P34Management of Pregnancy Complicated by Anti‐hrB and/or Anti‐HrB.

Anti‐hr^B and anti‐Hr^B are rare alloantibodies, so far found exclusively in people of Black African descent. There is no data available regarding haemolytic transfusion reactions in association with anti‐hr^B, and precise information is limited. Anti‐Hr^B may cause transfusion reactions, but no data is available. Selection of blood for transfusion support for patients with these alloantibodies imposes a special challenge in the UK, as, in the case of anti‐hr^B (if accompanied with anti‐D) it is difficult to locate suitable antigen negative blood, whilst Hr^B‐ blood is almost unknown amongst the UK donor population. Two antenatal cases are reported, one with anti‐hr^B, and one with anti‐Hr^B. Weak anti‐D was also identified in the serum in both cases. For the former case, r“r” ( dcE/dcE) units were provided to cover the delivery. The baby was delivered by vaginal route. Cord sample DAT was negative, with no evidence of haemolytic disease of the newborn (HDN). The patient did not require transfusion. The patient was known to have anti‐hr^B in her previous pregnancy, and there was no evidence of HDN in that pregnancy. Anti‐Hr^B may cause haemolytic transfusion reaction. In the latter case, there are two options: either to import extremely rare D‐, Hr^B blood from South Africa or to provide rare Rh_null units. The patient received two Rh_null units to cover for Caesarean Section and transfusion was uneventful. Although the cord sample DAT was positive (Anti‐IgG 2+, ‐C3d1+) the infant's delivery Hb level was 15.2 g dL^‐1 and bilirubin was within the normal range. No therapy was required. A literature search confirms that there is not much data available regarding the clinical significance of anti‐hr^B and anti‐Hr^B. The few previous reports indicate that both anti‐hr^B and anti‐Hr^B appear not to cause HDN. Our cases supported that HDN is not associated with both anti‐hr^B and anti‐Hr^B. The cases reported here illustrate the complexity in providing transfusion support for these patients. Further case reports are warranted to establish the clinical relevance of these rare antibodies.     

Analysis of RhCE variants among 806 individuals in France: considerations for transfusion safety, with emphasis on patients with sickle cell disease

BACKGROUND: DNA testing has enabled the documenting of numerous variants of RHCE alleles, especially in individuals of African origin. The risk for production of clinically significant alloantibodies to Rh antigens of patients carrying variant RHCE alleles has led us to analyze the different RhCE variants investigated by molecular biology. Alloimmunization was analyzed regarding the RHCE genetic profile. STUDY DESIGN AND METHODS: Samples from 806 individuals with altered expression of RhCE antigens and/or producing anti‐RhCE in the presence of the corresponding antigen were analyzed. RESULTS: A total of 572 individuals were shown to express RhCE variants. Variant RHCE*ce alleles and RH haplotypes were identified in 83% of cases, the most frequent ones being the R^N haplotype, the ceMO allele, the (C)ce^s haplotype/ce^s1006 allele, and the ceAR allele identified in 36, 23, 20, and 17% of the tested samples, respectively. The absence of a high‐prevalence Rh antigen was documented in 93 individuals. Partial C and partial e were expressed by 53% of individuals with RhCE variants. Rh antibodies were identified in 127 (20%) of 623 patients. They were found to be alloantibodies in 48 (38%) of these 127 patients. Alloimmunization against a high‐prevalence Rh antigen was detected in 25% of cases. CONCLUSION: The challenge in clinical red blood cell (RBC) transfusion of patients with sickle cell disease, notably, would be to provide not only phenotypically matched, but also genetically matched, RBC units regarding RhCE variants.     

A novel RHCE*ce 48C, 733G allele with Nucleotide 941C in Exon 7 encodes an altered red blood cell e antigen

BACKGROUND: Several RHCE*ce alleles have in common a 733C>G (Leu245Val) change. Some encode an altered expression of e on red blood cells (RBCs) and individuals with such RBCs can make e‐like alloantibodies. The identification of an apparent anti‐hr^B in the serum of an E?e+ African American patient prompted us to analyze her DNA, which revealed a novel RHCE*ce allele. We also screened blood samples from African Americans to determine the frequency of the novel allele. STUDY DESIGN AND METHODS: Hemagglutination tests and molecular analyses were performed by standard procedures. RESULTS: Analysis of the proband's DNA revealed RHCE*ce 48C/C, 733G/G, 941T/C, and 1006G/T. Of 272 samples from African Americans, 257 were RHCE*941T/T (wild type), and 15 (6%) were RHCE*941T/C. Of these 15, 14 were RHCE*ce/ce, 10 with 733C/G and four with 733G/G, and one was RHCE*ce/cE, 733C/G. Cloning experiments confirmed the Nucleotide 941 change and showed that 48C, 733G, 941C, and 1006T were carried on the same allele. RBCs from the 15 samples carrying the RHCE*941C variant typed V/VS+ and hr^B+^W. CONCLUSION: This study identifies a novel allele, RHCE*ce 48C, 733G, 941C, 1006T which is predicted to encode 16Cys, 245Val, 314Ala, and 336CyS and was shown to encode c, V/VS, and an altered expression of e and hr^B antigens. The clinical significance of the antibody found in the proband is not established because E+e? RBC components were transfused to the patient. The novel RHCE*ce 48C, 733G, 941C, 1006T allele was present in 5.5% of samples from African Americans and thus, in this small cohort, it had a frequency of 0.028.     

The low‐prevalence Rh antigen STEM (RH49) is encoded by two different RHCE*ce818T alleles that are often in cis to RHD*DOL

BACKGROUND: STEM (RH49) is a low‐prevalence antigen in the Rh blood group system. A scarcity of anti‐STEM has precluded extensive study of this antigen. We report that two alleles with a RHCE*ce818C>T change encode a partial e, and a hr^S?, hr^B+, STEM+ phenotype and that both alleles are frequently in cis to RHD*DOL1 or RHD*DOL2. STUDY DESIGN AND METHODS: Blood samples were from donors and patients in our collections. Hemagglutination, DNA, and RNA testing was performed by standard techniques. RESULTS: Fourteen STEM+ samples were heterozygous RHCE*ce818C/T: six had RHCE*ceBI and eight had a novel allele, RHCE*ceSM. Eleven were heterozygous for RHD*DOL1 or RHD*DOL2. Eleven samples, previously typed STEM?, had RHCE*ce818C/C (consensus nucleotide). RBCs from informative STEM+ samples were e+/? hr^S? hr^B+. One person who was heterozygous RHCE*ceBI and RHCE*cE had an anti‐e‐like antibody in her plasma, and one person, who was hemizygous for RHD*DOL2, had anti‐D in her plasma. CONCLUSIONS: We show that two alleles with a RHCE*ce818C>T change (RHCE*ceBI and RHCE*ceSM) encode a hr^S? hr^B+ STEM+ phenotype. In addition, both alleles are frequently in cis to RHD*DOL1 or RHD*DOL2 and RHCE*ceBI encodes a partial e antigen. In the small cohort of samples tested, RHD*DOL invariably traveled with RHCE*ce818T. Our study also confirmed the presumption that RHD*DOL2, like RHD*DOL1, encodes a partial D antigen and the low‐prevalence antigen DAK.     

DIIIa and DIII Type 5 are encoded by the same allele and are associated with altered RHCE*ce alleles: clinical implications

BACKGROUND: The partial D phenotype DIIIa was originally reported to be associated with 455A>C in Exon 3, 602C>G in Exon 4, and 667T>G in Exon 5. Other alleles with these changes were subsequently identified and designated DIII Types 5, 6, and 7, as they had additional alterations. The observation that DNA samples associated with the DIIIa phenotype had more changes than those originally reported motivated us to reanalyze the DIIIa probands (BP and DJ) from the original study. We also studied additional DIIIa samples to clarify the RHD background and establish the associated RHCE. STUDY DESIGN AND METHODS: Hemagglutination testing was performed by standard methods. RHD and RHCE were analyzed by combinations of polymerase chain reaction–restriction fragment length polymorphism, exon‐specific sequencing, cloning, or direct sequencing of Rh‐cDNAs. RESULTS: The RHD alleles from BP, DJ, and 58 additional DIIIa samples had the three reported nucleotide changes as well as 186G>T, 410C>T, and 819G>A. The DIIIa allele was associated with several altered RHCE*ce‐alleles, the prominent one being ceS (48C, 733G, 1006T). CONCLUSION: The DIIIa phenotype is associated with six RHD changes, five of which encode amino acid changes, and partial DIIIa and DIII Type 5 are encoded by the same RHD allele. In all samples, RHD*DIIIa was inherited with altered RHCE*ce. Patients with partial DIIIa are at risk for production of alloanti‐D, but they are also at risk for alloanti‐e, ‐c, or antibodies to high‐prevalence Rh antigens if there is no conventional RHCE*ce in trans. Among 39 patients studied, 16 had alloanti‐D and 27 had alloanti‐e or anti‐hrB.     

The new platelet alloantigen Caba: a single point mutation Gln716His on the α2 integrin

BACKGROUND: Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is caused by maternal alloimmunization against fetal platelet (PLT) antigens, inherited from the father and absent from maternal PLTs. STUDY DESIGN AND METHODS: A 29‐year‐old mother gave birth to a severely thrombocytopenic newborn (16 × 10⁹ PLTs/L) leading to PLT transfusion therapy associated with intravenous immunoglobulins. The outcome was uneventful. Maternal serum showed a specific positive reaction with the antigen‐capture assay (monoclonal antibody [MoAb]‐specific immobilization of PLT antigens) only when it was tested with the paternal PLTs and a panel of MoAbs against glycoprotein (GP)Ia‐IIa (α₂β₁ integrin) suggesting the implication of a new PLT antigen. RESULTS: Nucleotide sequence analysis of GPIa cDNA of the father and newborn showed a nucleotide substitution at position 2235 (2235G > T according to the international nomenclature). This substitution induces a Q716H amino acid change in the GPIa mature protein, located outside the I domain involved in cell adhesion for collagen. In vitro analysis of recombinant Chinese hamster ovary (CHO) cells expressing wild‐type or mutant (Q716H) human GPIa allowed us to demonstrate that this single amino acid substitution is responsible and sufficient for inducing Cab^a antigen expression. Adhesion of CHO cells to collagen was not modified by the Cab polymorphism, nor by the maternal anti‐Cab^a alloantibodies, indicating that the mutation does not affect the function of integrin α₂β₁. In a Caucasian population study, none of the 104 unrelated blood donors was found to be Cab^a(+). CONCLUSION: We describe here a new PLT alloantigen Cab^a involved in a severe case of FNAIT. Laboratory investigation for the “common” PLT alloantigens is no longer sufficient to evaluate neonatal alloimmune thrombocytopenia in suspected cases.     

PAR-1-dependent pp60src activation is dependent on protein kinase C and increased [Ca2+]i: evidence that pp60src does not regulate PAR-1-dependent Ca2+ entry in human platelets

Summary. Background: The role of the tyrosine kinase pp60^src in PAR‐1‐dependent Ca²⁺ entry was investigated in human platelets. pp60^src plays a role in thapsigargin (TG)‐evoked store‐operated Ca²⁺ entry (SOCE), which is thought to be a major component of thrombin‐evoked Ca²⁺ entry. Methods: pp60^src tyr⁴¹⁶ phosphorylation was used to assess pp60^src activation. Fura‐2‐loaded platelets were used to monitor intracellular Ca²⁺ concentration ([Ca²⁺]_i). Results: Activation of PAR‐1 with the specific agonist SFLLRN increased pp60^src activation within 10 s. This required phospholipase C (PLC) activity, Ca²⁺ release and a rise in intracellular Ca²⁺. PP2, an inhibitor of Src‐family tyrosine kinases, inhibited SFLLRN‐evoked Ca²⁺ entry, but also inhibited Ca²⁺ release and the extrusion of Ca²⁺ by the plasma membrane Ca²⁺ ATPase. Actin polymerization and conventional protein kinase C (cPKC) activity were required for TG‐ and SFLLRN‐evoked pp60^src activation. Although Gö6976, an inhibitor of cPKCs, inhibited TG‐evoked SOCE, it had little effect on SFLLRN‐ or thrombin‐evoked Ca²⁺ entry. Conclusions: These data indicate that stimulation of PAR‐1 leads to activation of pp60^src in human platelets, through PLC and cPKC activation, Ca²⁺ release and actin polymerization. However, as PKC and actin polymerization are not needed for SFLLRN‐evoked Ca²⁺ entry, we suggest that pp60^src is also not required. The apparent inhibition of SFLLRN‐evoked Ca²⁺ entry by PP2 is likely to be secondary to reduced Ca²⁺ release. These data argue against a contribution of this SOCE pathway to PAR‐1‐dependent Ca²⁺ entry.     

Clinically significant red blood cell antibodies in chronically transfused patients: a survey of Chinese thalassemia major patients and literature review

BACKGROUND: Red blood cell (RBC) alloimmunization is reported to occur at an incidence of 5.2% to 23.5% among patients with thalassemia requiring chronic transfusion. With very limited data on alloimmunization among the Chinese population, a territory‐wide study has been performed to look at its prevalence among Chinese thalassemia major patients. STUDY DESIGN AND METHODS: A retrospective study was conducted by reviewing RBC request records for patients with thalassemia major in Hong Kong from 2006 to 2009. Demographic information and serologic data were retrieved for analysis. RESULTS: A total of 382 patients were identified and consisted of 190 males and 192 females with a median age of 23 ± 10.4 (range, 0.25 to 52) years. Eighty‐eight patients (23.0%) were reported to have RBC antibodies. Of them, 114 alloantibodies, 18 autoantibodies, and 19 unidentified antibodies were identified. Anti‐E (42, 39.3%), anti‐Mi^a/Mur (33, 30.85%), anti‐c (14, 13.1%), and anti‐Jk^a (seven, 6.55%) were the commonest antibodies reported. However, one case of anti‐K (0.9%) and two cases of anti‐Fy^b (1.9%) were reported. Seven of the 18 patients with autoantibodies contained a total of 13 alloantibodies. They were anti‐E (five, 38.4%), anti‐Mi^a/Mur (four, 30.8%), anti‐Jk^a (two, 15.4%), anti‐c (one, 7.7%), and anti‐Fy^b (one, 7.7%). CONCLUSION: It is the first comprehensive study on Chinese thalassemia major patients. Clinically significant alloantibodies are different from those observed in the Western population, although antibodies developed against Rh antigens are still common. Chinese patients are less likely to have antibodies against Kell and Duffy blood group antigens, but are more prone to develop antibodies against the Miltenberger antigens.     

The lymphocyte Na+/H+ antiport: activation in primary hypertension and during chronic NaCl-loading

Abstract. Increased activity of the Na⁺/H⁺ antiport may be a major abnormality in essential hypertension. The activity of this transport system was investigated in lymphocytes from 13 patients with untreated essential hypertension (Ht) and 13 normotensive control subjects (Nt) on an ad libitum (130–170 mmol d^-1) NaCl intake. Furthermore, the effects of different states of NaCl balance on lymphocyte Na⁺/H⁺ antiport were evaluated in two groups of Nt volunteers receiving 20 vs. 300 mmol d^-1 (n= 8) and 85 vs. 200 mmol d^-1 (n= 14) of NaCl for 1 week each and in seven Ht patients (20 vs. 300 mmol NaCl d^-1 for 1 week each). Additionally, during the 20 and 300 mmol/d NaCl intake red blood cell membrane transport was studied in eight subjects. For the determination of lymphocyte antiport activity, cells were loaded with the cytosolic pH (pH_i) indicator bis-carboxyethyl carboxyfluorescein (BCECF-AM) and acidified by addition of different amounts of Na⁺-propionate (5–40 mM). Initial pH_i-recovery was taken as the activity of the antiport system and plotted against pH_i-values after acidification. Non-linear regression analysis yielded higher ’apparent’ maximal transport rates in Ht than Nt (Nt: 2·00 pL 0·22; Ht: (3·81 pL 0·59)·10^-3 s^-1; P < 0·025). In contrast, baseline pH_i-values and pH_i-values at half-maximal activity (pK) were identical in Nt and Ht. In normotensive control subjects on an NaCl intake of 20, 85, 200 and 300 mmol d^-1 for 7 d, ’apparent’ maximal transport rates averaged 2.75 0·20, 2·89 0·17, 2·81 ± 0·18 and (3·62 ± 0·25) · 10^-3 s^-1, respectively. Thus, antiport activity was significantly (P < 0·05) stimulated on the 300 mmol d^-1 intake as compared to the three other NaCl intakes. The extreme intakes of NaCl (20 vs. 300 mmol d^-1) in normotensive volunteers did not affect the erythrocyte Na⁺/K⁺ pump, Na⁺/K⁺ cotransport and Na⁺/Li⁺ countertransport. Our study supports the concept that a group of patients with primary hypertension exhibit an activated Na⁺/H⁺ antiport. Furthermore, our data demonstrate that a chronic high intake of NaCl is associated with an increase in lymphocyte antiport activity towards the high values observed in primary hypertension.     

Met5-enkephalin-Arg6-Phe7 (MEAP): A Cardioprotective Hormonal Opioid

Background: Acute myocardial ischemia is an important cause of morbidity and mortality worldwide. The heart and other organs can be rendered more resistant to the deleterious effects of ischemia through a variety of preconditioning strategies, including treadmill exercise and brief ischemia of skeletal muscle. Some of the beneficial effects of these preconditioning strategies appear to be mediated by as‐of‐yet unidentified hormonal opioids. Objectives: To test the hypothesis that endogenous opioids of the enkephalin class are capable of improving ischemic tolerance and acting in a hormonal manner. Methods: In phase one of the investigation, the authors assessed the cardioprotective potential of all four known enkephalins. This was achieved by subjecting isolated buffer‐perfused rabbit hearts to a 25‐minute period of test ischemia and two hours of reperfusion (protocol 1) after receiving treatment with either saline vehicle (controls) or increasing concentrations of purified enkephalins. On the basis of results from these initial studies, the authors performed additional experiments (protocol 2) to determine whether Met⁵‐enkephalin‐Arg⁶‐Phe⁷ (MEAP) could be absorbed from skeletal muscle and exert a cardioprotective effect. Specifically, MEAP or vehicle (controls) was given intramuscularly 24 hours before the hearts were harvested. A similar assessment of ischemic tolerance as described in protocol 1 was then performed. Postischemic myocardial viability (infarct size) was assessed in all cases by triphenyltetrazolium chloride (TTC) staining. Hemodynamic parameters and infarct sizes for concentration‐dependence studies were compared by two‐way analysis of variance, and infarct sizes from protocol 2 studies were compared by using Student's t‐test (significance set at p ≤ 0.05). Results: Mean infarct size in control hearts (± SEM) was 33% (± 4%) and 36% (± 6%) for protocol 1 and 2, respectively. Of the four enkephalins tested in protocol 1, only MEAP treatment showed a tendency toward cardioprotection. Interestingly, an alternative enkephalin, methionine⁵‐enkephalin‐Arg⁶‐Gly⁷‐Leu⁸, tended to exert an injurious effect. In protocol 2, MEAP treatment 24 hours before ischemia significantly reduced infarct size (14%± 4%) compared with controls, suggesting that it can be released from muscle and exert a distant cardioprotective effect. Conclusions: When given either directly to the heart or absorbed from a distant tissue, MEAP induces cardioprotection, supporting the hypothesis that it can act as a hormonal modulator of ischemic tolerance.     

Functional characterisation of a complex mutation in the α(1,4)galactosyltransferase gene in Taiwanese individuals with p phenotype

Background and objective: Individuals with p phenotype lack P1, P^k and P antigens on red blood cells, presumably as a result of deficiency in the enzyme α(1,4)galactosyltransferase (A4GALT). The aim of this study was to explore the molecular background of a Taiwanese family with p phenotype. Materials and methods: Blood samples from two p siblings and seven family members were investigated. The coding region of the A4GALT gene was analysed by polymerase chain reaction and direct sequencing. The wild‐ and mutant‐complementary DNAs (cDNAs) of A4GALT were cloned into an expression vector and transfected to Chinese hamster ovary (CHO) cells. P^k expression on the transfected cells was analysed by flow cytometry and the activities of A4GALT were measured by high‐performance liquid chromatography. Results: The two individuals with p phenotype were homozygous for the complex mutation, which was caused by a combined deletion and insertion between nt 418 and 428. No expression of P^k and no enzyme activity were observed in cells transfected with the mutant construct. Conclusion: The first case of p phenotype in Taiwan was caused by a non‐functional allele resulting from a homozygous complex mutation of A4GALT gene.     

Benefits of blood group genotyping in multi‐transfused patients from the south of Brazil

We evaluated the usefulness of blood group genotyping as a supplement to hemagglutination to determine the red blood cell (RBC) antigen profile of polytransfused patients with hematological diseases and renal failure. Seventy‐nine patients were selected. They all received more than three units of blood and eight (10%) had already clinical significant alloantibodies occurring alone or in combination against Rh, K, Fya, and Di antigens. DNA was prepared from blood samples and RHCE*E/e, KEL*01/KEL*02, FY*01/FY*02 and JK*01/JK*02 alleles were determined by using PCR‐RFLP. RHD*/RHD*Ψ and RHCE*C/c were tested using multiplex PCR. Discrepancies for Rh, Kell, Duffy, and Kidd systems were found between the phenotype and genotype‐derived phenotype in 16 of the 38 chronically transfused patients. The genotypes of these patients were confirmed by DNA array analysis (HEA Beadchip^?; Bioarray Solutions, Warren, NJ). Genotyping was very important for the determination of the true blood groups of the polytransfused patients, helped in the identification of suspected alloantibodies and in the selection of antigen‐negative RBCs for transfusion. J. Clin. Lab. Anal. 24:311–316, 2010. © 2010 Wiley‐Liss, Inc.     

RHD*DOL1 and RHD*DOL2 encode a partial D antigen and are in cis with the rare RHCE*ceBI allele in people of African descent

BACKGROUND: Several studies showed in people of African descent the existence of a genetic linkage between RHD alleles encoding a variant D antigen and a given altered RHCE*ce allele. RHCE*ceBI is a rare allele encountered in people of African descent, that encodes a Hr– hr^S– Rhce protein. Our study shows that RHCE*ceBI appears to be genetically linked to two very similar variant RHD alleles, RHD*DOL1 and RHD*DOL2, and demonstrates for the first time that DOL‐2 is a partial D antigen. STUDY DESIGN AND METHODS: After finding out an individual with both RHCE*ceBI and RHD*DOL presumed to be in cis, we hypothesized a genetic linkage between those two genes. All individuals (n = 7) known to carry RHCE*ceBI in our laboratory, including the index case, were fully investigated at the serologic and molecular level. RESULTS: One individual with alloanti‐D, being homozygous for RHCE*ceBI and RHD*DOL2, allowed us to confirm the genetic linkage between those two genes, as well as the partial D status of DOL‐2. In the six RHCE*ceBI remaining individuals, three were found with RHD*DOL2 and 3 with RHD*DOL1, likely in cis. Three of them made an alloanti‐D; one was DOL‐1 and two were DOL‐2. CONCLUSION: The rare RHCE*ceBI allele appears to be in cis either with RHD*DOL1 or with RHD*DOL2 in people of African descent. DOL‐1 and DOL‐2 must be considered as partial D antigens. We recommend a systematic search for RHD*DOL1 and RHD*DOL2 in people found to carry RHCE*ceBI and vice versa, especially in patients with sickle cell disease.     

Anti-U-like as an alloantibody in S-s-U- and S-s-U+(var) black people

BACKGROUND: S, s, and U antigens belong to the MNS system. They are carried by glycophorin B (GPB), encoded by GYPB. Black people with the low‐prevalence S?s? phenotype, either U? or U+^var, can make a clinically significant anti‐U. Anti‐U‐like, a cold immunoglobulin G autoantibody quite commonly observed in S?s+U+ black persons, was previously described to be nonreactive with ficin‐, α‐chymotrypsin‐, and pronase‐treated red blood cells (RBCs); nonreactive or weakly reactive with papain‐treated RBCs; and reactive with trypsin‐treated RBCs. Here we describe, in S?s? people from different molecular backgrounds, an alloantibody to a high‐prevalence GPB antigen, which presents the same pattern of reactivity with proteases as autoanti‐U‐like. STUDY DESIGN AND METHODS: Four S?s? patients with an alloantibody to a high‐prevalence GPB antigen were investigated by serologic and molecular methods. RESULTS: An alloantibody was observed in two S?s?U?/Del GYPB, one S?s?U+^var/GYPB(P2), and one S?s?U+^var/GYPB(NY) patients. As this alloantibody showed the same pattern of reactivity with proteases as autoanti‐U‐like, we decided to name it “anti‐U‐like.” Anti‐U‐like made by the two S?s?U? patients was reactive with the S?s?U+^var RBCs of the two other patients. CONCLUSION: S?s?U?/Del GYPB, S?s?U+^var/GYPB(P2), and S?s?U+^var/GYPB(NY) patients can make an alloanti‐U‐like. Anti‐U‐like made by S?s?U? people appears reactive with GYPB(P2) and GYPB(NY) RBCs, which both express a weak and partial U‐like reactivity. We recommend transfusing S?s?U? RBCs in S?s?U? patients showing alloanti‐U‐like. Our study contributes to a better understanding of alloimmunization to GPB in black people and confirms importance of genotyping in S?s? patients, especially those with sickle cell disease to be frequently transfused.     

Effectiveness of strategies to screen for blood donors with RH variants in a mixed population

IntroductionPatients with RH variants presenting antibodies directed to RH high frequency antigens or multiple RH antibodies might, in some occasions, be better served with RH genotype-matched units, requiring screening for RH variants among blood donors. To date, strategies to identify donors with RH variants were restricted to selecting individuals of African descent based on self-reported race, what can be inaccurate in racially mixed population. Our goal was to: 1) Screen for donors with RH variants in a mixed population using self-declared race and Rh phenotype as selection criteria; and 2) Verify if including the Duffy null genotype in the screening algorithm increases its effectiveness.MethodsBrazilian donors were included if self-declared as black and phenotyped as R0r or R1r. All individuals were genotyped for RHCE exons 1, 5, 6 and 7 and for the FY*B c.−67 T > C polymorphism in order to determine the Duffy null genotype. RHD variants were searched for in cases of altered RHCE.ResultsAmong 2500 blood donors, 217 fulfilled the inclusion criteria and were enrolled. Fifty-three (24.4 %) had a predicted clinically relevant Rh phenotype (partial antigens or lack of high frequency antigens). Twelve donors (5.5 %) had a predicted RhCE phenotype lacking either hrB or hrS. Most cases with predicted lack of high frequency antigens (66.7 %) occurred in donors with the Duffy null genotype.ConclusionSelecting donors based on self-declared race, Rh phenotype and Duffy null genotype is feasible and effective in identifying RH variants lacking Rh high frequency antigens among racially mixed donors.