Titers of ABO antibodies in group O blood donors

BACKGROUND: Plasma components of group O blood donations are rarely submitted to ABO antibody titrations even though it is well known that passively acquired antibodies may destroy the recipient's own red cells and tissue grafts. OBJECTIVE: Thus, group O donations stratified by gender and age were randomly titrated to identify the best source of products for apheresis and exsanguinous transfusion. METHODS: Samples from 603 blood donors were tested by ABO antibody titration using the conventional tube technique at room temperature. ABO antibody levels higher than 64 were considered high. After correction for gender, statistical analyses were performed using the Fisher exact and Kruskal-Wallis tests. RESULTS: Most donors in the blood bank were male (65.7 percent). ABO antibody titers ranged from 1 to 2048. The estimations of prevalence for the titers were: anti-A,B < 128 = 86.9 percent and > 128 = 2.16 percent; Anti-A > 128 = 9.29 percent and anti-B > 128 = 4.81 percent. Low mean titers for both anti-A and anti-B antibodies were found in over 50-year-old men (p-value = 0.040). High anti-B antibody levels were found in young women (p-value = 0.002). CONCLUSION: This study confirms that over 50-year-old O group men should be selected as blood donors in non-identical ABO transfusion situations. Also, titration of ABO antibodies in blood banks will increase safety in non-identical ABO transfusions.

Recuperação autóloga de sangue intra-operatória: validação com marcador tumoral específico em câncer de próstata / Intraoperative Autologous Blood Recovery: validation with a specific tumour marker in prostate cancer

INTRODUÇÃO: Padrões de metilação aberrante em amostras de DNA de pacientes com câncer são marcadores moleculares sensíveis. A hipermetilação na região promotora de GSTP-1 está presente em mais de 90% dos pacientes com câncer de próstata e pode ser avaliada através de técnicas de PCR. A recuperação autóloga intra-operatória durante cirurgia oncológica não tem sido recomendada devido ao risco de células tumorais estarem circulantes neste sangue. Nosso objetivo é demonstrar que o sangue recuperado de cirurgia oncológica pode estar livre de células tumorais após a utilização de filtros para remoção de leucócitos e irradiação, através da hipermetilação do promotor de GSTP-1 como marcador. MÉTODOS: Realizamos recuperação autóloga intraoperatória em prostatectomia radical sem a reinfusão do sangue. Somente os casos com hipermetilação do promotor de GSTP-1 nas amostras de tumor fresco foram incluídas. Uma amostra de sangue periférico foi colhida na indução anestésica. O sangue recuperado foi colhido ao longo da cirurgia e então submetido à lavagem; filtração e irradiação (25 Gy). As amostras foram estudadas em cada etapa para detectar a presença de células de tumor de próstata contaminantes, através de ensaios qualitativos e de “real time” PCR metilação específica. RESULTADOS: Detectamos células de tumor de próstata no sangue recuperado através da presença de metilação para GSTP-1 nos ensaios de PCR qualitativos. Após filtração e irradiação as análises de “real time” PCR confirmaram a ausência de metilação, sugerindo a ausência de células viáveis. DISCUSSÃO: Utilizando uma abordagem epigenética não evidenciamos célula tumoral viável ou DNA no sangue recuperado desses pacientes após filtração e irradiação. Esses resultados apontam para a segurança da recuperação de sangue associando filtração e irradiação em cirurgia oncológica...

INTRODUCTION: Aberrant DNA methylation patterns provide a powerful sensitive detection molecular marker to cancer. GSTP-1 hypermethylation is present in more than 90% of prostate cancer patients and can be measured by PCR-based techniques. Blood salvage during cancer surgery is limited due to the potential presence of circulating tumour cells. We aimed to show that intraoperative salvaged blood can be freed of tumour cells after leucodepletion filters and irradiation of washed blood using GSTP-1 hypermethylation as a biomarker. METHODS: We performed intraoperative blood recovery in radical prostatectomy without reinfusion. Only cases with GSTP-1 hypermethylation in the fresh tumour samples were included. A peripheral blood sample was collected during anaesthesia induction. Salvaged blood was collected throughout the surgery and then submitted to washing, leukoreduction and irradiation. Samples were studied stepwise for the presence of prostate tumour cell contamination using qualitative and realtime methylation specific PCR. RESULTS: Prostate tumour cells detected by positive results for GSTP-1 in washed salvaged blood became negative after filtration and irradiation in qualitative PCR. It was confirmed by quantitative assay, thus suggesting the absence of viable cells. DISCUSSION: Using an epigenetic approach no tumour viable cell or DNA was found in the salvaged blood of these patients after filtration and irradiation (25Gy). These results point to the safety of blood salvage with filtration and irradiation in cancer surgery (AU)