An Experimental Study Comparing the Expansion of Peripheral Blood Natural Killer (NK) Cells Cultured with Artificial Antigen-Presenting Cells, in the Presence or Absence of Bone Marrow Mesenchymal Stem Cells (MSCs).

NK cells have been seen as potential agents in adoptive immunotherapy for cancer. The main challenge for the success of this approach is to obtain a great quantity of activated NK cells for adoptive transfer. The present study had aimed to evaluate the effect of a feeder layer of irradiated MSCs in the in vitro expansion of NK cells. MSCs were obtained from the bone marrow (BM) cells remaining in the bag and filter used in the transplantation of hematopoietic stem cells. NK cells were obtained from peripheral blood (PB) of healthy volunteers. NK expansion and activation were stimulated by culture with artificial antigen-presenting cells (aAPCs) and IL-2, in the presence or absence of BM-MSCs. NK cell proliferation, phenotypic expression and cytotoxic activity were evaluated. Both culture conditions showed high NK purity with predominance of NK CD56brightCD16+ subset post expansion. However, cultures without the presence of MSCs showed higher NK proliferation, expression of activation markers (CD16 and NKG2D) and related cytotoxic activity. In this experimental study, the presence of a feeder layer of irradiated BM-MSCs interfered negatively in the expansion of PB-NKs, limiting their growth and activation. Further investigation is needed to understand the mechanisms of NK-MSC interaction and its implications.

Cut-off value for absolute lymphocytes as an alternative for the immunophenotypic analysis of CD3+ T cells in the monitoring of immunosuppressive therapy with thymoglobulin.

INTRODUCTION: Immunosuppression of T lymphocytes is required for preventing acute rejection after transplantation and for the treatment of chronic autoimmune and inflammatory diseases. The laboratory monitoring for this therapy is the measurement of T cells by immunophenotyping, aiming the target value of less than 20 cells per µL. OBJECTIVE: To establish a cut-off point for the total number of lymphocytes in the automated blood cell count that reflects less than twenty T cells µL by immunophenotyping. METHODS: We studied and evaluated 242 kidney transplant patients that had results of automated blood cell count and quantification of T cells by immunophenotyping technique. The patients were divided into two groups, depending on the T lymphocyte immunophenotyping rates established by lower and higher than 20 cells per µL. After, we evaluated the cut-off point for lymphocytes in the blood cell count with a specificity of 100% to exclude patients with high levels of T lymphocytes. RESULTS: We found that the cut-off point of 70 lymphocytes per µL obtained by automated blood cell count showed 100% of specificity to exclude patients with T-cell counts higher than 20 cells per µL by immunophenotyping. CONCLUSION: The results found in this study may be helpful to monitor the immunosuppressive therapy in kidney transplant patients in places where a flow cytometer is not available, or when this equipment is not present in the full routine.

Cut-off value for absolute lymphocytes as an alternative for the immunophenotypic analysis of CD3+ T cells in the monitoring of immunosuppressive therapy with thymoglobulin / Valor de corte para linfócitos absolutos como alternativa para análise imunofenotípica de células T CD3+ no monitoramento de terapia imunossupressora com timoglobulina

Abstract Introduction: Immunosuppression of T lymphocytes is required for preventing acute rejection after transplantation and for the treatment of chronic autoimmune and inflammatory diseases. The laboratory monitoring for this therapy is the measurement of T cells by immunophenotyping, aiming the target value of less than 20 cells per µL. Objective: To establish a cut-off point for the total number of lymphocytes in the automated blood cell count that reflects less than twenty T cells µL by immunophenotyping. Methods: We studied and evaluated 242 kidney transplant patients that had results of automated blood cell count and quantification of T cells by immunophenotyping technique. The patients were divided into two groups, depending on the T lymphocyte immunophenotyping rates established by lower and higher than 20 cells per µL. After, we evaluated the cut-off point for lymphocytes in the blood cell count with a specificity of 100% to exclude patients with high levels of T lymphocytes. Results: We found that the cut-off point of 70 lymphocytes per µL obtained by automated blood cell count showed 100% of specificity to exclude patients with T-cell counts higher than 20 cells per µL by immunophenotyping. Conclusion: The results found in this study may be helpful to monitor the immunosuppressive therapy in kidney transplant patients in places where a flow cytometer is not available, or when this equipment is not present in the full routine.

Resumo Introdução: A imunossupressão de linfócitos T é necessária para a prevenção da rejeição aguda em transplantes e no tratamento de doenças autoimunes e inflamatórias crônicas. O seu monitoramento laboratorial consiste na quantificação dos linfócitos T realizada pela técnica de imunofenotipagem, na qual o valor preconizado é manter inferior a 20 células/µL. Objetivo: Estabelecer um ponto de corte para o número de linfócitos totais no hemograma automatizado que reflita uma contagem de linfócitos T inferior a 20 células/µL por imunofenotipagem. Métodos: Foram avaliados 242 pacientes transplantados renais que continham resultados do hemograma automatizado e quantificação de linfócitos T por imunofenotipagem. Os pacientes foram divididos em dois grupos, conforme os valores de linfócitos T estabelecidos pela imunofenotipagem: inferiores e superiores a 20 células/µL. A partir disto, foi avaliado o ponto de corte de linfócitos no hemograma com especificidade de 100% para excluir os pacientes com valores elevados de linfócitos T. Resultados: Este estudo evidenciou que o ponto de corte de 70 linfócitos/µL obtidos pelo hemograma automatizado apresentou especificidade de 100% para excluir os pacientes com contagens de linfócitos T superiores a 20 células/µL na imunofenotipagem. Conclusão: Esta pesquisa poderá auxiliar no monitoramento da terapia imunossupressora em pacientes transplantados renais em locais que não possuem um citômetro de fluxo disponível, ou ainda quando este equipamento não se faz presente na rotina integral.

Reference interval determination of hemoglobin fractions in umbilical cord and placental blood by capillary electrophoresis.

INTRODUCTION: Umbilical cord and placental blood (UCPB) is a rich source of hematopoietic stem cells widely used to treat diseases that did not have effective treatments until recently. Umbilical cord and placental blood banks (UCPBBs) are needed to be created to store UCPB. UCPB is collected immediately after birth, processed, and frozen until infusion. Detection of abnormal hemoglobins is one of UCPB screening tests available. The objective of the present study was to determine the reference interval for HbA, HbF, and HbA2 in UCPB using capillary electrophoresis. Methods: Observational retrospective study of UCPB samples undergoing hemoglobin electrophoresis was performed between April 2012 and May 2013. We analyzed 273 UCPB samples. All cords met the criteria of BrasilCORD. RESULTS: We found 19.9% (10.5­36.7%) for HbA, 80.1% (62.7­89.4%) for HbF, and 0.1% (0.0­0.6%) for HbA2. Data were expressed as median (P2.5­P97.5). CONCLUSION: Establishing specific reference intervals is the best option for most tests because such ranges reflect the status of the population in which the tests will be applied. The use of appropriate reference intervals ensures that clinical labs provide reliable information, thus enabling clinicians to correctly interpret results and choose the best approach for the target population.