alloimmune thrombocytopenia (FNAIT) is most commonly due to maternal HPA-1a antibodies. HPA-1a typing followed by screening for anti-HPA-1a antibodies in HPA-1bb women may identify first pregnancies at risk. Our goal was to review results from previous published studies to examine whether the maternal antibody level to HPA-1a could be used to identify high-risk pregnancies. Materials and Methods: The studies included were categorized by recruitment strategies: screening of unselected pregnancies or samples analyzed from known or suspected FNAIT patients. Results: Three prospective studies reported results from screening programmes, and 10 retrospective studies focused on suspected cases of FNAIT. In 8 studies samples for antibody measurement, performed by the monoclonal antibody immobilization of platelet antigen (MAIPA) assay, and samples for determining fetal/neonatal platelet count were collected simultaneously. In these 8 studies, the maternal antibody level correlated with the risk of severe thrombocytopenia. The prospective studies reported high negative predictive values (88–95%), which would allow for the use of maternal anti-HPA-1a antibody level as a predictive tool in a screening setting, in order to identify cases at low risk for FNAIT. However, due to low positive predictive values reported in prospective as well as retrospective studies (54–97%), the maternal antibody level is less suited for the final diagnosis and for guiding antenatal treatment. Conclusion: HPA-1a antibody level has the potential to predict the severity of FNAIT

Postnatal intervention for the treatment of FNAIT : a systematic review

Objective: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is associated with life-threatening bleeding. This systematic review of postnatal management of FNAIT examined transfusion of human platelet antigen (HPA) selected or unselected platelets, and/or IVIg on platelet increments, hemorrhage and mortality. Study design: MEDLINE, EMBASE and Cochrane searches were conducted until 11 May 2018. Result: Of 754 neonates, 382 received platelet transfusions (51%). HPA-selected platelets resulted in higher platelet increments and longer response times than HPA-unselected platelets. However, unselected platelets generally led to sufficient platelet increments to 30 × 10 9 /L, a level above which intracranial hemorrhage or other life-threatening bleeding rarely occurred. Platelet increments were not improved with the addition of IVIg to platelet transfusion. Conclusion: Overall, HPA-selected platelet transfusions were more effective than HPA-unselected platelets but unselected platelets were often effective enough to achieve clinical goals. Available studies do not clearly demonstrate a benefit for addition of IVIg to platelet transfusion