Although the graft-versus-leukemia effect of allogeneic bone marrow transplantation (BMT) is of paramount importance in the maintenance of disease remission, the role played by the autologous T-cell response in antitumor immune surveillance is less defined. We evaluated the emergence of antileukemia cytotoxic T-lymphocyte precursors (CTLp's) and the correlation of this phenomenon with maintenance of hematologic remission in 16 children with acute myeloid leukemia (AML), treated with either chemotherapy alone (5 patients) or with autologous BMT (A-BMT, 11 patients). Antileukemia CTLp's were detectable in 8 patients in remission after induction chemotherapy; none of them subsequently had a relapse. Of the 8 patients who did not show detectable CTLp frequency while in remission after induction chemotherapy, 7 subsequently experienced leukemia relapse. In patients undergoing A-BMT, molecular fingerprinting of the TCR-Vβ repertoire, performed on antileukemia lines, demonstrated that selected antileukemia T-cell clonotypes, detectable in bone marrow before transplantation, survived ex vivo pharmacologic purging and were found in the recipient after A-BMT. These data provide evidence for an active role of autologous T cells in the maintenance of hematologic remission and also suggest that quantification of antileukemia CTLp frequency may be a useful tool to identify patients at high risk for relapse, thus potentially benefiting from an allogeneic antitumor effect.

Este estudo, tem como o objetivo determinar a freqüência das hemoglobinopatias em neonatos, que realizaram a coleta para o Teste de Triagem Neonatal para Distúrbios Metabólicos no Hospital de Clínicas de Porto Alegre. O método utilizado para a determinação das variantes da hemoglobina, foi eletroforese por focalização isoelétrica em amostra de sangue total, coletadas em papel filtro por punção do calcanhar. Para confirmação diagnóstica dos casos alterados, foram realizadas eletroforeses das hemoglobinas em acetato de celulose com pH 8,6 e em citrato de ágar com pH 6,2, em amostra de sangue total dos neonatos e dos seus progenitores. Foram analisados, 1.615 indivíduos, e identificada a presença da hemoglobina S em 20 amostras e da hemoglobina C em seis amostras. Esses valores, correspondem a uma freqüência de 1,2% para o gene da anemia falciforme e 0,4% para o gene da doença de hemoglobina C, independente da raça ou ascendência. Esses dados, sugerem que a inclusão da triagem neonatal universal para hemoglobinopatias nos projetos já implementados para fenilcetonúria e hipotireoidismo congênito, apresenta vantagens e deve ser considerada pelos programas de saúde.

Aims: The aim of this study is to develop a population pharmacokinetic (PopPK) model for intravenous busulfan in children that incorporates variants ofGSTA1, gene coding for the main enzyme in busulfan metabolism.Methods: Busulfan concentration–time data was collected from 112 children and adolescents (median 5.4 years old, range: 0.1–20) who received intravenous busulfan during the conditioning regimen prior to stem cell transplantation. Weight, sex, baseline disease (malignantvs.non‐malignant), age, conditioning regimen andGSTA1diplotypes were evaluated as covariates of pharmacokinetic parameters by using nonlinear mixed effects analysis. The ability to achieve the target AUC_24h(3600–6000 μM min⁻¹) was assessed by estimating the first dose based on the present PopPK model and by comparing the results with other available models in children.Results: A one‐compartment model with first‐order elimination best described the data. Allometric scaling of weight and a factor of busulfan metabolism maturation were included in the base model.GSTA1diplotypes were found to be a significant covariate of busulfan clearance, which was 7% faster in rapid metabolizers and 12% slower in poor metabolizers, in comparison with normal ones. Busulfan doses calculated using the parameters of the proposed PopPK model were estimated to achieve the target AUC in 85.2% of the cases (95% CI 78.7–91.7%).Conclusion: This is the first PopPK for busulfan that successfully incorporatedGSTA1genotype in a paediatric population. Its use may contribute to better prediction of busulfan exposure in children and adolescents since the first dose, by tailoring the dose according to the individual metabolic capacity.