Rearrangement of T-cell delta locus in lymphoproliferative disorders

Studies of lymphoproliferative disorders using immunoglobulin and T- cell receptor genes have contributed to our understanding of clonality and lineages of these disorders. In this study, we examined the rearrangement of the recently discovered T-cell delta chain genes in a variety of lymphoproliferative diseases. We show here that six of 14 T- cell lymphomas and five of 23 B-cell lymphomas or B-cell leukemia cell lines have rearranged the delta loci, while two of two hyperimmune reactions retain germline configuration within these genes. Seven of ten cases of AILD were rearranged, and Lennert's lymphoma, which has been previously described as a T-cell malignancy, also contains rearrangements in the delta chain genes (three of five). Large cell anaplastic lymphomas positive for the activation antigen CD 30 also contain rearrangement in about one-half (five of 11) of the tumors examined. Two of seven of the Hodgkin's lymphomas studied contained a rearrangement for this gene. This study indicates that this newly identified T-cell delta gene is useful in evaluating clonality but is not lineage specific. However, with only one exception (in 28 rearrangements), this gene rearranges in tumors with gamma and beta chain gene rearrangements, indicating that when used in conjunction with the other TcR genes, delta rearrangement may also be useful in evaluating lineages.     

There are differences in cytogenetic abnormalities among histologic subtypes of the non-Hodgkin's lymphomas

Although many recurring chromosome abnormalities have been found in malignant lymphoma (ML) in recent years, their relationship to histology remains largely undefined. We have correlated, in the same tumor mass, chromosome findings with histology, defined by the International Working Formulation for Clinical Usage, in 120 patients. We find differences among histologies in the frequency of normal metaphases and the modal number of the predominant abnormal clone. In addition, most histologies have been significantly (P less than .01) associated with specific chromosome abnormalities. In particular, ML, follicular, predominantly small cleaved cell was associated with t(14;18)(q32;q21); ML, follicular, mixed small cleaved cell and large cell with t(14;18)(q32;q21) and trisomy 8; ML, follicular, predominantly large cell with trisomy 7 and breaks in 17q21-q25; ML, diffuse, mixed small cell and large cell with breaks in 11p; ML, diffuse, large cell with trisomy 21 and breaks in 2q and 9q; ML, large cell, immunoblastic with breaks at 6q21; and ML, small noncleaved cell with t(8;14)(q24;q32). Only the associations with t(14;18) and t(8;14) have been previously reported. The associated chromosome abnormality usually occurred in 30% to 70% of a given histology, raising the possibility that cytogenetics may add important prognostic information in lymphoma as it does in the acute leukemias.     

云南边境地区氯喹及与青蒿琥酯伍用治疗前后恶性疟原虫pfcrt 和pfmdr1抗药性有关基因点突变的变化特征

目的　了解氯喹单用及与青蒿琥脂伍用治疗恶性疟前后 ,pfcrt和 pfmdr1抗药性有关基因的点突变变化特征。　 方法　使用PCR RFLP技术检测基因点突变。　结果　氯喹及与青蒿琥脂伍用治疗前后的所有样本都发现有恶性疟原虫pfcrt基因氨基酸编码 76突变为苏氨酸的特征。但是 ,氯喹治疗前 ,5 0 % pfmdr1基因氨基酸编码 86为天冬酰氨酸 (野生型 ) ,而剩余的 5 0 %为野生型和突变型 (苏氨酸 )的特征。氯喹治疗后 ,在 18个复燃的病例中 ,83 .3 %的 pfmdr1基因 86位点为野生型 ,剩余的 16.7%是混合型。氯喹与青蒿琥脂伍用治疗前 ,3个样本携带混合型基因型 ,剩余的 (86% )为野生型 ,但治疗后 ,所有样本只携带野生型。　结论　这些结果可能支持这样的假说 :pfcrt基因突变起主导作用 ,但 pfmdr1基因突变增强了氯喹抗药性的效果。     

Age-specific regulation of clotting factor IX gene expression in normal and transgenic mice

Factor IX (FIX), a circulating serine protease that serves as an essential component of the blood coagulation pathway, has been shown to increase with age in humans. We show here that murine FIX mRNA and activity levels also increase with age. Furthermore, one form of hemophilia B, hemophilia B Leyden, which is caused by mutations within the promoter region of the FIX gene, has a distinct age-dependent phenotype. To determine the source of the age-related increases in FIX gene expression, we have analyzed the regulation of the normal FIX gene promoter and FIX Leyden gene promoter with the +13 mutation during aging by generating transgenic mice that contain the -189 to +21 bp promoter segment ligated to a chloramphenicol acetyltransferase reporter gene. We have established that the normal FIX promoter and the Leyden promoter transgenes are expressed in a tissue-specific manner in vivo. The normal FIX promoter transgene does not show any differences in the pattern of expression with age or sex of the organism, whereas the Leyden promoter transgene showed age-dependent male-specific expression. This is the first demonstration of the FIX Leyden phenotype in a transgenic mouse model.     

Genetic analysis is consistent with the hypothesis that NF1 limits myeloid cell growth through p21ras

Children with neurofibromatosis, type 1 (NF-1) are at increased risk of developing malignant myeloid disorders and their bone marrows frequently show loss of the normal allele of the NF1 tumor-suppressor gene. NF1 encodes a protein called neurofibromin, which accelerates guanosine triphosphate (GTP) hydrolysis on the p21ras (Ras) family of signaling proteins. We used a genetic approach to test the hypothesis that NF1 negatively regulates myeloid cell growth through its effect on Ras. This model predicts that, if RAS mutations and loss of NF1 function deregulate myeloid growth by the same biomechanical mechanism, then activating RAS mutations will be restricted to children with malignant myeloid disorders who do not have NF-1. We studied 71 children, including 28 with bone marrow monosomy 7 syndrome (Mo7), 35with juvenile chronic myelogenous leukemia (JCML), three with other forms of preleukemia, and five with acute myelogenous leukemia (AML), for activating mutations of KRAS and NRAS. The incidence of RAS mutations was 21% (12 of 55) in patients without NF-1 and 0% (zero of 16) in children with NF-1 (P = .04). Among the 55 patients who did not have NF-1, we found RAS mutations in four of 27 with Mo 7, in five of 24 with JCML, in two of 3 with AML, and in a patient with myeloproliferative syndrome (MPS). These data from primary human cancer cells provide strong genetic evidence that NF1 limits the growth of myeloid cells by regulating Ras.     

Characterization of Thy-1 (CDw90) expression in CD34+ acute leukemia

Thy-1 (CDw90) is a phosphatidylinositol-anchored cell surface molecule which, when coexpressed with CD34 in normal human bone marrow, identifies a population of immature cells that includes putative hematopoietic stem cells. To date, the characterization of Thy-1 expression has been confined largely to normal tissues and cell lines. In this study, we evaluated the frequency and intensity of Thy-1 expression as defined by reactivity with the anti-Thy-1 antibody 5E10 in 38 cases of CD34+ acute leukemia (21 acute myelogenous leukemia [AML], 8 chronic myelogenous leukemia [CML] in blast crisis, and 9 acute lymphoblastic leukemia [ALL]). In 34 of 38 cases (89%) the CD34+ cells lacked expression of the Thy-1 antigen. High-density Thy-1 expression was found in 1 case of CML in lymphoid blast crisis, and low- density Thy-1 expression was identified on a portion of the leukemic cells in 2 cases of AML with myelodysplastic features, and 1 case of CML in myeloid blast crisis, suggesting a possible correlation between Thy-1 expression and certain instances of stem cell disorders such as CML and AML with dysplastic features. In contrast, the dissociation of Thy-1 and CD34 expression in the majority of acute leukemias studied suggests that the development of these leukemias occurs at a later stage than the hematopoietic stem cell. Characterization of Thy-1 expression in acute leukemia may eventually provide insights into the origin of the disease. In addition, separation of leukemic blasts from normal stem cells based on Thy-1 expression may prove useful in assessing residual disease, as well as in excluding leukemic blasts from stem cell preparations destined for autologous bone marrow or peripheral stem cell transplantation.     

Interaction of hemoglobin E and pyrimidine 5' nucleotidase deficiency

A Bangladeshi family is described in which the genes for both hemoglobin E (Hb E) and pyrimidine 5' nucleotidase deficiency are segregating. An individual homozygous for both these conditions has a severe hemolytic anemia, whereas family members who are homozygous for Hb E are asymptomatic and those homozygous for pyrimidine 5' nucleotidase deficiency have the mild hemolytic anemia that is characteristic of this disorder. Globin-chain synthesis experiments have shown that the mechanism underlying the interaction between these two genotypes is a marked decrease in the stability of Hb E in pyrimidine 5' nucleotidase-deficient red blood cells (RBCs). It has also been found that in the enzyme-deficient RBCs in which Hb E is highly unstable, free alpha-chains, though not beta E-chains, acoumulate on the membrane. In view of the increasing evidence that the hemolysis associated with pyrimidine 5' nucleotidase deficiency results not only from an increase in the level of erythrocyte pyrimidines, but also from inhibition of the hexose monophosphate shunt activity in young erythrocytes, it is likely that the marked instability of Hb E in the enzyme-deficient cells results from oxidant damage acting on a mildly unstable Hb variant. These observations may have important implications for the better understanding of the pathophysiology of Hb E/beta-thalassemia, globally the commonest important form of thalassemia.     

The place of high-dose BEAM therapy and autologous bone marrow transplantation in poor-risk Hodgkin's disease. A single-center eight- year study of 155 patients

Although high-dose chemotherapy and autologous bone marrow transplantation (ABMT) are increasingly being used for the treatment of relapsed and resistant Hodgkin's disease, there have been few large, single-center studies reported with adequate follow-up to allow full evaluation of this therapeutic modality. We present 155 poor-risk Hodgkin's disease patients who received high-dose BEAM (BCNU, etoposide, cytosine arabinoside, and melphalan) chemotherapy and ABMT who have been studied over a period of 8 years. All patients had either not attained a remission on mechlorethamine, vincristine, procarbazine, prednisone-type therapy and had poor prognostic features at presentation, not attained a complete remission or relapsed within 1 year of an initial alternating regimen, or not attained remission with two or more lines of treatment. At the time of ABMT the relapse status of the patients was as follows: 46 patients were primarily refractory to induction therapy, 7 were good partial responders, 52 were in first relapse, 37 in second relapse, and 13 in third relapse. Seventy-eight patients had chemoresistant disease, 33 had chemosensitive disease at the time of ABMT, and 44 were untested for chemosensitivity at latest relapse. The procedure related mortality in the first 90 days post-ABMT of 10% overall. At 3 months 43 patients (28%) were assessed as complete responders, 72 patients had a partial response (46%), and 24 patients (16%) had no response or progression of disease. However, by 6 months, 53 (24%) patients were assessed as complete responders and 51 (33%) patients had nonprogressive disease. Forty-five patients had received radiotherapy post-ABMT to residual masses (41 patients) or to previous sites of bulk disease (4 patients). The actuarial overall and progression-free survival at 5 years was 55% and 50%, respectively. On multivariate analysis patients with bulk (masses > 10 cm), heavily pretreated patients (those receiving three or more lines of treatment) and females had a significantly poorer prognosis. Relapse status was also significant for progression-free survival in that patients in second (60%) and third relapse (70%) had a better prognosis than those in first relapse (44%) or with primary refractory disease (33%). Response to prior chemotherapy did not predict for progression-free survival. These results enable comparisons to be made between high-dose chemotherapy with ABMT and conventional dose salvage therapy. Furthermore, although the results as a whole are highly encouraging, certain groups carry an unfavorable prognosis.     

A staphylococcal slide test for detection of antineutrophil antibodies

We describe a simple test for direct or indrect detection of antineutrophil antibodies. Sensitized leukocytes adherent to glass slides and fixed with paraformaldehyde can be stored in buffer for at least 3 wk. Killed Cowan I staphylococci, containing protein A, bind to sensitized but not control cells, and binding is ascertainable by light microscopy. Indirect tests were positive for 39/41 patients suspected of having immune neutropenia and found to have antineutrophil antibodies by an indirect radiochemical opsonic method. Fifty-four control sera from healthy persons, patients with bone marrow failure, or with immune complex diseases without neutropenia, gave negative indirect tests. Direct tests for cell-bound antibody could be done even during severe neutropenia by reacting fixed autologous cells with staphylococci in the absence of added serum. In some patients only the direct test was positive.