Hematopathology and molecular hematology最新文献

We demonstrated significant growth inhibition by retinoic acid (RA) of HTLV-I (+) T-cell lines (ATL-2 and HUT102), but not HTLV-I (-) T-cell lines (MOLT-4 and Jurkat). We hypothesized that the mechanism of growth inhibition by RA depends on an imbalance in redox potential. To examine the effect of exogenous thiol compounds for the growth of HTLV-I (+) T-cell lines by RA, HTLV-I (+) T-cell lines were cultured with several thiol compounds (thioredoxin, L-cystine, and GSH), following addition of 13-cis RA or ATRA, respectively, in cultured with thiol free medium. Unexpectedly, thiol compounds alone did not restore growth inhibition of HTLV-I (+) T-cell lines. However, when those cells were preincubated with thiol compounds for 24 hours, no growth inhibition by 13-cis RA or ATRA was observed. These results suggest that thiol compounds are associated strongly with sensitivity to RA of HTLV-I (+) T cells, but not of HTLV-I (-) T cells and that thiol compounds serve an important role on HTLV-I (+) T cells.

We employed the nonpalindromic adaptor-PCR (NPA-PCR) method to amplify T-cell receptor (TCR) alpha- and beta-chain transcripts from the spleen of normal SJL mice. The NPA-PCR method has been specifically designed for the amplification of transcripts with variable or unknown 5' ends, such as TCRs and immunoglobulins (Ig). This method has certain distinct advantages over existing two-sided PCR methods for the amplification of TCR transcripts. Two NPA-PCR amplifications are sufficient to amplify all the TCR transcripts (one for the alpha-chain and another one for the beta-chain). Amplification of TCR transcripts by classical two-sided PCR requires a minimum of 45 amplification reactions for the murine TCR (20 for the V alpha families and 25 for the V beta families), using 45 different V-family-specific amplification primers. cDNA was synthesized from spleen RNA, using oligonucleotides complementary to sequences of either the murine TCR C alpha or C beta regions. The NotI restriction site was conjugated to these primers and therefore, a NotI restriction site was incorporated at the 3' end of the cDNA. A double-stranded nonpalindromic adaptor (EcoRI-XmnI strand and XmnI G strand, which are complementary to each other) was ligated onto both ends of the double-stranded cDNA. The adaptor was removed from the 3' end by NotI nuclease digestion whereas the adaptor was retained at the 5' end. Two rounds of PCR amplification were carried out. In the first, the EcoRI-XmnI adaptor was used as 5' end amplification primer; an antisense C region primer, designated mC alpha 2 or mC beta 2 (for the alpha- and beta-chain, respectively), was used as 3' amplification primer. In the second round of PCR amplification the same 5' end primer and a 3' end antisense primer, designated mC alpha 1 or mC beta 1, were used. These mC alpha 1 and mC beta 1 primers are located 5' to the mC alpha 2/mC beta 2 primers that were used for the first amplification. The amplified transcripts were cloned. Colonies were screened using a 32P-labeled probe, either C alpha or C beta, located 5' to those used for the last amplification and many positive clones were isolated and sequenced. All clones were unique when compared to each other, as anticipated for polyclonal T-cell populations. Comparison of the sequences obtained to those in the GENBANK/EMBL database revealed that they were typical of mouse alpha- or beta-chain TCR. With the exception of two beta-chain TCR transcripts, all the sequences shown here (36 alpha-chain and 20 beta-beta chain) have not been previously reported to the GENBANK/EMBL database.

A 34-year-old male acutely presented with widely disseminated malignant melanoma, a microangiopathic hemolytic anemia, and disseminated intravascular coagulation. Although the patient had a history of intense childhood exposure to ultraviolet light and an occupational exposure to organic dyes, he had no history of a precursor skin lesion. The histopathology of the patient's bone marrow revealed sheets of malignant cells immunoreactive with S-100, HMB-45, and vimentin and also staining positively for melanin. A bone marrow aspirate revealed myeloid precursors filled with melanin-bearing vacuoles. Immunophenotypic analysis of the patient's bone marrow by flow cytometry revealed a paucity of hematopoietic cells. A karyotypic analysis of the patient's tumor cells demonstrated an abnormal hypertriploid composite clone characterized by multiple numerical and structural abnormalities. Although the patient was treated aggressively with transfusional support, heparin, and chemotherapy, he expired 3 weeks after diagnosis. This is the first recognized case of metastatic melanoma occurring in association with a microangiopathic hemolytic anemia.

The t(2;5) (p23;q35) that is frequently detected in anaplastic large cell lymphoma (ALCL) fuses the nucleophosmin (NPM) gene on chromosome 5 to a novel tyrosine kinase gene designated anaplastic lymphoma kinase (ALK) on chromosome 2. The fusion of NPM and ALK genes results in the production of chimeric transcripts containing NPM amino-terminal sequences fused to the ALK carboxy-terminal catalytic domain. Because fusion transcripts and proteins in almost all t(2;5)-positive cell lines and tumors are identical, it is likely that the chromosomal breaks involve the same introns of NPM and ALK genes. We have previously developed a long-range genomic DNA-PCR assay to amplify the genomic NPM-ALK break points. Using high-molecular-weight DNA extracted from 2 ALCL cell lines and from 9 primary ALCLs known to be t(2;5)-positive, we have demonstrated that all 11 amplicons were of different sizes, suggesting that the t(2;5) break points were unique and involved the same introns on both chromosomes. We decided to confirm this and map the t(2;5) break points by genomic DNA sequencing. Using the same long-range DNA-PCR technique, primers from the ALK locus, and normal genomic DNA, we sequenced the ALK intron involved in t(2;5). We subsequently sequenced all 11 amplicons from t(2;5)-positive ALCL cell lines and tumors. Comparison of the sequences derived from ALCL amplicons with the published sequences of intron 4 from the NPM locus (910 bp) and with the newly sequenced intron from the ALK locus (1935 bp) accurately mapped all break points and demonstrated that their nucleotide sequences were unique. We conclude that the genomic t(2;5) break points can be easily mapped by sequencing the amplicons generated from genomic DNA with long-range PCR and that they are unique for each patient. The sequences of the break points and of the newly identified ALK intron may be useful in the construction of patient-specific primers for monitoring and determination of the clinical relevance of minimal residual disease.

The HELLP syndrome is a dangerously severe form of preeclampsia associated with multiorgan system damage and occurs in 0.2-0.6% of all pregnancies. It usually presents with abdominal pain, often in the setting of preeclampsia. In most cases, HELLP is initiated by inadequate placental vessel development with subsequent placental ischemia, leading to the release of circulating vasoconstrictors. These powerful vasoconstrictors include thromboxane A2, angiotensin, prostaglandin F2, and endothelin-1. The ischemic placenta also produces fewer vasodilators, such as prostacyclin, prostaglandin, E2, and nitric oxide. The ensuing imbalance in vasoactive substances causes intense systemic vasospasm and multiorgan endothelial damage. Multiple genetic, coagulation, and immunologic disorders also appear to contribute to the endothelial damage. Fibrin and platelets are then deposited on the endothelial surfaces leading to the hemolytic anemia, elevated liver enzymes, and low platelets of the HELLP syndrome. The most reliable laboratory tests for the diagnosis of HELLP are a complete blood count with peripheral smear, lactate dehydrogenase, serum transaminases, and urinalysis. Supportive tests include serum haptoglobin, D-dimer fragment levels, lactate dehydrogenase isoenzymes, total bilirubin, prothrombin times, and activated partial thromboplastin times. Lactate dehydrogenase and the platelet count are the two best tests to monitor the course of the disease. Prompt delivery is the treatment of choice. The intensity of the HELLP syndrome peaks 24 hours after delivery. Extended atypical HELLP has been successfully treated with plasma exchange. The clinical laboratory professional plays an important role in the diagnosis, follow-up, and treatment of patients with the HELLP syndrome.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hematologic stem cell disorder classified as an intravascular hemolytic anemia. Abnormal blood cells are deficient in glycosylphosphatidyl inositol (GPI)-anchored proteins. Deficiencies of GPI-anchored complement regulatory proteins, such as decay accelerating factor (DAF) and CD59, render red cells very sensitive to complement and result in complement-mediated hemolysis and hemoglobinuria. In the affected hematopoietic cells from patients with PNH, the first step in biosynthesis of the GPI anchor is defective. Three genes are involved in this reaction step and one of them, an X-linked gene termed PIG-A, is mutated in affected cells. Granulocytes and lymphocytes from the same patient have the same mutation, indicating that a somatic PIG-A mutation occurs in hematopoietic stem cells. The PIG-A gene is mutated in all patients with PNH reported to date. We review these recent advances in the understanding of the molecular pathogenesis of PNH. Furthermore, we present an hypothesis regarding the predominance of the PNH clone, caused by positive selection by hematopoietic suppressive cytokines, such as transforming growth factor (TGF)-beta. In addition, we discuss the possibility of cure for PNH through molecular therapeutic strategy using gene transfer techniques. (Key words: paroxysmal nocturnal hemoglobinuria, glycosylphosphatidylinositol-anchored proteins, PIG-A, clonal dominance, growth advantage, transforming growth factor-beta, gene therapy, molecular therapeutic approach).

Both the L-type pyruvate kinase gene (PKLR) and glucocerebrosidase (GBA) gene are on band q21 of chromosome 1 in humans. Two overlapping P1 bacteriophage clones containing PKLR and GBA were identified and mapped, defining the locations of these two genes as well as those of the GBA pseudogene (psi GBA) metaxin (MTX), the MTX pseudogene (psi MTX), and thrombospondin 3 (THBS3). The distance between the 5' ends of GBA and PKLR was determined to be 71 kb. The direction of transcription PKLR gene was convergent to that of the GBA gene. All 195 Gaucher disease patients homozygous for the 1226G mutation, representing 390 chromosomes with the 1226G mutation, had a PvuII -/- GBA haplotype and a C/C at nt 1705 of the PKLR gene (-/- haplotype). All 56 Gaucher disease patients who were 1226G/84GG compound heterozygotes manifested a -/+ GBA haplotype and 55 of 56 patients were -/+ at PKLR nt 1705. Only 1 patient with 1226G/84GG genotype showed a crossover with the PKLR polymorphism, with a -/- haplotype at nt 1705. Similarly, 9 patients deficient in pyruvate kinase with the PKLR 1529A/1529A genotype were all found to have the same -/- GBA haplotype.

Desmopressin was administered intranasally to seven patients with von Willebrand disease (type 1: 4 patients, type 2A: 3 patients) to assess the response and safety. von Willebrand factor antigen ranged from 8% to 60% before treatment and increased significantly after intranasal DDAVP administration (the median relative increase: two- to threefold). Factor VIII levels also increased substantially over baseline levels after intranasal administration. Before treatment ristocetin cofactor activity was 32 +/- 12% in patients with type 1 vWD and 9 +/- 5% in patients with type 2A vWD. After intranasal administration, the levels of ristocetin cofactor activity increased to 56 +/- 21% and 29 +/- 9%, respectively. The bleeding time was normalized in 86% of the patients. The abnormality of vWF multimers in type 1 vWD returned more or less to normal after intranasal DDAVP administration whereas that in type 2A vWD did not. The intranasal administration of DDAVP is safe and effective for minor bleeding episodes and is adaptable for home use in patients with type 1 and type 2A vWD.

Phenotypic conversion from acute myeloid leukemia (AML) to acute lymphoblastic leukemia (ALL) is rare. A 38-year-old man was initially diagnosed as having AML (FAB-M2) associated with the t(8;21)(q22;q22) chromosomal abnormality. The blasts showed myeloperoxidase (MPO) activity and CD13 antigen expression. He showed complete remission after standard chemotherapy for AML. However, the patient relapsed with blasts showing ALL morphology (FAB-L1), MPO negativity, and CD19 antigen expression 33 months after cessation of AML therapy. Cytogenetic analysis at relapse was unsuccessful. Molecular analysis of ALL blasts revealed immunoglobulin heavy-chain gene and MLL gene rearrangements but no AML1 gene. MLL gene rearrangement or the 11q23 chromosomal abnormality has been associated with therapy-related leukemia. The subsequent ALL in our patient may have been induced by the chemotherapy including daunorubicin, known as a topoisomerase II inhibitor.

The mechanism of action of interferon-alpha (IFN-A) in chronic myelogenous leukemia (CML) is not known, but some evidence points at the immune modulation properties of IFN-A. We conducted a prospective analysis on 49 patients with CML in chronic phase treated with IFN-A in order to identify the effect of therapy on different lymphocyte subpopulations as determined by flow cytometric quantification and whether this effect is associated with the response to IFN-A. The absolute number of lymphocytes was similar in all patients regardless of response to IFN-A. In patients achieving a complete cytogenetic response (CCGR) there was a rebound of the absolute count of CD3+, CD4+, CD8+, and CD19+ lymphocytes after discontinuation of therapy with IFN-A. Patients with resistant disease, as well as patients with hematologic response but no cytogenetic response, showed a lower absolute number of CD19+ cells than patients with any cytogenetic response. Patients who achieved a CCGR had a higher absolute number of CD56+ cells than patients with lesser response or no response to IFN-A, and this persisted after discontinuation of therapy. We conclude that an increase in absolute number of CD19+ and CD56+ lymphocytes is observed in CML patients achieving a CCGR with IFN-A compared to patients with lesser responses. These changes could have functional consequences in the control of the disease.