Trombocitopenia neonatal: Revisión. II. Trombocitopenias no inmunes; transfusión de plaquetas / Neonatal thrombocytopenia: A review.II. Non-immune thrombocytopenia; platelet transfusion

Las trombocitopenias de causa no inmunológica son ocasionadas por múltiples patologías; las más frecuentes son las debidas a infecciones extra- o intrauterinas y las secundarias a otras patologías involucradas en la interrelación niño-placenta-madre. En este segundo artículo, se enumeran sus causas y se describen en detalle las distintas patologías. La transfusión de plaquetas es ampliamente utilizada en neonatología, tanto para tratamiento como para profilaxis de hemorragias. Sin embargo, no hay aún consenso generalizado sobre el umbral de recuento plaquetario conveniente para indicar la transfusión ni sobre sus reales indicaciones. Se comentan artículos recientes sobre las distintas estrategias propuestas. Se enfatiza la discusión sobre los múltiples efectos adversos de las transfusiones de plaquetas, cuyo conocimiento está cambiando el paradigma relativo a sus indicaciones, lo que sugiere que se debe aplicar una política mucho más restrictiva al respect

Non-immune thrombocytopenia is caused by multiple pathologies; the most common causes are extra- or intrauterine infections, whereas secondary cases result from other pathologies involved in the fetal-placental-maternal interface. This second article lists its causes and provides details of the different pathologies. Platelet transfusion is widely used in neonatology, both as treatment and as bleeding prophylaxis. However, there is no general consensus about the platelet count threshold that is convenient to indicate a transfusion or actual indications. Recent articles are commented regarding the different proposed strategies. The emphasis is on discussing the multiple adverse effects of platelet transfusions because knowledge about them is changing the paradigm for indications, suggesting that a much more restrictive policy is required

Anaphylactic Transfusion Reaction in a Patient with Anhaptoglobinemia: The First Case in Korea

Anaphylactic transfusion reactions are rare complications of blood transfusions. Anhaptoglobinemia, a condition that has high incidence in Asia, can cause allergic transfusion reactions or anaphylaxis in severe cases. A 50-yr-old Korean woman was diagnosed with relapsed acute promyelocytic leukemia. She developed thrombocytopenia during chemotherapy and an anaphylactic transfusion reaction on the 4th and 5th platelet transfusions immediately after the transfusion of the platelet concentrates was initiated. Blood analysis showed no detectable serum haptoglobin. We examined her genetic phenotype and detected anhaptoglobinemia, which occurs because of an allelic deletion in the Hp gene cluster. The presence of an antibody against haptoglobin was detected by performing ELISA. To prevent anaphylactic reactions, apheresis platelets were transfused after washing. Consequently, anaphylactic transfusion reactions did not develop. Here, we report the first case of anhaptoglobinemia causing anaphylactic transfusion reaction in Korea.

Identification of platelet refractoriness in oncohematologic patients

OBJECTIVES: To identify the occurrence and the causes of platelet refractoriness in oncohematologic patients. INTRODUCTION: Platelet refractoriness (unsatisfactory post-transfusion platelet increment) is a severe problem that impairs the treatment of oncohematologic patients and is not routinely investigated in most Brazilian services. METHODS: Forty-four episodes of platelet concentrate transfusion were evaluated in 16 patients according to the following parameters: corrected count increment, clinical conditions and detection of anti-platelet antibodies by the platelet immunofluorescence test (PIFT) and panel reactive antibodies against human leukocyte antigen class I (PRA-HLA). RESULTS: Of the 16 patients evaluated (median age: 53 years), nine (56 percent) were women, seven of them with a history of pregnancy. An unsatisfactory increment was observed in 43 percent of the transfusion events, being more frequent in transfusions of random platelet concentrates (54 percent). Platelet refractoriness was confirmed in three patients (19 percent), who presented immunologic and non-immunologic causes. Alloantibodies were identified in eight patients (50 percent) by the PIFT and in three (19 percent) by the PRA-HLA. Among alloimmunized patients, nine (64 percent) had a history of transfusion, and three as a result of pregnancy (43 percent). Of the former, two were refractory (29 percent). No significant differences were observed, probably as a result of the small sample size. CONCLUSION: The high rate of unsatisfactory platelet increment, refractoriness and alloimmunization observed support the need to set up protocols for the investigation of this complication in all chronically transfused patients, a fundamental requirement for the guarantee of adequate management.

Contaminação bacteriana em concentrados plaquetários: identificação, perfil de sensibilidade aos antimicrobianos e sepse associada à transfusão / Bacterial contamination on platelet concentrates: identification, antimicrobial susceptibility profile and transfusion-related sepsis

INTRODUÇÃO: Devido à sepse bacteriana associada à transfusão de concentrados plaquetários (CPs) ter sérias consequências clínicas para os pacientes, alguns procedimentos têm sido incorporados na preparação e no controle de qualidade dos componentes sanguíneos para reduzir o risco da contaminação bacteriana. Este artigo descreve a prevalência da contaminação bacteriana dos CPs que foram transfundidos, o espectro bacteriano detectado com seu perfil de sensibilidade aos antimicrobianos e as reações transfusionais nos receptores. MÉTODOS: Um total de 292 CPs (278 randômicos e 14 por aférese), proveniente do Hemocentro do Estado do Rio Grande do Sul (HEMORGS) de Santa Maria foi testado. As quantidades de 100μL e 200μL foram coletadas da porção tubular da bolsa de plaquetas e semeadas utilizando dois tipos de metodologias. RESULTADOS: Em cinco unidades(1,7 por cento; 5/292) foram isoladas bactérias pela metodologia qualitativa e apenas uma pela quantitativa. Staphylococcus epidermidis foi o microrganismo identificado em todas as amostras. Dois pacientes apresentaram sepse associada à transfusão com desfecho fatal. CONCLUSÕES: A contaminação bacteriana pelas transfusões de CPs constitui-se num importante problema de saúde pública devido a sua associação com altas taxas de morbidade e mortalidade. Neste estudo, somente microrganismos gram-positivos foram isolados sendo que nenhuma amostra obtida por aférese apresentou contaminação.

INTRODUCTION: Bacterial sepsis associated with the transfusion of platelet concentrates (PCs) results in serious clinical implications for patients. Given these implications, certain procedures have been integrated into the preparation and quality control of blood components to reduce the risk of bacterial contamination. This article describes the prevalence of bacterial contamination on transfused PCs, the bacterial spectrum detected and their antimicrobial susceptibility profile and transfusion reactions in receptors. METHODS: A total of 292 PCs (278 random and 14 per apheresis) from the Blood Center of the State of Rio Grande do Sul (HEMORGS), located in the city of Santa Maria, were tested. Quantities of 100μL and 200μL were collected from platelet bag tubing and seeded using two methodologies. RESULTS: Using the qualitative methodology, bacteria were isolated in five units (1.7 percent; 5/292), while only one was isolated using the quantitative methodology. Staphylococcus epidermidis was the microorganism identified in all samples. Two patients died of transfusion-related sepsis. CONCLUSIONS: Bacterial contamination due to PC transfusion is considered a major public health problem due to its association with high rates of morbidity and mortality. In this study only gram-positive microorganisms were isolated and none of the samples obtained by apheresis presented contamination.

Cytokine generation in stored platelet concentrate: comparison of two methods of preparation.

BACKGROUND & OBJECTIVES: Contaminating white blood cells (WBCs) in stored platelet concentrates (PC) are the main source of pro-inflammatory cytokines including interleukin-6 (IL-6), interleukin- 8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) that are implicated in transfusion reactions. We compared the levels of these cytokines in stored platelet preparations prepared by two methods. Effect of pre-storage leucofiltration on these cytokine levels was also studied. METHODS: Twelve units of pooled PCs were prepared by platelet rich plasma (PRP) method and buffy-coat (BC) method each and stored for 5 days. IL-6, IL-8 and TNF-alpha levels were measured in platelet supernatants on day 0, 1, 3 and 5 of the storage using commercially available immunoassays. Pre-storage leucofiltration was done in 4-pooled units of PRP-PC and cytokine levels compared with unfiltered PCs. RESULTS: Median IL-6 levels increased from day 0 to day 5 in both PRP-PC and BC-PC. In PRP-PC, IL-8 increased from <3 pg/ml on day 0 to 817 pg/ml on day 5, while in BC-PC the corresponding levels were 10 and 346.5 pg/ml, respectively. No significant increase in levels of TNF-alpha was observed in BC-PC during storage period, while levels increased significantly in PRP-PC on day 1 only. There was no significant change in the levels of all three cytokines in leucofiltered PCs over 5 days of storage. INTERPRETATION & CONCLUSION: Findings of our study showed that method of preparation and WBC content are the critical factors in determining the cytokine levels in stored PCs.

Platelet therapy.

Thrombocytopenia is a major cause of bleeding episodes at all ages. The pathophysiology, causes of thrombocytopenia and clinical presentation have been reviewed briefly. However the emphasis has been laid on various aspects of platelet support such as indications and amount of platelet support essential for management of bleeding episodes with the help of platelet concentrates, single donor platelets. Strategies for management of platelet transfusion refractoriness has also been included for effective management of bleeding episodes in these conditions.

Immediate transfusion reactions

Immediate transfusion reactions were characterized in recipients of 15,990 RBCs, 18,013 platelets, 409 single donor platelets, 3,451 FFP and 1,507 units of cryoprecipitate. The overall incidence of immediate reactions was 0.2. Allergic reactions occurred in 40 patients, febrile non-hemolytic in 36 patients, bacterial contamination in 2 patients, circulatory overload in 3 patients and mechanical hemolysis in one patient. Three patients had nonspecific reactions. The incidence of immediate transfusion reactions was low when compared with similar studies. Possible causes are under-reporting transfusion reactions and the use of leukoreduced components.

Aloinmunización plaquetaria en pacientes onco-hematológicos politransfundidos: estudio prospectivo en adultos y niños / Platelet alloimmunization in patients with multiple transfusions. Prospective study in adults and children

Background: Refractoriness continues to he a major complication of platelet transfusion therapy in patients with multiple transfusions: Despite most cases are secondary to non-immune causes, the most serious is that associated to alloimmunization. The incidence and consequences of HLA and non-HLA (platelet specific) antibodies are unknown in our country. Aim: To prospectively determinate the frequency and characteristic of post transfusion alloimmunization and the incidence of platelet specific antibodies. Patients and methods: Forty one adults and 24 children with a recently diagnosed malignancy and undergoing chemotherapy that required multiple transfusions were studied. Screening for antiplatelet antibodies (platelet membrane ELISA) was performed before the first transfusion, every four weeks or whenever the 1 hour corrected count increment for platelet transfusions was lower that 5000. Platelet specific antibodies werw identified with a monoclonal antibody-specific immobilization of platelet antigens (MAIPA), with anti-GPIIb, GPIIb/IIIa, GPIa/lia and anti-HLA class I. Results: Adult patients received an averafge of 10.2 ñ 5.5 units of red blood cells and 58.6 ñ 35.4 units of platelets. Children received 4.8 ñ 3.7 units of red blood cells and 9.6 ñ 6.7 units of platelets. HLA antibodies appeared in 7 of 41 adult patients (17 percent), platelet specific alloantibodies were found in two patients (one anti GP Ia/IIa and one anti GP ib). Platelet refractoriness appeared in three alloimmunized patients. No Child had detectable serum antibodies during follow up. Conclusions: Platel transfusion refractoriness of immune origin occurs infrequently in our population and the presence of platelet antibodies does not mean that it will appear. The use of leukocyte depleted blood components to prevent refractoriness cannot be justified at this time

Aplasia medular / Aplastic anemia

Se estudiaron retrospectivamente 54 pacientes con diagnóstico de Anemia Aplásica (AA) desde enero de 1983 a junio 1992 en el Hospital Nacional Cayetano Heredia. Información completa se obtuvo en 51 casos. Treintaidos (62.7 por ciento) fueron del sexo masculino y 19 (37.3 por ciento) del femenino. La edad promedio fué 25 años, 51 por ciento de los pacientes estuvieron en los primeros 20 años de vida. 32 pacientes (62.7 por ciento) dieron antecedentes de un probable agente causal de la aplasia en el último año previo al diagnóstico. Se encontró una incidencia de 4.05 casos por 100,000 pacientes atendidos y de 4.8 casos por cada 10,000 egresos en nuestro hospital. Anemia aplásica severa (AAS) fué observada en el 83.7 por ciento de los casos. Anemia aplásica no severa (AANS) en el 16.3 por ciento y 10 por ciento de los pacientes tuvieron anemia aplásica muy severa (AAMS). Dieciseis pacientes recibieron altas dosis de 6 metil Prednisolona, 4 pacientes globulina antilinfocítica y el resto andrógeno y tratamiento de soporte. El 50 por ciento de los fallecidos fué por sepsis, el 42.9 por ciento por sangrado en el SNC y 7.1 por ciento por sepsis y sangrado. La probabilidad de sobrevida fue ligeramente mayor en el grupo tratado con altas dosis de 6-meti-prednisolona que en el grupo con andrógenos y tratamiento de soporte