Mariana R. B. Mello

Elevated plasma levels and platelet‐associated expression of the pro‐thrombotic and pro‐inflammatory protein, TNFSF14 (LIGHT), in sickle cell disease

Chronic vascular inflammation and endothelial activation may initiate vaso‐occlusion in sickle cell disease (SCD). TNFSF14 (CD258; LIGHT), a recently‐identified pro‐thrombotic and pro‐inflammatory tumour necrosis factor (TNF)‐superfamily cytokine, has a potent activating effect on endothelial cells. We evaluated whether TNFSF14 production is altered in SCD and whether platelets contribute to this production. TNFSF14 was measured in platelet‐free plasma from healthy‐control individuals (CON), steady‐state sickle cell anaemia (SCA), SCA on hydroxycarbamide therapy (SCAHC) and haemoglobin SC (HbSC) patients. Mean plasma TNFSF14 was significantly increased in SCA, SCAHC and HbSC, compared to CON individuals. In SCA/SCAHC patients, plasma TNFSF14, showed no correlation with haematological variables, but was significantly correlated with serum lactate dehydrogenase and inflammatory markers (CD40LG , IL8 and ICAM1). Platelet‐membrane TNFSF14 expression was significantly augmented on SCA platelets, and correlated with platelet activation; furthermore, measurement of platelet TNFSF14 release indicated that platelets may be a major source of circulating TNFSF14 in SCA. Interestingly, high plasma TNFSF14 was significantly associated with elevated tricuspid regurgitant velocity (≥2·5 m/s) in a population of SCA/SCAHC patients. The pro‐inflammatory and atherogenic cytokine, TNFSF14, could contribute to endothelial activation and inflammation in SCA; future investigations may confirm whether this protein contributes to major clinical complications of the disease, such as pulmonary hypertension, and represents a potential therapeutic target.

Erythropoiesis-driven regulation of hepcidin in human red cell disorders is better reflected through concentrations of soluble transferrin receptor rather than growth differentiation factor 15

Growth differentiation factor 15 (GDF‐15) is a bone marrow‐derived cytokine whose ability to suppress iron regulator hepcidin in vitro and increased concentrations found in patients with ineffective erythropoiesis (IE) suggest that hepcidin deficiency mediated by GDF‐15 may be the pathophysiological explanation for nontransfusional iron overload. We aimed to compare GDF‐15 production in anemic states with different types of erythropoietic dysfunction. Complete blood counts, biochemical markers of iron status, plasma hepcidin, GDF‐15, and known hepcidin regulators [interleukin‐6 and erythropoietin (EPO)] were measured in 87 patients with red cell disorders comprising IE and hemolytic states: thalassemia, sickle cell anemia, and cobalamin deficiency. Healthy volunteers were also evaluated for comparison. Neither overall increased EPO, nor variable GDF‐15 concentrations correlated with circulating hepcidin concentrations (P = 0.265 and P = 0.872). Relative hepcidin deficiency was found in disorders presenting with concurrent elevation of GDF‐15 and soluble transferrin receptor (sTfR), a biomarker of erythropoiesis, and sTfR had the strongest correlation with hepcidin (rS = −0.584, P < 0.0001). Our data show that high concentrations of GDF‐15 in vivo are not necessarily associated with pathological hepcidin reduction, and hepcidin deficiency was only found when associated with sTfR overproduction. sTfR elevation may be a necessary common denominator of erythropoiesis‐driven mechanisms to favor iron absorption in anemic states and appears a suitable target for investigative approaches to iron disorders. Am. J. Hematol. 89:385–390, 2014.

Hidroxiuréia em pacientes com síndromes falciformes acompanhados no Hospital Hemope, Recife, Brasil

The use of hydroxyurea increases concentrations of fetal hemoglobin (Hb F) in sickle cell disease patients. It has been used in adults and in trials with children with the aim of preventing events such as episodes of pain or stokes. The objective of this study was to analyze the efficacy and side effects of Hydroxyurea in children with ages ranging from 5 to 17 years and also in young adults with SS or Sβ0 hemoglobinopathies. The patients were treated in the outpatient clinic of the Hemope Hospital. Young patients were treated with hydroxyurea at 10 mg/kg/day which was increased by 5 mg/kg/day at 8-week intervals until reaching a maximum dose of 25 mg/kg/day. For adults, the treatment started at 500 mg/day and increased until a dose of 1000 mg/day was reached. Total Hb F levels and the Mean Corpuscular Volume rose with hydroxyurea therapy and there was a reduction of events involving pain as well as the necessity of hospitalization among the pediatric patients. With the over 18year-old patients, a better clinical state was noticed together with a rise in hemoglobin levels and a reduction in the reticulocyte, leukocyte and platelet counts. No signs or symptoms in respect to drug toxicity were evidenced in either group. The use of hydroxyurea seems to be safe and effective in both children and young adults with sickle cell disease. The drug also improves theO uso de hidroxiureia promove a elevacao dos niveis de hemoglobina fetal (Hb F) em pacientes portadores de sindromes falciformes (SF) e o medicamento vem sendo estudado em varios grupos de pacientes, incluindo adultos e criancas. O presente trabalho analisou a eficacia e tolerabilidade do uso de hidroxiureia em criancas na faixa etaria entre 5 e 17 anos de idade e em adultos jovens acima de 18 anos, portadores de hemoglobinopatia SS ou Sb0 que foram acompanhados regularmente no ambulatorio do Hospital Hemope. Os pacientes pediatricos foram tratados com dose inicial de hidroxiureia de 10 mg/kg/dia, a qual era aumentada em 5 mg/kg por dia em intervalos de oito semanas, ate a dose maxima de 25 mg/kg/dia. Para os adultos, o tratamento foi iniciado com 500 mg/dia de hidroxiureia ate a dose maxima de 1g/dia. Foi observada reducao do numero de crises algicas assim como do numero de internacoes hospitalares, elevacao do nivel de Hb F e do Volume Corpuscular Medio, no grupo pediatrico. Entre os pacientes maiores de 18 anos, tambem se observou melhora clinica e significância estatistica com aumento dos valores da hemoglobina e reducao dos valores de reticulocitos, leucocitos e plaquetas. Nao foram observados sinais ou sintomas sugestivos de toxicidade medicamentosa em ambos os grupos. O uso de hidroxiureia em todos os pacientes parece ser seguro e eficaz e assegura melhora da qualidade de vida e beneficios a seus familiares. Ademais, as doses preconizadas de hidroxiureia aparentemente nao foram mielotoxicas, nao tendo sido necessaria a suspensao do tratamento em nenhum dos pacientes.

Molecular characteristics and chromatin texture features in acute promyelocytic leukemia

BackgroundAcute promyelocytic leukemia is a cytogenetically well defined entity. Nevertheless, some features observed at diagnosis are related to a worse outcome of the patients.MethodsIn a prospective study, we analyzed peripheral (PB) leukocyte count, immunophenotype, methylation status of CDKN2B, CDKN2A and TP73; FLT3 and NPM1 mutations besides nuclear chromatin texture characteristics of the leukemic cells. We also examined the relation of these features with patient’s outcome.ResultsAmong 19 cases, 4 had a microgranular morphology, 7 presented PB leukocytes >10x109/l, 2 had FLT3-ITD and 3 had FLT3-TKD (all three presenting a methylated CDKN2B). NPM1 mutation was not observed. PB leukocyte count showed an inverse relation with standard deviation of gray levels, contrast, cluster prominence, and chromatin fractal dimension (FD). Cases with FLT3-ITD presented a microgranular morphology, PB leukocytosis and expression of HLA-DR, CD34 and CD11b. Concerning nuclear chromatin texture variables, these cases had a lower entropy, contrast, cluster prominence and FD, but higher local homogeneity, and R245, in keeping with more homogeneously distributed chromatin. In the univariate Cox analysis, a higher leukocyte count, FLT3-ITD mutation, microgranular morphology, methylation of CDKN2B, besides a higher local homogeneity of nuclear chromatin, a lower chromatin entropy and FD were associated to a worse outcome. All these features lost significance when the cases were stratified for FLT3-ITD mutation. Methylation status of CDNK2A and TP73 showed no relation to patient’s survival.Conclusionin APL, patients with FLT3-ITD mutation show different clinical characteristics and have blasts with a more homogeneous chromatin texture. Texture analysis demonstrated that FLTD-ITD was accompanied not only by different cytoplasmic features, but also by a change in chromatin structure in routine cytologic preparations. Yet we were not able to detect chromatin changes by nuclear texture analysis of patients with the FTLD-TKD or methylation of specific genes.