Vox Sanguinis International forum on the selection and preparation of blood components for intrauterine transfusion

Abstract

The indication for IUT in our institution has to date been limited to red cell alloimmunization due to anti-D. Alpha thalassaemia and congenital infections such as Parvovirus are not uncommon in this region of the world, but the foetal and neonatal specialists in our centre have generally not advocated IUT for them. Certainly, we would not embark on an IUT programme for HbBarts that would be considered as incompatible with life. Question 2 Anti-D has been the only reason for IUT in our population. We identify anti-D in 0Á35% of our non-transfused female population, mainly from the antenatal clinic. The majority of this is due to anti-D administered through the antenatal anti-D prophylaxis programme, but we do get 1-2 cases that occur as a result of RhD immunization resulting in moderate to severe HDFN. The common antibodies we otherwise identify in our nontransfused female population (prevalence in parentheses) are anti-Mi a (0Á24%), anti-Le a (0Á24%), anti-E (0Á14%) and anti-M (0Á12%). As you would note, these antibodies are rarely associated with HDFN. Anti-K and anti-c which are more commonly associated with HDFN has a prevalence of only 0Á01% in our population of non-transfused females. Question 3 We only perform 1-2 IUTs per year. In 2018, we had no IUT procedures and in 2019, we have only performed one procedure to date. Blood sample testing Question 4 Foetal red cell typing is limited to ABO and RhD, C, c, E and e phenotyping. Blood product selection (Red blood cell (RBC) concentrates): Question 5 We select Group O red cells, preferably from a donor with low titres of anti-A/B. If a suitable donor with low anti-A/ B titre cannot be located, we will elect to reconstitute the red cells with AB plasma. Question 6 We obtain allogeneic red cells from our pool of selected donors. Question 7 All red cell units supplied are K negative as well as antigen matched as close as possible to the maternal phenotype. At the minimum, the red cells supplied must be CcEe-matched. Question 8 Units supplied would be considered Day-0, as we prepare red cells from a fresh bleed on the day of the IUT procedure. The donor workup which includes ABO and RhD typing, red cell phenotyping, antibody screening, IAT crossmatch with maternal plasma, anti-A/B titration as well as microbiology testing (HIV, HBV, HCV, TPPA, NAT) would be completed prior to the donation from a sample obtained from the donor not more than 72 h before the planned blood collection. e18 Question 9 Whole blood is collected into a collection bag containing CPD (Citrate, Phosphate and Dextrose) prior to processing. Question 10 No, we do not assess CMV status. CMV prevalence is high within our population, and we therefore have found it difficult to maintain a pool of suitable CMV donors.

Survey of intrauterine red blood cell (RBC) transfusion practices in the United States

“…Prophylactic matching of additional antigens beyond identified maternal alloantibodies is variable depending on the country, institution, and availability of RBCs. 18 Some studies found that extended matching for all IUTs was not possible for all women, but decreased alloimmunization occurred in women who received IUTs with extended prophylactic antigen matching for Fy(a), Fy(b), Jk(a), Jk(b), and S antigens. 19,20 This study is limited by its response rate (53%) and sampling method.…”

“…This current report focuses on variability on blood component selection and processing only and addresses variability between various US institutions. 18 Despite these limitations, this study provides important data regarding contemporary transfusion medicine practices for IUTs performed in the US.…”

“…A recent VOX international forum by Clarke et al provides an overview of the international IUT practices ranging from indications; pre‐transfusion sample collection and testing; blood component selection; blood administration, post‐transfusion monitoring; and transfusion traceability. This current report focuses on variability on blood component selection and processing only and addresses variability between various US institutions 18 . Despite these limitations, this study provides important data regarding contemporary transfusion medicine practices for IUTs performed in the US.…”

“…Approximately 75% of responding centers indicated that all units were matched only for the implicated antibody/antibodies, while three centers noted that they provided all units with maternal antigen‐matched for Rh and Kell. Prophylactic matching of additional antigens beyond identified maternal alloantibodies is variable depending on the country, institution, and availability of RBCs 18 . Some studies found that extended matching for all IUTs was not possible for all women, but decreased alloimmunization occurred in women who received IUTs with extended prophylactic antigen matching for Fy(a), Fy(b), Jk(a), Jk(b), and S antigens 19,20 …”

Intrauterine transfusion: an international review of practice and policy

“…Potential participants were selected by the authors and the editor of the International forum series and included individuals and facilities on 5 continents (Table 1 participating countries). Ten responses were received from a range of clinical and laboratory providers serving large regional or national programmes (3 respondents) to hospital-based programmes caring for local patients (7 respondents) [2].…”