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Biomedical subjects

D Joshua

Publications and source records attributed to D Joshua.

At least 19 recordsLinked to original sources
PubMed2001

Missense C168T in the Wiskott--Aldrich Syndrome protein gene is a common mutation in X-linked thrombocytopenia.

We describe a large Syrian--Lebanese family who clinically manifest X-linked thrombocytopenia (XLT). To date, five family members have undergone splenectomy with rapid and sustained normalization of their platelet numbers. Genomic analysis demonstrated that affected men in this cohort had the missense C168T (Thr45Met) mutation in exon 2 of the Wiskott-Aldrich Syndrome protein (WASp) gene. Exon 2 is the commonest site for mutations associated with XLT and mild forms of WAS, and the C168T missense mutation is the most frequent. Detection of this mutation by restriction enzyme digestion provides an efficient screening test for prompt identification and for assessment of female carrier status.

Adult↗
PubMed2000

B7-2-positive myeloma: incidence, clinical characteristics, prognostic significance, and implications for tumor immunotherapy.

Deficiencies in B7:CD28 costimulation are considered to be one of the major causes of the failure to generate a tumor-specific immune response. Up-regulating the expression of the B7 molecules on malignant B cells has been shown to stimulate cytotoxic T cells. Plasma cells from patients with myeloma express a tumor-specific idiotype but lack CD80 (B7-1) and have a variable expression of CD86 (B7-2). This study has identified the incidence and clinical significance of high CD86 expression on plasma cells at diagnosis and studied the ability of trimeric human CD40 ligand (huCD40LT) to up-regulate the expression of the B7 family on malignant plasma cells. CD86 expression on plasma cells was increased in 54% of the patients studied at diagnosis (n = 35) and was associated with a significantly shorter survival (median, 28 versus 57 months; chi(2) = 4.6; P =.03) and a higher tumor load (patients with more than 50% bone marrow plasma cells, 47% versus 6%; chi(2) = 7.2; P =.005). CD86 expression was highest on immature and primitive plasma cells (CD38(++), CD45(+)) of both patients and controls and was associated with a CD40(+), CD20(+), CD19(-), CD138(+) phenotype. The shortened survival was associated with high CD86 only on mature (CD38(++), CD45(-)) plasma cells (chi(2) = 7.6; P =.006). There was no significant correlation between high CD86 and other known prognostic markers, including serum beta(2)-microglobulin, serum thymidine kinase, and labeling index. The addition of huCD40LT to short-term cultures up-regulated both CD80 and CD86 expression on B cells (CD19(+)) and CD80 on plasma cells (CD38(++)), but did not up-regulate CD86 expression on plasma cells. Thus, B7-2-positive myeloma consists of a subgroup of patients with a relatively poor prognosis, and CD40LT may be useful in immunotherapy protocols because it up-regulates CD80 expression on malignant plasma cells without inducing B7-2-positive myeloma. (Blood. 2000;96:1274-1279)

Adult↗
PubMed2000

CD34+ selection of autologous peripheral blood stem cells for transplantation following sequential cycles of high-dose therapy and mobilization in multiple myeloma.

A potential problem of autologous transplantation in the treatment of multiple myeloma (MM) is the infusion of tumor cells. CD34+ selection has been used to purge autografts in MM and it is also possible to reduce tumour cell contamination of autografts by cytotoxic drug therapy prior to peripheral blood stem cell (PBSC) collection. To evaluate the effectiveness of a protocol combining multiple cycles of high-dose therapy and CD34+ selection to reduce tumour contamination of PBSC autografts, 34 MM patients were entered on a treatment schedule comprising two sequential cycles of mobilisation, CD34+ selection, and transplantation following high-dose therapy. In the second cycle of mobilisation there was a five-fold reduction in tumour contamination of the stem cell harvest (0.5 x 106/kg) compared with the first cycle (2.5 x 106/kg). In the 97 CD34+ selection procedures performed a median of 185 x 108 mononuclear cells (MNC) were processed yielding a median of 0.98 x 108 CD34+-enriched cells. CD34+ cells were enriched 68-fold from 1. 3% to 88.6%. The median yield of CD34+ cells was 42.2%. Following CD34+ selection the tumour cell contamination of the leukapheresis product was reduced by a median of 2.7 logs. This study demonstrates that in multiple myeloma a significant reduction in the malignant contamination of stem cell autografts can be achieved by combining the in vivo purging effect of cytotoxic therapy with in vitro purging by CD34+ selection.

Adult↗
PubMed1999

The bone marrow plasma cell labeling index by flow cytometry.

The bone marrow plasma cell labeling index is the most important prognostic indicator for patients with multiple myeloma. Traditionally, this test has been performed as a two color immunofluorescent microscope technique which is time consuming and requires a degree of subjectivity in its interpretation. We have assessed various adaptations of this method to flow cytometry. A bromodeoxyuridine method has been compared with a propidium iodide DNA method to detect cells in S phase and CD38-FITC has been compared with CD38-FITC + CD138-FITC and CD38-biotin + streptavidin FITC to identify plasma cells. The mean channel fluorescent intensity of the plasma cell peaks for each of these markers was 12. 7, 17.4 and 35.3 respectively demonstrating the superiority of CD38-biotin + streptavidin FITC. Analysis after propidium iodide staining provided a good correlation with the slide technique (r = 0. 71; P < 0.0001) but the bromodeoxyuridine method did not correlate with the slide method (r = 0.09; P = NS). The labeling index values obtained from either of the flow methods were greater than the microscopic method. Thus a labeling index of >4% will replace the traditional >1% threshold for identifying patients with a significantly increased labeling index. The advantages of the new method are that it takes less time to perform, is more objective and provides additional data on ploidy and cell cycle status.

ADP-ribosyl Cyclase↗
PubMed1999

Syngeneic stem cell transplantation for HIV-related lymphoma.

The treatment of human immunodeficiency virus (HIV)-related lymphoma is beset by a number of therapeutic limitations. High-dose chemotherapy followed by peripheral blood stem cell transplantation (PBSCT) for relapsed disease is one option, but may be compromised by unacceptable treatment-related morbidity and mortality. We describe an HIV-positive male with relapsed immunoblastic non-Hodgkin's lymphoma (NHL) who successfully received salvage chemotherapy followed by a syngeneic PBSCT from his HIV-negative (hepatitis C positive) brother. At 15 months post-transplant he remains in complete remission with low-level HIV viral load, an improved CD4 lymphocyte count and absent anti-hepatitis C antibodies. We believe selected patients with relapsed HIV-related NHL should be considered for high-dose therapy.

Adult↗
PubMed1999

Acute promyelocytic leukaemia complicating multiple myeloma: evidence of different cell lineages.

The association of leukemia and multiple myeloma is well described usually as a complication of chemotherapy but also in the absence of chemotherapy or at diagnosis. Such leukemias are typically acute myeloid leukemia (AML), particularly myelomonocytic subtype, and cases of acute promyelocytic leuke (APL) are rarely reported. Controversy exists as to whether myeloma and AML originate from a single haematopoietic progenitor or arise from different cell lineages. We report a case of a 58 year old female who developed APL 10 months following diagnosis of nonsecretory light chain (kappa) myeloma which had been treated with local spinal irradiation and low dose oral melphalan and prednisone. Clonality had originally been demonstrated by light chain restriction (kappa) of her bone marrow plasma cells whilst immunoglobulin heavy chain and T cell receptor genes were germ line. At development of APL cytogenetics revealed t(15;17) and PML-RAR fusion gene was detected by RT-PCR. The patient was treated with all-trans retinoic acid (ATRA) and received 2 cycles of consolidation chemotherapy with Idarubicin. Following this therapy the t(15;17) and PML-RAR were both undetectable whilst the clonal population of kappa staining plasma cells persisted. This particular patient represents a rare case of APL complicating multiple myeloma with persistence of the myeloma clone but disappearance of PML-RAR alpha RNA following therapy. This case study appears to support the argument that the APL and myeloma originated from distinct cell lineages.

Antibiotics, Antineoplastic↗
PubMed1998

Longitudinal analysis of circulating myeloma cells detected by allele specific mRNA in situ hybridization.

Individual myeloma cells in the peripheral blood of 7 patients with multiple myeloma were detected by mRNA in situ hybridization (ISH) using biotinylated antisense oligonucleotide probes to non-germline sequences of the CDR3 region of the immunoglobulin heavy chain gene. Peripheral blood samples from these patients were studied over a period of 2-3 years. The number of circulating myeloma cells varied from 0.1-23% of the mononuclear cell population. Longitudinal studies showed that the highest number of circulating myeloma cells were present during escape phase and thus the percentage of mRNA ISH+ cells correlated with the clinical state of the patient. This technique is the most accurate means of monitoring and quantitating individual myeloma cells in the peripheral blood of patients with myeloma and provides insight into the relevance of circulating myeloma cells.

Adult↗
PubMed1998

Aggressive natural killer cell leukemia/lymphoma.

A 32 year old Caucasian male presented with fever, massive hepatosplenomegaly and lymphadenopathy. Peripheral blood and bone marrow findings were consistent, both morphologically and immunophenotypically, with a natural killer cell leukemia/lymphoma. The disease was rapidly progressive and was fatal within five days after presentation.

Adult↗
PubMed1997

Plasma cells in peripheral blood stem cell harvests from patients with multiple myeloma are predominantly polyclonal.

A flow cytometric technique has been developed to detect individual plasma cells in PBSC harvests and to establish light chain restriction as a surrogate marker of their clonality. Plasma cells were identified by high intensity CD38 (CD38++) and cytoplasmic immunoglobulin (cIg) expression. The ratio of cytoplasmic kappa to lambda expression was used to detect light chain restriction. All 25 PBSC harvests studied contained CD38++/cIg plasma cells (mean 0.7%, range 0.03-2%). Harvests from non-myeloma patients also contained plasma cells (mean 0.4%, range 0.01-1.5%). Most of the plasma cells detected in the harvests from myeloma patients were immature (CD45+/CD45++) rather than mature (CD45-). When the total plasma cell population was studied, definite isotype restriction could be detected in only 16% of harvests. Light chain restriction was found in 53% of harvests when the mature plasma cells (CD45-) were analysed but only in 9% of harvests when immature (CD45+/CD45++) plasma cells were analysed. Five percent of patients with myeloma had detectable light chain restriction in peripheral blood CD19+ cells. There was concordance between the ratio of malignant (CD19-/CD56+) to normal (CD19+/CD56-) plasma cells and light chain expression in 86% of patients studied. This study has demonstrated that the majority of plasma cells in PBSC harvests from patients with myeloma are not only immature but are also predominantly polyclonal and that monoclonality is best detected in mature plasma cells.

ADP-ribosyl Cyclase↗
PubMed1997

The prognostic significance of T cell receptor beta gene rearrangements and idiotype-reactive T cells in multiple myeloma.

Clonal T cell populations with idiotype specificity are present in the peripheral blood of a proportion of patients with multiple myeloma. We have identified the presence of both T cell subpopulations with a specificity for autologous immunoglobin fragments and T cell receptor beta gene rearrangements in peripheral blood samples of patients with myeloma. T cell receptor beta gene rearrangements were detected in 38 of 119 patient samples (32%) and were more common in progressive disease (70%), than at diagnosis (25%) or in stable disease (23%). The 38 patients who had T cell receptor beta gene rearrangements detected at any time had a better overall survival (median not yet achieved) than the patients who never had rearrangements detected (median 45 months, n = 49; chi2 = 6.2, P < 0.01). All 12 patients with T cell receptor beta gene rearrangements at diagnosis are still alive whereas the median survival for 28 patients with a germline configuration at diagnosis was 40 months (chi2 = 5.8, P > 0.01). The presence of T cell receptor beta gene rearrangements even conferred a survival advantage during progressive disease (median survival 44 months vs 19 months; chi2 = 8.7, P < 0.003). Two colour flow cytometry with biotinylated autologous immunoglobulin fragments demonstrated idiotype-reactive T cells in the peripheral blood of five out of 15 patients all of whom had T cell gene rearrangements. The remaining 10 patients had neither idiotype-reactive T cells nor a detectable T cell receptor beta gene rearrangement in concurrent samples. Thus in patients with myeloma there was a good correlation between the presence of T cell receptor beta gene rearrangements and idiotype-reactive T cells. Patients with a rearranged T cell receptor beta gene had a significantly better prognosis.

Aged↗
PubMed1997

Disease progression in patients with multiple myeloma is associated with a concurrent alteration in the expression of both oncogenes and tumour suppressor genes and can be monitored by the oncoprotein phenotype.

The dysregulation of specific oncogenes due to either mutation or activation has previously been reported in a small number of patients with myeloma but the extent of oncogene dysregulation during the course of the disease is not known. The oncoprotein phenotype of plasma cells in 146 bone marrow samples from 81 patients with multiple myeloma was determined by dual colour flow cytometry using a predetermined panel of 8 monoclonal antibodies. High intensity CD38 expression was used to distinguish the plasma cell population and the cells were permeabilised to detect intracellular antigen expression. In situ hybridization using biotinylated cDNA probes for c-myc and bcl-2 was used to determine mRNA expression and to validate the flow cytometric assay. The normal range of expression for each of 6 oncoproteins (c-myc, c-fos, c-neu, bcl-2, p-ras, p53 mutant) and 2 tumour suppressor gene products (p53 wild and Rb) was determined in plasma cells from 33 normal bone marrows. Disease progression was associated with the concurrent abnormal expression of at least one oncogene and one tumour suppressor gene where as stable disease was associated with a normal expression of at least one or both (chi2 = 34.1; p < 0.001). At diagnosis there was a correlation between serum beta2 microglobulin and the concurrent overexpression of both an oncoprotein and a tumour suppressor gene product. Longitudinal studies of 33 different patients over 4 years, suggests that the progressive evolution of myeloma is a multistep process of genomic instability producing ongoing alterations in the expression of both oncogenes and tumour suppressor genes.

Adult↗
PubMed1996

A randomized study of high-dose cytarabine in induction in acute myeloid leukemia.

High-dose cytarabine (ara-c) may overcome cytarabine resistance in leukemic blasts. It has been used as a successful salvage and in postremission therapy but not as initial induction treatment. Patients aged 15 to 60 years, presenting with newly diagnosed acute myeloid leukemia (AML) were randomized to receive either high-dose cytarabine, 3 g/m2 12 hourly on days 1, 3, 5, and 7 for 8 doses, daunorubicin 50 mg/m2 days 1 to 3, etoposide 75 mg/m2 days 1 to 7, (HIDAC-3-7) or standard dose cytarabine 100 mg/m2 continuous intravenous infusion for 7 days with daunorubicin and etoposide at the same dose and schedule as above (7-3-7). Patients could receive a second or third induction course if complete remission (CR) was not achieved. All patients received the same postinduction consolidation therapy (5-2-5) for 2 courses. Eligible patients had no prior chemotherapy or myelodysplastic disease. Patients have been followed for a median of 4.5 years. Of 301 patients treated, complete response (CR) was achieved in 71% with HIDAC-3-7 and 74% with 7-3-7. For patients in CR, the estimated median remission duration was 45 months with HIDAC-3-7 and 12 months with 7-3-7 (P = .0005 univariate analysis, P = .0004 multivariate analysis). The estimated percentage of patients relapse free 5 years after achieving a CR was 49% on HIDAC-3-7 and 24% on 7-3-7. Patients in CR tended to survive longer with HIDAC-3-7 but there were no overall survival differences between the two arms. HIDAC-3-7 was associated with significantly more toxicity in induction with more leukopenia, thrombocytopenia, nausea, and vomiting and eye toxicity (all P < .001) but a similar incidence of severe central nervous system and cerebellar toxicity compared to 7-3-7. The consolidation treatment was the same in both arms but caused significantly more leukopenia and thrombocytopenia in patients previously treated with HIDAC-3-7 induction (P < .0001). We conclude that a dose-effect exists for cytarabine in AML and that HIDAC-3-7 prolongs remission duration and disease-free survival and is tolerable when used as initial induction therapy in patients with de novo AML.

Acute Disease↗
PubMed1996

The labelling index of primitive plasma cells determines the clinical behaviour of patients with myelomatosis.

For patients with multiple myeloma the most important laboratory correlate of prognosis and disease activity is the bromodeoxyuridine (BrdUrd) plasma cell labelling index (LI). However, the traditional immunofluorescent microscope LI technique, like other manual enumeration assays, can suffer from poor precision and accuracy. In this study the LI of different subpopulations of plasma cells (CD38++) as determined by flow cytometry was correlated with disease state. The mean LI of the total CD38++ population was significantly higher (2.7 +/- 0.4%) than the LI determined by the traditional slide technique (0.6 +/- 0.1%) for 65 samples tested. Primitive plasma cells (CD38++, CD45++) had a higher labelling index than mature plasma cells (CD38++, CD45-) (7.0 +/- 1.3% v 1.8% +/- 0.3%) and in one patient the LI of the primitive plasma cells was 46%. In addition, the LI of the mature plasma cells was lower than the total plasma cell population. As expected, there was a significant difference between the LI of patients in plateau phase and progressive disease but this difference was greatest when the LI of the primitive plasma cells was studied (9.2 +/- 2.9% v 2.2 +/- 0.7%; z = 19.9, P < 0.001). This study has raised some concerns about the sensitivity and accuracy of the traditional labelling index and has shown that the increased LI associated with progressive disease is almost entirely attributable to an increase in the LI of the primitive plasma cell subpopulation and that the LI of primitive plasma cells provides a more clinically significant correlation with disease status than the traditional assay.

ADP-ribosyl Cyclase↗
PubMed1996

Autologous red cell recovery and relapse of multiple myeloma after bone marrow transplantation: is this a graft-versus-myeloma effect?

We report a patient who, following an allogeneic bone marrow transplant for multiple myeloma, recovered autologous erythropoiesis which was rapidly followed by relapse of her multiple myeloma. We postulate that the loss of the graft (as demonstrated by loss of donor erythropoiesis) and subsequent relapse of the multiple myeloma may be support for the existence of a graft-versus-myeloma effect.

Adult↗
PubMed1995

Idiotypic oligonucleotide probes to detect myeloma cells by mRNA in situ hybridization.

An mRNA in situ hybridization (ISH) method which used non-radioactive idiotypic oligonucleotide probes has been used to detect malignant cells in the bone marrow and peripheral blood of patients with multiple myeloma. For each of two patients with multiple myeloma a pair of biotinylated antisense oligonucleotide probes (18-22mer) was prepared from non-germline sequences of the rear-ranged immunoglobulin heavy chain (IgH) gene. These oligonucleotide sequences were not homologous with any previously published sequence. The probes from each patient were specific as shown by a failure to hybridize to any cells from six other myeloma patients and four normal individuals. Specific staining of IgH gene mRNA occurred only when the myeloma cells and the sequence of the probe used were from the same patient. Using simultaneous fluorescent immunocytochemistry it was shown that more than 95% of the ISH-positive cells expressed the malignant light chain in their cytoplasm. ISH positive cells were found in 1-4% of the peripheral blood mononuclear fraction of these two patients. These studies show that idiotypic oligonucleotide IgH gene probes can be used to identify individual cells belonging to the malignant clone and offer the possibility of developing innovative tumour-specific therapeutic procedures using antisense technology for patients with myeloma.

Base Sequence↗
PubMed1995

Prophylactic ganciclovir is more effective in HLA-identical family member marrow transplant recipients than in more heavily immune-suppressed HLA-identical unrelated donor marrow transplant recipients. Australasian Bone Marrow Transplant Study Group.

A multi-centre Australasian study of the efficacy of prophylactic ganciclovir in 88 recipients of marrow allografts at high risk for post-transplant cytomegalovirus (CMV) disease was conducted. The actuarial incidence of CMV disease was 10% in 74 recipients of HLA-identical family member transplants given ganciclovir but was 33% in 14 recipients of HLA-identical unrelated donor transplants given more immune-suppression pre- and post-transplant (P = 0.006). CMV disease developed in 4 of the 14 recipients of HLA-identical unrelated donor transplants at a median of 59 days post-transplant and was associated with concurrent graft-versus-host disease (GVHD) in 2 of the 4. CMV disease occurred in 5 of 74 recipients of an HLA-identical family member transplant at a median of 137 days post-transplant and was associated with concurrent moderate to severe GVHD in 4 of the 5. Thus the risk of CMV disease was higher in recipients who were not genotypically identical for HLA with their donors and who (in consequence) were given more immune-suppression than HLA-identical family member transplant recipients. Additionally, CMV disease can occur beyond the period of prophylactic ganciclovir administration (first 3 months post-transplant) in patients developing significant chronic GVHD and prophylaxis should be reintroduced at that time in such patients.

Adolescent↗
PubMed1994

Trends in bacterial infections in febrile neutropenic patients: 1986-1992.

BACKGROUND: Bacterial infection is a major cause of morbidity and mortality in neutropenic patients. AIMS: (1) To review patterns and trends in bacterial infections in three cohorts of febrile neutropenic patients managed by a single unit over a seven year period. (2) To relate any changes to the use of central venous (Hickman's) catheters and high-dose cytosine arabinoside chemotherapy. METHODS: Retrospective review of the results of initial bacteriological work-up performed on 344 episodes of febrile neutropenia. The three cohorts were 1986-87 (n = 102), 1989-90 (n = 92) and 1991-92 (n = 150). RESULTS: (1) The ratio of gram-negative to gram-positive bacteraemias fell from 1.36 in the first cohort to 1.05 in the second and 0.40 in the third (p = 0.03). There was a fall in both percentage and number of gram-negative isolates coupled with a rise in the frequency of gram-positive isolates. (2) Coincidentally there was a rise in the frequency of positive cultures from Hickman catheter entry wounds and an increasing frequency of simultaneous isolation of the same organism from the catheter entry site and the blood. The types of organisms isolated from catheter entry wounds showed a trend towards fewer gram-negative and more gram-positive. (3) A relationship was observed between the use of high-dose cytosine arabinoside chemotherapy and the incidence of bacteraemia (p = 0.025) but not with the change in types of organisms. CONCLUSIONS: Over seven years we have documented a major change in the types of infections, particularly bacteraemias, seen in febrile neutropenic patients. In our institution the more widespread use of intravenous catheters and high-dose cytosine arabinoside chemotherapy have been identified as two possible contributing factors.

Bacteremia↗