The typical characteristics of mesenchymal stem cells (MSCs) can be affected by inflammatory microenvironment; however, the exact contribution of HTLV-1 to MSC dysfunction remains to be elucidated. In this study, we demonstrated that MSC cell surface molecules VCAM-1 and ICAM-1 are upregulated by contact with HTLV-1, and HLA-DR was most highly expressed in MSCs co-cultured with MT2 cells. The expression levels of VCAM-1 and HLA-DR were increased in MSCs cultured in the presence of PBMCs isolated from HTLV-1-infected symptomatic individuals compared with those cultured with cells from asymptomatic infected individuals or healthy subjects. HTLV-1 does not impair the MSC differentiation process into osteocytes and adipocytes. In addition, MSCs were efficiently infected with HTLV-1 in vitro through direct contact with HTLV-1-infected cells; however, cell-free virus particles were not capable of causing infection. In summary, HTLV-1 can alter MSC function, and this mechanism may contribute to the pathogenesis of this viral infection.

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Extended blood group genotyping is an invaluable tool used for prevention of alloimmunization. Genotyping is particularly suitable when antigens are weak, specific antisera are unavailable, or accurate phenotyping is problematic because of a disease state or recent transfusions. In addition, genotyping facilitates establishment of mass-scale patient-matched donor databases. However, standardization of genotyping technologies has been hindered by the lack of reference panels. A wellcharacterized renewable reference panel for standardization of blood group genotyping was developed. The panel consists of genomic DNA lyophilized and stored in glass vials. Genomic DNA was extracted in bulk from immortalized lymphoblastoid cell lines, generated by Epstein-Barr virus transformation of peripheral blood lymphocytes harvested from volunteer blood donors. The panel was validated by an international collaborative study involving 28 laboratories that tested each DNA panel member for 41 polymorphisms associated with 17 blood group systems. Overall, analysis of genotyping results showed >98% agreement with the expected outcomes, demonstrating suitability of the material for use as reference. Highest levels of discordance were observed for the genes CR1, CD55, BSG, and RHD. Although limited, observed inconsistencies and procedural limitations reinforce the importance of reference reagents to standardize and harmonize results. Results of stability and accelerated degradation studies support the suitability of this panel for use as reference reagent for blood group genotyping assay development and standardization.

Objectives:The aim of this study was to verify the possibility of performing prophylactic Rh genotype-matching in Brazilian patients with sickle cell disease (SCD) and identify the genotypes that are lacking or insufficient in our donor cohort.Background: Rh alloimmunisation is still a challenge in transfused patients with SCD. Rh genotype-matching may mitigate Rh alloimmunisation. Methods/Materials:We examined the transfusion requests for antigen-matched donor units in SCD patients with Rh variants and compared the Rh altered alleles in the patients to the Rh allele frequency in a selected donor population. For each patient and donor, RBC antigen genotyping was performed using HEA, RHD and RHCE BeadChip arrays. Sequencing was used to clarify inconclusive results. Twenty-one patients and 956 Brazilian blood donors were genotyped.Results: According to our matching strategies, 47·6% of patients filled most of their unit requests, but 52·4% of patients had insufficient donors to fill their annual transfusion needs. We found different combinations of RHCE variant alleles in patients and donors, but the most frequent genotypes that are lacking or insufficient in our donor cohort are those associated with the lack of hr B and hr S high prevalence antigens and those co-inherited with altered RHD alleles. Conclusion:Our study shows that the provision of compatible blood with Rh genotype-matching in Brazilian patients with SCD can be feasible but challenging and, efficient strategies of recruitment of African-Brazilian donors must be developed.

False-positive and false-negative reactions exist for serological and molecular antigen typing methods. If the predicted phenotype is inconsistent with the patient`s known antibodies or serological phenotype, the discrepancy must be investigated. False-negative and false-positive results are clinically problematic in blood donors and patients. In this study, we investigated discrepant results between serology and molecular testing in patients and blood donors that occurred in daily molecular laboratory practice over a two year-period. SCD patients represented a large percentage of our cases of discrepancies but we also observed a high prevalence of discrepancies between phenotypes and genotypes in blood donors. The main reasons that led to discrepancies were recent transfusions and limitations of phenotyping. Discrepancies classified as false positive phenotype/ true negative genotype and false negative phenotype/true positive genotype occurred mainly in patients with recent transfusions and individuals with RH variants while those classified as true negative phenotype/false positive genotype involved null phenotypes due to silent genes. Despite the limitations of molecular methods currently employed, we found more false-negative and false-positive phenotypes than genotypes demonstrating that genotyping is more efficient to define the blood types, especially in transfusion dependent patients.

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The characterization of cell types that are susceptible to HTLV-1 infection is essential to understand of the biology of virus infection and the pathophysiology of HTLVrelated diseases. In the present study, we investigated bone marrow (BM) cells from asymptomatic carriers (HAC) and symptomatic HTLV-1 individuals. Initially, we observed an infiltrated of CD4 + T-cell lymphocytes in BM from HTLV-1 individuals when compared to healthy controls (p≤0.02). The proviral DNA of BM HTLV-1 CD4 +