Allele frequencies were comparable to those described in other Brazilian studies. Rare HPA-9 alleles were described in Brazilians for the first time. A mutation near the HPA-2 polymorphism suggests that complementary methods might be necessary in specific cases. PLT genotyping by microarray proved to be fast, accurate, and reliable.

According to the Brazilian Association of Organ Transplants, in 2015, 19,408 bone transplants were performed in Brazil, over 90% by Dental Surgeons. The surgical technique itself has a respectable number of reports regarding its clinical efficacy, as measured by long-term survival of dental implants in grafted areas. Uncertainty remains, however, as to whether fresh frozen grafts from human bone donors remain immunologically innocuous in the body of the host. Six male with no previous medical history of note, including systemic diseases, surgery or blood transfusion were selected. These patients underwent reconstructive procedures (sinus lifting) using fresh frozen human bone from a tissue bank. All patients had venous blood samples collected prior to surgery and 6 months after the procedure. Anti-HLA analysis for the detection of HLA (human leukocyte antigen) antibodies was performed using methods such as the LABScreen PRA Class I and Class II, LABScreen Single Antigen Class I and Class II, Luminex Platform. Reactive individuals to the screening tests (LABScreen PRA) were further investigated to determine the specificity of the antibodies detected (LABScreen Single Antigen) with a cutoff value of median fluorescence intensity ≥500. As a result, it was observed that two patients (33%) were positive in screening tests, one presenting with anti-HLA Class I and II sensitization and the other with anti-HLA class II. The specificity analysis showed that the patients sensitized to HLA class II presented 4 specificities, 3 of which immunologically relevant. In the second individual, 23 specificities were identified, 6 of which immunologically important for HLA class I and 4 specificities for HLA class II, 3 of these were immunologically important. All specificities detected had average fluorescence. These findings are suggestive that sinus-lifting procedures with allogeneic bone can induce immunological sensitization.

Background A considerable number of RHD alleles responsible for weak and partial D phenotypes have been identified. Serologic determination of these phenotypes is often doubtful and makes genetic analysis of RHD gene highly desirable in transfusion recipients and pregnant women. We analyzed the RHD gene in a cohort of pregnant women with doubtful D phenotypes. Methods RHD genotyping was performed on 104 cases with D typing discrepancies or with history of serologic weak D phenotype. Laboratory‐developed DNA tests, RHD BeadChip (Bioarray Solutions, Immucor), and sequencing were used to identify the RHD alleles. Results Molecular analyses showed 23 of 104 (22%) pregnant women were RHD*weak D types 1, 2, or 3 and not at risk for anti‐D. Fifty‐one (49%) were RHD*weak partial 4.0, 6 RHD*weak D type 38 (6%), 1 RHD*weak D type 45 (1%), 1 RHD*weak D type 67 (1%), and potentially at risk for being alloimmunized and making anti‐D. Partial D was identified in 22 of 104 (21%) patients and definitively at risk for anti‐D. Discussion Appropriate classification of RhD phenotypes is recommended for correct indication of RhIG in pregnant women. However, the serologic distinction between RhD‐negative and RhD‐positive phenotypes is a difficult task in the case of D variants due to the variations in serologic testing. Our results show a great variability in RHD variant alleles in pregnant women from this population of high admixture. According to these results, 78% of these obstetric patients are at risk for anti‐D and candidates for RhIG.

Objective Low levels of neutrophils can be an intrinsic condition, with no clinical consequences or immunity impairment. This condition is the benign constitutional neutropenia (BCN), defined as an absolute neutrophils count (ANC) 2000 cells/mm. Diagnosis of BCN is of exclusion where patients are submitted to blood tests and possibly to invasive diagnostic search until secondary causes of neutropenia are ruled out. The natural history of the disease suggests benign evolution and Brazilian study showed an overall frequency of 2.59%. The main mechanisms include reduced neutrophil production, increased marginalization, extravasation to the tissues and immune destruction. Genetic studies showed strong association between the single nucleotide variant rs2814778 located on chromosome 1q23.2 in the promoter region of the atypical chemokine receptor 1 (Duffy blood group system) gene (ACKR1, also termed DARC) and BCN. The aim of this study is to evaluate FY phenotypes and genotypes including the analysis of the rs 2814778 SNP in Brazilian patients with BCN in order to determine an effective diagnostic tool, allowing reassurance of the patient and cost reduction in their care. Methods Case control study, with 94 individuals (18 patients and 76 controls). Phenotyping was performed by gel test and genotyping was performed by PCR-RFLP. Results White blood cell (WBC) and absolute neutrophils (AN) counts showed lower levels in patients compared to controls. In the patient group 83.3% were genotyped as FY*B/FY*B. The SNP rs2814778 (-67T > C) was identified in 77.8% of the patients genotyped as FY*B-67C/FY*B-67C. In the control group, 72.7% were homozygous for the wild type and 23.3% were heterozygous. Conclusion This study reinforces that FY phenotyping and genotyping can be used to detect most people with BCN, avoiding excessive diagnostic investigation. Besides, this procedure may reduce health costs and be reproductible in clinical practice.

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Background Post-transfusion purpura (PTP) is a rare yet serious disease characterized by severe thrombocytopenia occurring after a blood transfusion. It is caused by alloimmunization against platelet antigens, anti-HPA-1a being the most frequent antibody. We report two cases of PTP and discuss the clinical presentation, diagnosis and management of this serious condition. Case Report Case 1) Female patient, 90 years old, Caucasian, had a fracture in the umerus and head trauma in 2012, followed by upper GI bleeding. Four days after receiving two units of packed RBCs, she presented with a low platelet count (14.000/mm3), petechiae, gum bleeding and oozing from venipuncture sites. The platelet count further dropped to 2.000/mm3the following day. HPA genotyping and HPA antibody identification by MAIPA were performed to investigate post-transfusion purpura, which showed: HPA1bb, 3aa, 5aa and 15ab and presence of antibodies anti-HPA-1a. IVig 400 mg/kG was infused in two consecutive days, with normal platelet counts observed after a week. Two of her three children had the same HPA1bb genotype and performed a matched platelet and RBC donation by apheresis. One matched RBC unit was transfused to correct symptomatic anemia caused by bystander hemolysis seven days after the first transfusion. No platelet transfusions were needed. Case 2) Female patient, 29 years old, afrodescendant, had a hemorrhagic shock after an emergency hysterectomy due to placenta percreta in 2012. She received 14 RBC units, 10 fresh frozen plasmas and 10 units of cryoprecipitate. Two days later, another surgery was necessary to remove a retained coagulum, and she received 10 units of random platelets. Five days later, the platelet count dropped to 5.000/mm3, followed by sudden anemia (Hb=9--> 4,5 g/dL), without clinical or laboratory signs of hemolysis or evidence of bleeding, with normal coagulation times. HPA genotyping and antibody identification by MAIPA were performed and showed an HPA1bb genotype and presence of an anti-HPA-1a antibody. No platelet transfusions were administered and IVig 500mg/Kg was prescribed for 2 days. Only washed RBC units were transfused thereafter. The platelet count rose four days after starting IVig to 134.000/mm3, yet a second course of IVig was necessary a week later to reach normal platelet counts. Discussion Both reports illustrate severe thrombocytopenia in patients who presented with sudden thrombocytopenia up to a week after blood transfusion. Platelet alloimmunization happens after exposure to HPA antigens by transfusion or pregnancy, and severe thrombocytopenia occurs as an anamnestic response after reexposure to platelet antigens in any blood product that contains contaminating platelet membranes. The thrombocytopenia may evolve as an autoimmune process, which may also cause hemolytic anemia due toa bystander phenomenom. Diagnosis is based on the identification of the antibody in the serum of a patient who lacks the corresponding antigen, anti-HPA-1a being the most common. IVig 0,5-1g/Kg for 2 days is the treatment of choice. The RBC units must be washed to avoid exposure to platelet membranes and recurrence of thrombocytopenia. In future transfusions, washed RBCs or HPA1bb blood products should be used. Disclosures: No relevant conflicts of interest to declare.

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.

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.