VALERIA BRITO OLIVEIRA
Projetos de Pesquisa
Unidades Organizacionais
PAHC, Hospital das Clínicas, Faculdade de Medicina
LIM/31 - Laboratório de Genética e Hematologia Molecular, Hospital das Clínicas, Faculdade de Medicina
LIM/31 - Laboratório de Genética e Hematologia Molecular, Hospital das Clínicas, Faculdade de Medicina
18 resultados
Resultados de Busca
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- 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.
- Duffy null genotype or Fy(a-b-) phenotype are more accurate than self-declared race for diagnosing benign ethnic neutropenia in Brazilian population(2017) DINARDO, C. L.; KERBAUY, M. N.; SANTOS, T. C.; LIMA, W. M.; DEZAN, M. R.; OLIVEIRA, V. B.; MENDRONE-JUNIOR, A.; ROCHA, V.; VELLOSO, E. D. R. P.
- 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.
- Defining the clinical relevance of red blood cell autoantibodies by Monocyte Monolayer Assay(2018) CONRADO, Marina C. A. V.; D'AVILA, Amanda N.; VIEIRA, Juliana B.; BONIFACIO, Silvia L.; GOMES, Francisco C. A.; DEZAN, Marcia R.; OLIVEIRA, Valeria B.; RIBEIRO, Ingrid H.; TUCUNDUVA, Luciana T. C. M.; MENDRONE-JUNIOR, Alfredo; ROCHA, Vanderson; DINARDO, Carla L.BackgroundThe Monocyte Monolayer Assay (MMA) is an in vitro simulation of red blood cell (RBC) alloantibody behavior. It has been classically applied to predict the risks of post-transfusion hemolytic reactions when transfusing incompatible RBC units. Quantifying erythrophagocytosis by MMA may be an interesting option for situations where there is doubt whether a RBC autoantibody is mediating significant hemolysis. Here, we present three situations involving RBC autoantibodies in which the MMA was decisive for clarifying the diagnosis and choosing the best clinical treatment. Case ReportCase 1. Pregnant patient with severely anemic fetus exhibited warm autoantibody without signs of hemolysis. MMA revealed 30% of monocyte index (MI) highlighting that fetal hemolysis was caused by maternal autoantibody. Prednisone was prescribed with fetal clinical improvement. Cases 2 and 3. Two patients with the diagnosis of mixed auto-immune hemolytic anemia and poor response to corticosteroids were evaluated using MMA. The resulting MI was less than 10% in both cases, suggesting that the cold-agglutinin rather than the warm auto-IgG was responsible for overt hemolysis. Treatment with rituximab was begun, with good clinical response. ConclusionMMA can be used to evaluate the ability of RBC autoantibodies to mediate overt hemolysis. It can be especially useful to determine the role played by cold and warm auto-antibodies in mixed auto-immune hemolytic disease, helping to define the best treatment option.
- 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.
- Using droplet digital PCR to screen for rare blood donors: Proof of principle(2020) DEZAN, Marcia Regina; PERON, Ana Claudia; OLIVEIRA, Theo Gremen Mimary; OLIVEIR, Valeria Brito; GOMES, Carolina Nunes; SALLES, Nanci A.; ROCHA, Vanderson; MENDRONE-JUNIOR, Alfredo; DINARDO, Carla LuanaBackground: Digital droplet PCR (ddPCR) is a very sensitive high throughput genotyping methodology. To date, the use of ddPCR in immunohematology is restricted to fetal genotyping of red blood cell antigens. Our hypothesis is that this technology could be applied to screen for rare red blood cell genotypes, such as Di(b-). Methods: Nucleic acid of 3168 donors was extracted for viral screening routine in pools of 6, which were converted into three types of 48-donor pools: control pools (only DI*B/*B samples), pools with varying amount of DI*A/*B samples (n = 1-5) and a pool with one rare DI*A/*A sample. Pools were genotyped using ddPCR to detect and quantify DI*A and DI*B alleles. Results: DI*A allele was accurately detected in all pools containing Di(a + b+) samples and in the pool containing one Di(a + b-) sample. No copies were detected in the control pools (n = 60). The ratio between the number of DI*A and DI*B copies varied significantly between the pools and the triplicates. Conclusion: The proposed ddPCR assay was accurate in identifying the rare DI*A allele in large pools of donors and can be applied to screen for Di(b-) phenotype. The strategy can potentially be extended to search for other rare RBC phenotypes.
- Association between FY*02N.01 and the severity of COVID-19: initial observations(2022) CONRADO, Marina C. A. V.; DEZAN, Marcia R.; OLIVEIRA, Valeria Brito; ZIZA, Karen Chinoca; FANCISCANI, Tila; ROCHA, Vanderson; MENDRONE-JUNIOR, Alfredo; DINARDO, Carla LuanaIntroduction: The pro-inflammatory immune response underlies severe cases of COVID-19. Antigens of the Duffy blood group systems are receptors for pro-inflammation chemokines. The ACKR1 c.-67T>C gene variation silences the expression of Duffy antigens on erythrocytes and individuals presenting this variant in homozygosity have impaired inflammatory response control. Our aim was to evaluate the association between the ACKR1 c.-67T>C and the severity of COVID-19. Methods: This was a retrospective single-center case-control study, enrolling 164 participants who were divided into four groups: 1) Death: COVID-19 patients who died during hospitalization; 2) Hospital Discharge: COVID-19 patients who were discharged for home after hospitalizations; 3) Convalescent Plasma Donors: COVID-19 patients who were not hospitalized, and; 4) Controls: patients with diagnosis other than COVID-19. Patients were genotyped for the ACKR1 c.-67T>C (FY*02 N.01 allele) and the frequency of individuals presenting the altered allele was compared between the groups. Results: The groups significantly differed in terms of the percentage of patients presenting at least one FY*02N.01 allele: 36.8% (Death group), 37% (Hospital Discharge group), 16.1% (Convalescent Plasma group) and 16.2% (Control group) (p = 0.027). The self-declared race (p < 0.001) and the occurrence of in hospital death (p = 0.058) were independently associated with the presence of the FY*02N.01 allele. Hypertension (p < 0.001), age (p < 0.001) and the presence of at least one FY*02N.01 allele (p = 0.009) were independently associated with the need for hospitalization. Conclusion: There is a suggestive association between the presence of the FY*02N.01 and the severity of COVID-19. This may be a mechanism underlying the worse prognosis for Afro descendants infected with SARS-CoV-2. (c) 2022 Published by Elsevier Espana, S.L.U. on behalf of Associacao Brasileira de Hematologia, Hemoterapia e Terapia Celular. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
- 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.