Clinical and laboratory haematology最新文献

Erythrocytes resistant to standard lysing reagents are known to occur in sickle cell disease. These lyse-resistant erythrocytes can cause aberrant automated leucocyte counts and differentials. The ability of the Cell-Dyn 3500 automated haematology analyser to eliminate resistant erythrocytes and accurately count and differentiate leucocytes was evaluated. Samples were obtained from paediatric patients with sickle cell disease or haemoglobin SC disease. The Cell-Dyn 3500, using impedance and optical counting with a hypotonic salt "extended lyse mode', was compared to the Cell-Dyn 3000, an optical analyser that also uses a hypotonic salt lyse, the Cell-Dyn 400, a "hard detergent lyse' impedance counter, and a reference 400-cell manual white cell differential (National committee for Clinical Laboratory Standards [NCCLS] Approved Guideline H20-A). Seventy-five samples from patients with sickle cell disease or haemoglobin SC disease were evaluated for total leucocyte count, percentage of lymphocytes, percentage of neutrophils, and nucleated red blood cells (NRBC) flags. The Cell-Dyn 3500 correlated well with Cell-Dyn 400 leucocyte counts, with a correlation coefficient of 0.95. When compared to the manual differential, the correlation coefficient for lymphocytes was 0.93 and for neutrophils 0.95. The Cell-Dyn 3500 NRBC flag had a sensitivity of 47.7% and a specificity of 80.6%. The predictive value of a positive flag was 77.7%. The Cell-Dyn 3500's extended lyse mode clearly enhances the accuracy of leucocyte counts and differentials in patients with sickle cell disease.

We describe post-splenectomy lymphocytosis (PSL) in 23 patients, a majority (20/23) of whom have undergone splenectomy as a staging procedure for Hodgkin's disease. The absolute lymphocyte count ranged from 4.0 to 8.7 x 10(9)/l. The lymphocytosis was noted 4-242 (median 70) months after splenectomy and persisted almost unchanged in most patients on prolonged follow up (median 50 months). Immunophenotyping of the lymphocytes revealed no monoclonal B cell population.

Three methods for detection of warm type IgG autoantibody were evaluated using 400 blood samples from 147 patients suspected of autoimmune haemolytic anaemia (AIHA). Three direct antiglobulin techniques (DAT) were used: conventional tube DAT, gel-DAT by micromethod and gel-DAT enzyme linked antiglobulin test (ELAT). Eluate examinations confirmed the presence of autoantibodies on red cells. These tests were compared directly using 126 selected blood samples from 85 patients with IgG molecules on their red cells detected by the gel test. In 106 of these samples, collected from 65 patients with clinical symptoms of AIHA, the presence of autoantibody was confirmed by acid elution. The ELAT was positive in 100 samples (94%), 87 samples for tube DAT (82%). The ELAT as well as the tube DAT was negative in 20 samples with non-reactive eluates by gel test. The gel-DAT was therefore not fully specific and detected IgG on red cells of patients with hypergammaglobulinaemia. However, due its higher sensitivity it proved useful as a screening test. The ELAT allowed changes in the number of IgG molecules per red cell to be monitored quantitatively. Both methods play a part in the diagnosis and monitoring patients with warm type IgG auto-antibody.

We describe a patient with essential thrombocythaemia who developed multiple myeloma 7 years after an initial diagnosis of essential thrombocythaemia. A 50-year-old white female presented in 1987 with a 2 year history of low backache, painful swollen ankles and burning feet. Her laboratory investigations suggested a diagnosis of essential thrombocythaemia. Initially she was treated with busulphan without much benefit for 6 months. Subsequently she was treated with hydroxyurea with significant relief of her symptoms and reduction in her platelet count. Seven years after her initial presentation she developed bone pains and anaemia with laboratory investigations confirming a diagnosis of multiple myeloma.

Computer clinical decision-support systems require validation before clinical use. This study compared recommendations on warfarin dosage adjustment and timing of the next appointment made by an algorithm with those made by experienced and inexperienced clinicians. Data abstracted from the records of 125 patients seen regularly in the anticoagulant clinic were used. The algorithm recommended dose changes and next appointment for cases with INRs between 1.8 to 4.2 (therapeutic range 2.0-3.0) and between 2.3 to 5.3 (therapeutic range 3.0-4.5). Beyond these values the algorithm referred the cases to "see doctor'. Compared to experienced clinicians, the algorithm was better at "recognising' difficult patients than inexperienced clinicians (kappa = 0.43 and 0.32 respectively). There was no statistically significant difference between all decision makers in dosage recommendations for the non-difficult cases, but there was much more variation amongst the inexperienced clinicians. The interval recommendations were statistically different between and within the different decision-makers. The inexperienced clinicians tended to give relatively longer intervals for a given dose change. In conclusion, the algorithm performs better than inexperienced clinicians and as well as experienced clinicians for the non-difficult cases.

The CD20 antigen has been regarded as a B lineage specific, 35 kDa, non-glycosylated membrane phosphoprotein, which functions as either a Ca2+ ion channel or as a regulatory protein of such a channel. Weak expression of CD20 (CD20dim), however, has recently been reported on a sub-population of T lymphocytes. We present results which confirm the existence of a CD20dim T lymphocyte population and show that such cells have a reduced antibody-binding capacity, when compared to CD20bright B-cells (10337 +/- 642 and 346311 +/- 24264 respectively). In addition, CD20dim cell counts vary with age, with the highest levels occurring in octogenarians: cord blood 0.3 +/- 0.1% (n = 13), 20-60 year-old group 2.1 +/- 1.1% (n = 18) and individuals > or = 61 years of age 6.9 +/- 3.2% (n = 10) (P < 0.001). Further characterization of CD20dim T cells, using three colour flow cytometry, demonstrated a predominantly memory cytotoxic phenotype, in that the cells were CD8+CD28+CD45RO+T-CR alpha beta +CD38-HLA-DR-.