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Background The Kell system, encoded by the KEL gene, is one of the most clinically important blood group systems. Molecular defects may lead to the absence of Kell antigen expression. The very rare KEL:5 results from silent KEL genes, also called KELnull alleles. In a few cases, the rare KEL:1,−2 phenotype may be associated with silent KEL*02 alleles. Study Design and Methods The aim of this study was to perform DNA investigations to identify silent KEL alleles among 10 KEL:-5 patients and 121 individuals presenting the rare KEL:1,−2 phenotype. Serologic investigations were performed on patients' red blood cells and serum. The KEL gene analysis was done by using a Bead Chip assay ( HEA Version, 1.2, Immucor), real-time polymerase chain reaction, and/or sequencing of all 19 exons of the KEL gene. Results In KEL:-5 patients, two novel KELnull alleles were described: 821 G> A being the second described KELnull allele on a KEL*01 backbone and 184 Tdel. In the 121 KEL:1,−2 individuals, nine (7.4%) were found to display a discordant KEL:1,−2 phenotype and KEL*01/KEL*02 genotype. Three novel silent KEL*02 alleles were described: 1084 C> A, 1708 G> A, and IVS11+5g>a. Conclusion The number of silent KEL alleles and the notion that KEL null alleles are on a KEL*02 background may evolve in the coming years. Systematic DNA analysis showed that the number of discordant phenotype/genotype results, related to silent KEL*02 alleles was higher than expected in France. These data emphasize that clinical practice based on DNA analysis for blood group antigens requires caution and should improve the performance of the blood group phenotype prediction. [ABSTRACT FROM AUTHOR]

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- hrS- 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. [ABSTRACT FROM AUTHOR]

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. Samples from 806 individuals with altered expression of RhCE antigens and/or producing anti-RhCE in the presence of the corresponding antigen were analyzed. 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 haplotype, the ceMO allele, the (C)ce haplotype/ ce1006 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. 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. [ABSTRACT FROM AUTHOR]

BACKGROUND: The KN blood group system, which consists of nine antigen specificities, is located on complement receptor Type 1 (CR1/CD35). CR1, a complement regulatory protein, acts as a vehicle for immune complex clearance. CR1 exhibits a red blood cell (RBC) density polymorphism. CR1 sites on RBCs in normal individuals range from 150 to 1200 molecules per cell. CR1 density polymorphism is regulated by HindIII restriction fragment length polymorphism and Q981H and P1786R polymorphisms in Caucasians. Yet, the role of the different polymorphisms in determining the CR1 density on RBCs remains unknown. The “null” serologic KN phenotype, known as Helgeson phenotype, was reported to be related with a very low CR1 density, less than 150 molecules per cell. STUDY DESIGN AND METHODS: The aim of this work was to investigate whether the KN-negative phenotype displayed by 60 individuals was related to the CR1 density by performing the phenotypic and genetic analysis of CR1 and to investigate the molecular background associated with the KN system. RESULTS: We showed that the Helgeson-like phenotype had a prevalence of 12% in this population. The overall genotype/phenotype concordance was 90%. Among individuals with a KN-negative phenotype, the prevalences of Kn(a–), McC(a–), Sl1-negative, Sl3-negative, and KCAM-negative deduced phenotype were 37, 12, 29, 7, and 24%, respectively. CONCLUSION: From our data, we suggest that the definition of the Helgeson phenotype must be revised, since the latter may be due not only to a very low CR1 density on RBCs, but also to the absence of expression of a high-prevalence KN antigen. [ABSTRACT FROM AUTHOR]

BACKGROUND: Since their description in the 1970s, anti-HrB (antibody against a high-prevalence Rh antigen) and anti-hrB (anti-e–like antibody) are still a subject of debate about representing two aspects of a global immune response or being two independent antibodies. STUDY DESIGN AND METHODS: The aim of this study was to evaluate the immune response against the antigens of Rh system of 30 individuals presenting a hrB(RH31)− phenotype. Genomic analysis of RH genes was performed in all individuals. RESULTS: Among the 30 individuals, 27 had a HrB(RH34)− phenotype. No immunization against Rh antigens was found in 16 individuals. Three individuals made anti-D only, whereas six individuals made anti-HrB (four with anti-hrB and two without anti-hrB) and two individuals made anti-hrB without anti-HrB. Among the 30 individuals, three had a HrB+ phenotype. No immunization against Rh antigens was found in one individual, whereas two individuals made anti-hrB; the genomic analysis of selected individuals showed the presence of a (C)ces haplotype, either Type 1 or Type 2, and a DIII Type 5 ces haplotype, in the homozygous state, in compound heterozygosity with each other or in heterozygosity with a DcE haplotype. Genomic data were in accordance with serologic data. CONCLUSION: Our data provide the evidence that anti-HrB and anti-hrB are independent antibodies, defining two different specificities. These antibodies may be produced by individuals expressing variants of RhCE protein. Serologic and molecular data indicate that e antigen encoded by the (C)ces haplotype is a partial antigen. In individuals carrying a (C)ces haplotype, the risk and the type of alloimmunization to Rh antigens are related to the second Rh haplotype. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the Rh blood group system, published observations showed that the c antigen has the fewest variant forms of the principal antigens in this system. The partial nature of the c antigen was only reported in c+ Rh:−26 persons and to be associated with the ces(340) allele. This study reports the first case of alloanti-c related to a (C)ces haplotype. STUDY DESIGN AND METHODS: Serologic and genetic studies were performed on blood samples of a multitransfused 40-year-old African patient with sickle cell disease displaying a DCcee phenotype. RESULTS: Red blood cells (RBCs) of the patient displayed normal expression of C, c, e, ce antigens either with routine reagents or with monoclonal antibodies. Analyses of DNA and Rh transcripts showed that the patient carried a (C)ces/DCe genotype. The patient's serum contained anti-D, anti-c, anti-E, anti-e, anti-V, anti-Jsa, and anti-S. Anti-c was isolated from the mixture of antibodies by using absorption and adsorption-elution techniques. Anti-c provided consistent reactions with c+ RBCs. Reactions were stronger with c+ ce+ RBCs than with c+ ce− RBCs. No agglutination of RBCs from individuals carrying a homozygous (C)ces genotype was observed. CONCLUSION: These data provide the evidence that anti-c in our patient was an alloanti-c and, consequently, that (C)ces haplotype encodes a partial c antigen. The clinical significance of anti-c related to this haplotype should be evaluated in the future. [ABSTRACT FROM AUTHOR]

BACKGROUND: The rare HrB– phenotype is encoded by the (C)ces haplotype when present at the homozygous state. This haplotype contains two altered genes: a hybrid RHD-CE-Ds gene segregated with a ces allele of RHCE (733C>G and 1006G>T substitutions in Exon 5 and Exon 7 respectively). The aim of this study was to further investigate the molecular background of the (C)ces haplotype. STUDY DESIGN AND METHODS: Twelve individuals with depressed C and/or depressed e phenotype were selected from their genomic DNA analysis showing both 733C>G and 1006G>T substitutions. Phenotypic expression of low- and high-prevalence Rh antigens was studied. Complete sequences of RHD and RHCE transcripts were analyzed when obtained. RESULTS: A new hybrid RHD-CE-Ds gene (Exons 1 and 2; complete Exon 3; Exons 8, 9, and 10 from RHD; and Exons 4 through 7 from RHCE) segregated with a ces allele, which genomic organization was almost identical to that of the classical (C)ces haplotype, is described. The two different (C)ces haplotypes encoded two different patterns of Rh antigen expression. Although both encoded weak e, VS, and did not produce D, V, hrB, or HrB antigens, the new haplotype encoded a much weaker C antigen and red blood cells lacked expression of Rh42, in contrast to the classic (C)ces haplotype. CONCLUSION: The study showed the heterogeneity of the molecular background of the weak C, VS+, hrB–, HrB– phenotype in the black population. The screening of blood donors in this population for hrB– or HrB– phenotype should implement the molecular characterization of Rh genes. [ABSTRACT FROM AUTHOR]

BACKGROUND: Jra is a high-prevalence red cell (RBC) antigen. The clinical significance of anti-Jra is controversial. When hemolytic disease of the fetus and newborn (HDFN) occurred, most reported cases were clinically mild. We report the first case of fatal HDFN due to anti-Jra. CASE REPORT: A 28-year-old Caucasian woman with transfusion history was monitored at the 29th week of pregnancy (G4P1). An ultrasound scan showed fetal cardiomegaly and hepatomegaly. An antibody directed against a high-prevalence antigen was detected, but without conclusive identification. An emergency cesarean section was performed at the 36th week. The newborn was hydropic and showed severe anemia. Death occurred 30 hours after birth. MATERIALS AND METHODS: Serologic methods were performed to investigate the mother's RBCs and serum. An in vitro functional cellular assay and semiquantitative measurement of anti-Jra were used to determine the clinical significance of the antibody. RESULTS: Anti-Jra was identified in the serum and Jr(a−) phenotype was confirmed. The anti-Jra titer was 1024, with predominant immunoglobulin (Ig)G1 and minor IgG4 subclasses. The functional cellular assay was consistent with an antibody unlikely to cause HDFN. Semiquantitative measurement of anti-Jra showed a reactivity equivalent to a 25 IU per mL (5 µg/mL) concentration of anti-D, a value associated with a significant risk of HDFN. CONCLUSION: This is the first documented case of fatal HDFN due to anti-Jra. Therefore, we recommend close monitoring of pregnant women with a high-titer anti-Jra, especially those with an incompatible transfusion history and/or multiple pregnancies. This case report provides new arguments about the clinical significance of anti-Jra in the transfusion setting. [ABSTRACT FROM AUTHOR]

BACKGROUND: It has long been known that relative immunogenicity is a characteristic of protein red blood cell (RBC) antigens, but the mechanisms remain unclear. The aim of this work was to elucidate the mechanisms underlying this relative immunogenicity. STUDY DESIGN AND METHODS: Two RBC antigens were used as a model—the highly immunogenic K antigen (KEL1) and the less immunogenic Fya antigen (FY1)—and analyzed the distribution of DRB1* molecules in two groups of Caucasian individuals producing anti-Fya (n = 29) or anti-K (n = 30) alloantibodies. These experimental results were compared to the results generated by TEPITOPE, a DRB1* peptide–binding motif prediction algorithm. RESULTS: It was found that within the anti-Fya group, the DRB1*04 phenotypic frequency was 100 percent, indicating that the DRB1*04 molecule is the restriction molecule. In the anti-K group, numerous DRB1* molecules were identified, demonstrating a high degree of histocompatibility promiscuity, corresponding to the predominant molecules in the Caucasian population. These findings were confirmed by TEPITOPE. CONCLUSION: These results strongly suggest that protein RBC intrinsic immunogenicity depends on the distribution of DRB1* restriction molecules. [ABSTRACT FROM AUTHOR]

Aims Effects of cardiac resynchronization therapy (CRT) in patients with right ventricular pacing and congestive heart failure (CHF) have only been reported in limited series. CRT in patients with atrial fibrillation remains controversial. Patients with AV junctional ablation offer a unique opportunity to study the effects of CRT in patients with right ventricular pacing combined with atrial fibrillation. Methods and results We studied 16 consecutive patients with permanent atrial fibrillation treated by AV junctional ablation. After a mean follow-up of 20±19 months (6 weeks to 5 years) they were successfully upgraded to biventricular pacing for severe CHF. Parameters were prospectively evaluated at baseline and at 6 months. Conclusion CRT improves left ventricular performance and functional status in patients with permanent atrial fibrillation and prior remote right ventricular pacing. [ABSTRACT FROM PUBLISHER]

BACKGROUND: Jra is a high-prevalence red cell (RBC) antigen. The clinical significance of anti-Jra is controversial. When hemolytic disease of the fetus and newborn (HDFN) occurred, most reported cases were clinically mild. We report the first case of fatal HDFN due to anti-Jra. CASE REPORT: A 28-year-old Caucasian woman with transfusion history was monitored at the 29th week of pregnancy (G4P1). An ultrasound scan showed fetal cardiomegaly and hepatomegaly. An antibody directed against a high-prevalence antigen was detected, but without conclusive identification. An emergency cesarean section was performed at the 36th week. The newborn was hydropic and showed severe anemia. Death occurred 30 hours after birth. MATERIALS AND METHODS: Serologic methods were performed to investigate the mother's RBCs and serum. An in vitro functional cellular assay and semiquantitative measurement of anti-Jra were used to determine the clinical significance of the antibody. RESULTS: Anti-Jra was identified in the serum and Jr(a−) phenotype was confirmed. The anti-Jra titer was 1024, with predominant immunoglobulin (Ig)G1 and minor IgG4 subclasses. The functional cellular assay was consistent with an antibody unlikely to cause HDFN. Semiquantitative measurement of anti-Jra showed a reactivity equivalent to a 25 IU per mL (5 µg/mL) concentration of anti-D, a value associated with a significant risk of HDFN. CONCLUSION: This is the first documented case of fatal HDFN due to anti-Jra. Therefore, we recommend close monitoring of pregnant women with a high-titer anti-Jra, especially those with an incompatible transfusion history and/or multiple pregnancies. This case report provides new arguments about the clinical significance of anti-Jra in the transfusion setting. [ABSTRACT FROM AUTHOR]

Background: RH molecular analysis has enabled the documentation of numerous variants of RHD and RHCE alleles, especially in individuals of African origin. The aim of the present study was to determine the type and frequency of D and/or RhCE variants among blood donors of African origin in France, by performing a systematic RH molecular analysis, in order to evaluate the implications for blood transfusion of patients of African origin., Materials and Methods: Samples from 316 African blood donors, whose origin was established by their Fy(a-b-) phenotype, were first analysed using the RHD and RHCE BeadChips Kit (BioArray Solutions, Immucor, Warren, NJ, USA). Sequencing was performed when necessary., Results: RHD molecular analysis showed that 26.2% of donors had a variant RHD allele. It allowed the prediction of a partial D in 11% of cases. RHCE molecular analysis showed that 14.2% of donors had a variant RHCE allele or RH [RN or (C)ces] haplotype. A rare Rh phenotype associated with the loss of a high-prevalence antigen or partial RhCE antigens were predicted from RHCE molecular analysis in 1 (0.3%) and 17 (5%) cases, respectively., Discussion: Systematic RHD and RHCE molecular analysis performed in blood donors of African origin provides transfusion-relevant information for individuals of African origin because of the frequency of variant RH alleles. RH molecular analysis may improve transfusion therapy of patients by allowing better donor and recipient matching, based not only on phenotypically matched red blood cell units, but also on units that are genetically matched with regards to RhCE variants.

Whether or not patients whose red blood cells (RBCs) carry certain weak D types produce anti-D, and if they do whether it is allo- or auto anti-D, remains controversial. The aim of this study was to determine the serologic features of anti-D in individuals expressing a weak D other than type 1 or type 2 and to assess whether the anti-D was an allo- or autoantibody. Serologic D typing and molecular analyses were performed on 748 individuals.Serologic characterization of anti-D included autologous controls,direct antiglobulin test, elution, and titration of anti-D before and after adsorption of serum onto autologous RBCs. From molecular analyses, 459 individuals exhibited a weak D type. We described seven novel RHD variant alleles. The most frequent types of weak D were type 1 (30.1%), type 2 (23.7%), type 4.0 (10.2%), type 4.2.2(20.3%), type 11 (3.9%), and type 15 (3.7%). Anti-D was identified in the sera of 9 of 47 individuals with weak D type 4.0, in 14 of 93 with weak D type 4.2.2, in 1 of 18 with weak D type 11, in 1 of 17 with weak D type 15, and in 1 weak D type 33 individual.Anti-D was demonstrated to be an alloantibody in weak D type 4.0, type 4.2.2, and type 15 individuals, but an autoantibody in weak D type 11 and type 33 individuals. In conclusion, only a complete serologic investigation of individuals with a given weak D type identified by molecular analysis allows concluding on the nature of the antibody. Transfusing weak D type 4.2.2 and type 15 patients with D- RBC units and proposing anti-D immunoprophylaxis to women with these weak D types should be considered.

Aims: Effects of cardiac resynchronization therapy (CRT) in patients with right ventricular pacing and congestive heart failure (CHF) have only been reported in limited series. CRT in patients with atrial fibrillation remains controversial. Patients with AV junctional ablation offer a unique opportunity to study the effects of CRT in patients with right ventricular pacing combined with atrial fibrillation. The aims of the present study were to evaluate the effects of upgrading to biventricular pacing patients with CHF, permanent atrial fibrillation, and prior ablation of the atrioventricular (AV) junction followed by conventional right ventricular pacing., Methods and Results: We studied 16 consecutive patients with permanent atrial fibrillation treated by AV junctional ablation. After a mean follow-up of 20+/-19 months (6 weeks to 5 years) they were successfully upgraded to biventricular pacing for severe CHF. Parameters were prospectively evaluated at baseline and at 6 months. The 14 surviving patients at 6 months demonstrated significant improvement (P<0.02) in New York Heart Association class but the exercise test parameters remained unchanged. Cardiothoracic ratio decreased by 5% (P=0.04), end-systolic diameter by 8% (P=0.001), end-diastolic diameter by 4% (P=0.08), systolic pulmonary artery pressure by 17% (P<0.0001) and mitral regurgitation area by 40% (P<0.05). Ejection fraction increased by 17% (P=0.11) and fractional shortening by 24% (P=0.01)., Conclusion: CRT improves left ventricular performance and functional status in patients with permanent atrial fibrillation and prior remote right ventricular pacing.