Entre outubro de 1997 e julho de 1999 pesquisou-se a refratariedade plaquetária em 15 pacientes na fase precoce do TMO alogênico e autoplástico, com idade variando de 1 a 66 anos no Hospital São Camilo. Para esta avaliação, foram utilizados os seguintes parâmetros: evolução clínica, cálculo corrigido do incremento plaquetário (CCI), teste de microlinfocitotoxicidade dependente de complemento (CDC) e ensaios plaquetários por aderência de células vermelhas em fase sólida (SPRCA). A refratariedade plaquetária foi definida como falha de resposta a uma transfusão de dois concentrados de plaquetas ABO compatíveis, quando o cálculo corrigido do incremento plaquetário (CCI) de uma hora pós-transfusional era inferior a 7,5 ou de 24 horas < 4,5. Apenas a análise do CCI de 24 horas mostrou significância estatística. A refratariedade plaquetária foi detectada em 80,0 % dos casos, tendo como causa principal os fatores não imunológicos, como: anfotericina 66,66%, doença veno-oclusiva hepática 53,33%, febre de origem indeterminada 40,0%, esplenomegalia epistaxe leve, febre, melena grave, hematêmese grave e infecção bacteriana 20,0%. Melena leve, enterorragia grave, epistaxe moderada e grave 13,33%, enquanto CIVD, enterorragia moderada e grave 6,66%. Os fatores imunológicos foram representados pela presença da reação aguda do enxerto contra hospedeiro (aGVHD) em 33,0% e infecção por citomegalovírus (CMV) em 13,33%, embora a detecção de auto-anticorpos tenha sido negativa. Conclui-se que a análise do CCI pós-transfusional de 24 horas mostrou ser um método de escolha para detecção da refratariedade e de útil aplicabilidade em pacientes trombocitopênicos refratários, em particular naqueles submetidos ao TMO.
From October 1997 to July 1999, platelet refractoriness was studied in 15 patients, aged from 1 to 66 years old, in the early stage of allogeneic and autologous BMT, carried out at the São Camilo Hospital. The following parameters were used for this analysis: daily clinical progress, 1- and 24 hour-post-transfusion platelet corrected count increment (CCI),complement-dependent microlymphocytotoxicity test (CDC) sensitized by human antiglobulin (AGH) and solid phase red blood cell adherence (SPRCA) platelet analysis. Platelet concentrated products were obtained from automated cell separator machines, filtered through retention filters of pre-storage leukocyte reduction and, subsequently, stored at room temperature for a maximum of 96 hours. Each platelet unit featured on average 0.51 x 10(4) leukocytes, with platelet cell counts of 3.58 x 10(11). The mean pH of each thrombocytapherese concentrate was 6.34 and was storage for 32 hours and 21 minutes. Platelets concentrates were transfused on a prophylactic basis, when the platelet counts were below 20 x 10(9) /L or above these values in cases of therapeutic intervention or bleeding. The platelet refractory potential was defined as the lack of response to a transfusion of two compatible ABO platelet concentrate products confirmed by the reduction in platelet CCI 1 hour after transfusion was less than 7.5 or 24 hours after transfusion was less than 4.5. Only the 24-hour CCI analysis showed statistically significance with the platelets refractoriness occurring in 80.0% of the cases, as a consequence of non-immune factors, such as, amphotericin 66.66%, veno-occlusive disease 53.33 %, undetermined fever 40.0%, splenomegaly, slight nose bleeds, fever, severe melene, severe hematemesis and bacterial infection, 20.0%. Slight melene, severe enterorrhagia and moderate and severe nose bleeds 13.33%, whereas CIVD, moderate and severe enterorrhagia were 6.66%. The presence of immune factors was detected by GVHD and CMV infections that were identified in 33.33% and 13.33% of the cases, respectively, although the detection of autoantibodies was negative. The conclusion is that the 24-hour post-transfusion CCI analysis has proven to be a predictor of platelet refractoriness and a useful test in refractory thrombocytopenic patients, mainly those undergoing BMT.
