Clinical and laboratory haematology最新文献

Cytology, cytochemistry, immunophenotyping and cytogenetic analysis have specific roles in the diagnosis and management of various haematological neoplasms. Careful examination of Romanowsky-stained films of blood and bone marrow is fundamental in all haematological diagnosis and, when considered together with clinical and haematological features, indicates which of the more specialized techniques are most likely to be useful. The major role of cytochemistry is in the diagnosis of acute myeloid leukaemia and the myelodysplastic syndromes. The major role of immunophenotyping is in the diagnosis of the chronic lymphoproliferative disorders and of acute leukaemia which is not obviously myeloid. Cytogenetic analysis has a role in confirming the diagnosis of chronic granulocytic leukaemia and gives important supplementary information in the acute leukaemias and the myelodysplastic syndromes.

Flow cytometric reticulocyte counting including their maturation fractions was performed with a Sysmex R-3000 automated analyser during follow-up after induction and/or consolidation with combination chemotherapy in patients with acute leukaemias (AL, n = 39; 58 courses) and malignant lymphomas (ML, n = 21; 29 courses). The ML patients received granulocyte colony stimulating factor (G-CSF) in addition after chemotherapy. During the leucopenic phase only reticulocytes of low fluorescence ratio (LFR) at extremely low concentration (< 10 x 10(9)/l) were found. After a median interval of 17 days (range 8-43), the middle fluorescence fraction (MFR) began to rise, preceding high fluorescence ratio (HFR) reticulocytes by a median of 1 day in AL patients with complete or partial remission. In ML patients, MFR and HFR reticulocytes appeared more often simultaneously after a median interval of only 11 days (range 8-15) and increased faster during the first week of marrow recovery showing a pattern different from AL. Granulocytes passed the critical limit of 0.5 x 10(9)/l at a median of 5 days after appearance of MFR reticulocytes in AL but in ML on the same day as MFR and HFR (day 0). The absolute reticulocyte concentration reached the lower limit of the reference range after about 10 days in AL. Thus, finding MFR and, to a lesser extent, HFR at very low cell concentrations, may serve as sensitive early indicators of marrow recovery after chemotherapy and are much more sensitive parameters than the absolute reticulocyte concentration. The higher median values for reticulocytes (total, HFR and MFR) after G-CSF therapy suggests that G-CSF is not lineage specific and may also stimulate erythroid precursor cells.

Microvascular occlusion is known to be a feature of myeloproliferative diseases. Acute manifestations are well documented in individuals causing a variety of symptoms. However, it is not known whether ongoing microvascular changes are present in asymptomatic individuals. We investigated this further by using retinal intravenous fluorescein angiography to image the microvasculature in patients with myeloproliferative disease. In our group of patients fluorescein angiography did not show any ongoing microvascular damage. There appears to be no intrinsic retinal vasculopathy in patients with myeloproliferative disease, suggesting that acute symptomatic events are caused by microemboli in an otherwise normal vascular tree.

The increased precision of flow cytometric techniques permits the recognition of small differences even in the low or normal range of the reticulocyte count. Moreover, measurement of the RNA content of reticulocytes makes possible the identification of the youngest highly fluorescent macroreticulocytes (HFR) prematurely delivered from bone marrow in conditions of increased erythropoietic stimulation. The aim of this study was the definition, using the dedicated flow cytometers Sysmex R-1000 or R-3000 (Toa Medical Electronics Ltd, Kobe, Japan), of reticulocyte absolute number and HFR percentage in patients with haematological disorders prior to any treatment. Analysis of 54 healthy subjects and 100 untreated patients with five types of haematological disease is presented. In haemolytic anaemias (15 cases) both the reticulocyte count and HFR were greatly increased and the reticulocyte count was inversely correlated with Hb level, as in the reference population. In polycythaemia vera (20 cases) reticulocytes were moderately increased and directly correlated with Hb. In dyserythropoietic syndromes (20 cases) reticulocytes were low and HFR moderately increased; HFR showed an inverse correlation with Hb. In acute myeloid leukaemia (30 cases) reticulocytes were low and HFR increased; reticulocytes correlated with both HFR and Hb. In acute lymphoid leukaemia (15 cases), while the reticulocyte count did not differ from the reference group, the HFR was increased. These results provide reference values for the evaluation of reticulocyte counts and HFR in haematological diseases. From a physiopathological standpoint, they suggest that in anaemic patients the reticulocyte count directly reflects effective bone marrow erythrocyte production, while the proportion of circulating HFR more closely reflects the intensity of erythropoietic stimulation.

The haematology laboratory of the Royal Postgraduate Medical School is required to handle an increasing workload with decreasing financial resources. An investment in technology was made in order to improve efficiency, meet future demands and to meet high technical standards. This required an increase in automation in the Full Blood Count section with staff redeployed into growth areas. The Sysmex HST 330, comprising an SE 9000 full blood count analyser, R 3000 reticulocyte counter, SP 1 film preparation unit, linked by a transport system was chosen as a comprehensive system. To fully exploit the reflex-testing capabilities and maximize the potential of the HST a computerized decision-making algorithm was developed. We have been able to evaluate the impact of a highly automated approach to FBC screening in a busy diagnostic laboratory.

To determine the incidence of delta+ 27 thalassaemia in Northern Sardinia we examined blood samples from 750 Sardinian schoolboys by PCR-based molecular analysis. The incidence of delta+ 27 mutation was 1.2% in this study, i.e. twice as high as previously described on the basis of phenotypical studies; the frequency of the beta-thalassaemia is 10.5% and their interaction has been calculated at 0.0003. The majority of delta+ 27 carriers are characterized by a HbA2 level lower than 1.9% and the mean HbA2 level is significantly lower than in normal subjects. All compound heterozygotes for delta+ 27 and beta-thalassaemia show a silent beta-thalassaemic phenotype related to normalization of their HbA2 levels. This study suggests that delta+ 27 thalassaemia should be borne in mind in counselling at-risk couples in which one member has the typical high HbA2 beta-thal trait while the other shows normal or borderline HbA2 level. In these subjects, PCR-based ECO O 109 I digestion of the delta globin gene allows rapid detection of the delta+ 27 mutation.