Characterisation of the coding sequence and fine mapping of the human DFFRY gene and comparative expression analysis and mapping to the Sxrb interval of the mouse Y chromosome of the Dffry gene

DFFRY (the Y-linked homologue of the DFFRX Drosophila fat-facets related X gene) maps to proximal Yq11.2 within the interval defining the AZFa spermatogenic phenotype. The complete coding region of DFFRY has been sequenced and shows 89% identity to the X-linked gene at the nucleotide level. In common with DFFRX , the potential amino acid sequence contains the conserved Cys and His domains characteristic of ubiquitin C-terminal hydrolases. The human DFFRY mRNA is expressed in a wide range of adult and embryonic tissues, including testis, whereas the homologous mouse Dffry gene is expressed specifically in the testis. Analysis of three azoospermic male patients has shown that DFFRY is deleted from the Y chromosome in these individuals. Two patients have a testicular phenotype which resembles Sertoli cell-only syndrome, and the third diminished spermatogenesis. In all three patients, the deletions extend from close to the 3' end into the gene, removing the entire coding sequence of DFFRY. The mouse Dffry gene maps to the Sxrb deletion interval on the short arm of the mouse Y chromosome and its expression in mouse testis can first be detected between 7.5 and 10.5 days after birth when type A and B spermatogonia and pre-leptotene and leptotene spermatocytes are present.      

Platelet membrane studies in the May-Hegglin anomaly

Since studies of the giant platelets in the Bernard-Soulier syndrome have shown decreased electrophoretic mobility, decreased sialic acid, and an abnormality in a membrane glycoprotein, we performed similar studies on the giant platelets from two patients with the May-Hegglin anomaly. The patients' platelet electrophoretic mobilities did not differ from control. Although the total sialic acid contents of the patients' platelets were greater than control when calculated per platelet, they were very similar to control when normalized for differences in platelet volume and surface area. When platelet proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis there were no differences between the glycoproteins of control and patient platelets as judged by the patterns of periodic acid Schiff staining and fluorescein-labeled concanavalin A binding. Similarly, patterns of surface glycoprotein labeling by neuraminidase/galactose oxidase/KB3H4 were identical. We conclude that unlike the giant platelets in the Bernard-Soulier syndrome, those of the May-Hegglin anomaly are not associated with a membrane abnormality detectable by these techniques.     

Efficient retroviral transduction of human bone marrow progenitor and long-term culture-initiating cells: partial reconstitution of cells from patients with X-linked chronic granulomatous disease by gp91-phox expression

The primary immunodeficiencies are attractive candidates for the development of gene therapy approaches based on the transduction of hematopoietic cells. We have constructed a high-titer recombinant retrovirus for expression of gp91-phox, deficiencies of which cause the X-linked form of chronic granulomatous disease (X-CGD). We have used this vector to transduce human bone marrow, using either unfractionated mononuclear cells or purified CD34+ cells as targets and evaluated several infection protocols. Efficient gene transfer to progenitors and long-term culture-initiating cells (LTC-IC) was obtained for each target population. Importantly for potential clinical application, this could be achieved without the use of exogenous cytokines or polybrene. Progenitors representing each of the lineages detectable in vitro were transduced at equal efficiencies. The vector was shown partially to restore gp91-phox deficiency and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity in transduced cells derived from X- CGD patients. These data demonstrate that it is possible to transduce primitive human hematopoietic cells efficiently and reconstitute NADPH oxidase.     

Radiographic damage in large joints in early rheumatoid arthritis: relationship with radiographic damage in hands and feet, disease activity, and physical disability

An assessment of the onset of radiographic damage in the large joints (hip, knees, shoulders, elbows, ankles and tarsus) in patients with early rheumatoid arthritis, and the relationship of the progression of large joint damage with joint damage in hands and feet, with physical disability, and with cumulative disease activity, was performed in a prospective 6 yr follow-up study. Large joint damage appeared to be an early phenomenon with 20% of the patients having some damage in at least one large joint within 1 yr, and 50% of the patients within 6 yr after disease onset. Radiographic damage in large joints was significantly related to the damage in hands and feet, the physical disability index, and the cumulative disease activity. The initial disease activity at study entry was the only prognostic factor that reached significance.      

Effect of Campath-1H antibody on human hematopoietic progenitors in vitro

The humanized antibody CAMPATH-1H has been shown in pilot studies to be beneficial in the treatment of lymphoid malignancy and other lymphoproliferative diseases. The antigen recognized by this antibody is not confined to lymphoid cells, and work with rat antibodies of similar specificity has not eliminated the possibility of damage to human hematopoietic progenitors, particularly those capable of repopulating bone marrow and sustaining hematopoiesis. This study aimed to discover if hematopoietic progenitor cells were affected by treatment with CAMPATH-1H, with or without human complement. Bone marrow mononuclear cells from healthy volunteers were treated with saturating concentrations of CAMPATH-1H, human complement, or CAMPATH- 1H plus human complement. The CD34-positive fraction of the mononuclear cells was treated similarly. Residual progenitor activity was measured in the colony-forming unit-granulocyte, erythroid, monocyte, megakaryocyte assay and compared with untreated controls. There was no significant difference (at the 5% level) between treated and control cells. Mononuclear cells were divided into CAMPATH-1H-positive and CAMPATH-1H-negative fractions by fluorescein isothiocyanate-CAMPATH-1H labeling and fluorescence-activated cell sorter separation. Hematopoietic progenitors were predominantly found in the CAMPATH-1H- negative fraction. Furthermore, mononuclear cells treated with CAMPATH- 1H and complement were equivalent to controls in experiments that investigated the capacity of these cells to form hematopoietic foci in long-term cultures.     

Patterns of hematopoietic lineage involvement in children with neurofibromatosis type 1 and malignant myeloid disorders

Children with neurofibromatosis type 1 (NF1) are at increased risk of developing malignant myeloid disorders, particularly juvenile chronic myelogenous leukemia/juvenile myelomonocytic leukemia (JCML/JMML). We investigated bone marrows from 11 such patients (8 boys and 3 girls) and detected allelic losses at the NF1 locus in 4 of them and probable losses in 2 others. To determine which hematopoietic cell lineages were derived from the abnormal clones, Epstein-Barr virus (EBV)-transformed cell lines and CD34+ cells were analyzed from 3 children with JCML with allelic losses in unfractionated marrow. CD34 cells from these 3 patients lacked the normal NF1 allele, whereas EBV cell lines retained it. Erythroblasts plucked from the burst-forming unit-erythroid colonies of one of these children lacked the normal NF1 allele. We also studied a 10-month-old boy with NF1 who developed an unusual myeloproliferative syndrome. His bone marrow and EBV cell line both showed loss of the normal NF1 allele. In our series and in the literature, male sex and maternal transmission of NF1 were associated with the highest risk of myeloid leukemia. These data (1) provide strong genetic evidence that NF1 functions as a tumor-suppressor in early myelopoiesis, (2) confirm the clonal nature of JCML/JMML, (3) suggest that the elevation in fetal hemoglobin seen in JCML/JMML is a result of primary involvement of erythroid progenitors in the malignant clone, (4) show consistent loss of NF1 in the CD34 cells of affected children and show that the malignant clone may also give rise to pre-B cells in some cases, and (5) implicate epigenetic factors in the development of leukemia in children with NF1.     

Prolonged administration of granulocyte colony-stimulating factor (filgrastim) to patients with Fanconi anemia: a pilot study

This report examines the effect of filgrastim (granulocyte colony- stimulating factor, [G-CSF] in 12 patients with neutropenia [absolute neutrophil count [ANC] < 1,000/mm3]) caused by Fanconi anemia (FA). Two of 14 patients who were evaluated for study entry were ineligible because of unsuspected cytogenetic abnormalities in their bone marrow (BM). G-CSF was started at 5 micrograms/kg/d. All patients had an increase in their ANC at week 8 (mean increase = 15,664/mm3). The median ANC during therapy was 5,030/mm3. Eight of 10 patients who completed 40 weeks on study maintained an ANC > 1,500/mm3 on G-CSF given every-otherday. Four patients had an increase in their platelet count by week 8 without transfusion (maximum increase = 23,000 to 45,000/mm3); however, platelet counts fell toward baseline levels as the G-CSF dose was reduced. BM CFU-MK were increased at week 8 in three of four evaluable patients. Four patients who did not receive red blood cell transfusions had an increase in their hemoglobin level of at least 2.0 g/dL. A fifth patient had a red blood cell transfusion in week 2 and then had a similar increase in hemoglobin level without subsequent transfusion. Eight of 10 patients who completed 40 weeks of treatment showed increases in the percentage of BM CD34+ cells measured by flow cytometry. The same proportion showed increases in peripheral blood CD34+ cells. Increased BM cellularity and myeloid hyperplasia were constant findings and were associated with increased expression of the proliferating cell nuclear antigen. Adverse experiences were mild fever (1 patient) and a new BM cytogenetic abnormality at week 40 (1 patient). This study shows that prolonged administration of G-CSF exerts a stimulatory effect on the BM of FA patients and may be used to maintain a clinically adequate ANC in these patients. G-CSF has beneficial effects on multiple hematopoietic lineages in some patients and may be a good candidate for use in combination cytokine protocols for FA patients with progressive aplastic anemia. G-CSF use results in an increase in circulating CD34+ cells, a finding with important implications for future gene transfer protocols.     

Polymorphonuclear neutrophils from human immunodeficiency virus- infected patients show enhanced activation, diminished fMLP-induced L- selectin shedding, and an impaired oxidative burst after cytokine priming

Impaired polymorphonuclear neutrophil (PMN) function may contribute to the onset of certain life-threatening bacterial and fungal infections in human immunodeficiency virus (HIV)-infected patients. Published data on PMN functional activity in HIV infection are controversial, possibly because most studies have involved PMNs isolated from their blood environment by means of various procedures that may differently affect surface receptor expression and thereby alter cellular responses. We therefore used flow cytometry to study the expression of adhesion molecules at the PMN surface, actin polymerization, and the oxidative burst of whole-blood polymorphonuclear neutrophils in 42 HIV-infected patients at different stages of the disease. These PMNs were activated in vivo, as demonstrated by increased expression of the adhesion molecule CD11b/CD18, reduced L-selectin antigen expression, increased actin polymerization, and increased H2O2 production. The alterations were present in asymptomatic patients with CD4+ cell counts greater than 500/microL and did not increase with the progression of the disease. Stimulation by bacterial N-formyl peptides showed dysregulation of L-selectin shedding and decreased H2O2 production after ex vivo priming with tumor necrosis factor alpha or interleukin-8 (IL-8). These latter impairments, which correlated with the decrease in CD4+ lymphocyte numbers and with IL-8 and IL-6 plasma levels, could contribute to the increased susceptibility of HIV-infected patients to bacterial infections.     

Loss of attachment to fibronectin with terminal human erythroid differentiation

Human erythroblastic progenitors (colony-forming unit-erythroid [CFU-E] and burst-forming unit-erythroid [BFU-E]) have been shown to attach to fibronectin (Fn), a property that might be involved in the local regulation of erythropoiesis. In this study, we have investigated changes in cell attachment to Fn upon terminal erythroid differentiation. We first purified CFU-E from human marrow by avidin- biotin immune rosetting. This negative selection procedure yielded a cell population containing approximately 80% blasts that, after characterization by colony-assays and electron microscopy, appeared to consist of CFU-E (10% to 15%) and their immediate progeny (85% to 90%), here defined as "preproerythroblasts." In the presence of erythropoietin, purified cells differentiated into reticulocytes in 7 to 10 days. Cell attachment to Fn was inversely correlated to the stage of differentiation of the erythroid cell: more than 50% of the CFU-E population reproducibly adhered to Fn, whereas at most 30% of the preproerythroblasts had the same capacity. Adhesion was further lost at late maturation stages, and a constant finding was the inability of reticulocytes to adhere to Fn. Finally, CFU-E adhesion to Fn was blocked by polyclonal lgG raised against the Fn receptor and by a monoclonal antibody against VLA-5. These results demonstrate that adhesion to Fn is developmentally regulated during normal human erythropoiesis. Restriction of its expression to CFU-E and its first divisions strikingly correlates with the migratory capacity of these cells.