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Christian Thiede

Publications and source records attributed to Christian Thiede.

33 records · Page 2Linked to original sources
PubMed2004

Hematopoietic stem cell transplantation for complete IFN-gamma receptor 1 deficiency: a multi-institutional survey.

OBJECTIVES: To evaluate the outcome of hematopoietic stem cell transplantation (HSCT) in a series of patients with inherited complete IFN-gamma receptor 1 (IFNgammaR1) deficiency. STUDY DESIGN: We report 8 patients who received altogether 11 HSCT from family donors, including 10 HLA-identical (5 siblings and 5 relatives) and 1 HLA-haplo-identical donors. Five grafts were T-cell depleted, and conditioning regimens varied in intensity. RESULTS: Four patients died within 8 months after HSCT. Two of these deaths were due to specific complications related to mycobacterial infection. There was no or very low (2%) donor cell engraftment in 2 survivors. Only 2 patients are in full remission of mycobacterial disease 5 years after HSCT. These are the only patients who received non-T-cell-depleted grafts from an HLA-identical sibling after a fully myeloablative conditioning regimen. CONCLUSIONS: HSCT can lead to prolonged remission of mycobacterial disease in children with complete IFNgammaR1 deficiency. However, optimal control of mycobacterial infection before HSCT and the use of a non-T-cell-depleted transplant from an HLA-identical sibling after a fully myeloablative conditioning regimen are recommended.

Child↗
PubMed2004

Strategies and clinical implications of chimerism diagnostics after allogeneic hematopoietic stem cell transplantation.

Analysis of donor chimerism has become a routine method for the documentation of engraftment after allogeneic hematopoietic stem cell transplantation (HSCT). In recent years several groups have also focused on the application of this technique for the detection of relapsing disease after allogeneic HSCT. This review addresses technical issues (sensitivity, specificity) and discusses the advantages and limitations of methods currently used for chimerism analysis and their usefulness for the detection of MRD. In addition, the potential impact of novel procedures, e.g. subset chimerism or real-time PCR-based procedures, is discussed.

Hematopoietic Stem Cell Transplantation↗
PubMed2004

Diagnostic chimerism analysis after allogeneic stem cell transplantation: new methods and markers.

Analysis of chimerism after allogeneic hematopoietic cell transplantation is important for assessing engraftment and the early detection of graft failure. In addition, the monitoring of minimal residual disease and early detection of imminent relapse has also become an important issue. Novel transplant procedures, for example dose-reduced conditioning protocols, rely on chimerism analysis to guide intervention, i.e. the reduction of immunosuppression or infusion of donor lymphocytes. During the last 30 years, several methods for the analysis of chimerism after hematopoietic cell transplantation have been published. Currently, fluorescent in situ hybridization (XY-FISH) analysis of sex chromosomes after transplantation from a sex-mismatched donor or analysis of polymorphic DNA sequences, i.e. short tandem repeats (STR) or variable number of tandem repeats (VNTR), are the most widely used procedures used in the assessment of chimerism. Two major diagnostic fields can be defined for chimerism analysis: the period of engraftment and the detection of minimal residual disease. Although STR-PCR and FISH analysis are very useful in the diagnosis of engraftment and graft failure, they are only of limited use in the monitoring of minimal residual disease, largely because of its limited level of sensitivity (1-5% for the minor population). Several novel procedures to improve this level of detection have been reported in recent years. One focus has been the use of real-time PCR techniques based on analysis of the Y-chromosome or, more recently, single nucleotide polymorphism (SNPs). These procedures combine quantitative analysis with high sensitivity (10(-4) to 10(-6)), and hold great potential for the future. In addition, the combination of cell sorting based on leukemia-specific immunophenotype and STR-PCR has been successfully used for minimal residual disease detection. First clinical data using these procedures indicate that intervention (e.g. the reduction of immunosuppression or donor lymphocyte infusion) may be effective in the minimal residual disease situation, even in high risk diseases like acute myeloid leukemia and acute lymphoblastic leukemia. The optimal timing of these diagnostic interventions is a critical issue and has to be further optimized. Whether this will ultimately improve the survival of patients with leukemia after transplantation has to be shown in prospective studies.

Animals↗
PubMed2003

Conditioning with fludarabine and targeted busulfan for transplantation of allogeneic hematopoietic stem cells.

A regimen of busulfan and cyclophosphamide is standard therapy before transplantation of allogeneic hematopoietic stem cells in patients with chronic myelogenous leukemia (CML) or myelodysplastic syndrome (MDS). The clinical trial reported here was undertaken to test the hypothesis that fludarabine can replace cyclophosphamide in this regimen and facilitate donor engraftment with reduced toxicity. The conditioning regimen consisted of 30 mg/m2 intravenous fludarabine daily from day -9 to day -6, and oral busulfan given at 1 mg/kg 4 times a day every 6 hours from day -5 to day -2, with doses adjusted to target plasma levels of 900 +/- 100 ng/mL at steady state. Cyclosporine and methotrexate were used for prophylaxis for graft-versus-host disease. Enrolled were 42 patients with high-risk CML (n = 4) or MDS (n = 38). The median patient age was 52 years (range, 12-65 years). Mobilized blood stem cells were obtained from HLA-compatible siblings (n = 16) or unrelated donors (n = 26). Engraftment was achieved in all patients, and the day-100 regimen-related mortality was 7%. With a median follow-up of 18 months (range, 13-27 months), the probabilities of overall survival, disease-free survival, and nonrelapse mortality were 42.4%, 34.9%, and 24%, respectively. These data indicate that the combination of fludarabine and targeted busulfan is sufficiently immunosuppressive to facilitate engraftment of blood stem cells from HLA-matched siblings and unrelated donors. Based on these encouraging results, further studies of fludarabine and targeted busulfan are warranted in standard-risk patients.

Adolescent↗
PubMed2003

Sensitivity toward tyrosine kinase inhibitors varies between different activating mutations of the FLT3 receptor.

Activating mutations of FLT3 have been detected in patients with acute myeloid leukemia (AML). Two distinct types of FLT3 mutations are most common: internal tandem duplication (ITD) of sequences coding for the juxtamembrane domain and point mutations at codon 835 (Asp835) within the kinase domain. Both types of mutations constitutively activate the tyrosine kinase activity of FLT3 in experimental systems and result in factor-independent proliferation of Ba/F3 and 32D cells. Recently, novel mutations within the activation loop were identified in patients with AML: deletion of isoleucine 836 (Ile836del) and an exchange of isoleucine 836 to methionine plus an arginine insertion (Ile836Met+Arg). To examine whether the Ile836 mutations result in constitutive activation of the FLT3 receptor, we introduced both mutant FLT3 cDNAs transiently into HEK 293 cells. Both mutant FLT3 receptors were constitutively autophosphorylated in the absence of ligand and kinase activity led to constitutive activation of downstream signaling cascades as determined by activation of the STAT5 (signal transducer and activator of transcription 5) pathway. When stably expressed in the growth factor-dependent cell lines Ba/F3 and 32D, both deletion and insertion mutants led to factor-independent proliferation, indicating that both mutants have transforming capabilities. We then examined the sensitivity of the FLT3 ITD, FLT3 Asp835Tyr, and the novel FLT3 receptor mutants toward the kinase inhibitors AG1296, PKC412, and SU5614. We show that these FLT3 kinase inhibitors have distinct inhibitory potencies against different activating FLT3 receptor mutants. These results suggest that it may be useful to determine the exact kind of FLT3 mutation when applying receptor kinase inhibitors in clinical trials.

Acute Disease↗
PubMed2003

Comparative analysis of MLL partial tandem duplication and FLT3 internal tandem duplication mutations in 956 adult patients with acute myeloid leukemia.

Partial tandem duplication (PTD) of the MLL gene and internal tandem duplication (ITD) of the juxtamembrane region of the FLT3 receptor tyrosine kinase gene have been described in acute myeloid leukemia (AML) patients, preferentially in those with normal cytogenetics. These alterations have been associated with a poor prognosis. In our study, we analyzed the prevalence and the potential prognostic impact of these aberrations in a large unselected and well-defined cohort of 956 patients with AML. Results were correlated with cytogenetic data and clinical outcome. MLL PTD was detected by RT-PCR, subsequent nucleotide sequencing, and Southern blotting. The overall incidence was found to be 5.0% (48/956), whereas FLT3 ITD was detected in 19.2% (184/956). Sixteen cases were positive for both alterations. The rate of MLL PTD in FLT3 ITD positive patients was significantly higher than that in FLT3 ITD negative patients [16/184 (8.7%); 32/772 (4.1%); P = 0.025]. However, both aberrations were highly increased in patients with normal karyotype (MLL PTD 35/431, P = 0.004; FLT3 ITD 132/334, P < 0.001). When restricted to this subgroup, the rate of MLL PTD in patients with FLT3 mutations was not significantly increased. No statistically significant differences were detected between patients positive for MLL PTD and patients negative for MLL PTD in the rate of complete remissions or the overall survival, although we did see a significantly shorter disease-free survival in patients age 60 or younger. In conclusion, although there is an overlap in the mutational spectrum in AML with FLT3 ITD and MLL PTD mutations, our data do not support a common mechanistic basis. Although associated with inferior disease-free survival, the results of this study do not unequivocally support the notion that MLL PTD mutations represent an independent prognostic factor.

Adolescent↗
PubMed2003

B-cell monoclonality is associated with lymphoid follicles in gastritis.

The gold standard for diagnosis of gastric MALT lymphoma is histopathology. Polymerase chain reaction-based assays to detect the expansion of monoclonal B cells have also been used to corroborate the diagnosis. However, there are conflicting data on monoclonal B-cell expansion in gastritis. We asked about its frequency in graded gastritis cases. Lymphocytic infiltration in gastric biopsies was graded according to Wotherspoon in 129 cases. The histologic diagnosis ranged from normal gastric mucosa to suspicious for gastric MALT lymphoma. To search for a monoclonal B-cell population, a semi-nested polymerase chain reaction strategy was used for amplification of rearranged VDJ sequences of the immunoglobulin heavy chain gene. Of 106 evaluable samples, 18 were found to be monoclonal. The detection of a monoclonal B-cell population was strongly associated with the presence of lymphoid follicles. In cases with lymphoid follicles, detection of monoclonality was independent of Wotherspoon grading; there is no significant difference between cases being suspicious for lymphoma and those not. We found B-cell monoclonality to be a more frequent than expected finding in gastritis and to be strongly associated with the presence of lymphoid follicles; thus, its presence is of little significance in patient management.

B-Lymphocytes↗
PubMed2002

MDR1 gene polymorphisms affect therapy outcome in acute myeloid leukemia patients.

Allelic variants of the MDR-1 gene have been shown recently to influence protein expression and P-glycoprotein (P-gp) function in healthy volunteers. Therefore, 405 acute myeloid leukemia patients were investigated for somatic genotypes of the three most frequent single nucleotide polymorphisms (SNPs) in exons 12, 21, and 26. In all three loci, homozygous wild-type alleles were classified as genotype A, heterozygous as B, and homozygous mutant (alternative) allele as C. Patients with the C genotype in exons 12 and 26 showed a lower median age (both P < 0.05). Additionally, the C genotype in exons 12 and 26 was associated with cytogenetic poor risk aberrations (both P < 0.05). A possible regulatory impact of the SNPs on MDR1 mRNA expression was investigated by a Real time-PCR assay. MDR1 expression was strongly correlated with a decreased complete remission rate (P = 0.01) but failed to predict decreased overall survival (OS). There was a significant association of the A genotype in exons 21 (P = 0.05) and 26 (P < 0.05) with lower MDR1 expression, whereas the B variants showed highest MDR1 values at all three investigated gene loci. The A genotype in exon 26 was associated with lower OS (P < 0,01). In these patients, worse OS is likely attributable to an increased risk of relapse (P < 0.001). We were able to detect a linkage disequilibrium of the investigated SNPs, indicating combined polymorphisms that could affect the regulation of MDR1 expression. The A genotype of all SNPs demonstrated both lowest MDR1 values and significantly decreased OS (P < 0.05) with a high probability of relapses (P < 0.01). These observations indicate that allelic variants of the MDR1 gene may influence therapy outcome by additional mechanisms, different from P-gp expression on acute myeloid leukemia blasts, possibly involving pharmacokinetic effects of P-gp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

Correction of complete interferon-gamma receptor 1 deficiency by bone marrow transplantation.

Complete interferon-gamma receptor 1 (IFNgammaR1) deficiency is a primary immunodeficiency disease characterized by high susceptibility to recurrent, severe mycobacterial and other intracellular infections. We here report the first successful treatment of the disorder by bone marrow transplantation (BMT). The 8-year-old girl had suffered from recurrent mycobacterial infections in the past and had developed liver cirrhosis with portal hypertension. For conditioning, fractionated total body irradiation (TBI) was used in combination with cyclophosphamide and antithymocyte globulin (ATG). The patient received red cell-depleted bone marrow from her HLA-identical sister. The transplantation course was uneventful and 4 years later, the child remains in excellent clinical condition and free of mycobacterial infections. She has stable mixed lymphohematopoietic chimerism after repeat T-cell transfusions. Liver disease has not further deteriorated. This experience shows that correction of IFNgammaR1 deficiency is possible by BMT and complications of the disease can be controlled.

Bone Marrow Transplantation↗
PubMed2002

Analysis of FLT3-activating mutations in 979 patients with acute myelogenous leukemia: association with FAB subtypes and identification of subgroups with poor prognosis.

Constitutive activation of the FLT3 receptor tyrosine kinase, either by internal tandem duplication (ITD) of the juxtamembrane region or by point mutations in the second tyrosine kinase domain (TKD), has been described in patients with acute myelogenous leukemia (AML). We analyzed the prevalence and the potential prognostic impact of FLT3 mutations in 979 AML patients. Results were correlated with cytogenetic data and the clinical response. FLT3-ITD mutations were found in 20.4% and FLT3-TKD mutations in 7.7% of the patients. Each mutation was associated with similar clinical characteristics and was more prevalent in patients with normal karyotype. Significantly more FLT3 aberrations were found in patients with FAB M5, and fewer were found in patients with FAB M2 and M6. Although less frequent in patients with cytogenetic aberrations, FLT3-ITDs were found in 13 of 42 patients with t(15;17) and in 9 of 10 patients with t(6;9). The prevalence of the ITD allele on the DNA level was heterogeneous, ranging from faint mutant bands in some patients to predominant mutant bands in others. Based on quantitative analysis, the mutant-wild-type (wt) ratio ranged from 0.03 to 32.56 (median, 0.78). Patients with a high mutant/wt ratio (ie, greater than 0.78) had significantly shorter overall and disease-free survival, whereas survival in patients with ratios below 0.78 did not differ from those without FLT3 aberrations. Multivariate analysis confirmed a high mutant/wt ratio to be a strong independent prognostic factor. Taken together, these data confirm that FLT mutations represent a common alteration in adult AML. Constitutive activation may be associated with monocytoid differentiation. A high mutant/wt ratio in ITD-positive patients appears to have a major impact on the prognostic relevance.

Adult↗
PubMed2002

Kinetics of stem cell engraftment and clearance of leukaemia cells after allogeneic stem cell transplantation with reduced intensity conditioning in chronic myeloid leukaemia.

It is hypothesised that an effective graft-vs.-leukaemia reaction contributes substantially to the therapeutic effect of reduced intensity conditioning stem cell transplantation in chronic myeloid leukaemia. However, kinetic data on eradication of leukaemia cells and stem cell engraftement which could support this assumption are lacking. Thus, we investigated bcr/abl fusion transcripts and haematopoietic chimerism in 14 patients undergoing such a transplantation protocol. Ten of them obtained a complete molecular remission, and two patients achieved haematologic remissions but remained bcr/abl positive. Weekly determinations of bcr/abl transcript numbers by qualitative and quantitative polymerase chain reaction and donor chimerism revealed that 10 responders cleared bcr/abl positive cells from the peripheral blood within a median of 9 wk (range 3-22 wk). The close relation (P = 0.0075) between the first occurrence of graft-vs.-host disease and the complete clearance of bcr/abl positive blood cells argues in favour of an effective graft-vs.-leukaemia reaction.

Adult↗
PubMed2002

T(11;18) is a marker for all stage gastric MALT lymphomas that will not respond to H. pylori eradication.

BACKGROUND & AIMS: Eradication of Helicobacter pylori leads to cure of gastric mucosa-associated lymphoid tissue (MALT) lymphoma in 75% of localized cases. However, prolonged follow-up is necessary to determine whether a lymphoma responds to therapy. In a small series of cases, we showed that t(11;18)(q21;q21)-positive MALT lymphomas failed to respond to H. pylori eradication. The present study aimed to verify this finding in a large cohort and confirm whether the translocation predicts the response of stage I(E) tumors, for which clinical staging has little prognostic value. METHODS: A total of 111 patients with H. pylori-positive gastric MALT lymphoma treated with antibiotics were studied. Clinical staging was undertaken before therapy. The response of lymphoma to H. pylori eradication was determined by histologic examination of gastric biopsy specimens. Diagnostic biopsy specimens were analyzed for t(11;18)(q21;q21) by reverse-transcription polymerase chain reaction of the API2-MALT1 transcript. RESULTS: Forty-seven of the 48 patients who showed complete regression had lymphoma at stage I(E), whereas 43 of the 63 nonresponsive cases were at stage I(E) and the remaining cases at stage II(E) or above. t(11;18)(q21;q21) was detected in 2 of 48 complete-regression cases, and these positive cases showed relapse of lymphoma in the absence of H. pylori reinfection. In contrast, the translocation was present in 42 of the 63 nonresponsive cases, including 26 of 43 (60%) at stage I(E). CONCLUSIONS: t(11;18)(q21;q21)-positive gastric MALT lymphomas, including those at stage I(E), do not respond to H. pylori eradication. Detection of the translocation should help the clinical management of patients with gastric MALT lymphoma.

Adult↗
PubMed2002

Allogeneic transplantation after reduced conditioning in high risk patients is complicated by a high incidence of acute and chronic graft-versus-host disease.

Background and Objectives. We studied the toxicity and efficacy of reduced intensity conditioning followed by allogeneic stem cell transplantation in 50 patients over 50 years old or with relative contraindications against myeloablative regimens. Diagnoses were chronic myeloid leukemia (n=15), acute myeloid leukemia (n=9), myelodysplastic syndromes (n=9), lymphoma (n=11) and refractory solid tumors (n=6). Design and Methods. Donors were identical siblings (n=25), non-identical family members (n=6) and unrelated volunteers (n=19). Peripheral blood stem cells (n=36) or bone marrow (n=14) were transplanted. The conditioning regimen consisted of fludarabine 180 mg/m(2), busulphan 8 mg/kg and rabbit antithymocyte globulin 40 mg/kg (Fresenius). Graft-versus-host disease (GVHD) prophylaxis was carried out with cyclosporin A (CSA) alone (n=17) or in combination with methotrexate (n=18) or mycophenolate mofetil (n=15). Results. Neutrophil counts >0.5/nL and platelet counts > 20/nL were reached after 17 (range 0-66) and 19 days (range 0-111), respectively. Three graft failures occurred. Fever lasted for a median of 2 days (range 0-15). Six patients developed veno-occlusive disease of the liver. Acute GVHD grade II-IV occurred in 47% of the patients and chronic GVHD in 46%. The 1-year overall survival probability was 44% (95% CI: 30-58%). GVHD-related complications were a major cause of the probability of 1-year non-relapse mortality of 31% (95% CI: 16-46%). Interpretation and Conclusions. In conclusion, the regimen itself can be carried out safely in patients with relative contraindications against myeloablative conditioning. However, GVHD causes significant non-relapse mortality in high risk patients.

Acute Disease↗