ABSTRACT
White cell (WBC)-reduction filters have been shown to be effective in removing infectious agents from infected blood products. In this study, the mechanisms of Trypanosoma cruzi (T. cruzi) retention by WBC-reduction filters were assessed. Human packed red blood cell (PRBC) and platelet concentrate (PC) samples were contaminated with T. cruzi organisms (Y strain; 3.4 x 10(6)/ml), and then filtered using WBC-reduction experimental filters that provided about 3 log10 WBC removal. Transmission electron microscopy sections showed that T. cruzi parasites were removed from contaminated PRBC and PC samples primarily by mechanical mechanism without interacting with filter fibers or blood cells. In addition, we found that T. cruzi parasites were also removed by a direct fiber adhesion. These data indicate that T. cruzi parasites are removed from infected blood not only by mechanical mechanism but also by biological mechanism probably mediated by parasite surface proteins.
Subject(s)
Leukocytes/parasitology , Trypanosoma cruzi/isolation & purification , Animals , Hemofiltration/methods , Humans , Leukocytes/ultrastructure , Microscopy, Electron/methodsABSTRACT
A presença de leucócitos nos produtos hemoterápicos alogênicos transfundidos tem sido associada à ocorrência de determinadas reaçöes transfusionais, tais como a reaçäo transfusional febril näo-hemolítica, a aloimunizaçäo e refratariedade à transfusäo de plaquetas, a doença enxerto-versus-hospedeiro, e a efeitos imuno-modulatários. Além disso, os leucócitos podem ser vetores de transmissäo de agentes infecciosos, tais como o CMV, o HTLV-I/II e o EBV. Tem sido postulado que a remoçäo dos leucócitos em hemocomponentes mediante uso de filtros leucocitários pode prevenir a ocorrência dessas reaçöes. Entretanto, a eficácia clínica da desleucotizaçäo permanece sem definiçäo. Tem sido sugerido que a remoçäo de 1 log(10) de leucócitos previne a reaçäo transfusional näo-hemolítica, a remoçäo de 2 log(10) pode prevenir a transmissäo de viroses, enquanto que a remoçäo de maior ou igual 3 log(10) pode ser necessária para a prevençäo de aloimunizaçäo plaquetária. Entretanto, devido à carência de estudos que analisem apropriadamente as vantagens do uso clínico rotineiro dos filtros, permanecem sem completa definiçäo quais säo as reais indicaçöes clínicas para o uso de hemocomponentes desleucotizados; quais säo os graus de desleucotizaçäo necessários para prevenir as diferentes reaçöes; e se a remoçäo dos leucócitos deve ser realizada antes ou após o armazenamento de hemocomponente. Dessa maneira, somente estudos clínicos prospectivos poderäo definir o custo-benefício da aplicaçäo clínica de filtros leucocitários em hemoterapia.
Subject(s)
Humans , Blood Component Removal/methods , Blood Transfusion , Leukocytes , Blood Transfusion/adverse effects , FiltrationABSTRACT
Leukocytes present in allogeneic blood components have been associated with adverse effects to the recipient. These include the development of febrile transfusion reactions, alloimmunization to human leukocyte antigens, graft-versus-host disease, and immunomodulatory effects. In addition, such leukocytes may be the vector of infectious agents such as CMV, HTLV-I/II, and EBV. It has been postulated that the use of white blood cell filters to reduce the leukocyte content in allogeneic blood products may minimize the occurrence of these biological adverse effects associated with leukocytes present in transfused blood products. However, it is still to be determined the clinical effectiveness of leukodepletion. It has been suggested that 1 log10 leukocyte reduction prevents febrile non-hemolytic transfusion reactions; that a 2 log10 reduction may prevent the transmission of viruses; and that a > or = 3 log10 reduction may be necessary to prevent platelet alloimmunization. However, because there are no data available as guidelines for the use of leukodepleted blood products for most clinical indications, the use of white cell filters should be restricted to selected patients for whom such data exist. Properly designed prospective clinical trials are necessary to provide data to help to define the cost-benefit of the clinical application of leukodepletion.
Subject(s)
Blood Component Removal/methods , Blood Transfusion , Leukocytes , Filtration , Humans , Transfusion ReactionSubject(s)
Anemia, Aplastic/diagnosis , Adolescent , Adult , Aged , Anemia, Aplastic/etiology , Blood Cell Count , Bone Marrow/pathology , Child , Female , Hepatitis/complications , Humans , Male , Middle Aged , Pesticides/adverse effects , PrognosisABSTRACT
Os autores analisam 21 casos consecutivos de aplasia a fim de avaliar os fatores de importancia prognostica. Assim, estudam os dados clinicos, hemograma e biopsia de medula ossea ao diagnostico,e aplicam os indices de Lynch e Camitta. Os pacientes foram reavaliados clinica e laboratorialmente aos 3 meses de evolucao, e repetem o indice de Camitta. Observam tambem o tempo de evolucao, obito e suas causas. Dos parametros medidos, previram mau prognostico o tempo de historia menor de 3 meses, presenca de sangramento importante, e a biopsia de medula mostrando ausencia total de hemopoiese e/ou linfocitose. Os indices prognosticos, por si sos, nao tiveram importancia decisiva. Por isso, segundo o material dos autores, foi mais importante uma avaliacao clinica multifatorial do que dados hematologicos ou indices prognosticos isolados
