Dear Sir,The Rh blood group system is determined by the highly homologous RHD and RHCE genes located on the first chromosome, which encode for the RhD and RhCE polypeptides. D antigen is of special clinical relevance in the fields of transfusion medicine and obstetrics. Owing to its high immunogenicity, D antigen can induce the production of alloantibodies and thus cause posttransfusion haemolytic reaction and haemolytic disease of the newborn (Wagner et al., 2000).About 0·2-1% of the European population are carriers of structurally altered RHD alleles encoding for various types of weak D proteins. At the molecular level, point mutations resulting in amino acid substitutions in the intracellular or transmembranous segments of RhD protein are causing weak D phenotypes. More than 170 different RHD alleles closely related to the expression of the respective D phenotype, including more than 70 weak D types, have been discovered to date (Flegel, 2007). Some weak D types (types 1, 2 and 3) are not associated with the development of alloantibodies; however, alloimmunisation in weak D types 4·2, 11 and 15 carriers have been reported (Flegel, 2006). Owing to the extremely small phenotypic variation, particular weak D types are very difficult to differentiate by serology and can only be identified by molecular methods, thus enabling definitive decision on the mode of transfusion treatment and the need of anti-D prophylaxis in pregnant women. The individuals who are carriers of weak D types 1, 2 and 3 can receive transfusion of D+ red blood cell (RBC) units, although such pregnant women do not require anti-D prophylaxis. Thus, the unnecessary utilisation of D− RBC units and RhIg is avoided (Flegel and Wagner, 2002).Particular segments of the RHD gene sequence are multiplied by RHD genotyping using primers specific for the known mutations characterising particular weak D types by use of the polymerase chain reaction with sequence-specific priming (PCR-SSP). This procedure is employed to determine polymorphism of the weak D types.

Background: Anti-Rh17 is a rare red blood cell (RBC) antibody to high-frequency antigens that may cause severe hemolytic disease of the fetus and newborn (HDFN). Despite the rarity of HDFN caused by Anti-Rh17, this antibody was reported in many different populations. Emergency transfusions, especially exchange transfusions, present a huge problem if no compatible RBCs of phenotype D-- are available. Methods: Here we report obstetrical histories of three women and describe their pregnancies complicated by anti-Rh17 antibodies. We summarized published cases of pregnancies complicated by anti-Rh17 and reviewed transfusion treatment and outcomes. Additionally, a simplified flowchart for the management of such pregnancies is proposed. Results: Four pregnancies were affected by severe HDFN, and three of them ended with perinatal death. In the fourth case, the baby was born hydropic and icteric and the condition was rapidly deteriorating. Emergency exchange transfusion was performed with incompatible O-negative RBC units in AB-negative plasma. The baby was discharged on the 14th day in good health. In the available literature, 15 women and 22 pregnancies were reported, 20 of them developed severe HDFN. According to the data, intrauterine transfusion for treatment of HDFN was the most common form of treatment with the donation of the mother’s blood. Different options for exchange transfusion were described, including incompatible RBCs. Conclusion: In more than 90% of described pregnancies of HDFN caused by anti-Rh17 antibody, transfusion treatment was required. Therefore, RBC from D-- phenotype has to be available. According to published data, in emergent circumstances when maternal and blood from donor with phenotype D-- is not available, incompatible exchange transfusion is a better choice than delaying transfusion when it is necessary. It is of essential importance that pregnancies with high risk of HDFN due to anti-Rh17 are managed by a multidisciplinary team (transfusion medicine specialist, obstetrician, neonatologist) in a highly specialized tertiary institution.

Background: To evaluate the incidence, the consequences, and the prevention strategy of anti-D alloimmunizations of D variant carriers in the obstetric population of Split-Dalmatia County, Croatia. Methods: RhD immunization events were evaluated retrospectively for the period between 1993 and 2012. Women were tested for RhD antigen and irregular antibodies. Those with anti-D antibody who were not serologically D- were genotyped for RHD. They were evaluated for their obstetric and transfusion history and their titer of anti-D. The neonates were evaluated for RhD status, direct antiglobulin test (DAT), hemoglobin and bilirubin levels, transfusion therapy as well as phototherapy and outcome. Results: Out of 104,884 live births 102,982 women were tested for RhD antigen. Anti-D immunization occurred in 184 women which accounts for 0.9% of individuals at risk of anti-D formation. 181 cases occurred in women serologically typed as D-. Three women were partial D carriers (DVa n = 2, DNB n = 1), initially typed RhD+, and recognized as D variant carriers after the immunization occurred. Anti-D titer varied from 1:1 to 1:16. Six children were RhD+, four had positive DAT, and two underwent phototherapy. Conclusion: Anti-D immunization occurred in pregnant partial D carriers (DVa, DNB). RhD+ children had serologic markers of hemolytic disease of the fetus and newborn (HDFN), with no cases of severe HDFN.

The most common partial D variant in our population is DVa. It is recommended to use cell lines which do not strongly agglutinate DVa variant in routine RhD typing. The appropriate choice of reagents will enable the serology methods to recognize the cases in which RHD genotyping is required.

Background: Identifying high-risk patients for transfusion after cardiac operations would alter postoperative management. The aim of this study was to investigate closure time (CT) measured by platelet function analyzer (PFA) for prediction of bleeding and transfusions. Methods: 66 patients were scheduled for coronary artery bypass graft (CABG) surgery and 30 patients for valve repair and replacement (non-CABG). Measurements of PFA-100® CT for collagen and adenosine diphosphate (cADP) and collagen and epinephrine (cEPI) were performed 15 min after protamine administration. Blood loss was measured, and the amount of transfusion products was recorded postoperatively. Results: The study demonstrated significant differences between CABG patients with cADP-CT ≥ 118 s and those with cADP-CT < 118 s with regard to blood loss for 24 h (p = 0.001) and blood loss for 25-48 h (p = 0.003) as well as fresh frozen plasma (p = 0.015), platelet (p > 0.001) and red blood cell (p = 0.002) units given in 48 postoperative h. There were no differences cardiopulmonary bypass when was applied. In non-CABG patients, there were no differences in blood loss and transfusion requirements with respect to cADP-CT and cEPI-CT. Conclusion: Postoperative platelet dysfunction measured by a prolonged cADP-CT was significant predictor of blood loss and transfusion in CABG patients.