Weak D types 38 and 11: determination of frequencies in a Brazilian population and validation of an easy molecular assay for detection

Dezan, Marcia Regina; Oliveira, Vítor Hugo de; Conrado, Marina C. A. V.; Luz, Fabio; Gallucci, A.; Oliveira, Théo Gremen Mimary de; Sabino, Éster Cerdeira; Rocha, Vanderson; Mendrone, Alfredo; Dinardo, Carla Luana

doi:10.21307/immunohematology-2020-040

Cited by 2 publications

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“…While RHCE*CeRN and RHD*D‐CE(4–7)‐D underlie cases of weak C and e among people of African descent, and RHCE*JAL and RHCE*ceMO justify weak c and e in this same population, other RHCE alleles encode weak antigens among Caucasians ( RHCE*CeVA , RHCE*CeMA , and RHCE*cE I to IV ) 5–7 . Even though there are descriptions of the distribution of variant RHD among people of multiethnic ancestry, 8–10 data referring to the variant RHCE encoding weak antigens in mixed populations, such as Brazilians, are yet incomplete and may be important information, considering some genotypes can be associated with the risk of alloimmunization.…”

Section: Introductionmentioning

confidence: 99%

Variant genotypes associated with reduced expression of RhCE antigens among Brazilian blood donors

et al. 2021

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Background The genetic diversity of the RHCE gene locus has been explored in diverse populations of different racial backgrounds. Data referring to the diversity of RHCE encoding weakened expression of C, c, E, and e in multiethnic populations is still incomplete. Methods Samples from Brazilian blood donors presenting reduced expression of C, c, E, or e on gel method were selected for the study. All exons and flanking introns of RHCE were genotyped though direct Sanger sequencing for the included donors. Results Sixty‐six donors were included: 23 with weak C, 22 with weak c, 6 with weak E, 14 with weak e, and 1 with weak c and E. Among the samples with weak C, the following altered RH*C were encountered: RHCE*CeMA (n = 3), RHCE*Ce941C (n = 1), and RHCE*CeVA (n = 1). RHD*D‐CE(4–7)‐D was detected in six cases, RHCE*CE was presumably present in five cases, and seven cases were unexplained. Two altered alleles underlay the weak c phenotype: RHCE*ceJAL (n = 20) and RHCE*ce340T (n = 2), and two altered RHCE justified weak e: RHCE*ceMO (n = 6) and RHCE*ceJAL (n = 8). Three variant RHCE were associated with weak E: RHCE*cEJU (n = 4), RHCE*cE382C (n = 1), and RHCE*cEIV (n = 1). The RHCE*cE905A justified one case of weak c and E. Conclusion We describe the distribution of RHCE variants found in association with weak expression of C, c, E, and e in blood donors of multiethnic origin, which differs in comparison to that previously reported for people of African or Caucasian descent.

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Section: Introductionmentioning

confidence: 99%

Variant genotypes associated with reduced expression of RhCE antigens among Brazilian blood donors

et al. 2021

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Standardization of a multiplex assay to identify weak D types in a mixed-race Brazilian population

Silva,

Dezan,

Cruz

et al. 2023

Immunohematology

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RH allele variability is caused by several types of variants, resulting in altered RhD and RhCE phenotypes. Most of the weak D phenotypes in European-derived populations are weak D types 1, 2, or 3, which are not involved in alloimmunization episodes. However, the Brazilian population is racially diverse, and the accuracy of molecular and serologic tests developed in recent years has allowed for the identification of other RH variants, that are common in the Brazilian population, such as weak D type 38 or weak partial 11, the latter involved in alloimmunization cases. Furthermore, patients with these two weak D variants must be transfused with D– red blood cell units, as do patients with weak D type 4 or DAR, which are also common D variants in Brazil. Weak D type 38 and weak partial 11 can be serologically misclassified as weak D types 1, 2, or 3 in patients, based on European experience, or as D– in donors. Additionally, pregnant women may unnecessarily be identified as requiring Rh immune globulin. RhCE phenotypes are reliable indicators of RhD variants. For individuals with the Dce phenotype, the preferred approach is to specifically search for RHD*DAR. However, when encountering DCe or DcE phenotypes, we currently lack a developed method that assists us in rapidly identifying and determining the appropriate course of action for the patient or pregnant woman. Two multiplex assays were proposed: one for the identification of RHD*weak partial 11, RHD*weak D type 38, and RHD*weak D type 3 and another for RHD*weak D type 2 and RHD*weak D type 5. The multiplex assays were considered valid if the obtained results were equivalent to those obtained from sequencing. Expected results were obtained for all tested samples. The proposed multiplex allele-specific polymerase chain reaction assays can be used in the molecular investigation of women of childbearing age, patients, and blood donors presenting a weak D phenotype with DCe or DcE haplotypes in a mixed-race population, such as Brazil.

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Weak D types 38 and 11: determination of frequencies in a Brazilian population and validation of an easy molecular assay for detection

Cited by 2 publications

References 30 publications

Variant genotypes associated with reduced expression of RhCE antigens among Brazilian blood donors

Variant genotypes associated with reduced expression of RhCE antigens among Brazilian blood donors

Standardization of a multiplex assay to identify weak D types in a mixed-race Brazilian population

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