Red blood cell alloimmunization in 184 patients with myeloid neoplasms treated with azacitidine - A retrospective single center experience

Alloimmunization to Red Blood Cell (RBC) antigens frequently occurs in patients with myeloid neoplasms (AML, MDS and CMML) and potentially poses the patient at risk for delayed hemolytic transfusion reactions and limited supply of compatible RBC-units. However, there is comparatively little data on transfusion associated characteristics in this patient cohort. We therefore retrospectively analyzed transfusion requirements and clinical outcomes of 184 patients with myloid neoplasms treated with azacitidine at the Paracelsus Medical University Salzburg, which were included in the Austrian Registry of Hypomethylating Agents. The mean blood component requirements for AML, MDS and CMML were 39.8, 67.4 and 31.4 RBC units and 31.7, 27.6 and 19.1 platelet (PLT) units respectively. In spite of an extended and stringent RBC unit matching policy (ABO, RhD, RhCcEe and K antigens), 20 (11%) patients formed at least one alloantibody ("allo-group"), whereas 164 patients (89%) did not ("non-allo-group"). The most frequent antibody specificity was anti-E, followed by anti-Wra -Lua, -D, -C and -Jka. Alloimmunization was associated with higher numbers of transfused RBC units (68 vs. 38; p=0.001), as well as with longer time under transfusion (16.7 vs. 9.4 months; p=0.014). Median overall survival (OS) did not differ significantly between the "allo"- and "non-allo-group".

Pilot PET Study to Assess the Functional Interplay Between ABCB1 and ABCG2 at the Human Blood-Brain Barrier

ABCB1 and ABCG2 work together at the blood-brain barrier (BBB) to limit brain distribution of dual ABCB1/ABCG2 substrates. In this pilot study we used positron emission tomography (PET) to assess brain distribution of two model ABCB1/ABCG2 substrates ([(11) C]elacridar and [(11) C]tariquidar) in healthy subjects without (c.421CC) or with (c.421CA) the ABCG2 single-nucleotide polymorphism (SNP) c.421C>A. Subjects underwent PET scans under conditions when ABCB1 and ABCG2 were functional and during ABCB1 inhibition with high-dose tariquidar. In contrast to the ABCB1-selective substrate (R)-[(11) C]verapamil, [(11) C]elacridar and [(11) C]tariquidar showed only moderate increases in brain distribution during ABCB1 inhibition. This provides evidence for a functional interplay between ABCB1 and ABCG2 at the human BBB and suggests that both ABCB1 and ABCG2 need to be inhibited to achieve substantial increases in brain distribution of dual ABCB1/ABCG2 substrates. During ABCB1 inhibition c.421CA subjects had significantly higher increases in [(11) C]tariquidar brain distribution than c.421CC subjects, pointing to impaired cerebral ABCG2 function.

West Nile virus lineage 2 infection in a blood donor from Vienna, Austria, August 2014

Eastern Austria is neighbouring regions with ongoing West Nile virus (WNV) transmissions. Three human WNV infections had been diagnosed during the past decade in Austria. The Austrian Red Cross Blood Service (ARC-BS) started a first voluntary screening for WNV in blood donors from Eastern Austria by Nucleic Acid Testing (NAT) in June 2014. This is also the most extensive WNV surveillance programme in humans in Austria so far. In August 2014, one autochthonous WNV infection was detected in a blood donor from Vienna. By now, one in 67,800 whole blood donations was found to be positive for WNV RNA.

High-throughput multiplex PCR genotyping for 35 red blood cell antigens in blood donors

BACKGROUND AND OBJECTIVES

One to two per cent of patients in need of red cell transfusion carry irregular antibodies to red blood cell (RBC) antigens and have to be supplied with specially selected blood units. To be able to respond to those requests, blood centres have to screen a significant number of donors for a variety of antigens serologically, which is a costly and through the shortage of reagents, also limited procedure. To make this procedure more efficient, the Austrian Red Cross has developed a genotyping assay as an alternative approach for high throughput RBC typing.

MATERIALS AND METHODS

A multiplex polymerase chain reaction (PCR) assay was designed for typing 35 RBC antigens in six reaction mixes. The assay includes both common as well as high-frequency-alleles: MNS1, MNS2, MNS3 and MNS4; LU1, LU2, LU8 and LU14; KEL1, KEL2, KEL3, KEL4, KEL6, KEL7, KEL11, KEL17 and KEL21; FY1, FY2, FYB(WK) and FY0 (FYB(ES)); JK1 and JK2; DI1, DI2, DI3 and DI4; YT1 and YT2; DO1 and DO2; CO1 and CO2; IN1 and IN2. The assay was validated using 370 selected serologically typed samples. Subsequently 6000 individuals were screened to identify high frequency antigen (HFA)-negative donors and to facilitate the search for compatible blood for alloimmunized patients.

RESULTS

All controls showed complete concordance for the tested markers. The screening of 6000 donors revealed 57 new HFA-negative donors and the blood group database was extended by approximately 210,000 results.

CONCLUSION

The study shows that in practice, this high-throughput genotyping assay is feasible, fast and provides reliable results. Compared to serological testing, this molecular approach is also very cost-efficient.

ACTBP2 (alias ACTBP8) is localized on chromosome 6 (band 6q14)

The locus ACTBP2 (SE33) is localized on chromosome 6 (band 6q14). This has been demonstrated by typing a large Caucasoid three-generation kindred of Austrian origin for SE33 and several chromosome 6 markers.