Dante Mario Langhi

Expression levels of CD47, CD35, CD55, and CD59 on red blood cells and signal-regulatory protein-α,β on monocytes from patients with warm autoimmune hemolytic anemia

BACKGROUND: Animal models have shown that CD47‐deficient mice develop severe autoimmune hemolytic anemia (AIHA) because the binding of red blood cell (RBC) CD47 to signal‐regulatory protein (SIRP‐α) on macrophages contributes to the inhibition of phagocytosis. In contrast, complement‐inhibitory proteins such as CD35, CD55, and CD59 may protect RBCs against the lysis by complement.

Alloimmunization screening after transfusion of red blood cells in a prospective study

Background Several irregular red blood cell alloantibodies, produced by alloimmunization of antigens in transfusions or pregnancies, have clinical importance because they cause hemolysis in the fetus and newborn and in transfused patients. Objective a prospective analysis of patients treated by the surgical and clinical emergency services of Hospital de Clínicas of the Universidade Federal do Triângulo Mineiro (HC/UFTM), Brazil was performed to correlate alloimmunization to clinical and epidemiological data. Methods Blood samples of 143 patients with initial negative antibody screening were collected at intervals for up to 15 months after the transfusion of packed red blood cells. Samples were submitted to irregular antibody testing and, when positive, to the identification and serial titration of alloantibodies. The Fisher Exact test and Odds Ratio were employed to compare proportions. Results Fifteen (10.49%) patients produced antibodies within six months of transfusion. However, for 60% of these individuals, the titers decreased and disappeared by 15 months after transfusion. Anti-K antibodies and alloantibodies against antigens of the Rh system were the most common; the highest titer was 1:32 (anti-K). There was an evident correlation with the number of transfusions. Conclusions Given the high incidence of clinically important red blood cell alloantibodies in patients transfused in surgical and clinical emergency services, we suggest that phenotyping and pre-transfusion compatibilization for C, c, E, e (Rh system) and K (Kell system) antigens should be extended to all patients with programmed surgeries or acute clinical events that do not need emergency transfusions.

Rho kinase inhibition drives megakaryocyte polyploidization and proplatelet formation through MYC and NFE2 downregulation

The processes of megakaryocyte polyploidization and demarcation membrane system (DMS) formation are crucial for platelet production, but the mechanisms controlling these processes are not fully determined. Inhibition of Rho kinase (ROCK) signalling leads to increased polyploidization in umbilical cord blood‐derived megakaryocytes. To extend these findings we determined the effect of ROCK inhibition on development of the DMS and on proplatelet formation. The underlying mechanisms were explored by analysing the effect of ROCK inhibition on the expression of MYC and NFE2, which encode two transcription factors critical for megakaryocyte development. ROCK inhibition promoted DMS formation, and increased proplatelet formation and platelet release. Rho kinase inhibition also downregulated MYC and NFE2 expression in mature megakaryocytes, and this down‐regulation correlated with increased proplatelet formation. Our findings suggest a model whereby ROCK inhibition drives polyploidization, DMS growth and proplatelet formation late in megakaryocyte maturation through downregulation of MYC and NFE2 expression.

RHD gene polymorphisms in alloimmunized RhD-negative individuals with high rate of racial admixture

BACKGROUND The D-negative phenotype is the result of the total RHD gene deletion in almost all Caucasians, but it accounts for only about 20% in Africans and 70% in Asians. In Africans the RHDΨ that is one of the most important causes of the D-negative phenotype. We investigated the RHD polymorphisms in D-negative phenotype mixed Brazilians who have anti-D alloantibody. STUDY DESIGN AND METHODS Blood samples from 130 individuals previously typed as D-negative were phenotyped again using: (a) two tube reagents (Anti-D blend reagent, Cellular line TH-28, MS-26; and Anti-D polyclonal); (b) one gel test ID-Card for Rh subgroups including C(w) and K antigen; and (c) ABO/Rh (Anti-D blend reagent, Cellular line 175-2, LDM3). The method used for RHD screening detected the presence of RHD exon 10 and intron 4. Sequence analysis was performed on PCR products amplified from genomic DNA for all 10 exons RHD gene. RESULTS We found that 118/130 (90.8%) of D-negative tested individuals had total RHD gene deletion, while 12/130 (9.2%) showed RHD gene polymorphisms. The RHDΨ was found in 10 (7.7%) individuals, one sample (0.77%) hybrid RHD-CE-D(s) /RHDΨ, and another (0.77%) weak D type 4.2. CONCLUSIONS The results showed that the RHD gene was present in 9.2% of racially mixed Brazilians who produced usually clinically significant anti-D alloantibodies. Therefore, the data showed that careful attention is necessary for clinicians in applying RhD genotyping to transfusion medicine in populations with high rate of racial admixture.

RHD alleles and D antigen density among serologically D− C+ Brazilian blood donors

Dear Sir, The D-negative phenotype may be caused by the lack of functional RhD protein or by the presence of aberrant forms of RhD not expressing the D antigen. Numerous single nucleotide polymorphism (SNPs) changes in the RHD gene are currently known. The weak D has been shown to be caused by SNPs in most cases, leading to amino acid changes in the transmembraneous, or intracellular, parts of the D protein, consequently showing reduced D antigen density (Wagner et al., 1999; Wagner et al., 2000). Very weakly expressed weak D, or D only detectable by adsorption-elution techniques, named DELs, were frequently unidentified by routine serologic procedures, and large groups of completely unexpressed RHD alleles only became evident by DNA-typing methods (Gassner et al., 2005). Several studies have confirmed unexpressed RHD alleles in association with D − Ce or cE phenotypes (Gassner et al., 2005; Christiansen et al., 2010). The frequency of phenotypes dCcee and dccEe in the Brazilian population is approximately 0·6 and 0·2%, respectively (Cruz et al., 2012). At our Blood Centre, we consider C/E+ and D− blood donors as RhD-negative and therefore their blood is transfused into RhD-negative patients. Thus, in the present study we decided to investigate the molecular background in Brazilian blood donors phenotyped as D−C/E+. In addition, qualitative and quantitative analyses of the D antigen expressed by RBCs of D variants were performed. We investigated 520 blood donors from Southeast (São Paulo, SP) Brazil labelled D−C/E+ confirmed by the commercial anti-D Immunoglobulin G (IgG) (MS-26) + IgM (TH-28) and polyclonal antibodies against C, c, E and e (DiaMed, Latino América S.A., Brazil). The samples were screened by polymerase chain reaction (PCR) with sequence-specific primers for the presence of RHD in two genomic regions, intron 4 (primers RHI41 and RHI42) and exon 10 (primers EX10F, RHD3′-UTR and RHCE 3′-UTR). Samples identified as RHD gene-positive were sequenced in full length for all 10 RHD exons (Legler et al., 2001; Qun et al., 2005). The sequences were analysed using a sequencing Kit (Big Dye Terminator v1.1, applied Biosystems, Weiterstadt, Germany) and a genetic analyser (ABI 3100, Applied Biosystems, Foster City, CA, USA). The samples that have demonstrated the RHD variants by the molecular methods were further analysed with different antiD MoAbs, by gel cards using anti-D MoAbs IgG (clone ESD1) (DiaMed, Latino América S.A., Brazil) and by haemagglutination

Is there justification for universal leukoreduction

The Associacao Brasileira de Hematologia, Hemoterapia e Terapia Celular (ABHH), the institution that represents the Associacao Medica Brasileira (AMB) in respect to hematology, transfusion therapy and cell therapy in Brazil hereby states: Prospective randomized studies have not demonstrated any positive clinical impact with the universal use of blood components in which the initial number of leukocytes has been reduced (universal leukoreduction). For this reason, universal leukoreduction remains a technically controversial topic. The current consensus is that leukoreduction has defined indications in the prevention of three blood transfusion complications only: (i) non-hemolytic febrile reactions when the patient has had this reaction previously; (ii) platelet refractoriness caused by alloimmunization against leukocyte antigens and (iii) the transmission of cytomegalovirus

Guidelines on Beta-thalassemia major - regular blood transfusion therapy: Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular: project guidelines: Associação Médica Brasileira - 2016

he guidelines project is a joint initiative of the Associação édica Brasileira and the Conselho Federal de Medicina. It aims o bring together information in medicine to standardize onduct in order to help decision-making during treatment. he data contained in this article were prepared by and re recommended by the Associação Brasileira de Hematologia, emoterapia e Terapia Celular (ABHH). Even so, all possible conucts should be evaluated by the physician responsible for

Reação transfusional hiper-hemolítica em pacientes portadores de anemia falciforme: relato de dois casos

The chronic character of sickle cell anemia associated with the greater capacity to liberate oxygen by the Hb S, results in patients exhibiting few symptoms in relation to the anemia and they do not require regular hemacias transfusions. Nevertheless, in the face of acute complications, the additional drop in hemoglobin can precipitate an imbalance in the cardio-respiratory function and put the life of the patient at risk, making blood transfusion therapy of utmost importance. In the light of the increased frequency of transfusions to which these patients are submitted, knowledge of the main risks and an adequate diagnosis of the complications caused by transfusional therapy are of fundamental importance. An atypical form of transfusional reaction, denominated hyperhemolytic transfusional reaction was recently described in sickle cell anemia patients after the transfusion of apparently compatible hemacias. In this case, previous conditions can exacerbate the hemolytic condition and put the life of the patient at risk. The pathophysiological conditions of this disease are not yet understood well and the treatment consists of suspending transfusions, corticoid therapy and / or administration of immunoglobulin. The aim of this work is o present two case reports of hyperhemolytic transfusional reaction in sickle cell anemia patients.

Antibodies to human neutrophil antigen HNA-3b implicated in cases of neonatal alloimmune neutropenia: ANTI-HNA-3B IMPLICATED IN CASES OF NAIN

Neonatal alloimmune neutropenia results from maternal alloimmunization to human neutrophil antigens. The alloantibodies involved in neonatal alloimmune neutropenia are against human neutrophil antigens HNA‐1a, HNA‐1b, HNA‐1c, HNA‐1d, HNA‐2, HNA‐3a, HNA‐4a, HNA‐4b, and HNA‐5a; however, to date, antibodies specific to HNA‐3b have not been reported.

Autoimmune hemolytic anemia: transfusion challenges and solutions

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