RESUMO
T cryptantigen can be exposed on the red cell membrane as a result of removal of terminal glycosides, either by bacterial enzymes or by incomplete synthesis of the cell membrane due to somatic mutation, usually caused by a neoplasm. T-activated erythrocytes have been observed in different pathologies, but they have not been seen associated with other abnormalities of red blood cell proteins described in myelodysplastic syndromes or acute leukaemias. A patient with initial diagnosis of refractory anaemia that evolved into erythroleukaemia showed prolonged T-activation, a depressed A blood-group antigen and an increase of foetal haemoglobin, simultaneously. The evolutive pattern of T-activation suggests more an abnormal erythropoiesis than an enzymatic effect and a certain relationship with the haemolytic syndrome.
Assuntos
Sistema ABO de Grupos Sanguíneos , Anemia Refratária/sangue , Antígenos Glicosídicos Associados a Tumores , Dissacarídeos/análise , Hemoglobina Fetal/análise , Leucemia Eritroblástica Aguda/sangue , Anemia Refratária/patologia , Antígenos de Neoplasias/análise , Eritropoese , Feminino , Humanos , Leucemia Eritroblástica Aguda/etiologia , Pessoa de Meia-Idade , Pré-Leucemia/sangueAssuntos
Doenças da Medula Óssea/patologia , Hematopoese , Pré-Leucemia/patologia , Adolescente , Doenças da Medula Óssea/sangue , Doenças da Medula Óssea/genética , Pré-Escolar , Aberrações Cromossômicas , Transtornos Cromossômicos , Ensaio de Unidades Formadoras de Colônias , Feminino , Humanos , Lactente , Masculino , Pré-Leucemia/sangue , Pré-Leucemia/genéticaRESUMO
Six children who developed acute myelomonocytic leukemia presented with a preleukemic syndrome. The incidence of preleukemic presentation of AMML was 17% of children with acute nonlymphocytic leukemia, or 2.9% of all children with acute leukemia at this institution, incidences similar to those in adults. During the preleukemic phase, which lasted from three to 35 months, all children had anemia, all had infectious complications, and three of six had hemorrhagic tendencies. Three received steroids before the diagnosis of AMML, and all had some objective response. Two patients died before receiving therapy for AMML. Four children who received AMML therapy with combinations including cytosine arabinoside and an anthracycline achieved complete remission. Ultimately, all patients died. Clues to diagnosis of preleukemia include unexplained cytopenias, either absolute or functional, peripheral blasts, progressive megaloblastosis with an elevated B12 value, dyserythropoiesis, abnormalities of nuclear segmentation, nonrandom chromosomal alterations, and reduced marrow colony to cluster ratio in vitro. Until there is a highly effective therapy for ANLL, precisely when to treat the child with preleukemia remains uncertain. However, treatment should be started before infectious complications or hemorrhagic tendencies become life-threatening.