Pre-analytical parameters associated with unsuccessful karyotyping in myeloid neoplasm: a study of 421 samples

Cytogenetics is essential in myeloid neoplasms (MN) and pre-analytical variables are important for karyotyping. We assessed the relationship between pre-analytical variables (time from collection to sample processing, material type, sample cellularity, and diagnosis) and failures of karyotyping. Bone marrow (BM, n=352) and peripheral blood (PB, n=69) samples were analyzed from acute myeloid leukemia (n=113), myelodysplastic syndromes (n=73), myelodysplastic syndromes/myeloproliferative neoplasms (n=17), myeloproliferative neoplasms (n=137), and other with conclusive diagnosis (n=6), and reactive disorders/no conclusive diagnosis (n=75). The rate of unsuccessful karyotyping was 18.5% and was associated with the use of PB and a low number of nucleated cells (≤7×10³/µL) in the sample. High and low cellularity in BM and high and low cellularity in PB samples showed no metaphases in 3.9, 39.7, 41.9, and 84.6% of cases, respectively. Collecting a good BM sample is the key for the success of karyotyping in MN and avoids the use of expensive molecular techniques.

Novel mutations associated with pyruvate kinase deficiency in Brazil

BACKGROUND

Pyruvate kinase deficiency is a hereditary disease that affects the glycolytic pathway of the red blood cell, causing nonspherocytic hemolytic anemia. The disease is transmitted as an autosomal recessive trait and shows a marked variability in clinical expression. This study reports on the molecular characterization of ten Brazilian pyruvate kinase-deficient patients and the genotype-phenotype correlations.

METHOD

Sanger sequencing and in silico analysis were carried out to identify and characterize the genetic mutations. A non-affected group of Brazilian individuals were also screened for the most commonly reported variants (c.1456C>T and c.1529G>A).

RESULTS

Ten different variants were identified in the PKLR gene, of which three are reported here for the first time: p.Leu61Gln, p.Ala137Val and p.Ala428Thr. All the three missense variants involve conserved amino acids, providing a rationale for the observed enzyme deficiency. The allelic frequency of c.1456C>T was 0.1% and the 1529G>A variant was not found.

CONCLUSION

This is the first comprehensive report on molecular characterization of pyruvate kinase deficiency from South America. The results allowed us to correlate the severity of the clinical phenotype with the identified variants.

Functional alterations of rabbit erythrocytes induced by Loxosceles gaucho venom

Loxoscelism is the syndrome caused by the brown spider Loxosceles gaucho bite in humans. Its effect on erythrocytes has been studied in humans, rabbits, pigs and guinea pigs. In this study, the damage that the L gaucho spider venom causes to the structure and function of erythrocytes in vivo was investigated in rabbits. Before and after the rabbits were envenomed, membrane proteins were studied through polyacrylamide gel electrophoresis and membrane function was ascertained using the osmotic fragility test, together with the highly sensitive technique of ektacytometry. Six New Zealand rabbits were inoculated by intradermal injection into the dorsal region (10 μg of venom/kg of body weight in 0.2 mL of saline). Blood was collected at 24, 48, 72 and 120 h after inoculation. The membrane protein study did not reveal any alteration in their relative band concentrations, but the osmotic fragility test showed increased hemolysis in slightly hypotonic sodium chloride solutions (at 0.6 and 0.55%). In addition, the ektacytometer study revealed greater deformability to increasing shear stress on the order of 3—30 Pascals when compared with controls, showing that the L gaucho venom does in fact alter red cell function. Human & Experimental Toxicology (2007) 26 , 817— 821

Molecular and cytogenetic abnormalities in acute myeloid leukemia: review and case studies

OBJECTIVE

To study the frequency of mutations that may lead to a good or bad prognosis, as well as their relation with the karyotype and immunophenotype in patients with acute myeloid leukemia.

METHODS

Thirty samples of patients with acute myeloid leukemia were studied, in which FLT3-ITD, FLT3-TKD and NPM1 mutations were investigated. All samples were submitted to immunophenotyping and 25 to karyotyping.

RESULTS

An occurrence of 33.3% NPM1 mutation and an equal number of FLT3-ITD mutation were observed. When only the cases with normal karyotype were studied, this figures increased to 50 and 40%, respectively. Eight percent of cases with normal karyotype and genotype NPM1+/FLT3- were included in the group of acute myeloid leukemia with good prognosis. The typical phenotype of acute myeloid leukemia with normal karyotype and mutated NPM1 (HLA-DR and CD34 negative) was not observed in this small series.

CONCLUSION

Good prognosis cases were identified in this series, emphasizing the need to include new genetic markers in the diagnostic routine for the correct classification of acute myeloid leukemia, to more properly estimate prognosis and determine treatment.

Iron overload in a teenager with xerocytosis: the importance of nuclear magnetic resonance imaging

To report a case of iron overload secondary to xerocytosis, a rare disease in a teenager, diagnosed, by T2* magnetic resonance imaging. We report the case of a symptomatic patient with xerocytosis, a ferritin level of 350ng/mL and a significant cardiac iron overload. She was diagnosed by T2* magnetic resonance imaging and received chelation therapy Ektacytometric analysis confirmed the diagnosis of hereditary xerocytosis. Subsequent T2* magnetic resonance imaging demonstrated complete resolution of the iron overload in various organs, as a new echocardiography revealed a complete resolution of previous cardiac alterations. The patient remains in chelation therapy. Xerocytosis is a rare autosomal dominant genetic disorder characterized by dehydrated stomatocytosis. The patient may present with intense fatigue and iron overload. We suggest the regular use of T2* magnetic resonance imaging for the diagnosis and control of the response to iron chelation in xerocytosis, and we believe it can be used also in other hemolytic anemia requiring transfusions.

Correlation between flow cytometry and histologic findings: ten year experience in the investigation of lymphoproliferative diseases

Objective: To demonstrate the advantages of correlating flow cytometry immunophenotyping with the pathology/ immunohistochemistry of lymph nodes or nodules in the diagnosis of lymphoproliferative diseases. Methods: A retrospective study was carried out of 157 biopsy or fine-needle aspiration lymph nodes/ nodule specimens taken from 142 patients, from 1999 and 2009. The specimens were simultaneously studied with fow cytometry and pathology at Hospital Israelita Albert Einstein. The specimens were prepared in hematoxylin/eosin, Giemsa, or monoclonal antibody stained slides for detecting specific antibodies for the purposes of pathology/immunohistochemical analysis. The samples were hemolyzed and marked with different monoclonal antibody panels for different antigens in fow cytometry immunophenotyping. Results: The diagnostic results of pathology/immunohistochemical studies and flow cytometry immunophenotyping agreed in 115 patients (81%), corresponding to 127 specimens, as follows according to the pathologic diagnosis: 63 patients with non-Hodgkin's B-cell lymphoma; 26 patients with reactive lymphoid hyperplasia; 5 patients with non-Hodgkin's T-cell lymphoma; 4 patients with atypical lymphoid proliferation; 5 patients with a chronic granulomatous inflammatory process; 5 patients with a non-hematologic diagnosis; 2 patients with granulocytic sarcoma; 2 patients with thymoma; 1 patient with byphenotypic leukemia; 1 patient with kappa plasmocytoma; 1 patient with Hodgkin's lymphoma. Subtypes of lymphomas could be classified by associating the two techniques: 19 patients with follicular lymphoma; 15 patients with diffuse large B-cell lymphoma; 7 patients with small lymphocytic B-cell lymphoma/chronic lymphocytic leukemia; 3 patients with mantle cell lymphoma; 1 patient with Burkitt's lymphoma; 1 patient with MALT type lymphoma; 1 patient with post-transplant lymphoproliferative disease; 2 patients with high grade non-Hodgkin's B-cell lymphoma; 1 patient with low grade non-Hodgkin's B-cell lymphoma not otherwise specified; 1 patient with Hodgkin's lymphoma; and 12 patients with B-cell non-Hodgkin's lymphoma not otherwise specified. Conclusion: Flow cytometry adds to the results of morphologic and immunohistochemical studies, facilitating a rapid and accurate diagnosis of lymphoproliferative diseases.