Developmental trajectories and cooperating genomic events define molecular subtypes of BCR::ABL1-positive ALL

ABSTRACT

Distinct diagnostic entities within BCR::ABL1-positive acute lymphoblastic leukemia (ALL) are currently defined by the International Consensus Classification of myeloid neoplasms and acute leukemias (ICC): "lymphoid only", with BCR::ABL1 observed exclusively in lymphatic precursors, vs "multilineage", where BCR::ABL1 is also present in other hematopoietic lineages. Here, we analyzed transcriptomes of 327 BCR::ABL1-positive patients with ALL (age, 2-84 years; median, 46 years) and identified 2 main gene expression clusters reproducible across 4 independent patient cohorts. Fluorescence in situ hybridization analysis of fluorescence-activated cell-sorted hematopoietic compartments showed distinct BCR::ABL1 involvement in myeloid cells for these clusters (n = 18/18 vs n = 3/16 patients; P < .001), indicating that a multilineage or lymphoid BCR::ABL1 subtype can be inferred from gene expression. Further subclusters grouped samples according to cooperating genomic events (multilineage: HBS1L deletion or monosomy 7; lymphoid: IKZF1-/- or CDKN2A/PAX5 deletions/hyperdiploidy). A novel HSB1L transcript was highly specific for BCR::ABL1 multilineage cases independent of HBS1L genomic aberrations. Treatment on current German Multicenter Study Group for Adult ALL (GMALL) protocols resulted in comparable disease-free survival (DFS) for multilineage vs lymphoid cluster patients (3-year DFS: 70% vs 61%; P = .530; n = 91). However, the IKZF1-/- enriched lymphoid subcluster was associated with inferior DFS, whereas hyperdiploid cases showed a superior outcome. Thus, gene expression clusters define underlying developmental trajectories and distinct patterns of cooperating events in BCR::ABL1-positive ALL with prognostic relevance.

The Gene Expression Classifier ALLCatchR Identifies B-cell Precursor ALL Subtypes and Underlying Developmental Trajectories Across Age

Current classifications (World Health Organization-HAEM5/ICC) define up to 26 molecular B-cell precursor acute lymphoblastic leukemia (BCP-ALL) disease subtypes by genomic driver aberrations and corresponding gene expression signatures. Identification of driver aberrations by transcriptome sequencing (RNA-Seq) is well established, while systematic approaches for gene expression analysis are less advanced. Therefore, we developed ALLCatchR, a machine learning-based classifier using RNA-Seq gene expression data to allocate BCP-ALL samples to all 21 gene expression-defined molecular subtypes. Trained on n = 1869 transcriptome profiles with established subtype definitions (4 cohorts; 55% pediatric / 45% adult), ALLCatchR allowed subtype allocation in 3 independent hold-out cohorts (n = 1018; 75% pediatric / 25% adult) with 95.7% accuracy (averaged sensitivity across subtypes: 91.1% / specificity: 99.8%). High-confidence predictions were achieved in 83.7% of samples with 98.9% accuracy. Only 1.2% of samples remained unclassified. ALLCatchR outperformed existing tools and identified novel driver candidates in previously unassigned samples. Additional modules provided predictions of samples blast counts, patient's sex, and immunophenotype, allowing the imputation in cases where these information are missing. We established a novel RNA-Seq reference of human B-lymphopoiesis using 7 FACS-sorted progenitor stages from healthy bone marrow donors. Implementation in ALLCatchR enabled projection of BCP-ALL samples to this trajectory. This identified shared proximity patterns of BCP-ALL subtypes to normal lymphopoiesis stages, extending immunophenotypic classifications with a novel framework for developmental comparisons of BCP-ALL. ALLCatchR enables RNA-Seq routine application for BCP-ALL diagnostics with systematic gene expression analysis for accurate subtype allocation and novel insights into underlying developmental trajectories.

Chemotherapy-induced release of ADAM17 bearing EV as a potential resistance mechanism in ovarian cancer

Ovarian cancer (OvCa) is the gynaecological disorder with the poorest prognosis due to the fast development of chemoresistance. We sought to connect chemoresistance and cancer cell-derived extracellular vesicles (EV). The mechanisms of how chemoresistance is sustained by EV remained elusive. One potentially contributing factor is A Disintegrin and Metalloprotease 17 (ADAM17)-itself being able to promote chemoresistance and inducing tumour cell proliferation and survival via the Epidermal Growth Factor Receptor (EGFR) pathway by shedding several of its ligands including Amphiregulin (AREG). We now demonstrate that upon chemotherapeutic treatment, proteolytically active ADAM17 is released in association with EV from OvCa cells. In terms of function, we show that patient-derived EV induce AREG shedding and restore chemoresistance in ADAM17-deficient cells. Confirming that ADAM17-containing EV transmit chemoresistance in OvCa, we propose that ADAM17 levels (also on EV) might serve as an indicator for tumour progression and the chemosensitivity status of a given patient.

Disruption of the sialic acid/Siglec-9 axis improves antibody-mediated neutrophil cytotoxicity towards tumor cells

Upregulation of surface expressed sialoglycans on tumor cells is one of the mechanisms which promote tumor growth and progression. Specifically, the interactions of sialic acids with sialic acid-binding immunoglobulin-like lectins (Siglecs) on lymphoid or myeloid cells transmit inhibitory signals and lead to suppression of anti-tumor responses. Here, we show that neutrophils express among others Siglec-9, and that EGFR and HER2 positive breast tumor cells express ligands for Siglec-9. Treatment of tumor cells with neuraminidases or a sialyl transferase inhibitor significantly reduced binding of a soluble recombinant Siglec-9-Fc fusion protein, while EGFR and HER2 expression remained unchanged. Importantly, the cytotoxic activity of neutrophils driven by therapeutic EGFR or HER2 antibodies in vitro was increased by blocking the sialic acid/Siglec interaction, either by reducing tumor cell sialylation or by a Siglec-9 blocking antibody containing an effector silenced Fc domain. In vivo a short-term xenograft mouse model confirmed the improved therapeutic efficacy of EGFR antibodies against sialic acid depleted, by a sialyltransferase inhibitor, tumor cells compared to untreated cells. Our studies demonstrate that sialic acid/Siglec interactions between tumor cells and myeloid cells can impair antibody dependent tumor cell killing, and that Siglec-9 on polymorphonuclear cells (PMN) is critically involved. Considering that PMN are often a highly abundant cell population in the tumor microenvironment, Siglec-9 constitutes a promising target for myeloid checkpoint blockade to improve antibody-based tumor immunotherapy.

Clinical and Cytogenetic Characteristics of Children With Leukemia 20-Year Retrospective Study

Acute leukemias are the most common malignant diseases in childhood. The aims of this retrospective cohort study were to investigate the frequency of cytogenetic abnormalities in acute pediatric leukemia; the correlation between cytogenetic abnormalities and 5-year survival; and the correlation between cytogenetic abnormalities and clinical and laboratory features. We included 105 patients; acute lymphoblastic leukemia (ALL) had 80.9% patients, B-cell lineage ALL (B-ALL) 84.7% of them, and T-cell lineage (T-ALL) 15.3%. The overall 5-year survival for B-ALL was 85.9% and for T-ALL was 84.6%. The most common cytogenetic abnormalities in patients with B-ALL were t(12;21)(p13.2;q22.1); ETV6-RUNX1 with 22.2% and hyperdiploidy with 19.4%. Our survival analysis showed that t(12;21)(p13.2;q22.1); ETV6-RUNX1 and t(1;19)(q23;p13.3); TCF3-PBX1 had the best 5-year survival with 100% of patients surviving, whereas t(v;11q23.3); KMT2A rearranged had the worst 5-year survival of just 33.3% of patients surviving after 5 years. We found no difference in 5-year survival in B-ALL when comparing clinical features. Acute myelogenous leukemia had 20 patients with 70.6% 5-year survival. The most common cytogenetic abnormality in acute myelogenous leukemia was t(8;21)(q21;q22.1); RUNX1-RUNX1T1 (20%). In conclusion, this study showed the correlation of different cytogenetic abnormalities with 5-year survival in B-ALL patients. Such correlation was not found when comparing clinical features and 5-year survival of patients with B-ALL. This emphasized the significance of cytogenetic analysis in pediatric leukemia.

FAT1 expression in T-cell acute lymphoblastic leukemia (T-ALL) modulates proliferation and WNT signaling

FAT atypical cadherin 1 (FAT1), a transmembrane protein, is frequently mutated in various cancer types and has been described as context-dependent tumor suppressor or oncogene. The FAT1 gene is mutated in 12-16% of T-cell acute leukemia (T-ALL) and aberrantly expressed in about 54% of T-ALL cases contrasted with absent expression in normal T-cells. Here, we characterized FAT1 expression and profiled the methylation status from T-ALL patients. In our T-ALL cohort, 53% of patient samples were FAT1 positive (FAT1pos) compared to only 16% FAT1 positivity in early T-ALL patient samples. Aberrant expression of FAT1 was strongly associated with FAT1 promotor hypomethylation, yet a subset, mainly consisting of TLX1-driven T-ALL patient samples showed methylation-independent high FAT1 expression. Genes correlating with FAT1 expression revealed enrichment in WNT signaling genes representing the most enriched single pathway. FAT1 knockdown or knockout led to impaired proliferation and downregulation of WNT pathway target genes (CCND1, MYC, LEF1), while FAT1 overexpressing conveyed a proliferative advantage. To conclude, we characterized a subtype pattern of FAT1 gene expression in adult T-ALL patients correlating with promotor methylation status. FAT1 dependent proliferation and WNT signaling discloses an impact on deeper understanding of T-ALL leukemogenesis as a fundament for prospective therapeutic strategies.

Insights into IGH clonal evolution in BCP-ALL: frequency, mechanisms, associations, and diagnostic implications

Introduction

The malignant transformation leading to a maturation arrest in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) occurs early in B-cell development, in a pro-B or pre-B cell, when somatic recombination of variable (V), diversity (D), and joining (J) segment immunoglobulin (IG) genes and the B-cell rescue mechanism of V_H replacement might be ongoing or fully active, driving clonal evolution. In this study of newly diagnosed BCP-ALL, we sought to understand the mechanistic details of oligoclonal composition of the leukemia at diagnosis, clonal evolution during follow-up, and clonal distribution in different hematopoietic compartments.

Methods

Utilizing high-throughput sequencing assays and bespoke bioinformatics we identified BCP-ALL-derived clonally-related IGH sequences by their shared 'DNJ-stem'.

Results

We introduce the concept of 'marker DNJ-stem' to cover the entirety of, even lowly abundant, clonally-related family members. In a cohort of 280 adult patients with BCP-ALL, IGH clonal evolution at diagnosis was identified in one-third of patients. The phenomenon was linked to contemporaneous recombinant and editing activity driven by aberrant ongoing D_H/V_H-DJ_H recombination and V_H replacement, and we share insights and examples for both. Furthermore, in a subset of 167 patients with molecular subtype allocation, high prevalence and high degree of clonal evolution driven by ongoing D_H/V_H-DJ_H recombination were associated with the presence of KMT2A gene rearrangements, while V_H replacements occurred more frequently in Ph-like and DUX4 BCP-ALL. Analysis of 46 matched diagnostic bone marrow and peripheral blood samples showed a comparable clonal and clonotypic distribution in both hematopoietic compartments, but the clonotypic composition markedly changed in longitudinal follow-up analysis in select cases. Thus, finally, we present cases where the specific dynamics of clonal evolution have implications for both the initial marker identification and the MRD monitoring in follow-up samples.

Discussion

Consequently, we suggest to follow the marker DNJ-stem (capturing all family members) rather than specific clonotypes as the MRD target, as well as to follow both VDJ_H and DJ_H family members since their respective kinetics are not always parallel. Our study further highlights the intricacy, importance, and present and future challenges of IGH clonal evolution in BCP-ALL.

Isocitrate dehydrogenase 1 mutation drives leukemogenesis by PDGFRA activation due to insulator disruption in acute myeloid leukemia (AML)

Acute myeloid leukemia (AML) is characterized by complex molecular alterations and driver mutations. Elderly patients show increased frequencies of IDH mutations with high chemoresistance and relapse rates despite recent therapeutic advances. Besides being associated with global promoter hypermethylation, IDH1 mutation facilitated changes in 3D DNA-conformation by CTCF-anchor methylation and upregulated oncogene expression in glioma, correlating with poor prognosis. Here, we investigated the role of IDH1 p.R132H mutation in altering 3D DNA-architecture and subsequent oncogene activation in AML. Using public RNA-Seq data, we identified upregulation of tyrosine kinase PDGFRA in IDH1-mutant patients, correlating with poor prognosis. DNA methylation analysis identified CpG hypermethylation within a CTCF-anchor upstream of PDGFRA in IDH1-mutant patients. Increased PDGFRA expression, PDGFRA-CTCF methylation and decreased CTCF binding were confirmed in AML CRISPR cells with heterozygous IDH1 p.R132H mutation and upon exogenous 2-HG treatment. IDH1-mutant cells showed higher sensitivity to tyrosine kinase inhibitor dasatinib, which was supported by reduced blast count in a patient with refractory IDH1-mutant AML after dasatinib treatment. Our data illustrate that IDH1 p.R132H mutation leads to CTCF hypermethylation, disrupting DNA-looping and insulation of PDGFRA, resulting in PDGFRA upregulation in IDH1-mutant AML. Treatment with dasatinib may offer a novel treatment strategy for IDH1-mutant AML.

Myeloid checkpoint blockade improves killing of T-acute lymphoblastic leukemia cells by an IgA2 variant of daratumumab

Antibody-based immunotherapy is increasingly employed to treat acute lymphoblastic leukemia (ALL) patients. Many T-ALL cells express CD38 on their surface, which can be targeted by the CD38 antibody daratumumab (DARA), approved for the treatment of multiple myeloma. Tumor cell killing by myeloid cells is relevant for the efficacy of many therapeutic antibodies and can be more efficacious with human IgA than with IgG antibodies. This is demonstrated here by investigating antibody-dependent cellular phagocytosis (ADCP) by macrophages and antibody-dependent cell-mediated cytotoxicity (ADCC) by polymorphonuclear (PMN) cells using DARA (human IgG1) and an IgA2 isotype switch variant (DARA-IgA2) against T-ALL cell lines and primary patient-derived tumor cells. ADCP and ADCC are negatively regulated by interactions between CD47 on tumor cells and signal regulatory protein alpha (SIRPα) on effector cells. In order to investigate the impact of this myeloid checkpoint on T-ALL cell killing, CD47 and glutaminyl-peptide cyclotransferase like (QPCTL) knock-out T-ALL cells were employed. QPTCL is an enzymatic posttranslational modifier of CD47 activity, which can be targeted by small molecule inhibitors. Additionally, we used an IgG2σ variant of the CD47 blocking antibody magrolimab, which is in advanced clinical development. Moreover, treatment of T-ALL cells with all-trans retinoic acid (ATRA) increased CD38 expression leading to further enhanced ADCP and ADCC, particularly when DARA-IgA2 was applied. These studies demonstrate that myeloid checkpoint blockade in combination with IgA2 variants of CD38 antibodies deserves further evaluation for T-ALL immunotherapy.

An alternative CYB5A transcript is expressed in aneuploid ALL and enriched in relapse

Background

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a genetically heterogenous malignancy with poor prognosis in relapsed adult patients. The genetic basis for relapse in aneuploid subtypes such as near haploid (NH) and high hyperdiploid (HeH) BCP-ALL is only poorly understood. Pathogenic genetic alterations remain to be identified. To this end, we investigated the dynamics of genetic alterations in a matched initial diagnosis-relapse (ID-REL) BCP-ALL cohort. Here, we firstly report the identification of the novel genetic alteration CYB5Aalt, an alternative transcript of CYB5A, in two independent cohorts.

Methods

We identified CYB5alt in the RNAseq-analysis of a matched ID-REL BCP-ALL cohort with 50 patients and quantified its expression in various molecular BCP-ALL subtypes. Findings were validated in an independent cohort of 140 first diagnosis samples from adult BCP-ALL patients. Derived from patient material, the alternative open reading frame of CYB5Aalt was cloned (pCYB5Aalt) and pCYB5Aalt or the empty vector were stably overexpressed in NALM-6 cells. RNA sequencing was performed of pCYB5Aalt clones and empty vector controls followed by differential expression analysis, gene set enrichment analysis and complementing cell death and viability assays to determine functional implications of CYB5Aalt.

Results

RNAseq data analysis revealed non-canonical exon usage of CYB5Aalt starting from a previously undescribed transcription start site. CYB5Aalt expression was increased in relapsed BCP-ALL and its occurrence was specific towards the shared gene expression cluster of NH and HeH BCP-ALL in independent cohorts. Overexpression of pCYB5Aalt in NALM-6 cells induced a distinct transcriptional program compared to empty vector controls with downregulation of pathways related to reported functions of CYB5A wildtype. Interestingly, CYB5A wildtype expression was decreased in CYB5Aalt samples in silico and in vitro. Additionally, pCYB5Aalt NALM-6 elicited a more resistant drug response.

Conclusions

Across all age groups, CYB5Aalt was the most frequent secondary genetic event in relapsed NH and HeH BCP-ALL. In addition to its high subgroup specificity, CYB5Aalt is a novel candidate to be potentially implicated in therapy resistance in NH and HeH BCP-ALL. This is underlined by overexpressing CYB5Aalt providing first evidence for a functional role in BCL2-mediated apoptosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-022-01041-1.

A retrospective observational study of the use of gastroprotection for patients on dual antiplatelet therapy in an acute trust in England

Introduction

Dual antiplatelet therapy (DAPT), a combination of aspirin and either clopidogrel, prasugrel or ticagrelor, is recommended for secondary prevention of ischaemic events (heart attack and stroke) in people with coronary artery disease. Patients taking DAPT may be at high gastrointestinal (GI) bleed risk if other factors (including advanced age, or concomitant use of medicines that are known to increase the risk of GI bleeds) are present. Such patients should be considered for gastroprotection e.g. a proton pump inhibitor (PPI) or H2 receptor antagonist.

Aim

To assess whether gastroprotection was prescribed for inpatients taking DAPT in a 750-bed acute hospital in England.

Methods

This was a retrospective analysis of existing data. Patient episodes involving prescription of DAPT upon discharge between April 2020 and April 2021 were extracted from the e-prescribing system (WellSky). Electronic records of the identified patient episodes were searched for co-prescription of either PPI or H2 antagonist. We also ascertained if patients on DAPT should have received gastro-protection using age 71 and over, and concomitant drugs as separate risk factors.

Results

Over this 13-month period there were 1693 patient episodes (mean age 72 years, 63% male) when DAPT was prescribed at discharge, of which gastroprotection was also prescribed in 1210 (71%). Of the 483 episodes when gastroprotection was not prescribed, 223 (46%) met the criterion of age as a risk factor for gastroprotection. There were a further 20 episodes of patients aged under 71 years not on gastroprotection but receiving an SSRI, NSAID, prednisolone, nicorandil or an anticoagulant.

Conclusion

We identified that gastroprotection was potentially missing in 243 (14%) of the total DAPT patient episodes. Though there is evidence for the use of PPIs reducing the risk of GI bleeding in patients treated with DAPT after percutaneous coronary intervention or acute coronary syndrome (1), studies have reported that gastroprotection has been missed in the at risk group (2). When considering newly initiated gastroprotection, various factors are considered e.g. any possible interaction with a PPI if one of the antiplatelets is clopidogrel. In addition, PPIs have adverse effects such as low sodium / magnesium, and this may be a reason for consideration of a H2 antagonist. Further work is required to make our prescribers and pharmacy team aware of the importance of considering gastroprotection for this patient cohort. The strength of this study is the extraction of data from our electronic prescribing system for a large cohort of patients prescribed specified antiplatelet medication. Our study has some potential limitations. First, it was conducted in a single centre in England; this might restrict the generalisability of our findings. Second, the retrospective nature of this study may introduce bias or other uncertainties. Third, we did not ascertain the indication for DAPT nor if patients came in on these drugs as opposed to being started during their admission. Fourth, we did not check risk factors for gastroprotection other than age and selected concomitantly prescribed drugs. Finally, we did not check if those not prescribed gastroprotection had significant contraindications other than electrolyte abnormalities.

References

(1) Guo H, Ye Z, Huang R. Clinical outcomes of concomitant use of proton pump inhibitors and dual antiplatelet therapy: a systematic review and meta-analysis. Front Pharmacol. 2021 Aug 2;12:694698.

(2) Sehested TSG, Carlson N, Hansen PW, Gerds TA, Charlot MG, Torp-Pedersen C, et al. Reduced risk of gastrointestinal bleeding associated with proton pump inhibitor therapy in patients treated with dual antiplatelet therapy after myocardial infarction. Eur Heart J. 2019;40(24):1963–70.

Long non-coding RNAs defining major subtypes of B cell precursor acute lymphoblastic leukemia

Background

Long non-coding RNAs (lncRNAs) have emerged as a novel class of RNA due to its diverse mechanism in cancer development and progression. However, the role and expression pattern of lncRNAs in molecular subtypes of B cell acute lymphoblastic leukemia (BCP-ALL) have not yet been investigated. Here, we assess to what extent lncRNA expression and DNA methylation is driving the progression of relapsed BCP-ALL subtypes and we determine if the expression and DNA methylation profile of lncRNAs correlates with established BCP-ALL subtypes.

Methods

We performed RNA sequencing and DNA methylation (Illumina Infinium microarray) of 40 diagnosis and 42 relapse samples from 45 BCP-ALL patients in a German cohort and quantified lncRNA expression. Unsupervised clustering was applied to ascertain and confirm that the lncRNA-based classification of the BCP-ALL molecular subtypes is present in both our cohort and an independent validation cohort of 47 patients. A differential expression and differential methylation analysis was applied to determine the subtype-specific, relapse-specific, and differentially methylated lncRNAs. Potential functions of subtype-specific lncRNAs were determined by using co-expression-based analysis on nearby (cis) and distally (trans) located protein-coding genes.

Results

Using an integrative Bioinformatics analysis, we developed a comprehensive catalog of 1235 aberrantly dysregulated BCP-ALL subtype-specific and 942 relapse-specific lncRNAs and the methylation profile of three subtypes of BCP-ALL. The 1235 subtype-specific lncRNA signature represented a similar classification of the molecular subtypes of BCP-ALL in the independent validation cohort. We identified a strong correlation between the DUX4-specific lncRNAs and genes involved in the activation of TGF-β and Hippo signaling pathways. Similarly, Ph-like-specific lncRNAs were correlated with genes involved in the activation of PI3K-AKT, mTOR, and JAK-STAT signaling pathways. Interestingly, the relapse-specific lncRNAs correlated with the activation of metabolic and signaling pathways. Finally, we found 23 promoter methylated lncRNAs epigenetically facilitating their expression levels.

Conclusion

Here, we describe a set of subtype-specific and relapse-specific lncRNAs from three major BCP-ALL subtypes and define their potential functions and epigenetic regulation. The subtype-specific lncRNAs are reproducible and can effectively stratify BCP-ALL subtypes. Our data uncover the diverse mechanism of action of lncRNAs in BCP-ALL subtypes defining which lncRNAs are involved in the pathogenesis of disease and are relevant for the stratification of BCP-ALL subtypes.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0692-3) contains supplementary material, which is available to authorized users.

Silencing of GATA3 defines a novel stem cell-like subgroup of ETP-ALL

Background

GATA3 is pivotal for the development of T lymphocytes. While its effects in later stages of T cell differentiation are well recognized, the role of GATA3 in the generation of early T cell precursors (ETP) has only recently been explored. As aberrant GATA3 mRNA expression has been linked to cancerogenesis, we investigated the role of GATA3 in early T cell precursor acute lymphoblastic leukemia (ETP-ALL).

Methods

We analyzed GATA3 mRNA expression by RT-PCR (n = 182) in adult patients with T-ALL. Of these, we identified 70 of 182 patients with ETP-ALL by immunophenotyping. DNA methylation was assessed genome wide (Illumina Infinium® HumanMethylation450 BeadChip platform) in 12 patients and GATA3-specifically by pyrosequencing in 70 patients with ETP-ALL. The mutational landscape of ETP-ALL with respect to GATA3 expression was investigated in 18 patients and validated by Sanger sequencing in 65 patients with ETP-ALL. Gene expression profiles (Affymetrix Human genome U133 Plus 2.0) of an independent cohort of adult T-ALL (n = 83) were used to identify ETP-ALL and investigate GATA3^low and GATA3^high expressing T-ALL patients. In addition, the ETP-ALL cell line PER-117 was investigated for cytotoxicity, apoptosis, GATA3 mRNA expression, DNA methylation, and global gene expression before and after treatment with decitabine.

Results

In our cohort of 70 ETP-ALL patients, 33 % (23/70) lacked GATA3 expression and were thus defined as GATA3^low. DNA methylation analysis revealed a high degree of GATA3 CpG island methylation in GATA3^low compared with GATA3^high ETP-ALL patients (mean 46 vs. 21 %, p < 0.0001). Genome-wide expression profiling of GATA3^low ETP-ALL exhibited enrichment of myeloid/lymphoid progenitor (MLP) and granulocyte/monocyte progenitor (GMP) genes, while T cell-specific signatures were downregulated compared to GATA3^high ETP-ALL. Among others, FLT3 expression was upregulated and mutational analyses demonstrated a high rate (79 %) of FLT3 mutations. Hypomethylating agents induced reversal of GATA3 silencing, and gene expression profiling revealed downregulation of hematopoietic stem cell genes and upregulation of T cell differentiation.

Conclusions

We propose GATA3^low ETP-ALL as a novel stem cell-like leukemia with implications for the use of myeloid-derived therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0324-8) contains supplementary material, which is available to authorized users.

Dnmt3a regulates myeloproliferation and liver-specific expansion of hematopoietic stem and progenitor cells

DNMT3A mutations are observed in myeloid malignancies, including myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). Transplantation studies have elucidated an important role for Dnmt3a in stem cell self-renewal and in myeloid differentiation. Here we investigated the impact of conditional hematopoietic Dnmt3a loss on disease phenotype in primary mice. Mx1-Cre-mediated Dnmt3a ablation led to the development of a lethal, fully penetrant myeloproliferative neoplasm with myelodysplasia (MDS/MPN) characterized by peripheral cytopenias and by marked, progressive hepatomegaly. We detected expanded stem/progenitor populations in the liver of Dnmt3a-ablated mice. The MDS/MPN induced by Dnmt3a ablation was transplantable, including the marked hepatomegaly. Homing studies showed that Dnmt3a-deleted bone marrow cells preferentially migrated to the liver. Gene expression and DNA methylation analyses of progenitor cell populations identified differential regulation of hematopoietic regulatory pathways, including fetal liver hematopoiesis transcriptional programs. These data demonstrate that Dnmt3a ablation in the hematopoietic system leads to myeloid transformation in vivo, with cell autonomous aberrant tissue tropism and marked extramedullary hematopoiesis (EMH) with liver involvement. Hence, in addition to the established role of Dnmt3a in regulating self-renewal, Dnmt3a regulates tissue tropism and limits myeloid progenitor expansion in vivo.

Development of an Epstein-Barr virus-associated lymphoproliferative disorder in a patient treated with azacitidine for chronic myelomonocytic leukaemia

Some chemotherapeutic agents can cause iatrogenic lymphoproliferative disorders. In analogy to what has been observed with other nucleoside analogues such as cladribine and fludarabine, we document the first case of an Epstein-Barr virus-positive, iatrogenic immunodeficiency-associated, lymphoproliferative disease, formally resembling polymorphic post-transplant lymphoproliferative disease in a patient treated with azacitidine (Vidaza) for chronic myelomonocytic leukaemia (CMML). A 78-year-old female patient was diagnosed with CMML in January 2012, and treatment with azacitidine was initiated, which lasted for five cycles from February until June 2012. The patient was hospitalized in June 2012 under the suspicion of pneumonia. Transformation of the CMML was suspected at that time too. During hospitalization, a generalized enlargement of the lymph nodes and the spleen was noticed. The patient rapidly deteriorated and finally died of respiratory insufficiency. At autopsy, an Epstein-Barr virus-associated lymphoproliferative disorder, resembling polymorphic post-transplant lymphoproliferative disease with involvement of the lymph nodes, the spleen and the lung and causing necrotizing pneumonia, was diagnosed. Diagnostic criteria for diffuse large B-cell lymphoma or infectious mononucleosis-like lymphoproliferative disease were not met. This is the first documented case of an azacitidine-associated lymphoproliferative disease, raising awareness for possible not yet known side effects of this drug, which should be kept in mind by oncologists and pathologists.

Synergistic activity of bortezomib and HDACi in preclinical models of B-cell precursor acute lymphoblastic leukemia via modulation of p53, PI3K/AKT, and NF-κB

PURPOSE

Relapse of disease and subsequent resistance to established therapies remains a major challenge in the treatment of childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). New therapeutic options, such as proteasome and histone deacetylase inhibitors (HDACi) with a toxicity profile differing from that of conventional cytotoxic agents, are needed for these extensively pretreated patients.

EXPERIMENTAL DESIGN

Antiproliferative and proapoptotic effects of combined HDACi/proteasome inhibitor treatments were analyzed using BCP-ALL monocultures, cocultures with primary mesenchymal stroma cells from patients with ALL, and xenograft mouse models. The underlying molecular mechanisms associated with combined treatment were determined by gene expression profiling and protein validation.

RESULTS

We identified the proteasome inhibitor bortezomib as a promising combination partner for HDACi due to the substantial synergistic antileukemic activity in BCP-ALL cells after concomitant application. This effect was maintained or even increased in the presence of chemotherapeutic agents. The synergistic effect of combined HDACi/BTZ treatment was associated with the regulation of genes involved in cell cycle, JUN/MAPK, PI3K/AKT, p53, ubiquitin/proteasome, and NF-κB pathways. We observed an activation of NF-κB after bortezomib treatment and the induction of apoptosis-related NF-κB target genes such as TNFαRs after concomitant treatment, indicating a possible involvement of NF-κB as proapoptotic mediator. In this context, significantly lower NF-κB subunits gene expression was detected in leukemia cells from patients who developed a relapse during frontline chemotherapy, compared with those who relapsed after cessation of frontline therapy.

CONCLUSION

These results provide a rationale for the integration of HDACi/BTZ combinations into current childhood BCP-ALL treatment protocols.

A randomized trial comparing 2 techniques of balloon kyphoplasty and curette use for obtaining vertebral body height restoration and angular-deformity correction in vertebral compression fractures due to osteoporosis

BACKGROUND AND PURPOSE

Vertebral compression fractures often result in pain and vertebral deformity. We compared 2 different balloon kyphoplasty techniques both using intraoperative curettage.

MATERIALS AND METHODS

Adults 50 years of age or older with osteoporosis and 1 acute VCF were randomized to undergo bilateral BKP in which the curette was used first (n = 57) followed by inflatable bone tamps or in which IBTs were used first, followed by curettage and a second IBT inflation (n = 55).

RESULTS

Mean procedure duration was 33.5 and 36.8 minutes, and fluoroscopy duration was 3.8 and 3.7 minutes for the CF and IBTF groups, respectively. Two-thirds of VCFs were wedge-shaped, and one-half had dynamic mobility. Anterior height restored postoperatively was 2.28 mm (95% CI, 1.49-3.08 mm; P < .001) and 2.78 mm (95% CI, 1.89-3.66 mm; P < .001) for CF and IBTF groups, representing ∼35% and 39% of lost height restored, but group differences were not significant (P = .4). Intraoperative anterior height gain attributed to dynamic mobility was 2.96 mm (95% CI, 1.92-4.00 mm; P < .001) and 3.05 mm (95% CI, 2.10-4.00 mm; P < .001); additional height attributed to IBT inflation was 1.09 mm (95% CI, 0.77-1.41 mm; P < .001) and 1.25 mm (95% CI, 0.68-1.82 mm; P < .001), representing a 37% and 41% increase. There was no significant height loss on IBT removal and cementation. Both groups had improved pain and ambulation. Asymptomatic leakage occurred in 15% of VCFs. There was 1 nonserious device-related hematoma (IBTF group). One new clinical VCF occurred in each group, but they were not device-related.

CONCLUSIONS

Both techniques resulted in significant vertebral body height and pain improvement. Procedure and adverse event data demonstrated safe curette use in conjunction with balloon kyphoplasty procedures.

High VLA-4 expression is associated with adverse outcome and distinct gene expression changes in childhood B-cell precursor acute lymphoblastic leukemia at first relapse

BACKGROUND

Resistance to therapy and subsequent relapse remain major challenges in the clinical management of relapsed childhood acute lymphoblastic leukemia. As the bone marrow environment plays an important role in survival and chemotherapy resistance of leukemia cells by activating different signaling pathways, such as the VLA-4 and PI3K/Akt pathways, we studied the prognostic and biological impact of VLA-4 expression in leukemia cells from children with relapsed B-cell precursor acute lymphoblastic leukemia and its influence on the sensitivity of the leukemia cells to drugs.

DESIGN AND METHODS

VLA-4 expression was quantified by real-time polymerase chain reaction in leukemia cells from 56 patients with relapsed acute lymphoblastic leukemia enrolled in the ALL-REZ BFM 2002 trial of the Berlin-Frankfurt-Münster study group. Gene expression changes related to VLA-4 expression were investigated by microarray-based mRNA profiling. The effect of VLA-4 signaling on proliferation and drug resistance was studied in co-cultures of leukemia and stromal cells.

RESULTS

High expression of VLA-4 at first relapse was associated with adverse prognostic factors, poor molecular response to therapy and significantly worse probabilities of event-free and overall survival. VLA-4 expression was an independent prognostic parameter. Comparing gene expression profiles of leukemia cells with high versus low VLA-4 expression, we identified 27 differentially expressed genes primarily involved in the PI3K/Akt, ephrin and Rho GTPase pathways. Blocking of VLA-4 signaling in combination with cytarabine treatment abolished the growth supportive effect of stromal cells.

CONCLUSIONS

Our results show that high VLA-4 expression is a marker of poor prognosis and a potential therapeutic target in children with relapsed acute lymphoblastic leukemia and confirm that cellular interactions and biological effects related to VLA-4 play a decisive role in the survival of leukemia cells and response to therapy. (ClinicalTrials.gov identifier: NCT00114348).

[(Over-)flowing bone: the rare disease of melorheostosis: clinical presentation and therapeutic concepts demonstrated by three cases]

Melorheostosis is a rare, benign, and sporadically occurring osteosclerosis of unknown cause. The onset of the disease is usually in early adulthood. Melorheostosis affects both genders, develops progressively, and is usually limited to one side of the human body. The sclerosis originates predominantly from the cortices of the long bones of the lower limbs and rarely the upper limbs. Frequently, the sclerosis involves the soft tissue surrounding the affected bones which may cause limitations in the range of motion, contractures, deformities, and pain. Melorheostosis is usually diagnosed by radiograms. Pain relief and restoration of the full range of motion are the primary goals of the therapeutic approach. A good outcome cannot always be achieved and a recurrence of the disease happens very often.

Benign giant cell tumor of the spine: an unusual indication for radiotherapy

INTRODUCTION

Giant cell tumors are rare primary bone tumors. Multicentricity as well as spinal localization is extremely rare.

CASE REPORT

We report about a 64-year-old female patient presenting with history of three osseous and one pulmonal manifestation of a benign giant cell tumor that have manifested metachronously within 23 years. The two periphery bone and the one pulmonal manifestation were treated surgically with success. Now, a further osseous lesion occurred at the seventh vertebra of the thoracic spine and was treated by dorsal instrumentation and replacement of the seventh vertebra. Nine months later, local recurrence of this benign giant cell tumor developed at the thoracic spine and was treated with radiotherapy with a total dose of 45 Gy. Three months after salvage radiotherapy definite local progress occurred localized within the former radiation treatment field. Due to neurological deficits a laminectomy and a stabilization of the destroyed sixth vertebra with bone cement was carried out. Histopathological examination again showed benign giant cell tumor without suspicion of malignancy.

CONCLUSION

In the literature the use of radiation therapy remains an appropriate therapy option in benign giant cell tumors with minimal adverse sequelae if primary surgical treatment is not feasible or fails. In cases of definitive radiotherapy a total dose > 45 Gy should be discussed.

Wirbelkörperersatz mit höhenvariablem Titanimplantat

OBJECTIVE

The reconstruction of the anterior column of the thoracolumbar spine is still controversial.

METHODS

The clinical notes and radiographs of 50 consecutive patients (29 M, 21 F, 43 years) treated with the Synex implant were reviewed at operation and at 12 and 20 months postoperatively.

RESULTS

Of 45 patients, 25 returned to pre-injury activities within 1 year and 29 of 39 within 20 months. Two-thirds of the patients who were followed up returned to their job. After 1 year 25 of 45 patients had no or mild limitations in their back function. Six months later this group decreased to 6 of 39 patients. Visual analog scale (VAS) decreased from 87/100 preoperatively to 65/100 at the 1-year follow-up. The average permanent reduction of the injured vertebrae was 16.9 degrees including 2.3 degrees loss of correction.

CONCLUSION

After reconstruction of the anterior column with the Synex implant only a minimal loss of correction or reduction was observed. The clinical outcome after use of the Synex implant appears promising. We recommend this implant as a valuable alternative for reconstruction of the anterior column of the thoracolumbar spine. However, long-term results are still required.

Vordere Pfeilerfraktur des Acetabulums mit dorsaler Impression

An unusual case of an anterior column fracture of the acetabulum with extended marginal impaction at the posterior column is presented. Fracture fixation was primarily performed by an ilioinguinal approach followed by a posterior approach with surgical dislocation of the hip to reduce the impacted fragments.

Femoral avulsion fracture of the posterior cruciate ligament in association with a rupture of the popliteal artery in a 9-year-old boy: a case report

Ruptures of the posterior cruciate ligament (PCL) and especially proximal bony avulsion fractures in children are very rare. This in combination with a rupture of the popliteal artery is extremely rare. Thus, an exact incidence is not available from the literature. Overall, these injuries are severe and often lead to chronic knee instability. We report a case of a 9-year-old boy who suffered a traumatic displacement of the left knee with a rupture of the popliteal artery. Prior to transfer to our department, he was treated by a saphenous vein bypass graft and by a transfixation of the knee using two oblique percutaneous pins. We performed magnetic resonance imaging (MRI) scan of the knee which revealed a femoral avulsion fracture of the PCL. Other ligaments and menisci were intact. A transosseous femoral fixation using non-absorbable stitches was carried out. A 1-year follow-up after surgery demonstrates intact peripheral perfusion and sensation, straight axes of both legs and a physiological gait. Minimal differences of the length and circumference of both legs could be measured. The posterior laxity (Lachman-test) was about 5/8 mm (right/left knee) and 2/5 mm (right/left knee) in 90 degrees flexion. The range of motion (extension/flexion) was 5/0/140 degrees -/5/100 degrees (right-left knee). Intact cruciate ligaments were confirmed by MRI. Minimal experience exists in treatment of combined injuries to the PCL and the popliteal artery in children.

[Ankylosing spondylitis. Therapy and complications of 34 spine fractures]

BACKGROUND

Spine fractures in ankylosing spondylitis (AS) are extremely unstable and associated with a high complication rate. The aim of this retrospective study was to evaluate the therapy and complications of these fractures in AS for a better understanding and management.

PATIENTS AND METHODS

A total of 32 patients with 34 traumatic spine fractures were treated from 1981 to 2002. Cause of trauma, fracture site, and neurological examination were assessed. Analyses of the management of the treatment and complications were performed.

RESULTS

Banal traumas resulted mostly in spinal fractures at the C 5/6 and C 6/7 level. Two patients were treated conservatively, while the others were stabilized operatively. Before therapy was undertaken, six patients suffered from a cervical radiculopathy, ten patients had an incomplete and two a complete paraplegia. After therapy, neurological status improved in eight patients, but one had a deterioration of neurological symptoms.

CONCLUSIONS

Dorsal or combined dorsoventral stabilization of these fractures is necessary for better mobilization of these patients and to avoid further complications.

[Operative management of cervical spine injuries in patients with Bechterew's disease]

Cervical spinal injuries in patients with ankylosing spondylitis are complex in their nature and management. This condition is associated with a high risk of dislocation and neurological impairment related to osseous instability due to almost absent compensatory mechanisms of the adjacent vertebral segments. Multilevel stabilization and dorsoventral instrumentation is usually required. We report on two patients suffering from ankylosing spondylitis who presented at our institute with cervical spine injuries in whom primary treatment had consisted of single-site stabilization which resulted in secondary fracture dislocation and implant failure. Secondary management by combined dorsoventral stabilization resulted in more rigid fixation and uneventful healing in both cases. We recommend careful assessment and well-planned management in these cases.

[Compound osteosynthesis as treatment for an osteoporotic LWK-1 burst fracture in a 76 year old female patient]

The surgical treatment of osteoporotic vertebral compression fractures is rarely necessary and is mostly done in fractures with neurological deficit. We present a case of compound osteosynthesis in an osteoporotic fracture of the first lumbar vertebra as a "salvage procedure" after a dislocation of a dorsal internal fixator in a 76 year old female sustaining incomplete paraplegia. In this case, an additional ventral stabilization using a vertebral body replacement was not practicable because of old age and previous pneumonia. We performed an additional compound osteosynthesis using bone cement because of insufficient stability when only using cement for augmentation of the pedicle screws.

[Principles of callus distraction]

Callus distraction is based on the principle of regenerating bone by continuous distraction of proliferating callus tissue. It has become the standard treatment of significant leg shortening and large bone defects. Due to many problems and complications, exact preoperative planning, operative technique and careful postoperative follow-up are essential. External fixators can be used for all indications of callus distraction. However, due to pin tract infections, pain and loss of mobility caused by soft tissue transfixation, fixators are applied in patients with open growth plates, simultaneous lengthening with continuous deformity corrections, and increased risk of infection. Distraction over an intramedullary nail allows removal of the external fixator at the end of distraction before callus consolidation (monorail method). The intramedullary nail protects newly formed callus tissue and reduces the risk of axial deviation and refractures. Recently developed, fully intramedullary lengthening devices eliminate fixator-associated complications and accelerate return to normal daily activities. This review describes principles of callus distraction, potential complications and their management.

[Surgical treatment of osseous metastases of the pelvis]

Metastases are the most frequent malignant tumors of the skeleton. Breast cancer is the most frequent primary tumor with osseous metastases followed by renal cell carcinomas, bronchial carcinomas, and thyroid tumors. The predominant localization of bone metastases is the spine, followed by the pelvis, femur, ribs, skull, sternum, and humerus. The overall incidence of bone metastases has increased due to improved diagnosis, prolonged survival by adjuvant therapy, and improved follow-up. Osseous metastases of the pelvis are usually diagnosed only late in the course of the disease because of their considerable delayed onset of clinical symptoms. Therefore, treatment is usually focused on a palliative approach to reduce pain and to improve the quality of life. We introduce three patients with bronchial, renal cell, and cholangiocellular carcinoma in an incurable tumor stage with osseous metastases in the pelvis. The metastatic osteolyses caused pain and symptoms of instability. Despite high doses of opiate analgesics, the patients were neither free of pain nor could they be mobilized. The palliative treatment included preoperative tumor embolization followed by tumor resection and implantation of a hip prosthesis. The preoperative embolization reduced intraoperative bleeding and made tumor resection, osteosynthesis, and implantation of the hip prosthesis possible. Mobilization with moderate pain could be achieved in these three patients for the rest of their lives.

[Integration of modern technologies in therapy of sarcomas of the pelvis. Computer-assisted hemipelvectomy and implantation of a "custom-made" Bonit gentamycin coated partial pelvic prosthesis]

The resection of primary malignancies in the pelvis is technically demanding as organs and structures are to be preserved and reconstruction of the defect as well as the postoperative function and rehabilitation are dependent on an optimal prosthesis. We present two patients with a sarcoma of the pelvis where for the first time a structured concept of technology integration led to a press-fit implantation of a hemipelvic prosthesis. This concept includes the design and production of a "custom-made" prosthesis as a hemipelvic substitute and the coating of this prosthesis with Bonit, a second-generation calcium phosphate, and gentamycin in watery solution. The tumor resection was done with computer-assisted surgery based on computed tomographies (CT) of the pelvis model done by rapid prototyping rather than on the CT of the patients' pelvis. With this procedure the presurgically simulated resection could be executed precisely with complete resection of the tumors and an accuracy which allowed an exact implantation of the prosthesis. The course was uneventful with primary healing and no sign of an infection or loosening after 6 months.

[Reosteosynthesis in dens pseudarthrosis. Case report and review of the literature]

According to general recommendations, unstable nonunions of the odontoid are treated by posterior fusion of the segments C1/C2 and transarticular screwosteosynthesis. The aim of the surgical procedure is to obtain secure reduction stabilization, and fusion of the nonunion. We present a case of secondary atlanto-axial instability treatment following of an odontoid nonunion. In this situation stability of C1/C2 was achieved by atlanto-axial fusion by transarticular screw fixation. The ventral parts of the broken implants were left in place. Diagnosis, treatment and complications of pseudarthrosis of the dens axis are discussed in the context of this case and of literature.

Outcome assessment after arthrolysis of the elbow

BACKGROUND

In the literature, the outcome after arthrolysis of the elbow is mainly assessed by range of motion (ROM). Our intention was to verify whether this parameter does sufficiently estimate the outcome after surgical arthrolysis.

METHODS

We performed a retrospective study using the validated Disability of the Arm, Shoulder, and Hand Questionnaire (DASH) as our reference outcome parameter. This score was compared with other outcome parameters such as ROM, Mayo Performance Index (MPI) and SF-36. A total of 59 patients who underwent arthrolysis of the elbow was evaluated 53 months after surgery on average.

RESULTS

The mean ROM was 101 degrees for flexion/extension with a relative gain of 60% and 134 degrees for pronation/supination with a relative gain of 58%. MPI was 84 points on average. The mean DASH was 17.6 and the mean SF-36 67.9. The correlation of these outcome parameters was calculated using Pearson's correlation (two-tailed, significance set at p<0.05). We found a high correlation between DASH and the physical function part of the SF-36 (Cov=-0.87, p<0.05). The correlation of DASH and MPI was moderate (Cov=0.71, p<0.05) and of DASH and ROM poor (Cov=-0.25, p<0.05).

CONCLUSION

ROM as a single parameter does not sufficiently assess the outcome of arthrolysis of the elbow.

[Osteosarcoma of the pelvisTwo case reports and review of the literature]

Primary malignant neoplasms of the bone are rare. One of the most common bone tumors is osteosarcoma, most often localized in the metaphysis of adolescent long bones. The sacrum is concerned in only about 1%. Primary bone sarcomas of the pelvis are usually recognized after they have grown to a considerable size. Osteosarcoma patients from Germany, Austria, and Switzerland are treated by neoadjuvant chemotherapy combined with complete surgical excision according to the Cooperative Osteosarcoma Study Group (COSS). Based on a review of the literature, diagnosis, treatment, and complications of two cases of sacrum osteosarcoma are introduced.

[Non-operative treatment of thoracolumbar spinal fractures. Long-term clinical results over 16 years]

Non-operative treatment of thoracolumbar fractures remains the standard treatment option for stable and slightly unstable spinal injuries at the level of the lower thoracic and lumbar spine. The purpose of the present retrospective study was to determine the outcome and long-term results of patients treated conservatively using either one of the two major non-operative treatment modalities: (1) functional, or (2) closed reduction and immobilisation by cast. The average follow-up time for the 43 patients reviewed was 16.3 years. They showed a radiologic increase in the average kyphosis angle of 5.2 degrees compared to the time of injury. No difference was noted between early functional therapy and treatment with closed reduction and immobilisation by cast. Patients with initial neurologic impairment showed a significant improvement ( P<0.05) in their neurologic status during the follow-up period. Results of validated psychometric questionnaires (SF-36, FSR, VAS-Spinescore) showed the characteristic pattern of a population with chronic back pain. In conclusion, a radiologic increase in the traumatic kyphotic deformity in patients with a non-operative treatment protocol has to be expected. Measurable negative physical and social long-term consequences can be anticipated after sustaining a type-A fracture of thoracolumbar vertebral bodies. Any correlation between radiologic and functional results has not been observed.

Failure of operative treatment in a child with osteoporosis-pseudoglioma syndrome

A 6-year-old girl with osteoporosis-pseudoglioma syndrome had operative treatment of a distal femur fracture that failed. Osteoporosis-pseudoglioma syndrome is an autosomal recessive syndrome combining severe premature osteoporosis with a bilateral eye disorder leading to early onset of blindness. Beginning in early childhood, the patient sustained multiple fractures of the left distal femur that were treated nonoperatively. At the age of 5 years the patient had a fracture of the left distal femur with an 80 degrees angulation in the sagittal plane. The patient was treated with internal stabilization because of gross bowing of the femur at the fracture site. Intraoperatively, anatomic reduction was achieved by insertion of a flexible nail but not without some intraoperative problems. Because of the severe osteoporosis, iatrogenic penetration and fracture of the femoral cortex by the nail occurred intraoperatively in the subtrochanteric region. In addition, a hip spica cast was applied. The nail was removed 1 week later. After 6 weeks wearing the hip spica cast, the patient's fracture healed with some shortening but with correction of the angulation in the sagittal plane. Internal stabilization seems to be potentially troublesome in patients with severe forms of this syndrome and severe bony deformities.

Fate of the transpedicular intervertebral bone graft after posterior stabilisation of thoracolumbar fractures

The authors present a retrospective clinical and radiological study addressing the outcome after posterior stabilisation of thoracolumbar fractures with intervertebral fusion via transpedicular bone grafting. The study included computed tomographic (CT) scan after implant removal for analysis of the intervertebral fusion and incorporation of the intervertebral bone graft and its influence on postoperative re-kyphosing. Twenty-nine patients with acute fractures of the thoracolumbar spine, treated between 1988 and 1995 at the Department of Trauma Surgery, Hannover Medical School, underwent posterior stabilisation and interbody fusion with transpedicular cancellous bone grafting. This study group was followed clinically and radiologically for a mean of 3.5 years. All patients underwent spiral CT scan with sagittal reconstruction after implant removal. Twenty-four type A, four type B, and one type C lesion were posteriorly stabilised and transpedicular intervertebral bone grafting was performed. The operative time averaged 2 h 50 min, the intraoperative fluoroscopy time 4 min 7 s, and the mean intraoperative blood loss was 376 ml. Four patients out of six with an incomplete neurologic lesion (Frankel/ASIA D) improved to Frankel/ASIA grade E. Two complications were observed: one delayed wound healing and one venous thrombosis with secondary pulmonary embolism. Compared to the preoperative status, our follow-up examinations demonstrated permanent social sequelae: the percentage of individuals able to do physical labor was reduced, whereas the proportion of unemployed or retired patients increased. The assessment of complaints and functional outcome with the Hannover Spine Score reflected a significant difference ( P<0.001) between the status before injury (96.6/100 points) and at follow-up (64.4/100 points). The radiographic follow-up revealed a mean loss of correction of 7.8 degrees ( P<0.005). CT scans after implant removal showed an interbody fusion and incorporation of the transpedicular bone graft in ten patients (34%). In another ten patients (34%), the CT scans demonstrated the interbody fusion at the anterior and posterior walls of the vertebral body via direct contact due to collapse of the disc space. In these patients, the bone graft was not incorporated and no central interbody fusion could be found. In nine patients (31%) neither interbody fusion nor incorporation of the transpedicular graft was achieved. A frequent and reliable intervertebral fusion could not be achieved with the described technique of transpedicular bone grafting. The ineffectiveness of the intervertebral graft was found to be a reason for postoperative re-kyphosing.

Complications in surgical treatment of thoracolumbar injuries

The range of surgical methods for operative treatment of thoracolumbar injuries, with their different ways of approach, grafts and techniques, remains wide. The authors present sources of error and specific complications based on their own experience and on the results of a multicenter study of the Spine Study Group of the German Trauma Association (DGU). A systematic overview of possible mistakes and complications is first presented in anatomical order. A detailed analysis is then presented of the complications reported in a multicenter study, carried out prospectively between 1994 and 1996, on 682 patients operated for acute traumatic injuries of the thoracolumbar spine. In 101 cases (15%) at least one complication occurred intra- or postoperatively. In 41 patients (6%) a revision was performed, and in 60 patients (9%) complications without operative revision were observed. These complications were analysed according to the chosen method of initial treatment.

[Effect of short-distance spondylodesis of the thoracolumbar transition on neighboring facet joints. A biomechanical study]

This study was performed to investigate the range of motion and the forces on the facet joints that are neighboured to spondylodesis on thoracolumbar spine. We used a special spine testing device for a continuous application of pure moments in each direction. For measuring the ranges of motion we used a magnetic tracking device for measuring forces on facet joints we chose a direct measuring system of quartz crystal and prepared for investigation of the spine. The biomechanical testing was done on 18 human spinal specimen. We investigated the range of motion and the forces on facet joints in T11/12 and L2/3 segment with a maximal loading of 8 Nm in each direction (flexion, extension, lateral bending and rotation). This was done before and after double level dorsal instrumentation T12-L2 with an internal fixateur. Statistical analysis was performed using the paired t-test and the Wilcoxon test (p < 0.05). After double level instrumentation there were significant larger ranges of motion in flexion and extension and significant larger forces on facet joints in left lateral bending in the T11/12 segment. No significant differences were found in the L2/3 segment. Our findings could be an indication for changing in joints loading. This could be an explanation for early degenerative changes in spinal segments adjacent to spondylodesis. The results confirm the demand of short segment instrumentation and early remove of implants to keep influence as low as possible.

Immunonutrition in patients after multiple trauma

Severe trauma threatens the life of the victim, both directly and indirectly via immunological dysregulation during the subsequent clinical course. Inflammatory or infectious episodes may complicate the clinical course and ultimately result in sepsis and multiple organ failure, which have mortality rates of up to 80%. Immunomodulatory intervention aims to ameliorate the early hyperinflammatory phase (systemic inflammatory response syndrome, SIRS) to avoid the development of sepsis. One of the immunomodulation strategies is enteral feeding supplemented with specific nutrients, such as glutamine, n-3-polyunsaturated fatty acids, and nucleotides ('immunonutrition'), because changes in the GALT (gut-associated lymphoid tissue) immune response may contribute to intestinal dysfunction and increase susceptibility to post injury gut-derived sepsis. In a prospective, randomized, double-blind, controlled study in twenty-nine patients suffering severe trauma we were able to show that immunonutrition (arginine, n-3-fatty acids, and nucleotides) significantly reduces the number of SIRS days per patient, and also lowers the multiple organ failure (MOF) score on day 3 and days 8-11 (P<0.05). Other studies have reported a reduction in septic complications and MOF rates, shortened hospital stay, and reduction in the use of antibiotics in patients randomized to the immune-enhancing diet. This improved clinical outcome was reflected in a reduction in hospital costs. In the recovery period after trauma (1-72 h after injury) a limitation of the inflammatory response of immunocompetent cells must be achieved as quickly as possible (<72 h). The only strategy available to clinicians caring for trauma patients is immunonutrition, and this should be strongly considered as a rational approach improving immune function and reducing septic complications in critically ill or injured patients.

[Biomechanical stability with a new artificial vertebral body implant. 3-dimensional movement analysis of instrumented human vertebral segments]

The authors present a new implant for vertebral body replacement in the thoracic and lumbar spine. The titanium implant is designated for reconstruction of the anterior column in injury, posttraumatic kyphosis or tumor of the thoracolumbar spine. The instrumentation has to be supplemented by a stabilizing implant. After positioning, the implant is distracted in situ, through which best contact to adjacent end-plates and 3-dimensional stability should be provided. The possibility of secondary dislocation or loss of correction should thereby be minimized.

OBJECTIVES

We investigated the biomechanical 3-dimensional stability in vitro, using Synex in combination with an anteriorly (Ventrofix) or a posteriorly (USS) stabilizing implant. The differences between both stabilizing implants were to be determined. Synex was compared with the "Harms titanium mesh cage" (MOSS) as vertebral body replacement.

METHODS

In a 3-dimensional spinal loading simulator, we determined the bisegmental (T12-L2) neutral zone (NZ), elastic zone (EZ), and range of motion (ROM) of 12 human cadaveric spines. After corpectomy of L1 we tested 4 groups of implant combinations: USS/Synex, USS/MOSS, Ventrofix/Synex, Ventrofix/MOSS. We analyzed the differences between each of the instrumentations as well as differences compared to the intact spine.

RESULTS

In most directions, significantly higher stability was achieved with USS, compared with Ventrofix and the intact specimen. For axial rotation, with no instrumentation the stability of the intact spine was restored. With Synex a significantly higher stability was noted for extension, lateral bending, and axial rotation in comparison with the Harms cage. A tendency towards more stability for flexion was additionally observed with Synex. When using MOSS in combination with USS, it was necessary to perform a third operative step for induction of intervertebral compression via the posterior fixator.

CONCLUSIONS

The posterior fixation was found to offer superior stability compared to the anterior one. Synex was at least comparable to MOSS for suspensory replacement of the vertebral body in the thoracolumbar spine. The evidence of higher biomechanical stability with Synex leads to the probability of a higher rigidity in vivo. Due to the distractability of Synex, a better intervertebral compression was achieved. Therefore, an additional tightening of the posterior fixator after insertion of Synex was not necessary, in contrast to the Harms cage.

Evaluation of the mobility of adjacent segments after posterior thoracolumbar fixation: a biomechanical study

An investigation was conducted into the effects of double-level T12-L2 posterior fixation on the mobility of neighboring unfused segments. The segmental mobility of adjacent segments above and below the fixation in ten cadaveric human thoracolumbar spine specimens was measured before and after fixation by biomechanical testing in flexion, extension, right lateral bending, and right rotation, and the data were compared. In flexion and extension, mobility of the segment above the double-level T12-L2 posterior fixation was significantly increased (P<0.05). In the adjacent segment below the fixation, there was no significant increased mobility after fixation for each moment applied. There is evidence that the adjacent segment above a double-level T12-L2 posterior fixation becomes more mobile, and this may lead to an accelerated degeneration in the facet joints due to increased stress at this point. This could be responsible for symptoms like low back pain after spinal surgery.

[Post-traumatic osteoid osteoma. Case report and review of the literature]

Osteoid osteoma is a painful benign bone neoplasm that is rarely described after trauma but should be suspected. A case of osteoid osteoma 19 years after a tibial fracture is presented. The patient had pain in the tibia for 6 years before the osteoid osteoma was confirmed. He had been operated on twice for suspected osteomyelitis although the clinical symptoms suggested an osteoid osteoma. The radiographic appearance as well as a bone scan confirmed the diagnosis. Removal of the nidus resulted in immediate pain relief. A precise preoperative diagnosis of the lesion based on clinical findings, standard radiographs, high-resolution CT, and bone scan is mandatory. It is important to recognize this uncommon entity to avoid morbidity associated with a prolonged delay in diagnosis.

[Development and validation of the Visual Analogue Scale (VAS) Spine Score]

The aim of the study was the development and validation of a new subjective rating scale for assessment of outcome in patients with thoracolumbar fractures and fracture dislocations. The VAS spine score consists of 19 score items, using 100-mm visual analogue scales. The items are answered by the patients independently of rater assessment. To measure the analogue scales and calculate the score, a computer-aided system was evolved consisting of self-developed software and digitizer board. The overall score is the mean of all items answered with values between 0 and 100. The individual score loss is calculated as the difference between the preinjury score and at follow-up with values between 0 and 100. The VAS spine score was tested for reliability with a group of 136 healthy volunteers. We performed a test-retest study with an interval of 24 h. For statistical analysis of the validity, we prospectively followed a group of 53 patients with the new outcome score. We chose patients with injuries of the thoracolumbar spine, all having been operatively treated by combined posterior-anterior stabilization and fusion between 1994 and 1996. In the reference group, the average test score was 91.95 (58-100) and 92.10 (58-100) at retest. The mean individual difference between test and retest scored 1.037 (0-8). A high reliability was proved by a strong correlation with a coefficient of 0.976 (p < 0.001). A high internal consistency of the VAS spine score was shown by a Cronbach-alpha of 0.9117. The mean score for the preinjury status of the patients was comparable to the reference group, amounting to 89.60 (21-100). The mean score at the time of implant removal was significantly (p < 0.001) decreased to 58.25 (13-97). Until the time of follow-up a significant (p < 0.001) increase was noted, and the group scored 66.08 (15-100) at follow-up. This was a significant (p < 0.001) difference compared with the preinjury status. The individual score loss averaged 24.1 (0-80). In the patient group we also noted a Cronbach-alpha > 0.95, indicating a high internal consistency. With the VAS spine score the authors have inaugurated a new tool for outcome measurement in the treatment of patients with thoracolumbar injuries. The study has proved the score to be both reliable and valid. The application of the score is helpful in analyzing the subjective outcome, and the results can be correlated with objective measures. The score is a useful tool for comparative clinical studies, addressing the outcome after different methods of treatment.

Surgical options for the treatment of severe tibial pilon fractures: a study of three techniques

OBJECTIVE

To determine whether long-term results of one of three different management protocols for severe tibial pilon fractures offer advantages over the other two.

DESIGN

In a retrospective study, patients were examined clinically and radiologically after internal fixation of severe tibial plafond fractures (i.e., 92 percent Type C fractures according to the AO-ASIF classification).

SETTING

Department of Traumatology, Hanover Medical School. Level I trauma center.

PATIENTS

Fifty-one of seventy-seven patients treated between 1982 and 1992 were examined clinically and radiologically at an average of sixty-eight months (range 13 to 130 months) after injury.

INTERVENTIONS

The patients were treated in three different ways: primary internal fixation with a plate following the AO-ASIF principles (n = 15), which was reserved for patients with closed fractures without severe soft tissue trauma; one-stage minimally invasive osteosynthesis for reconstruction of the articular surface with long-term transarticular external fixation of the ankle for at least four weeks (n = 28); and a two-stage procedure entailing primary reduction and reconstruction of the articular surface with minimally invasive osteosynthesis and short-term transarticular external fixation of the ankle joint followed by secondary medial stabilization with a plate using a technique requiring only limited skin incisions (a reduced invasive technique) (n = 8).

MAIN OUTCOME MEASUREMENTS

Objective evaluation criteria were infection rate, amount of posttraumatic arthritis, range of ankle movement, and number of arthrodeses. Subjective criteria were pain, swelling, and restriction of work or leisure activities.

RESULTS

Because only closed fractures were treated by primary internal fixation with a plate, there was a statistically significant difference (p < 0.005) in the distribution of open fractures between the three treatment groups. Fracture classification in these groups were not significantly different. All but four fractures were classified as Type C lesions according to the AO-ASIF system. The soft tissue was closed in 63 percent (n = 32) and open in 37 percent (n = 19). No significant relationship could be found between the soft tissue damage and degree of arthritis or between the type of surgical treatment and extent of posttraumatic arthritis. However, none of the patients who required secondary arthrodesis (23 percent of all cases) were in the group who had undergone two-step surgery (p < 0.05). The range of ankle movement was much greater in the two-step group than in the others; these patients also had less pain, more frequently continued working in their previous profession, and had fewer limitations in their leisure activities. These differences did not reach statistical significance. The incidence of wound infection did not differ significantly among the three groups.

CONCLUSIONS

On the basis of our results, we now prefer a two-step procedure for the treatment of severe tibial pilon fractures with extensive soft tissue damage. In the first stage, primary reduction and internal fixation of the articular surface is performed using stab incisions, screws, and K-wires. Temporary external fixation is applied across the ankle joint. After recovery of the soft tissues, the second stage entails internal fixation with a medial plate using a reduced invasive technique.