Molecular background of VS and weak C expression in blacks

Faas, B. H. W.; Beckers, Erik A.M.; Wildoer, P.; Ligthart, Peter; Overbeeke, M. A. M.; Zondervan, Hans A.; Borne, A. E. G. K. Von Dem; Schoot, C. Ellen van der

doi:10.1046/j.1537-2995.1997.37197176949.x

Cited by 158 publications

(181 citation statements)

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“…28 Amino acid substitutions that cause loss of epitopes in partial RH variants may be also associated with expression of new antigens referred to as "low-incidence" antigens because of their prevalence in the white reference population (Table 1). In blacks, some are highly prevalent, such as the RH20 (VS) antigen, encoded by the RHCE*ce S allele, 29 which is expressed in approximately 26% to 40% of persons of African origin. VS-negative SCD patients receiving blood from donors of same ethnic background can be potentially immunized to VS, but antibodies against VS are not routinely detected by screening tests because most test RBC reagents do not express VS.…”

Section: Rbc Alloimmunization Pathobiologymentioning

confidence: 99%

Red blood cell alloimmunization in sickle cell disease: pathophysiology, risk factors, and transfusion management

Yazdanbakhsh

Ware

Noizat‐Pirenne

2012

Blood

332

350

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Red blood cell transfusions have reduced morbidity and mortality for patients with sickle cell disease. Transfusions can lead to erythrocyte alloimmunization, however, with serious complications for the patient including life-threatening delayed hemolytic transfusion reactions and difficulty in finding compatible units, which can cause transfusion delays. In this review, we discuss the risk factors associated with alloimmunization with emphasis on possible mechanisms that can trigger delayed hemolytic transfusion reactions in sickle cell disease, and we describe the challenges in transfusion management of these patients, including opportunities and emerging approaches for minimizing this life-threatening complication. (Blood. 2012;120(3):528-537) IntroductionBlood transfusion remains a cornerstone of treatment of patients with sickle cell disease (SCD). Despite improved patient outcomes with hydroxyurea administration, indications for chronic transfusions have increased in the last 10 years and are associated with considerable reduction in morbidity and mortality, most notably in preventing first stroke in children. [1][2][3] However, transfusions can lead to erythrocyte alloimmunization with serious complications for the patient. These antibodies are often directed against antigens expressed on RBCs of white persons, which represent the majority of donors in Western countries. 4 Finding compatible units lacking those antigens can sometimes be difficult, and identifying and characterizing the antibodies can be timeconsuming and laborious, causing transfusion delays. Genetic as well as acquired patient-related factors are likely to influence the process of alloimmunization.The most serious consequence of alloimmunization in SCD patients is the risk of developing a delayed hemolytic transfusion reaction (DHTR), which can be life-threatening. In many cases of DHTR in SCD, the patient's hemoglobin level falls below the pretransfusion level, suggesting that, in addition to hemolysis of the transfused RBCs, the patient's own RBCs are lysed, a condition known as hyperhemolysis. Additional transfusions may exacerbate the hemolysis and further worsen the degree of anemia. The destruction of the patient's own RBCs in DHTR of SCD is partly explained by the presence of autoantibodies 5 because alloimmunization is known to trigger autoantibody production. However, DHTR/hyperhemolysis cases have also been reported in the absence of detectable alloantibodies or autoantibodies.In this review, we discuss the known risk factors associated with alloimmunization, then emphasize possible mechanisms that can trigger autoimmunization and DHTR in SCD, and finally describe the challenges in transfusion management of these patients. We emphasize opportunities and emerging approaches for minimizing this life-threatening complication. RBC alloimmunization pathobiologyAlloimmunization to erythrocytes involves multiple steps, including RBC antigen recognition, processing, and presentation of antigen by HLA class II to TCR, activation of CD4 ...

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Section: Rbc Alloimmunization Pathobiologymentioning

confidence: 99%

Red blood cell alloimmunization in sickle cell disease: pathophysiology, risk factors, and transfusion management

Yazdanbakhsh

Ware

Noizat‐Pirenne

2012

Blood

332

350

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“…Sequences from chimpanzee (Pan troglodytes Rh-like protein IIR, nucleic acid accession number L37050 23 ) were used for external rooting. The RHD alleles shown in the phylogeny tree were published previously 13,14,[16][17][18][24][25][26][27][28][29][30][31] or described in this study for DAU-0 to DAU-4 and DIII type 5.…”

Section: Phylogeny Of Rhd Allelesmentioning

confidence: 99%

“…11 Molecular analysis revealed that there are often multiple missense mutations, rather than single ones. 12 The molecular characterization of RHD alleles was hampered in Africans by the frequent occurrence of RHD, 13 Ccde s , 14 or the concomitant presence of 2 different partial D alleles. RHD and Ccde s do not express a D antigen, yet they harbor a grossly intact RHD allele or an RHD-CE-D hybrid allele, respectively, that often interferes with RHD polymerase chain reaction (PCR) and RHD-specific sequencing.…”

Section: Introductionmentioning

confidence: 99%

The DAU allele cluster of the RHDgene

Wagner

Ladewig

Angert

et al. 2002

Blood

135

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“…15 Besides RH:Ϫ18 and RH:Ϫ34 phenotypes, numerous Rhe variants are encountered in the black population. [16][17][18][19][20][21] Some variants are associated with the production of anti-e in a way similar to the production of anti-D by partial D individuals, the abnormality being restricted to the partial e situation. 12 Indeed, transfusion safety is also a problem for Dccee individuals producing alloanti-e, as the Rhe-negative RBCs that would be required are RhEpositive (e and E antigens have an antithetical relationship) and cannot be transfused to those RhE-negative individuals.…”

Section: Introductionmentioning

confidence: 99%