MARCIA REGINA DEZAN
Projetos de Pesquisa
Unidades Organizacionais
LIM/31 - Laboratório de Genética e Hematologia Molecular, Hospital das Clínicas, Faculdade de Medicina
11 resultados
Resultados de Busca
Agora exibindo 1 - 10 de 11
- Prevalence and laboratorial determinants of the clinical relevance of antibodies of undetermined specificity(2019) CONRADO, Marina Cavalcanti de Albuquerque da Veiga; CARDOSO, Regina A.; DEZAN, Marcia Regina; OLIVEIRA, Valeria Brito; NETO, Abel da Costa; ZIZA, Karen Chinoca; KRIEGER, Jose Eduardo; PEREIRA, Alexandre Costa; SABINO, Ester Cerdeira; ROCHA, Vanderson; MENDRONE-JUNIOR, Alfredo; DINARDO, Carla LuanaBackground and Objectives Antibodies of unknown specificity (AUS) are frequently identified in the pre-transfusion testing. These antibodies can be insignificant or potentially cause post-transfusion haemolysis. Information about the prevalence of clinically relevant AUS is still lacking. Our aim was to predict the potential clinical relevance of AUS using the monocyte monolayer assay (MMA) and to identify the clinical and laboratorial determinants of AUS' significance. Materials and Methods Antibodies of unknown specificity identified at a single institution from 2015-2017 were evaluated through MMA. A monocyte index (MI) of more than 5% was predictive of potential post-transfusion haemolysis. Results Thirty-two patients with AUS were included in the study. Of the studied AUS, 37 center dot 5% (12/32) presented with a monocyte index (MI) more than 5%. In the group of significant AUS, 41 center dot 7% of the patients presented with sickle cell disease (SCD) and the AUS were associated with Rh antibodies in 75% of the cases. In the group of insignificant AUS, only 10% of the patients had SCD and the association with Rh antibodies was detected in 20% of the cases. The presence of Rh antibodies was independently associated with the AUS clinical relevance (P = 0 center dot 012). Conclusion More than one-third of the AUS are potentially clinically relevant, and the association with Rh antibodies is predictive of AUS relevance. Services must honour AUS in the pre-transfusion process in order to ensure transfusion safety.
- Variant genotypes associated with reduced expression of RhCE antigens among Brazilian blood donors(2021) DEZAN, Marcia Regina; OLIVEIRA, Valeria B.; CONRADO, Marina C. A. V.; ROCHA, Mateus Cardoso da; LUZ, Fabio; GALLUCCI, Antonio; PEREIRA, Alexandre C.; KRIEGER, Jose E.; ROCHA, Vanderson; MENDRONE-JUNIOR, Alfredo; DINARDO, Carla LuanaBackground 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.
- Fc gamma R2B B2.4 haplotype predicts increased risk of red blood cell alloimmunization in sickle cell disease patients(2020) COSTA NETO, Abel; SANTOS, Flavia; RIBEIRO, Ingrid; OLIVEIRA, Valeria; DEZAN, Marcia; KASHIMA, Simone; COVAS, Dimas; PEREIRA, Alexandre; FONSECA, Guilherme; MOREIRA, Frederico; KRIEGER, Jose; GUALANDRO, Sandra; ROCHA, Vanderson; MENDRONE JR., Alfredo; DINARDO, Carla L.BACKGROUND Red blood cell (RBC) alloimmunization is an important transfusion complication which is prevalent among sickle cell disease (SCD) patients. Autoimmune diseases are a known risk factor for RBC alloimmunization, suggesting that autoimmunity and post-transfusion alloantibody development occur through similar physiopathological pathways. Polymorphisms in the Fc gamma R2B gene have already been associated with several autoimmune disorders and hypothetically could be associated with RBC alloimmunization. Our goal was to evaluate if important polymorphisms of Fc gamma R2B have an impact on the risk of RBC alloimmunization among SCD patients. STUDY DESIGN AND METHODS This was a case-control study in which alloimmunized and non-alloimmunized SCD patients were compared in terms of the genotype frequency of the Fc gamma R2B polymorphisms -386G/C, -120 T/A, and 695C/T, genotyped through direct Sanger sequencing. RESULTS A total of 237 patients met the eligibility criteria, 120 cases (alloimmunized) and 117 controls (non-alloimmunized). RBC alloimmunization was associated with female sex (p < 0.001), lifetime number of RBC units transfused (p = 0.002) and 120 T/A Fc gamma R2B genotype (p = 0.031). The Fc gamma R2B promoter region haplotype 2B.4 (386C120A) was positively associated with RBC alloimunization (p = 0.045). The logistic regression (LR) model identified female sex (OR 10.03, CI 95% 5.16-19.49; p < 0.001) and Fc gamma R2B 2B.4 haplotype (OR 4.55, CI95% 1.1118.65; p = 0.035) as independent predictors of RBC alloimmunization in SCD patients. CONCLUSION SCD patients with the Fc gamma R2B 2B.4 haplotype had over a fourfold higher risk for RBC alloimmunization. This highlights the role played by Fc gamma R2B on RBC alloimmunization and may be helpful in identifying the immune responders.
- Evaluation of the applicability and effectiveness of a molecular strategy for identifying weakD and DEL phenotype among D- blood donors of mixed origin exhibiting high frequency of RHD*(2018) DEZAN, Marcia Regina; GUARDALINI, Luis Giovani O.; PESSOA, Elaine; RIBEIRO, Ingrid Helena; OLIVEIRA, Valeria Brito; LUZ, Fabio; NOVAC, Denise Rossite; GALLUCCI, Antonio; BONIFACIO, Silvia; GOMES, Francisco; LEVI, Jose E.; PEREIRA, Alexandre C.; KRIEGER, Jose E.; MENDRONE-JUNIOR, Alfredo; ROCHA, Vanderson; DINARDO, Carla LuanaBACKGROUNDMolecular tests designed to detect the presence of active RHD gene among D- donors have been successfully applied in people of European ancestry, but not in admixed populations with a considerable frequency of RHD*. Our goal was to evaluate the performance of a molecular screening tool for identifying active RHD alleles among Brazilian blood donors classified as D- C+ and/or E+. STUDY DESIGN AND METHODSPools of five DNA samples of serologically D- C+ and/or E+ donors were checked by a RHD polymerase chain reaction (PCR) assay specific for RHD Intron 4 and Exon 7. When a pool result was positive, samples were genotyped individually for RHD Intron 4 and Exon 7, RHD*, RHCE*Cc, and RHD zygosity. Donors suspected of active RHD gene were further evaluated by whole-coding region and flanking intron direct sequencing. RESULTSA total of 405 donors were included. Two percent exhibited active RHD gene, codifying D-weak (38 and 45) or DEL phenotype. The most prevalent DEL allele was RHD*DEL1 (c.1227G>A), which is proven to be immunogenic. A high frequency of RHD* was detected in the donors with nondeleted RHD alleles (31%), far superior to the frequency of RHD variant alleles (15.5%). The proposed approach presented sensitivity of 100% and specificity of 85.7% for identifying active RHD gene. CONCLUSIONThe strategy of checking D- donors with RHD PCR followed by exclusion of RHD* allele has proved efficient in identifying weak-D and DEL phenotype in the Brazilian population.
- RHD and RHCE genotyping by next-generation sequencing is an effective strategy to identify molecular variants within sickle cell disease patients(2017) DEZAN, Marcia R.; RIBEIRO, Ingrid Helena; OLIVEIRA, Valeria B.; VIEIRA, Juliana B.; GOMES, Francisco C.; FRANCO, Lucas A. M.; VARUZZA, Leonardo; RIBEIRO, Roberto; CHINOCA, Karen Ziza; LEVI, Jose Eduardo; KRIEGER, Jose Eduardo; PEREIRA, Alexandre Costa; GUALANDRO, Sandra F. M.; ROCHA, Vanderson G.; MENDRONE-JUNIOR, Alfredo; SABINO, Ester Cerdeira; DINARDO, Carla LuanaBackground: The complexity of Rh genetic variation among sickle cell disease (SCD) patients is high. Conventional molecular assays cannot identify all genetic variants already described for the RH locus as well as foresee novel alleles. Sequencing RHD and RHCE is indicated to broaden the search for Rh genetic variants. Aims: To standardize the Next Generation Sequencing (NGS) strategy to assertively identify Rh genetic variants among SCD patients with serologic suspicion of Rh variants and evaluate if it can improve the transfusion support. Methods: Thirty-five SCD patients with unexplained Rh antibodies were enrolled. A NGS-based strategy was developed to genotype RHD and RHCE using gene-specific primers. Genotype and serological data were compared. Results: Data obtained from the NGS-based assay were gene-specific. Ten and 25 variant RHD and RHCE alleles were identified, respectively. Among all cases of unexplained Rh antibodies, 62% had been inaccurately classified by serological analysis and, of these, 73.1% were considered as relevant, as were associated with increased risk of hemolytic reactions and shortage of units suitable for transfusion. Conclusion: The NGS assay designed to genotype RH coding regions was effective and accurate in identifying variants. The proposed strategy clarified the Rh phenotype of most patients, improving transfusion support.
- High frequency of variant RHD genotypes among donors and patients of mixed origin with serologic weak-D phenotype(2018) DEZAN, Marcia Regina; OLIVEIRA, Valeria B.; GOMES, Carolina Nunes; LUZ, Fabio; GALLUCCI, Antonio J.; BONIFACIO, Silvia L.; ALENCAR, Cecilia Salete; SABINO, Ester C.; PEREIRA, Alexandre C.; KRIEGER, Jose E.; ROCHA, Vanderson; MENDRONE-JUNIOR, Alfredo; DINARDO, Carla L.Background Goal The current transfusion policy recommended for individuals with serologic weak-D phenotype is based on data derived from European-descent populations. Data referring to the distribution of RH alleles underlying weak-D phenotype among people of mixed origin are yet incomplete, and the applicability of European-based transfusion guidelines to this specific population is questionable. To evaluate the distribution of RHD variant genotype among individuals with serologic weak-D phenotype of both African and European descent. Methods Results Donors and patients of mixed origin and with serologic weak-D phenotype were selected for the study. They were investigated using conventional RHD-PCR assays and RHD whole-coding region direct sequencing. One hundred and six donors and 58 patients were included. There were 47 donors and 29 patients with partial-D genotype (47/106, 44.3%, and 29/58, 50%, respectively). RHD*DAR and RHD*weak D type 38 represented the most common altered RHD alleles among donors (joint frequency of 39.6%), while weak D types 1-3 accounted for 10.4% of the total D variant samples. RHD*DAR was the most common allele identified in the patient group (frequency of 31%), and weak D types 1-3 represented 29.3% of the total. Conclusion The frequency of partial D among mixed individuals with serologic weak-D phenotype is high. They should be managed as D-negative patients until molecular tests are complete.
- Effectiveness of strategies to screen for blood donors with RH variants in a mixed population(2020) ALMEIDA, Fabio Augusto Abreu de; DEZAN, Marcia Regina; OLIVEIRA, Valeria Brito; ALENCAR, Cecilia Salete; LUZ, Fabio; KRIEGER, Jose Eduardo; PEREIRA, Alexandre Costa; SABINO, Ester Cerdeira; ROCHA, Vanderson; MENDRONE-JUNIOR, Alfredo; DINARDO, Carla LuanaIntroduction: Patients 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. Methods: Brazilian 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. Results: Among 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. Conclusion: Selecting 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.
- Diversity of variant alleles encoding Kidd, Duffy, and Kell antigens in individuals with sickle cell disease using whole genome sequencing data from the NHLBI TOPMed Program(2021) DINARDO, Carla L.; OLIVEIRA, Theo G. M.; KELLY, Shannon; ASHLEY-KOCH, Allison; TELEN, Marilyn; SCHMIDT, Luciana C.; CASTILHO, Shirley; MELO, Karla; DEZAN, Marcia R.; WHEELER, Marsha M.; JOHNSEN, Jill M.; NICKERSON, Deborah A.; JAIN, Deepti; CUSTER, Brian; PEREIRA, Alexandre C.; SABINO, Ester C.Background Genetic variants in the SLC14A1, ACKR1, and KEL genes, which encode Kidd, Duffy, and Kell red blood cell antigens, respectively, may result in weakened expression of antigens or a null phenotype. These variants are of particular interest to individuals with sickle cell disease (SCD), who frequently undergo chronic transfusion therapy with antigen-matched units. The goal was to describe the diversity and the frequency of variants in SLC14A1, ACKR1, and KEL genes among individuals with SCD using whole genome sequencing (WGS) data. Study Design and Methods Two large SCD cohorts were studied: the Recipient Epidemiology and Donor Evaluation Study III (REDS-III) (n = 2634) and the Outcome Modifying Gene in SCD (OMG) (n = 640). Most of the studied individuals were of mixed origin. WGS was performed as part of the National Heart, Lung, and Blood Institute's Trans-Omics for Precision Medicine (TOPMed) program. Results In SLC14A1, variants included four encoding a weak Jk(a) phenotype and five null alleles (JK(null)). JKA*01N.09 was the most common JK(null). One possible JK(null) mutation was novel: c.812G>T. In ACKR1, identified variants included two that predicted Fy(x) (FY*X) and one corresponding to the c.-67T>C GATA mutation. The c.-67T>C mutation was associated with FY*A (FY*01N.01) in four participants. FY*X was identified in 49 individuals. In KEL, identified variants included three null alleles (KEL*02N.17, KEL*02N.26, and KEL*02N.04) and one allele predicting K-mod phenotype, all in heterozygosity. Conclusions We described the diversity and distribution of SLC14A1, ACKR1, and KEL variants in two large SCD cohorts, comprising mostly individuals of mixed ancestry. This information may be useful for planning the transfusion support of patients with SCD.
- -318C/T polymorphism of the CTLA-4 gene is an independent risk factor for RBC alloimmunization among sickle cell disease patients(2017) OLIVEIRA, V. B.; DEZAN, M. R.; GOMES, F. C. A.; GUALANDRO, S. F. Menosi; KRIEGER, J. E.; PEREIRA, A. C.; MARSIGLIA, J. D.; LEVI, J. E.; ROCHA, V.; MENDRONE-JUNIOR, A.; SABINO, E. C.; DINARDO, C. L.Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) molecule is expressed on T-lymphocyte membrane and negatively influences the antigen-presenting process. Reduced expression of CTLA-4 due to gene polymorphisms is associated with increased risk of autoimmune disorders, whose physiopathology is similar to that of post-transfusion red blood cell (RBC) alloimmunization. Our goal was to evaluate if polymorphisms of CTLA-4 gene that affect protein expression are associated with RBC alloimmunization. This was a case-control study in which 134 sickle cell disease (SCD) patients and 253 non-SCD patients were included. All patients were genotyped for the polymorphisms 49A/G and -318C/T of CTLA-4 gene. The genotype frequency of -318C/T differed significantly between alloimmunized and nonalloimmunized SCD patients, irrespective of clinical confounders (p=.016). SCD patients heterozygous for -318T allele presented higher risk of alloantibody development (OR: 5.4, CI: 1.15-25.6). In conclusion, the polymorphism -318C/T of CTLA-4 gene is associated with RBC alloimmunization among SCD patients. This highlights the role played by CTLA-4 on post-transfusion alloantibody development.
- SMIM1 intron 2 gene variations leading to variability in Vel antigen expression among Brazilian blood donors(2019) DEZAN, Marcia Regina; COSTA-NETO, Abel; GOMES, Carolina Nunes; RIBEIRO, Ingrid Helena; OLIVEIRA, Valeria Brito; V, Marina C. A. Conrado; OLIVEIRA, Theo Gremen M.; CARVALHO, Mariana L. P.; ARANHA, Aline Fernanda; BOSI, Silvia R. A.; SALLES, Nanci A.; KRIEGER, Jose Eduardo; PEREIRA, Alexandre Costa; SABINO, Ester Cerdeira; ROCHA, Vanderson; MENDRONE-JUNIOR, Alfredo; DINARDO, Carla Luana; LEVI, Jose EduardoBackground: There is a significant inter-individual heterogeneity of Vel antigen expression which can lead to inaccuracies on Vel phenotyping of blood donors and, potentially, to hemolytic post-transfusion reactions. Our aim was to evaluate the impact of genetic variants in the SMIM1 intron 2 on the expression of Vel antigen among Brazilian blood donors harboring the c.64_80del17 deletion in heterozygosity. Methods: Donors presenting the SMIM1 c.64_80del17 in heterozygosity were included in the study and subjected to SMIM1 intron 2 direct sequencing aiming to genotype the following polymorphisms: rs143702418, rs1181893, rs191041962, rs6673829, rs1175550 and rs9424296. Results: SMIM1 intron 2 sequencing was performed on two hundred donors presenting one c.64_80del17 allele. The rs1175550 polymorphism significantly impacted on Vel antigen expression. Variations in the strength of agglutination on Vel phenotyping were also observed according to the rs6673829 genotype, but this difference did not persist with statistical relevance after multivariate analysis. Conclusion: The presence of the rs1175550A allele of SMIM1 is significantly and independently associated with a decrease in Vel antigen expression. Even though the population in Brazil is intensely mixed, the allele frequencies obtained in the current study were very similar to that reported for Europeans.