PubMed Health⌕ Search

Biomedical subjects

T Dalianis

Publications and source records attributed to T Dalianis.

At least 19 recordsLinked to original sources
PubMed2004

Association between a high BK virus load in urine samples of patients with graft-versus-host disease and development of hemorrhagic cystitis after hematopoietic stem cell transplantation.

BK virus (BKV) load in urine alone or in combination with acute graft-versus-host disease (GVHD) was correlated to development of hemorrhagic cystitis (HC). BKV load in combination with acute GVHD discriminated the best, while BKV and viral load alone, but not GVHD, still showed predictive ability for HC.

Adult↗
PubMed2003

Genetic immunization is augmented by murine polyomavirus VP1 pseudocapsids.

To improve immune responses induced by DNA immunization, murine polyomavirus major capsid protein (VP1) pseudocapsids were complexed with a DNA plasmid encoding the p37 (p24 and p17) nucleocapsid proteins of the human immunodeficiency virus type 1 (HIV-1). A 10-fold increase in antibody titer was noted in mice given DNA plasmid together with VP1 pseudocapsids in comparison to animals that received DNA plasmid alone. Cell mediated responses to HIV-1 p24 occurred, but were not significantly augmented by delivering the DNA as a VP1 complex. We have consequently for the first time shown a carrier/adjuvant effect of polyomavirus pseudocapsids that strongly increased the humoral immune response in DNA immunization.

Animals↗
PubMed2003

Murine pneumotropic virus VP1 virus-like particles (VLPs) bind to several cell types independent of sialic acid residues and do not serologically cross react with murine polyomavirus VP1 VLPs.

The ability of murine pneumotropic virus (MPtV) major capsid protein VP1 to form virus-like particles (VLPs) was examined. MPtV-VLPs obtained were used to estimate the potential of MPtV to attach to different cells and to assess some characteristics of the MPtV cell receptor. Furthermore, to evaluate if MPtV-VLPs could potentially complement murine polyomavirus (MPyV) VP1 VLPs (MPyV-VLPs) as vectors for prime-boost gene therapy, the capability of MPtV-VLPs to serologically cross react with MPyV-VLPs and to transduce DNA into cells was examined. MPtV VP1 obtained in a recombinant baculovirus system formed MPtV-VLPs readily. MPtV-VLPs were shown by FACS analysis to bind to different cells, independent of MHC class I antigen expression. In addition, MPtV-VLPs did not cause haemagglutination of red blood cells and MPtV-VLP binding to cells was neuraminidase resistant but mostly trypsin and papain sensitive, indicating that the MPtV receptor lacks sialic acid components. When tested by ELISA and in vivo neutralization assays, MPtV-VLPs did not serologically cross react with MPyV-VLPs, suggesting that MPtV-VLPs and MPyV-VLPs could potentially be interchanged as carriers of DNA in repeated gene therapy. Finally, MPtV-VLPs were shown to transduce foreign DNA in vitro and in vivo. In conclusion, the data suggest that MPtV-VLPs, and possibly also MPtV, bind to several different cell types, that binding is neuraminidase resistant and that MPtV-VLPs should potentially be able to complement MPyV-VLPs for prime-boost gene transfer in vivo.

Animals↗
PubMed2001

Overrepresentation of point mutations in the Sp1 site of the non-coding control region of BK virus in bone marrow transplanted patients with haemorrhagic cystitis.

BACKGROUND: Haemorrhagic cystitis (HC) in allogeneic bone marrow transplanted (BMT) patients is associated with reactivation of BK virus (BKV) manifested as BK viruria. However, it has been suggested that BKV reactivation alone is not responsible for HC, since BKV can be detected in the urine of 50-90% of all adult BMT patients. OBJECTIVES: In the present study, we analysed if BK viruses with specific mutations in the non-coding control region (NCCR) or in the region encoding the major capsid protein (VP1) were more frequently associated to the appearance of HC in BMT patients. STUDY DESIGN: The NCCR and the region encoding VP1 of BKV excreted in the urine from 25 BMT patients, 16 with and nine without HC, were sequenced by an ABI Prism Big Dye terminator cycle sequencing ready reaction kit. RESULTS AND CONCLUSIONS: A statistically significant (P=0.019) overrepresentation of C to G mutations within the NCCR Sp1 binding site was observed in 7/16 (43%) patients with HC (six cases at position 249 (P=0.035) and one case at position 251), as compared with 0/9 (0%) of the patients without HC. Major differences were not observed in the VP1 sequences of patients with and without HC. BKV WW and WWT-variants as well as BKV subtype I were most commonly encountered in both groups of patients. In conclusion, C to G point mutations, within the BKV NCCR Sp1 binding site, were significantly more common in patients with HC, suggesting that these mutations may be indicative for the clinical diagnosis of HC and could influence the virulence of the virus.

BK Virus↗
PubMed2000

Human papillomavirus (HPV) DNA in tonsillar cancer: clinical correlates, risk of relapse, and survival.

Human papillomavirus (HPV) is more commonly found in tonsillar cancer than in other head and neck cancers. The importance of HPV status in tonsillar cancer for prognosis remains unclear. The aim of the present study was to investigate the frequency of HPV in tonsillar cancer and to correlate the presence of HPV with tumor stage, nodal status, grade of differentiation, risk of relapse, and survival. HPV DNA and HPV type were determined, using PCR, in pre-treatment biopsies from 60 cases of primary tonsillar cancer. All patients had undergone full-dose radiotherapy, 45% as the only treatment modality, and 55% in combination with surgery. HPV 16 was detected in 43% (26/60) of the cancers including 1 double infection of both HPV 16 and HPV 33. Patients with HPV(+) tonsillar cancer showed less risk of relapse within 3 years after diagnosis, with a better odds ratio of 4.18 as compared with HPV(-) patients (p = 0. 025). Furthermore, cause specific survival was significantly (p = 0. 047) better in patients with HPV(+) tonsillar carcinomas. At 3 years after diagnosis the survival rate was 65.3% in the HPV(+) group and 31.5% in the HPV(-) group, and at 5 years the survival rate was 53. 5% and 31.5%, respectively. The better outcome for patients with HPV(+) tonsillar cancer was independent of TNM stage, nodal status, gender and age. These results indicate that HPV status is a significantly favorable prognostic factor in tonsillar cancer and may be used as a marker in order to optimize the treatment of patients with this type of cancer.

Adult↗
PubMed2000

Epstein-Barr virus (EBV) load in bone marrow transplant recipients at risk to develop posttransplant lymphoproliferative disease: prophylactic infusion of EBV-specific cytotoxic T cells.

A semiquantitative polymerase chain reaction assay was used to monitor the blood levels of Epstein-Barr virus (EBV)-DNA in 9 patients receiving allogeneic bone marrow transplants (BMT). Four of 5 recipients of HLA-mismatched T-cell-depleted grafts showed a 4- to 5-log increase of EBV-DNA within 1 to 3 months after BMT. Administration of 2 to 4 infusions of 10(7) EBV-specific cytotoxic T-lymphocytes (CTLs)/m(2) starting from the time of maximal virus load resulted in a 2- to 3-log decrease of virus titers in 3 patients. One patient, who received a T-cell culture lacking a major EBV-specific component, progressed to fatal EBV-positive lymphoma. Administration of EBV-CTLs before the onset of the EBV-DNA peak resulted in stabilization of the virus titers within 2 to 3 logs above the normal levels in the fifth patient. A moderate increase of virus titers was also detected in 3 of 4 patients receiving unmanipulated HLA-matched grafts, whereas 1 patient with Wiskott-Aldrich syndrome reached a 5-log increase of EBV-DNA load within 70 days after BMT. Our results suggest that a rapid increase of circulating EBV-DNA occurs in the absence of EBV-specific T-cell precursors or in the presence of congenital immune defects that prevent the reestablishment of virus-specific immunity. Prophylactic administration of EBV-CTLs early after BMT appears to provide the most effective protection against the development of EBV-associated lymphoproliferative disease.

Adolescent↗
PubMed2000

Follow-up of chimerism, including T- and B-lymphocytes and granulocytes in children more than one year after allogeneic bone marrow transplantation.

In bone-marrow-transplanted children, early detection of graft failure, relapse, and other potentially treatable problems is facilitated by the use of polymerase chain reaction (PCR) assays that monitor whether blood and marrow cells are of recipient or donor origin. Presence of mixed donor-recipient chimerism (MC) within the first year after BMT frequently correlates with clinical problems. To study if MC detected one year or more post-BMT was also often associated with clinical problems, the chimeric status in 33 children surviving 1-11 yr (median: 2 yr) after BMT was investigated. A PCR with a sensitivity of 1-2%, using fluorescent primers analyzing DNA fragment length polymorphisms, was applied. T- and B-cells and granulocytes were immunomagnetically isolated and tested separately for all patients. Of the 33 patients, of whom 21 had received pretreatment including total body irradiation (TBI), 27 (82%) exhibited full donor chimerism. Six children (18%), four of whom had received pretreatment without TBI, had MC. In three of these children, all with aplastic anemia, isolated T-cell MC had not posed apparent clinical problems. In two patients, both with MC including B-cells, immune hemolytic anemia was observed. A sixth patient with AML presented with MC and relapse. In two of the six children MC was detected only by cell subset analysis. In conclusion, analysis of MC in leukocyte subsets is more informative than analysis of whole blood only and may reveal clinically important variations in the origin of different cell populations. The prevalence of MC is lower after the first year post-BMT, and when present is less often associated with clinical problems.

Adolescent↗
PubMed2000

Polyomaviruria in renal transplant patients is not correlated to the cold ischemia period or to rejection episodes.

Polyomaviruria was observed in one-third of all renal transplant patients, irrespective of whether their renal grafts came from a living or cadaver donor, and was not correlated to graft rejection episodes. This suggests that the renal graft ischemia period is not the major cause of polyomavirus reactivation and that reactivation of polyomavirus is not a dominant cause of graft rejection.

Adolescent↗
PubMed2000

Persistence and tissue distribution of DNA in normal and immunodeficient mice inoculated with polyomavirus VP1 pseudocapsid complexes or polyomavirus.

Introduction of DNA into normal and immunodeficient mice, alone or in complex with VP1 pseudocapsids, has been compared to DNA transfer by viral infection. Similar to natural infection and in contrast to plasmid alone, VP1 pseudocapsids efficiently introduced DNA, which remained for months in normal mice and possibly longer in B- and T-cell-deficient mice.

Animals↗
PubMed1998

Low incidence of acute graft-versus-host disease, using unrelated HLA-A-, HLA-B-, and HLA-DR-compatible donors and conditioning, including anti-T-cell antibodies.

BACKGROUND: Using unrelated bone marrow, there is an increased risk of graft-versus-host disease (GVHD). METHODS: HLA-A-, HLA-B-, and HLA-DR-compatible unrelated bone marrow was given to 132 patients. The diagnoses included chronic myeloid leukemia (n=43), acute lymphoblastic leukemia (n=29), acute myeloid leukemia (n=27), myelodysplastic syndrome (n=4), lymphoma (n=3), myeloma (n=1), myelofibrosis (n=1), severe aplastic anemia (n=12), and metabolic disorders (n=12). The median age was 25 years (range 1-55 years). HLA class I was typed serologically, and class II was typed by polymerase chain reaction using sequence-specific primer pairs. Immunosuppression consisted of antithymocyte globulin or OKT3 for 5 days before transplantation and methotrexate combined with cyclosporine. RESULTS: Engraftment was seen in 127 of 132 patients (96%). Bacteremia occurred in 47%, cytomegalovirus (CMV) infection in 49%, and CMV disease in 8%. The cumulative incidences of acute GVHD > or = grade II and of chronic GVHD were 23% and 50%, respectively. The 5-year transplant-related mortality rate was 39%. The overall 5-year patient survival rate was 49%; in patients with metabolic disorders and severe aplastic anemia, it was 61% and 48%, respectively. The disease-free survival rate was 47% in patients with hematological malignancies in first remission or first chronic phase and 38% in patients with more advanced disease (P=0.04). Acute GVHD was associated with early engraftment of white blood count (P=0.02). Poor outcome in multivariate analysis was associated with acute myeloid leukemia (P=0.01) and CMV disease (P=0.04). CONCLUSION: Using HLA-A-, HLA-B-, and HLA-DR-compatible unrelated bone marrow and immunosuppression with antithymocyte globulin, methotrexate, and cyclosporine, the probability of GVHD was low and survival was favorable.

Adolescent↗
PubMed1998

Detection of JC virus in cerebrospinal fluid (CSF) samples from patients with progressive multifocal leukoencephalopathy but not in CSF samples from patients with herpes simplex encephalitis, enteroviral meningitis, or multiple sclerosis.

JC virus (JCV) DNA was detected in cerebrospinal fluid (CSF) samples from patients with progressive multifocal leukoencephalopathy (PML) but not in CSF samples from patients with herpes simplex encephalitis, enteroviral meningitis, or multiple sclerosis. This suggests that inflammatory processes in the brain do not necessarily reactivate JCV, which further supports the proposal that the presence of JCV DNA in the CSF is diagnostic for PML.

Adult↗
PubMed1998

Engraftment and chimerism, particularly of T- and B-cells, in children undergoing allogeneic bone marrow transplantation.

The spectrum of pediatric bone marrow transplantation has changed in recent years. Mismatched and unrelated donor transplants are common, demanding an increased vigilance to detect incipient graft failure, secondary lymphoma as well as relapse and other problems, which now are potentially treatable. To diagnose these complications it may be important to know whether blood and marrow cells are of recipient or donor origin. To evaluate the role of mixed donor-recipient chimerism in relation to clinical problems we adapted a polymerase chain-reaction technique, using fluorescent primers analyzing DNA fragment length polymorphisms, to follow prospectively 17 bone marrow grafted children. To increase the precision of chimerism analysis, immunomagnetically isolated leukocyte populations were assayed in selected cases. Five patients encountered clinical problems related to chimerism. One infant with adenosine deaminase deficiency failed to engraft stem cells, yet succumbed to graft-versus-host disease, mediated by mature donor T-cells. Three children developed significant mixed chimerism. One of these three patients died in relapse of leukemia, while the two other patients who had received T-cell depleted grafts had persistent recipient T-cells, in spite of engraftment. After 5 months, these were displaced by donor T-cells in one of the patients. In the fifth patient, also after T-cell depleted BMT, a fatal donor cell lymphoma occurred. Twelve children had stable full chimerism or in one case a low grade mixed chimerism and remain disease-free throughout follow up (median 9 months). In conclusion, the analysis of chimerism, particularly of separated leukocyte populations, offers an almost indispensable insight and a basis for therapeutic decisions in complicated situations such as grafting involving unrelated or mismatched donors, graft manipulation, adoptive immunotherapy and in immunodeficiency patients.

B-Lymphocytes↗
PubMed1998

Primary BK virus (BKV) infection due to possible BKV transmission during bone marrow transplantation is not the major cause of hemorrhagic cystitis in transplanted children.

In allogeneic bone marrow transplanted (BMT) patients BK virus (BKV) reactivation has been associated with haemorrhagic cystitis (HC). However, it is far from obvious which patients will develop HC, since BKV, a human polyomavirus, is ubiquitious and infects children at an early age. To investigate if a primary BKV infection, as such or possibly due to transmission of BKV by the marrow graft during BMT, was correlated to the development of HC, 45 children were followed for possible BKV seroconversion and development of HC at different time points after BMT. Serum samples were collected from the 45 allogeneic BMT children and their donors before transplantation, and from the patients at 3, 6 and 12 months after BMT. These sera were analysed for the presence of specific antibodies towards BKV by hemagglutination inhibition (HAI) and by IgG- and IgM-class specific enzyme linked immunosorbent (ELISA) assays. Twelve of the 45 BMT children had a documented episode of HC or hematuria. All patients and 98% of the donors were HAI positive before BMT, while with ELISA 87% of the patients and 84% of the donors were positive. Moreover, most HC and hematuria children (11/12) were seropositive with both assays before BMT, making it impossible to investigate possible BKV transmission through the bone marrow graft during BMT by serology. Still, serological changes such as ELISA seroconversion, IgM antibodies and/or HAI titer increases were significantly (p=0.016) more common in patients with HC (58%) than without HC (24%), but these changes occured mainly after HC symptomatology had already resolved. However, there was a near significant difference (p=0.053) in BKV seroprevalence by ELISA among the donors of patients with HC or hematuria (67%) as compared to the donors (91%) of patients without HC.

Adolescent↗
PubMed1996

Polyoma tumor development in neonatally polyoma-virus-infected CD4-/- and CD8-/- single knockout and CD4-/-8-/- double knockout mice.

CD4-/- or CD8-/- single knockout as well as CD4-/-8-/- double knockout mice were infected with polyoma virus as newborns or 1 week after birth. The animals were followed for tumor development and virus persistence. Double knockout mice developed tumors at a higher incidence (29%) than either the CD8-/- or CD4-/- single knockout mice (11% and 2%, respectively). Persistence of polyoma virus was examined by PCR in one third of all animals included in the study. Seven of the 17 CD4-/-8-/- double knockout mice gave positive evidence of virus persistence up to 6 months p.i. where virus DNA was present in most organs. Corresponding tests in single knockout mice gave positive results of persistent viral DNA in 2 of the 19 CD8-/-and 2 of the 7 CD4-/-mice. In the single knockout mice polyoma DNA could only be detected in a more limited variety of organs compared to the double knockouts.

Animals↗
PubMed1996

Bone marrow transplantation in children using unrelated donors at Huddinge Hospital.

Twenty-eight out of 31 children that underwent bone marrow transplantation (BMT) from unrelated donors between 1984 and 1995 received HLA-A, HLA-B and HLA-DR matched unrelated donor (MUD) marrows as defined by serologic HLA class I and genomic HLA class II typing. Compared with 28 case-matched controls transplanted with HLA identical sibling donors, MUD patients received a more intensive conditioning. Twenty-six patients (93%) engrafted while two died of septicaemia during the aplastic phase. Two patients rejected their grafts and four developed Evans syndrome. All controls engrafted without incidents of rejection or Evans syndrome. The probability of acute graft-versus-host disease (GVHD) of grade II or above was 27% after MUD-BMT and 7% in the controls. The 5-year probability of survival was 60% in MUD patients and 89% after sibling BMT (p = 0.03). Leukaemia-free survival was 60% with one relapse in the MUD patients, and 59% with five relapses in the sibling group. Three children who received a mismatched donor marrow died, two of severe GVHD and one after graft rejection. In conclusion, today, a matched unrelated donor BMT is an acceptable alternative for many children who need a BMT but lack a suitable related donor.

Adolescent↗
PubMed1996

A short peptide eluted from the H-2Kb molecule of a polyomavirus-positive tumor corresponds to polyomavirus large T antigen peptide at amino acids 578 to 585 and induces polyomavirus-specific immunity.

A short peptide in complex with the H-2Kb molecule on PyRMA, a polyomavirus transfectant of the mouse lymphoma cell line RMA, was identified as a polyomavirus tumor-specific transplantation antigen. The peptide was obtained by affinity chromatography, acidic extraction, and reverse-phase high-pressure liquid chromatography (HPLC). In one HPLC fraction, a peptide sequence in which 5 of 8 amino acids, GKxGLxxA, corresponded to residues 578 to 585 of polyomavirus large T antigen was identified. In tumor rejection assays, we therefore tested three related synthetic peptides, corresponding to the octapeptide LT 578-585, GKTGLAAA; the nonapeptide LT 578-586, GKTGLAAAL; and the decapeptide LT 578-587, GKTGLAAALI. The octapeptide was found to give the most effective immunization against the outgrowth of the polyomavirus DNA-positive PyRMA tumor. However, none of the three peptides immunized against the original polyoma-virus-negative RMA line.

Amino Acid Sequence↗
PubMed1996

Presence of human polyomavirus DNA in the peripheral circulation of bone marrow transplant patients with and without hemorrhagic cystitis.

In BMT patients, shedding of BK virus (BKV) in the urine has been strongly but not absolutely correlated to hemorrhagic cystitis (HC). The possible presence of human polyomaviruses in peripheral blood leukocytes (PBLs), plasma, serum and urine in BMT patients and an association with HC was investigated by a nested PCR assay. Samples from allogeneic BMT patients with and without HC as well as from autologous BMT patients were analyzed. Human polyomaviruses were detected in urine and blood samples of both allogeneic and autologous BMT patients with and without HC. An association between the presence of a specific human polyomavirus in blood and HC was thus not observed.

Adolescent↗