Abstract Introduction Umbilical cord blood is an alternative source of hematopoietic progenitor cells for bone marrow transplantation; however, it is associated with a higher graft failure rate. The presence of a high rate of nucleated red blood cells (NRBCs) seems to be related to a greater capacity for engraftment, although is also associated with fetal distress conditions. We analyzed the correlation of the NRBC with quality parameters and its association with the utilization score of a cord blood unit. Study design and method Data of 3346 units collected in a public cord blood bank from May 2010 to December 2017 were analyzed, retrospectively, to identify factors associated with an increased number of nucleated red blood cells and its correlation with the engraftment capacity measured through total nucleated cells (TNCs) and CD34 positive cells. We also evaluated the utilization score of these units and identified an NRBC cutoff associated with a higher score. Results The median volume collected was 104 mL (42-255), the pre-processing TNC count was 144.77 × 107 (95.46-477.18), the post-processing TNC count was 119.44 × 107 (42.7-477.18), the CD34 count was 4.67 × 106 (0.31-48.01), the NRBC count was 5 (0-202) and the utilization score was 0.0228 (0.00143-0.9740). The NRBC showed a correlation with the collected volume, TNC and CD34 positive cells and a higher utilization score and the receiver operating characteristic (ROC) curve analysis identified the five NRBC/100 leukocytes cutoff that correlates better with the probability of use. No association with pathological conditions and the NRBC rate was observed. Conclusions The NRBC is a feasible parameter for the screening of the cord blood unit (CBU) and the minimum cutoff of five NRBC/100 leukocytes can be a strategy in conjunction with the TNC to identify better units for cord blood bank sustainability. transplantation however NRBCs (NRBCs 334 201 retrospectively TNCs (TNCs CD CD3 10 42255, 42255 42 255 , (42-255) preprocessing pre processing 14477 144 77 144.7 95.46477.18, 954647718 95.46 477.18 95 46 477 18 (95.46-477.18) postprocessing post 11944 119 44 119.4 42.7477.18, 42747718 42.7 7 (42.7-477.18) 467 4 67 4.6 0.3148.01, 0314801 0.31 48.01 0 31 48 01 (0.31-48.01) 0202 202 (0-202 00228 0228 0.022 0.001430.9740. 00014309740 0.00143 0.9740 . 00143 9740 (0.00143-0.9740) ROC (ROC NRBC100 100 NRBC/10 use observed CBU (CBU sustainability 33 20 1 4225 25 (42-255 1447 14 144. 46477 95.46477.18 95464771 9546 95.4 47718 477.1 9 47 (95.46-477.18 1194 11 119. 7477 42.7477.18 4274771 427 42. (42.7-477.18 6 4. 3148 0.3148.01 031480 031 0.3 4801 48.0 3 (0.31-48.01 020 (0-20 0022 022 0.02 001430 0.001430.9740 0001430974 000143 0.0014 09740 0.974 0014 974 (0.00143-0.9740 NRBC10 NRBC/1 2 422 (42-25 4647 95.46477.1 9546477 954 95. 4771 477. (95.46-477.1 747 42.7477.1 427477 (42.7-477.1 314 0.3148.0 03148 03 0. 480 48. (0.31-48.0 02 (0-2 002 0.0 0.001430.974 000143097 00014 0.001 0974 0.97 001 97 (0.00143-0.974 NRBC1 NRBC/ (42-2 464 95.46477. 954647 (95.46-477. 74 42.7477. 42747 (42.7-477. 0.3148. 0314 (0.31-48. (0- 00 0.001430.97 00014309 0001 0.00 097 0.9 (0.00143-0.97 (42- 95.46477 95464 (95.46-477 42.7477 4274 (42.7-477 0.3148 (0.31-48 (0 0.001430.9 0001430 000 09 (0.00143-0.9 (42 95.4647 (95.46-47 42.747 (42.7-47 0.314 (0.31-4 ( 0.001430. (0.00143-0. (4 95.464 (95.46-4 42.74 (42.7-4 (0.31- 0.001430 (0.00143-0 (95.46- (42.7- (0.31 (0.00143- (95.46 (42.7 (0.3 (0.00143 (95.4 (42. (0. (0.0014 (95. (0.001 (95 (0.00 (9 (0.0

ABSTRACT Objective: Describe the clinical and laboratory characteristics and the transfusion strategy of patients at Hospital Israelita Albert Einstein with platelet refractoriness and identify their etiological characteristics. Standardize the platelet immunofluorescence technique by flow cytometry as a test for platelet compatibility in immune platelet refractoriness in transfusion support. Methods: Review of medical records of refractory platelet patients followed at HIAE from January 2011 to May 2017. Clinical-demographic data, laboratory data and identification of the use of compatible genotyped platelets for patients in need of transfusion therapy were collected. The analyzed patients were classified according to the etiology of their platelet refractoriness. To standardize the FC-PIFT technique, blood group O platelets were incubated with serum from blood group AB donors and anti-IgG monoclonal antibody to determine the negative control. In order to verify the influence of the ABO system, monoclonal anti-IgG antibodies were incubated with blood group A or B platelets and with blood group O donor serum with isohemagglutinins below and above 1/64. Results: A total of 47 patients were evaluated, a 51% (24/47) preponderance of associated immune and non-immune factors (NIPR + IPR). The most common causes of NIPR + IPR were splenomegaly (54%) and the development of HLA antibodies (88%), consistent with the literature. For patients who required therapeutic transfusion, only a small portion received compatible genotyped platelets. Conclusion: Although 60% of patients could benefit from the therapeutic transfusion of genotyped platelets, only 10% were actually transfused with this type of blood component. This reaffirms the need for investments in a bank of genotyped platelet donors.

ABSTRACT Introduction: The Zika Virus (ZIKV) is a single-stranded RNA genome virus, belonging to the family Flaviviridae, genus Flavivirus. Outbreaks around the world have demonstrated that the presence of asymptomatic viremic blood donors provides an increase in the risk of transfusion transmission (TT) and nucleic acid test (NAT) screening has been proposed to ensure the blood safety. This study implemented an “in-house” method to detect ZIKV RNA in blood sample donations. Methods: Primary plasma tubes are submitted to nucleic acid extraction on an automated platform. After extraction, the NAT set-up is performed in the robotic pipettor, in which an amplification mixture containing primers and probes for ZIKV and Polio vaccine virus (PV) are added in duplex as an internal control. The real-time polymerase chain reaction is then performed in a thermocycler, using the protocol established by the supplier. Results: From May 2016 to May 2018, 3,369 samples were collected from 3,221 blood donors (confidence coefficient 95%), of which 31 were considered false positive (0.92%), as they did not confirm initial reactivity when repeated in duplicates and 14 (0.42%) had their results invalid due to repeat failure in the internal control, 4 (0.12%), due to insufficient sample volume and 2 (0.05%), due to automatic pipettor failures. No Zika RNA reactive sample was identified. Conclusion: The test showed feasible to be incorporated into the blood screening routine. Our data do not indicate the need to screen for ZIKV RNA in São Paulo during the evaluated period. However, a generic NAT system covering a group of flaviviruses which are circulating in the region, such as DENV and YFV, among others, could be a useful tool.

ABSTRACT Introduction: Platelet antibody identification is indispensable for diagnosing the human platelet antigen (HPA) or human leukocyte antigen (HLA) immunization, mostly because it can restrict the compatibility and results of transfusions. Correct detection of these antibodies is of utmost importance for the diagnosis and treatment. Method: We present 16 platelet alloimmunization results, comparing two tests with different technologies: the MAIPA (monoclonal antibody immobilization of platelet antigens), as a reference technique, and a bead-based assay, the Pak-Lx. Results: Eleven samples (68.75%) showed agreement in both techniques. Two tests were false negatives in the Pak-Lx: a pan-reactivity in GPIIbIIIa and an anti-HPA-9b. On the other hand, the Pak-Lx was more sensitive to detect a decreasing anti-HPA-5b. The Pak-Lx found an anti-HPA-2b positive, but with a low median fluorescent intensity (MFI), suggesting a false-positive result. Moreover, in one case, the MAIPA was negative for a positive Pak-Lx HLA. Conclusion: Antibody platelet diagnosis can sometimes be challenging. The methods seemed similar, the Pak-Lx being faster and simpler than the MAIPA, and they can be complementary to solve clinical issues.

ABSTRACT To describe a case of autologous chondrocyte implantation after cell culture contamination by Mycoplasma pneumoniae and the measures taken to successfully complete cell therapy in a patient with focal chondral lesion. A 45-year-old male patient, complaining of chronic pain on the knee and no history of trauma. He had a chondral lesion in the trochlear region of the femur and clinical tests compatible with pain in the anterior compartment of the knee. Conservative treatment failed to alleviate symptoms. Surgical treatment was indicated, but due to the size of the lesion, membrane-assisted autologous chondrocyte implantation was the technique of choice. Cartilage biopsies were collected from the intercondylar region of the distal femur. After isolation, chondrocytes were expanded ex vivo in a trained laboratory, for three weeks, and seeded onto a commercially available collagen membrane prior to implantation in the knee. Two days before surgery, a cell culture sample tested positive for Mycoplasma pneumoniae. The source of contamination was found to be autologous blood serum, extracted from the patient´s peripheral vein, and used to supplement the cell culture medium. After treating the patient with antibiotics, all procedures were repeated and the new final cell product, free from contaminants, was successfully implanted. We discuss the strategies available to deal with this situation, and describe the results of this particular case, which led to modifications in the autologous chondrocyte implant protocol.

ABSTRACT Objective Phase 1 clinical trial to determine feasibility, safety, and efficacy of a new advanced cell therapy product for treatment of knee articular cartilage injuries. Methods Three participants with knee focal chondral lesions were included, with no signs of osteoarthritis. Chondrocytes were obtained through knee arthroscopy, cultured in collagen membrane for 3 weeks at the laboratory, subjected to tests to release the cell therapy product, and implanted. All patients underwent a specific 3-month rehabilitation protocol, followed by assessments using functional and imaging scales. The main outcome was the incidence of severe adverse events. Results Three participants were included and completed the 2-year follow-up. There was one severe adverse event, venous thrombosis of distal leg veins, which was no associated with therapy, was treated and left no sequelae. The clinical and radiological scales showed improvement in the three cases. Conclusion The preliminary results, obtained with the described methodology, allow concluding that this product of advanced cell therapy is safe and feasible. ReBEC platform registration number: RBR-6fgy76

ABSTRACT The adherence to accreditation programs proves the institutions' voluntary effort to pursue the quality and safety of their products and services by meeting internationally accepted standards audited by experts in the field, external to the service. Meeting such standards often exceeds domestic legal requirements. However, service providers are not released from complying with the legal requirements, both local and international, pertinent to the field. Accreditation programs use the precepts of the quality management system to validate and standardize processes, monitor results through quality control, proficiency testing, and indicators, and perform risk management. For cellular therapy services, the assessing agencies available in our field are the AABB/ABHH (American Association of Blood Banks/Brazilian Association of Hematology, Hemotherapy and Cellular Therapy) and FACT-JACIE (Foundation for the Accreditation of Cellular Therapy-Joint Accreditation Committee, ISCT/EBMT). Both agencies require that the accredited organization meets all the standards defined in each program. Applying services also have to establish and comply with a quality management standard that demonstrates procedural interrelationship to ensure product and service quality. This paper aims to concisely outline the essential features of those two accreditation programs, along with a brief overview of the accreditation process under each of them.

ABSTRACT Chimeric antigen receptor T cells (CAR-T), especially against CD19 marker, present in lymphomas and acute B leukemia, enabled a revolution in the treatment of hematologic neoplastic diseases. The manufacture of CAR-T cells requires the adoption of GMP-compatible methods and it demands the collection of mononuclear cells from the patient (or from the donor), generally through the apheresis procedure, T cell selection, activation, transduction and expansion ex vivo, and finally storage, usually cryopreserved, until the moment of their use. An important aspect is the quality control testing of the final product, for example, the characterization of its identity and purity, tests to detect any contamination by microorganisms (bacteria, fungi, and mycoplasma) and its potency. The product thawing and intravenous infusion do not differ much from what is established for the hematopoietic progenitor cell product. After infusion, it is important to check for the presence and concentration of CAR-T cells in the patient’s peripheral blood, as well as to monitor their clinical impact, for instance, the occurrence of short-term, such as cytokine release syndrome and neurological complications, and long-term complications, which require patient follow-up for many years.

ABSTRACT Background: The treatment of multiple myeloma (MM) has evolved significantly in the past decade, and new drug combinations have improved the response rates and prolonged survival. Studies comparing different induction chemotherapy regimens have shown that triple combinations have better results than double combinations. However, comparisons among different triple combinations are rare in the literature. Methods: We retrospectively compared two triple combinations comprising bortezomib, cyclophosphamide and dexamethasone (VCD) versus thalidomide, cyclophosphamide and dexamethasone (CTD), and aimed at identifying which of the two combinations would yield better response rates following four induction cycles prior to hematopoietic cell transplantation in patients with untreated multiple myeloma. Results: We retrospectively reviewed the medical records of 311 patients from 24 different centers.The VCD regimen was used as induction therapy by 117 (37.6%) patients, whereas 194 (62.4%) patients received the CTD regimen. After four cycles of induction on an intention-to-treat basis, 54% of the patients in the VCD group achieved at least very good partial response versus 42.8% in the CTD group (p = 0.05). We observed no difference in neuropathy or thrombotic events rates among the two regimens. Conclusion: Our results corroborate the superiority of the triple combination regimes containing bortezomib over the triple combination with thalidomide as pre ASCT induction therapy in MM.

RESUMO A correta identificação dos anticorpos eritrocitários é fundamental na busca de sangue compatível e na prevenção das reações transfusionais hemolíticas. Anticorpos contra antígenos de alta prevalência são de difícil identificação, devido à raridade de sua ocorrência e à indisponibilidade de hemácias negativas para sua confirmação. Apresentamos aqui o caso de uma paciente do sexo feminino, 46 anos, com diagnóstico de hemoglobinopatia, que apresentou queda sintomática dos níveis de hemoglobina (5,3g/dL) após transfusão sanguínea, sugestiva de reação transfusional. O tipo sanguíneo da paciente era O RhD-positivo. A pesquisa de anticorpos irregulares foi positiva, demonstrando panreação contra todos os eritrócitos testados, mas não reativo ao ditiotreitol. Utilizando hemácias selecionadas negativas para antígenos de alta prevalência do nosso inventário, foi possível identificar no soro da mesma um anticorpo anti-Holley associado a um anti-E. A análise molecular confirmou que a paciente era negativa para os antígenos E e Holley, e as provas de compatibilidade com unidades fenotipadas confirmaram os resultados. Holley é um antígeno de alta prevalência do sistema sanguíneo Dombrock, cujo fenótipo negativo é extremamente raro em todas as populações e está associado a reações transfusionais hemolíticas. Trata-se de anticorpo de difícil identificação, pois os laboratórios precisam ter experiência na resolução de casos complexos, grande estoque de soros e eritrócitos raros, além de outras ferramentas, como enzimas, reagentes tiol e testes moleculares. A identificação correta de um anticorpo raro é inicial e obrigatória para a busca de doadores compatíveis, garantindo um suporte transfusional satisfatório.

ABSTRACT The correct identification of erythrocyte antibodies is fundamental for the searching for compatible blood and haemolytic transfusion reactions prevention. Antibodies against antigens of high prevalence are difficult to identify because of the rarity of their occurrence and unavailability of negative red cells for confirmation. We report a case of 46-years-old woman, diagnosed with hemoglobinopathy, and who had symptomatic fall in hemoglobin levels (5.3g/dL) after blood transfusion suggestive of transfusion reaction. The patient’s blood type was O RhD-positive. Irregular antibody screening was positive and demonstrated a panreaction against all erythrocytes tested, but this result was not reactive with dithiothreitol. Using negative red cells for antigens of high prevalence of our inventory we could identify in the serum of the same erythrocytes an anti-Holley antibody associated with anti-E. Molecular analysis confirmed that the patient was negative for E and Holley antigens. The crossmath with compatible units confirmed the results. Holley is a high prevalence antigen of the Dombrock blood system whose negative phenotype is extremely rare in all populations and is associated with hemolytic transfusion reactions. This is an antibody that is difficult to identify because laboratories need to have experience in solving complex cases, and have available a large stock of rare sera and erythrocytes, as well other tools such as enzymes, thiol reagents and molecular tests. The correct identification of a rare antibody is initial and mandatory for searching of compatible donors, and to guarantee a satisfactory transfusional support.

RESUMO Objetivo Descrever as frequências alélicas e haplotípicas de genes dos antígenos leucocitários humanos nos loci -A,- B e dos antígenos plaquetários humanos para os sistemas HPA-1 a 9, 11 e 15. Métodos Foram incluídos 867 doadores voluntários, saudáveis, não relacionados, que doaram plaquetas por aférese entre janeiro de 2011 e dezembro de 2014. A genotipagem foi realizada usando microarray BeadChip. A tipificação de resolução intermediária dos antígenos leucocitários humanos loci A e B foi realizada por meio de hibridização com sonda para oligonucleotídeos por sequência específica. Utilizamos análises multivariadas e o antígeno leucocitário humano de nossa população foi comparado com a do programa nacional de doadores de medula óssea norte-americano. Já os resultados dos antígenos plaquetários humanos foram comparados à revisão da literatura e a dados de populações de outros países. Resultados Os resultados do haplótipo de antígenos leucocitários humanos são mais parecidos com os dos hispânicos, seguidos dos caucasianos. Igualmente, a amostra de antígenos plaquetários humanos foi mais semelhante às da Argentina, do Rio Grande do Sul e da Itália. Conclusão Este foi o primeiro artigo a discutir antígenos plaquetários e leucocitários humanos simultaneamente. Genótipos raros ou associações de anticorpos podem dificultar o manejo clínico do paciente. Um banco de sangue com doadores genotipados permite um melhor resultado e transfusão possíveis. Estas informações podem servir de base para um banco de dados sobre polimorfismos de antígenos plaquetários.

ABSTRACT Objective To described the allele and haplotype frequencies of human leukocyte antigen genes at the -A, -B loci and human platelet antigen genes for human platelet antigen systems 1 to 9, 11 and 15 in blood. Methods We included 867 healthy unrelated volunteer donors who donated platelets between January 2011 and December 2014. Microarray genotyping was performed using a BeadChip microarray. Medium resolution typing of the human leukocyte antigen at loci A and B was carried out using sequence-specific oligonucleotide probe hybridization. We used multivariate analysis and our human leukocyte antigen population was compared to data from the United States national bone marrow donor program. Human platelet antigen results were compared to a literature review and data from around the world. Results Our human leukocyte antigen haplotype results were more similar to those of hispanics, followed by caucasians. Likewise, our human platelet antigen sample is more similar to those of Argentina, Rio Grande do Sul and Italy. Conclusion This was the first article that discusses human platelet antigen and human leukocyte antigen data together. Rare genotypes or antibody associations can make patient management difficult. A blood bank with genotyped donors allows for optimal transfusion and can contribute to better results. Our information can serve as basis for a database of platelet antigen polymorphisms.

Abstract Introduction: Pre-transfusion tests, essential for the release of blood components, may be affected by drugs. Monoclonal antibodies represent a class of medications increasingly used in the clinical practice, with anti-CD38 monoclonal antibodies (daratumumab) being a promising resource in the treatment of refractory myeloma. This monoclonal antibody recognizes CD38 in myeloma cells and interferes with pre-transfusion tests by causing panreactivity in indirect antiglobulin tests thereby clinically masking alloantibodies. Dithiothreitol is a reagent that breaks disulfide bonds and effectively destroys antigenic sites for CD38 on red blood cells. This study reports the immunohematological findings of pre-transfusion tests of patients with multiple myeloma receiving daratumumab and on solutions to prevent the interference of this monoclonal antibody. Methods: Serum samples from five patients on anti-CD38 monoclonal antibody treatment were evaluated. Tests performed included ABO/RhD typing, indirect antiglobulin test, direct antiglobulin test and eluate test. A daily evaluation was performed to determine the shelf life of dithiothreitol-treated red blood cells when stored in Alsever's solution. Results: No interference in the ABO/RhD typing results was noted but in all samples, a panreactivity was observed in indirect antiglobulin tests. Regarding the direct antiglobulin test, two samples presented positive results but negative eluates. In all samples, treatment of reagent red blood cells with 0.2 M dithiothreitol offset interference by anti-CD38 monoclonal antibodies. Dithiothreitol-treated red blood cells stored in Alsever's solution were stable for up to 15 days. Conclusion: Treatment of reagent red blood cells with dithiothreitol can be efficient and accessible to offset the interference of the anti-CD38 drug in pre-transfusion tests. The number of costly serological workups can be reduced by having stored dithiothreitol red blood cells with this proving to be a useful reagent for investigating anti-CD38.

RESUMO CONTEXTO E OBJETIVOS: Há nove anos, hematologistas e oncologistas se reúnem anualmente em um simpósio educacional organizado por um hospital brasileiro e outro norte-americano. Durante o Board Review 2015, uma pesquisa foi conduzida entre os participantes e avaliou as diferenças na conduta e opções de tratamento para o mieloma múltiplo (MM). DESENHO E LOCAL: Estudo transversal no simpósio educacional de hematologia em São Paulo. MÉTODOS: Hematologistas presentes no simpósio responderam a uma pesquisa por celular. RESULTADOS: Dos 350 inscritos, 217 responderam o questionário. A maioria dos participantes acredita que a terapia-alvo imune (iTA) pode ser efetiva para desacelerar a progressão do MM em pacientes que já foram muito tratados previamente, e que a exposição contínua à terapia pode gerar clones resistentes em pacientes com MM (76%). A maioria usa terapia de manutenção após transplante de células-tronco hematopoiéticas (95%) e 45% dos médicos a restringiriam a pacientes pós-transplante com doença de base de alto risco. As drogas de primeira linha adotada para os pacientes inelegíveis para transplante (PIT) foram bortezomibe-talidomida-dexametasona (31%), bortezomibe-dexametasona (28%), lenalidomina-dexametasona (Rd; 17%) e terapia baseada em melfalan (10%). A lenalidomida foi a droga de escolha para a manutenção pós-transplante para metade dos participantes. Nenhuma diferença significativa foi encontrada para idade ou tempo de experiência. CONCLUSÃO: As escolhas de tratamento para PIT foram altamente heterogêneas e o regime baseado em melfalan representou somente 10% das opções de primeira linha. Terapia de manutenção após transplante é opção comum. Alguns dos resultados do levantamento foram divergentes das evidências na literatura.

ABSTRACT CONTEXT AND OBJECTIVE: For the last nine years, hematologists and oncologists have gathered annually at an educational symposium organized by a Brazilian and an American hospital. During the 2015 Board Review, a survey among the attendees evaluated the differences in management and treatment methods for multiple myeloma (MM). DESIGN AND SETTING: Cross-sectional study during an educational hematology symposium in São Paulo, Brazil. METHODS: Hematologists present at the symposium gave responses to an electronic survey by means of mobile phone. RESULTS: Among the 350 attendees, 217 answered the questionnaire. Most of the participants believed that immunotargeting agents (iTA) might be effective for slowing MM progression in heavily pretreated patients (67%) and that continued exposure to therapy might lead to emergence of resistant clones in patients with MM (76%). Most of the physicians use maintenance therapy after hematopoietic stem cell transplantation (95%) and 45% of them would further restrict it to post-transplantation patients with underlying high-risk disease. The first-line drugs used for transplantation-ineligible patients (TI-MM) were bortezomib-thalidomide-dexamethasone (31%), bortezomib-dexamethasone (28%), lenalidomide-dexamethasone (Rd; 17%) and melphalan-based therapy (10%). Lenalidomide was the drug of choice for post-transplantation maintenance for half of the participants. No significant differences were observed regarding age or length of experience. CONCLUSION: The treatment choices for TI-MM patients were highly heterogenous and the melphalan-based regimen represented only 10% of the first-line options. Use of maintenance therapy after transplantation was a common choice. Some results from the survey were divergent from the evidence in the literature.

ABSTRACT Background: Successful transfusion of platelet refractory patients is a challenge. Many potential donors are needed to sustain human leukocyte antigen matched-platelet transfusion programs because of the different types of antigens and the constant needs of these patients. For a highly mixed population such as the Brazilian population, the pool size required to provide adequate platelet support is unknown. Methods: A mathematical model was created to estimate the appropriate size of an unrelated donor pool to provide human leukocyte antigen-compatible platelet support for a Brazilian population. A group of 154 hematologic human leukocyte antigen-typed patients was used as the potential patient population and a database of 65,500 human leukocyte antigen-typed bone marrow registered donors was used as the donor population. Platelet compatibility was based on the grading system of Duquesnoy. Results: Using the mathematical model, a pool containing 31,940, 1710 and 321 donors would be necessary to match more than 80% of the patients with at least five completely compatible (no cross-reactive group), partial compatible (one cross-reactive group) or less compatible (two cross-reactive group) donors, respectively. Conclusion: The phenotypic diversity of the Brazilian population has probably made it more difficulty to find completely compatible donors. However, this heterogeneity seems to have facilitated finding donors when cross-reactive groups are accepted as proposed by the grading system of Duquesnoy. The results of this study may help to establish unrelated human leukocyte antigen-compatible platelet transfusions, a procedure not routinely performed in most Brazilian transfusion services.

A púrpura trombocitopênica neonatal aloimune é uma doença grave, na qual a mãe produz anticorpos contra antígenos plaquetários fetais herdados do pai, e é ainda subdiagnosticada na prática clínica. É considerada o equivalente plaquetário da doença hemolítica do recém-nascido, com a diferença que o primeiro filho é afetado, apresentando trombocitopenia fetal e/ou neonatal. Há risco significativo de hemorragia intracraniana e sequelas neurológicas graves, com tendência a trombocitopenia mais grave e mais precoce nas gestações subsequentes. Este artigo relata um caso de trombocitopenia aloimune neonatal na segunda gestação afetada e discute diagnóstico, manejo e importância clínica dessa doença na prática clínica.

Neonatal alloimmune thrombocytopenia is a serious disease, in which the mother produces antibodies against fetal platelet antigens inherited from the father; it is still an underdiagnosed disease. This disease is considered the platelet counterpart of the RhD hemolytic disease of the fetus and newborn, yet in neonatal alloimmune thrombocytopenia the first child is affected with fetal and/or neonatal thrombocytopenia. There is a significant risk of intracranial hemorrhage and severe neurological impairment, with a tendency for earlier and more severe thrombocytopenia in subsequent pregnancies. This article reports a case of neonatal alloimmune thrombocytopenia in the second pregnancy affected and discusses diagnosis, management and the clinical importance of this disease.