Apparent Lack of BRAF V600E Derived HLA Class I Presented Neoantigens Hampers Neoplastic Cell Targeting by CD8+ T Cells in Langerhans Cell Histiocytosis

Langerhans Cell Histiocytosis (LCH) is a neoplastic disorder of hematopoietic origin characterized by inflammatory lesions containing clonal histiocytes (LCH-cells) intermixed with various immune cells, including T cells. In 50-60% of LCH-patients, the somatic BRAF ^V600E driver mutation, which is common in many cancers, is detected in these LCH-cells in an otherwise quiet genomic landscape. Non-synonymous mutations like BRAF ^V600E can be a source of neoantigens capable of eliciting effective antitumor CD8⁺ T cell responses. This requires neopeptides to be stably presented by Human Leukocyte Antigen (HLA) class I molecules and sufficient numbers of CD8⁺ T cells at tumor sites. Here, we demonstrate substantial heterogeneity in CD8⁺ T cell density in n = 101 LCH-lesions, with BRAF ^V600E mutated lesions displaying significantly lower CD8⁺ T cell:CD1a⁺ LCH-cell ratios (p = 0.01) than BRAF wildtype lesions. Because LCH-lesional CD8⁺ T cell density had no significant impact on event-free survival, we investigated whether the intracellularly expressed BRAF ^V600E protein is degraded into neopeptides that are naturally processed and presented by cell surface HLA class I molecules. Epitope prediction tools revealed a single HLA class I binding BRAF ^V600E derived neopeptide (KIGDFGLATEK), which indeed displayed strong to intermediate binding capacity to HLA-A^*03:01 and HLA-A^*11:01 in an in vitro peptide-HLA binding assay. Mass spectrometry-based targeted peptidomics was used to investigate the presence of this neopeptide in HLA class I presented peptides isolated from several BRAF ^V600E expressing cell lines with various HLA genotypes. While the HLA-A^*02:01 binding BRAF wildtype peptide KIGDFGLATV was traced in peptides isolated from all five cell lines expressing this HLA subtype, KIGDFGLATEK was not detected in the HLA class I peptidomes of two distinct BRAF ^V600E transduced cell lines with confirmed expression of HLA-A^*03:01 or HLA-A^*11:01. These data indicate that the in silico predicted HLA class I binding and proteasome-generated neopeptides derived from the BRAF ^V600E protein are not presented by HLA class I molecules. Given that the BRAF ^V600E mutation is highly prevalent in chemotherapy refractory LCH-patients who may qualify for immunotherapy, this study therefore questions the efficacy of immune checkpoint inhibitor therapy in LCH.

Enhanced human hematopoietic stem and progenitor cell engraftment by blocking donor T cell-mediated TNFα signaling

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative therapy, but the large number of HSCs required limits its widespread use. Host conditioning and donor cell composition are known to affect HSCT outcomes. However, the specific role that the posttransplantation signaling environment plays in donor HSC fate is poorly understood. To mimic clinical HSCT, we injected human umbilical cord blood (UCB) cells at different doses and compositions into immunodeficient NOD/SCID/IL-2Rgc-null (NSG) mice. Surprisingly, higher UCB cell doses inversely correlated with stem and progenitor cell engraftment. This observation was attributable to increased donor cell-derived inflammatory signals. Donor T cell-derived tumor necrosis factor-α (TNFα) was specifically found to directly impair the survival and division of transplanted HSCs and progenitor cells. Neutralizing donor T cell-derived TNFα in vivo increased short-term stem and progenitor cell engraftment, accelerated hematopoietic recovery, and altered donor immune cell compositions. This direct effect of TNFα on transplanted cells could be decoupled from the indirect effect of alleviating graft-versus-host disease (GVHD) by interleukin-6 (IL-6) blockade. Our study demonstrates that donor immune cell-derived inflammatory signals directly influence HSC fate, and provides new clinically relevant strategies to improve engraftment efficiency during HSCT.

Development and Initial Validation of the Macrophage Activation Syndrome/Primary Hemophagocytic Lymphohistiocytosis Score, a Diagnostic Tool that Differentiates Primary Hemophagocytic Lymphohistiocytosis from Macrophage Activation Syndrome

OBJECTIVE

To develop and validate a diagnostic score that assists in discriminating primary hemophagocytic lymphohistiocytosis (pHLH) from macrophage activation syndrome (MAS) related to systemic juvenile idiopathic arthritis.

STUDY DESIGN

The clinical, laboratory, and histopathologic features of 362 patients with MAS and 258 patients with pHLH were collected in a multinational collaborative study. Eighty percent of the population was assessed to develop the score and the remaining 20% constituted the validation sample. Variables that entered the best fitted model of logistic regression were assigned a score, based on their statistical weight. The MAS/HLH (MH) score was made up with the individual scores of selected variables. The cutoff in the MH score that discriminated pHLH from MAS best was calculated by means of receiver operating characteristic curve analysis. Score performance was examined in both developmental and validation samples.

RESULTS

Six variables composed the MH score: age at onset, neutrophil count, fibrinogen, splenomegaly, platelet count, and hemoglobin. The MH score ranged from 0 to 123, and its median value was 97 (1st-3rd quartile 75-123) and 12 (1st-3rd quartile 11-34) in pHLH and MAS, respectively. The probability of a diagnosis of pHLH ranged from <1% for a score of <11 to >99% for a score of  ≥123. A cutoff value of ≥60 revealed the best performance in discriminating pHLH from MAS.

CONCLUSION

The MH score is a powerful tool that may aid practitioners to identify patients who are more likely to have pHLH and, thus, could be prioritized for functional and genetic testing.

Langerhans cell histiocytosis is a neoplasm and consequently its recurrence is a relapse: In memory of Bob Arceci

Langerhans cell histiocytosis (LCH) remains a poorly understood disorder with heterogeneous clinical presentations characterized by focal or disseminated lesions that contain excessive CD1a+ langerin+ cells with dendritic cell features known as "LCH cells." Two of the major questions investigated over the past century have been (i) the origin of LCH cells and (ii) whether LCH is primarily an immune dysregulatory disorder or a neoplasm. Current opinion is that LCH cells are likely to arise from hematopoietic precursor cells, although the stage of derailment and site of transformation remain unclear and may vary in patients with different extent of disease. Over the years, evidence has provided the view that LCH is a neoplasm. The demonstration of clonality of LCH cells, insufficient evidence alone for neoplasia, is now bolstered by finding driver somatic mutations in BRAF in up to 55% of patients with LCH, and activation of the RAS-RAF-MEK-ERK (where MEK and ERK are mitogen-activated protein kinase and extracellular signal-regulated kinase, respectively) pathway in nearly 100% of patients with LCH. Herein, we review the evidence that recurrent genetic abnormalities characterized by activating oncogenic mutations should satisfy prerequisites for LCH to be called a neoplasm. As a consequence, recurrent episodes of LCH should be considered relapsed disease rather than disease reactivation. Mapping the complete genetic landscape of this intriguing disease will provide additional support for the conclusion that LCH is a neoplasm and is likely to provide more potential opportunities for molecularly targeted therapies.

Tertiary lymphoid structures are confined to patients presenting with unifocal Langerhans Cell Histiocytosis

Langerhans cell histiocytosis (LCH) is a neoplastic myeloid disorder with a thus far poorly understood immune component. Tertiary lymphoid structures (TLS) are lymph node-like entities which create an immune-promoting microenvironment at tumor sites. We analyzed the presence and clinical relevance of TLS in n = 104 H&E-stained, therapy-naive LCH lesions of non-lymphoid origin and applied immunohistochemistry to a smaller series. Lymphoid-follicular aggregates were detected in 34/104 (33%) lesions. In line with the lymphocyte recruitment capacity of MECA-79(+) high endothelial venules (HEVs), MECA-79(+)-expressing-LCH lesions (37/77, 48%) contained the most CD3(+) T-lymphocytes (p = 0.003). TLS were identified in 8/15 lesions and contained T-and B-lymphocytes, Follicular Dendritic Cells (FDC), HEVs and the chemokines CXCL13 and CCL21 representing key cellular components and TLS-inducing factors in conventional lymph nodes (LN). Lymphoid-follicular aggregates were most frequently detected in patients presenting with unifocal LCH (24/70, 34%) as compared to patients with poly-ostotic or multi-system LCH (7/30, 23%, p = 0.03). In addition, patients with lymphoid-follicular aggregates-containing lesions had the lowest risk to develop new LCH lesions (p = 0.04). The identification of various stages of TLS formation within LCH lesions may indicate a key role for the immune system in controlling aberrant histiocytes which arise in peripheral tissues.

Overexpression of LMO2 causes aberrant human T-Cell development in vivo by three potentially distinct cellular mechanisms

Overexpression of LMO2 is known to be one of the causes of T-cell acute lymphoblastic leukemia (T-ALL) development; however, the mechanisms behind its oncogenic activity are incompletely understood. LMO2-overexpressing transgenic mouse models suggest an accumulation of immature T-cell progenitors in the thymus as the main preleukemic event. The effects of LMO2 overexpression on human T-cell development in vivo are unknown. Here, we report studies of a humanized mouse model transplanted with LMO2-transduced human hematopoietic stem/progenitor cells. The effects of LMO2 overexpression were confined to the T-cell lineage; however, initially, multipotent cells were transduced. Three effects of LMO2 on human T-cell development were observed: (1) a block at the double-negative/immature single-positive stage, (2) an accumulation of CD4(+)CD8(+) double-positive CD3(-) cells, and (3) an altered CD8/CD4 ratio with enhanced peripheral T lymphocytes. Microarray analysis of sorted double-positive cells overexpressing LMO2 led to the identification of an LMO2 gene set that clustered with human T-ALL patient samples of the described "proliferative" cluster. In this article, we demonstrate previously unrecognized mechanisms by which LMO2 alters human T-cell development in vivo; these mechanisms correlate with human T-ALL leukemogenesis.

Successful Therapy Reduction and Intensification for Childhood Acute Lymphoblastic Leukemia Based on Minimal Residual Disease Monitoring: Study ALL10 From the Dutch Childhood Oncology Group

PURPOSE

Outcome of childhood acute lymphoblastic leukemia (ALL) improved greatly by intensifying chemotherapy for all patients. Minimal residual disease (MRD) levels during the first months predict outcome and may select patients for therapy reduction or intensification.

METHODS

Patients 1 to 18 years old with ALL were stratified on the basis of MRD levels after the first and second course of chemotherapy. Thereafter, therapy was substantially reduced in patients with undetectable MRD (standard risk) and intensified in patients with intermediate (medium risk) and high (high risk) levels of MRD. Seven hundred seventy-eight consecutive patients were enrolled. The method of analysis was intention-to-treat. Outcome was compared with historical controls.

RESULTS

In MRD-based standard-risk patients, the 5-year event-free survival (EFS) rate was 93% (SE 2%), the 5-year survival rate was 99% (SE 1%), and the 5-year cumulative incidence of relapse rate was 6% (SE 2%). The safety upper limit of number of observation years was reached and therapy reduction was declared safe.MRD-based medium-risk patients had a significantly higher 5-year EFS rate (88%, SE 2%) with therapy intensification (including 30 weeks of asparaginase exposure and dexamethasone/vincristine pulses) compared with historical controls (76%, SE 6%). Intensive chemotherapy and stem cell transplantation in MRD-based high-risk patients resulted in a significantly better 5-year EFS rate (78%, SE 8% v 16%, SE 8% in controls). Overall outcome improved significantly (5-year EFS rate 87%, 5-year survival rate 92%, and 5-year cumulative incidence of relapse rate 8%) compared with preceding Dutch Childhood Oncology Group protocols.

CONCLUSION

Chemotherapy was substantially reduced safely in one-quarter of children with ALL who were selected on the basis of undetectable MRD levels, without jeopardizing the survival rate. Outcomes of patients with intermediate and high levels of MRD improved with therapy intensification.

Activated Conventional T-Cells Are Present in Langerhans Cell Histiocytosis Lesions Despite the Presence of Immune Suppressive Cytokines

Langerhans cell histiocytosis (LCH) lesions are characterized by neoplastic CD1a(+)/Langerin(+) histiocytes (LCH-cells) and display many features of chronic inflammation. Cancer cells can escape immune-surveillance through intra-tumoral secretion of immune-suppressive cytokines. We therefore studied by immunohistochemistry the local cytokine milieu and phenotypic characteristics of T-cells and LCH-cells present in LCH lesions collected from 25 therapy naïve patients. LCH biopsies predominantly expressed interleukin-10 (IL-10) (10/25), transforming growth factor-beta (TGF-β) (9/25), or both cytokines (6/25). The absolute number of CD3(+)T-cells and the CD3(+)FOXP3(-) conventional cell (T-CONV) versus the CD3(+)FOXP3(+) regulatory T-cell (T-REG) was comparable for each suppressive cytokine profile (5:1). IL-10-expressing lesions contained, however, a higher proportion of T-CONV expressing the activation markers CD25 98% (38%-100%) and inducible costimulatory molecule (ICOS) 86% (47%-100%) than lesions wherein solely TGF-β was detected (CD25(+) 20% (6%-54%); ICOS(+) 29% (7%-51%)). Virtually all T-REG expressed CD25 and ICOS in IL-10 lesions, whereas TGF-β(+) lesions contained a lower proportion of ICOS(+) T-REG (P=0.05). IL-10(+) lesions contained more LCH-cells expressing high intensity of ICOS ligand (ICOSL) compared with TGF-β(+) lesions (P=0.03). ICOS expression by lesion-infiltrating T-CONV and T-REG positively correlated to the extent of ICOSL expression by LCH-cells (P=0.004). Our study points out that the combined detection of interlesional IL-10 and ICOSL expression by LCH-cells is associated with the highest prevalence of activated T-CONV. Immune profiling of LCH-affected tissues obtained at the time of diagnosis may set the stage for the development of new types of therapies, which aim at local boosting of immune cells that recognize and eliminate neoplastic LCH-cells.

The presence of CXCR4+ CD1a+ cells at onset of Langerhans cell histiocytosis is associated with a less favorable outcome

PURPOSE

Langerhans Cell Histiocytosis (LCH) is a neoplastic disorder characterized by tissue accumulating CD1a⁺ histiocytes which frequently carry somatic mutations. Irrespective of mutation status, these LCH-cells display constitutively active kinases belonging to the MAPK pathway. We evaluated, in retrospect, the contribution of individual components of the MAPK-activating and chemotaxis-promoting TNF-CXCR4-CXCL12 axis to LCH manifestation and outcome.

EXPERIMENTAL DESIGN

CXCR4, CXCL12 and TNF protein expression was immunohistochemically analyzed in 70 LCH-affected biopsies. The presence of CXCR4⁺CD1a⁺ cells in peripheral blood (PB) and/or bone marrow (BM) samples was evaluated by flowcytometry in 13 therapy-naive LCH-patients.

RESULTS

CXCL12 was detected in 68/70 (97%) biopsies. CXCR4⁺LCH-cells were present in 50/70 (71%) biopsies; their presence was associated with higher levels of intralesional TNF. Circulating CD1a⁺CXCR4⁺ cells were detected in 4/13 (31%) therapy-naïve LCH-patients which displayed BRAF^V600E (2/4), MAP2K1 (1/4) or no (1/4) mutations in their tissues. These CD11c co-expressing CD1a⁺CXCR4⁺cells migrated to CXCL12 in chemotaxis assays. Lesional CXCR4⁺LCH-cells were detected in 18/20 cases who presented with LCH manifestation at multiple sites and in 5/23 (22%) patients who developed additional lesions after initially presenting with a single lesion. The CXCR4 status at onset proved to be an independent risk factor for LCH reactivation in multivariate analysis (odds ratio 10.4, p = 0.034).

CONCLUSIONS

This study provides the first evidence that CXCR4 is involved in the homing and retention of LCH-cells in CXCL12-expressing tissues and qualifies CXCR4 as a candidate prognostic marker for less favorable disease outcome.

Transplant Outcomes for Children with T Cell Acute Lymphoblastic Leukemia in Second Remission: A Report from the Center for International Blood and Marrow Transplant Research

Survival for children with relapsed T cell acute lymphoblastic leukemia (T-ALL) is poor when treated with chemotherapy alone, and outcomes after allogeneic hematopoietic cell transplantation (HCT) is not well described. Two hundred twenty-nine children with T-ALL in second complete remission (CR2) received an HCT after myeloablative conditioning between 2000 and 2011 and were reported to the Center for International Blood and Marrow Transplant Research. Median age was 10 years (range, 2 to 18). Donor source was umbilical cord blood (26%), matched sibling bone marrow (38%), or unrelated bone marrow/peripheral blood (36%). Acute (grades II to IV) and chronic graft-versus-host disease occurred in, respectively, 35% (95% confidence interval [CI], 27% to 45%) and 26% (95% CI, 20% to 33%) of patients. Transplant-related mortality at day 100 and 3-year relapse rates were 13% (95% CI, 9% to 18%) and 30% (95% CI, 24% to 37%), respectively. Three-year overall survival and disease-free survival rates were 48% (95% CI, 41% to 55%) and 46% (95% CI, 39% to 52%), respectively. In multivariate analysis, patients with bone marrow relapse, with or without concurrent extramedullary relapse before HCT, were most likely to relapse (hazard ratio, 3.94; P = .005) as compared with isolated extramedullary disease. In conclusion, HCT for pediatric T-ALL in CR2 demonstrates reasonable and durable outcomes, and consideration for HCT is warranted.

Gene-expression and in vitro function of mesenchymal stromal cells are affected in juvenile myelomonocytic leukemia

An aberrant interaction between hematopoietic stem cells and mesenchymal stromal cells has been linked to disease and shown to contribute to the pathophysiology of hematologic malignancies in murine models. Juvenile myelomonocytic leukemia is an aggressive malignant disease affecting young infants. Here we investigated the impact of juvenile myelomonocytic leukemia on mesenchymal stromal cells. Mesenchymal stromal cells were expanded from bone marrow samples of patients at diagnosis (n=9) and after hematopoietic stem cell transplantation (n=7; from 5 patients) and from healthy children (n=10). Cells were characterized by phenotyping, differentiation, gene expression analysis (of controls and samples obtained at diagnosis) and in vitro functional studies assessing immunomodulation and hematopoietic support. Mesenchymal stromal cells from patients did not differ from controls in differentiation capacity nor did they differ in their capacity to support in vitro hematopoiesis. Deep-SAGE sequencing revealed differential mRNA expression in patient-derived samples, including genes encoding proteins involved in immunomodulation and cell-cell interaction. Selected gene expression normalized during remission after successful hematopoietic stem cell transplantation. Whereas natural killer cell activation and peripheral blood mononuclear cell proliferation were not differentially affected, the suppressive effect on monocyte to dendritic cell differentiation was increased by mesenchymal stromal cells obtained at diagnosis, but not at time of remission. This study shows that active juvenile myelomonocytic leukemia affects the immune response-related gene expression and function of mesenchymal stromal cells. In contrast, the differential gene expression of hematopoiesis-related genes could not be supported by functional data. Decreased immune surveillance might contribute to the therapy resistance and progression in juvenile myelomonocytic leukemia.

Humanized Chronic Graft-versus-Host Disease in NOD-SCID il2rγ-/- (NSG) Mice with G-CSF-Mobilized Peripheral Blood Mononuclear Cells following Cyclophosphamide and Total Body Irradiation

Chronic graft-versus-host disease (cGvHD) is the major source of late phase morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Humanized acute GvHD (aGvHD) in vivo models using NOD-SCID il2rγ-/- (NSG) mice are well described and are important tools for investigating pathogenicity of human cells in vivo. However, there have been only few reported humanized cGvHD mouse models. We evaluated if prolonged inflammation driven by low dose G-CSF-mobilized human PBMCs (G-hPBMCs) would lead to cGvHD following cyclophosphamide (CTX) administration and total body irradiation (TBI) in NSG mice. Engraftment was assessed in peripheral blood (PB) and in specific target organs by either flow cytometry or immunohistochemistry (IHC). Tissue samples were harvested 56 days post transplantation and were evaluated by a pathologist. Some mice were kept for up to 84 days to evaluate the degree of fibrosis. Mice that received CTX at 20mg/kg did not show aGvHD with stable expansion of human CD45+ CD3+ T-cells in PB (mean; 5.8 to 23.2%). The pathology and fibrosis scores in the lung and the liver were significantly increased with aggregation of T-cells and hCD68+ macrophages. There was a correlation between liver pathology score and the percentage of hCD68+ cells, suggesting the role of macrophage in fibrogenesis in NSG mice. In order to study long-term survival, 6/9 mice who survived more than 56 days showed increased fibrosis in the lung and liver at the endpoint, which suggests the infiltrating hCD68+ macrophages may be pathogenic. It was shown that the combination of CTX and TBI with a low number of G-hPBMCs (1x106) leads to chronic lung and liver inflammation driven by a high infiltration of human macrophage and mature human T cells from the graft, resulting in fibrosis of lung and liver in NSG mice. In conclusion this model may serve as an important pre-clinical model to further current understanding of the roles of human macrophages in cGvHD.

Significant Transplantation-Related Mortality from Respiratory Virus Infections within the First One Hundred Days in Children after Hematopoietic Stem Cell Transplantation

Respiratory viral infections (RVI) are important in hematopoietic stem cell transplantations (HSCT) and knowledge regarding incidence, morbidity, mortality, and long-term pulmonary complications is limited. We report a study to evaluate incidence and outcomes, both short and long-term, of RVI in children receiving HSCT. Between January 2000 and December 2012, 844 patients underwent hematopoietic stem cell transplantation (HSCT) at the Hospital for Sick Children: 491 were allogeneic and 353 were autologous. When screening for causes of death in the first year after HSCT in the 844 patients, we found that RVI as a cause of death was only evident in the first 100 days after HSCT. Fifty-four (6.5%) patients were found to have an RVI within the first 100 days after HSCT (allogeneic = 32, autologous = 22). Upper and lower respiratory tract infections were documented in 31 (57%) and 23 (43%) patients, respectively. Viruses were parainfluenza (35%), respiratory syncytial virus (28%), influenza (22%), adenovirus (7%), human metapneumovirus (4%), coronavirus (2%), and rhinovirus (2%). Three patients relapsed with their primary disease before day 100 and were excluded. The overall mortality for the remaining 51 patients was 10% (allogeneic = 4, autologous = 1). All 5 deaths were directly attributable to RVI and all 5 deaths occurred in patients with a lower respiratory tract infection. The remaining patients were followed for a median of 4.3 years (range, 1.4 to 11.8) and no chronic pulmonary complications were observed. A clear seasonal pattern for contracting RVI was evident with 65% of total RVI occurring between October and March (35 of 427 versus 19 of 417, P = .03). Given the significant mortality from RVI and the challenges in preventing them, choosing the time to start HSCT, whenever possible, may help prevent RVI and improve outcomes.

Mesenchymal stromal cells of osteosarcoma patients do not show evidence of neoplastic changes during long-term culture

Background

In vitro expanded mesenchymal stromal cells (MSCs) are increasingly used as experimental cellular therapy. However, there have been concerns regarding the safety of their use, particularly with regard to possible oncogenic transformation. MSCs are the hypothesized precursor cells of high-grade osteosarcoma, a tumor with often complex karyotypes occurring mainly in adolescents and young adults.

Methods

To determine if MSCs from osteosarcoma patients could be predisposed to malignant transformation we cultured MSCs of nine osteosarcoma patients and five healthy donors for an average of 649 days (range 601–679 days). Also, we compared MSCs derived from osteosarcoma patients at diagnosis and from healthy donors using genome wide gene expression profiling.

Results

Upon increasing passage, increasing frequencies of binucleate cells were detected, but no increase in proliferation suggestive of malignant transformation occurred in MSCs from either patients or donors. Hematopoietic cell specific Lyn substrate 1 (HLCS1) was differentially expressed (fold change 0.25, P value 0.0005) between MSCs of osteosarcoma patients (n = 14) and healthy donors (n = 9).

Conclusions

This study shows that although HCLS1 expression was downregulated in MSCs of osteosarcoma patients and binucleate cells were present in both patient and donor derived MSCs, there was no evidence of neoplastic changes to occur during long-term culture.

Electronic supplementary material

The online version of this article (doi:10.1186/s13569-015-0031-1) contains supplementary material, which is available to authorized users.

Serum Krebs Von Den Lungen-6 as a Biomarker for Early Detection of Bronchiolitis Obliterans Syndrome in Children Undergoing Allogeneic Stem Cell Transplantation

Bronchiolitis obliterans syndrome (BOS) is a devastating complication after allogeneic stem cell transplantation (allo-SCT). Early identification of high-risk patients is pivotal for success. Lung proteins, KL-6, CCSP, SP-A, and SP-D, measured in the serum may identify high-risk patients for BOS earlier than pulmonary function tests (PFTs) can identify changes or clinical symptoms. Lung proteins were measured in patients' serum at baseline and at 1, 3, 6, 9, 12, 18, and 24 months after transplantation along with history, clinical examination, and PFTs. Serum levels of lung proteins were also measured in healthy control subjects. The primary endpoint was the development of BOS confirmed by pathological biopsy or National Institutes of Health criteria. Between September 2009 and September 2011, 39 patients were enrolled. Six children developed BOS at a median time of 200 days (range, 94 to 282). KL-6 levels were low in control subjects, at a median of .1 U/mL (range, .1 to 1.5). Pre-SCT and 1-month KL-6 levels were significantly higher in surviving patients who developed BOS (n = 6) versus those who did not (n = 18) (pre-SCT: mean, 32.6 U/mL [IQR, 9.7 to 89.3] versus 5.8 U/mL [IQR, 2.1 to 12.6], P = .03; at 1 month: mean, 52.5 U/mL [IQR, 20.2 to 121.3] versus 11.4 U/mL [IQR, 5.7 to 36.0], P = .04). Three- and 6-month KL-6 levels continued to be higher in BOS group but were not statistically significant. CCSP, SP-A, and SP-D were not predictive. KL-6 measured in the serum of children receiving allo-SCT may identify patients at high risk for the development of BOS. These patients will benefit from intensive surveillance protocol and early therapy before irreversible lung damage.

MAP2K1 and MAP3K1 mutations in Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is now understood to be a neoplastic disease in which over 50% of cases have somatic activating mutations of BRAF. However, the extracellular signal-related (ERK) pathway is activated in all cases including those with wild type BRAF alleles. Here, we applied a targeted massively parallel sequencing panel to 30 LCH samples to test for the presence of additional genetic alterations that might cause ERK pathway activation. In 20 BRAF wild type samples, we found 3 somatic mutations in MAP2K1 (MEK1) including C121S and C121S/G128D in the kinase domain, and 56_61QKQKVG>R, an in-frame deletion in the N-terminal regulatory domain. All three variant proteins constitutively phosphorylated ERK in in vitro kinase assays. The C121S/G128D and 56_61QKQKVG>R variants were resistant to the mitogen-activated protein kinase kinase (MEK) inhibitor trametinib in vitro. Within the entire sample set, we found 3 specimens with mutations in MAP3K1 (MEKK1), including two truncation mutants, T779fs and T1481fs; T1481fs encoded an unstable and nonfunctional protein when expressed in vitro. T779fs was present in a specimen carrying BRAF V600E. The third variant was a single nucleotide substitution, E1286V, which was fully functional and is likely a germline polymorphism. These results indicate that LCH cells can harbor additional genetic alterations in the RAS-RAF-MEK pathway which, in the case of MAP2K1, may be responsible for ERK activation in a wild type BRAF setting. The resistance of some of these variants to trametinib may also have clinical implications for the combined use of RAF and MEK inhibitors in LCH.

Haematopoietic stem cell transplantation for refractory Langerhans cell histiocytosis: outcome by intensity of conditioning

Patients with Langerhans cell histiocytosis (LCH) refractory to conventional chemotherapy have a poor outcome. There are currently two promising treatment strategies for high-risk patients: the first involves the combination of 2-chlorodeoxyadenosine and cytarabine; the other approach is allogeneic haematopoietic stem cell transplantation (HSCT). Here we evaluated 87 patients with high-risk LCH who were transplanted between 1990 and 2013. Prior to the year 2000, most patients underwent HSCT following myeloablative conditioning (MAC): only 5 of 20 patients (25%) survived with a high rate (55%) of transplant-related mortality (TRM). After the year 2000 an increasing number of patients underwent HSCT with reduced intensity conditioning (RIC): 49/67 (73%) patients survived, however, the improved survival was not overtly achieved by the introduction of RIC regimens with similar 3-year probability of survival after MAC (77%) and RIC transplantation (71%). There was no significant difference in TRM by conditioning regimen intensity but relapse rates were higher after RIC compared to MAC regimens (28% vs. 8%, P = 0·02), although most patients relapsing after RIC transplantation could be salvaged with further chemotherapy. HSCT may be a curative approach in 3 out of 4 patients with high risk LCH refractory to chemotherapy: the optimal choice of HSCT conditioning remains uncertain.

Expression of the immune regulation antigen CD70 in osteosarcoma

Osteosarcoma is the most frequent bone cancer in children and young adults. The outcome of patients with advanced disease is dismal. Exploitation of tumor-immune cell interactions may provide novel therapeutic approaches. CD70-CD27 interactions are important for the regulation of adaptive immunity. CD70 expression has been reported in some solid cancers and implicated in tumor escape from immunosurveillance. In this study, expression of CD70 and CD27 was analyzed in osteosarcoma cell lines and tumor specimens. CD70 protein was expressed on most osteosarcoma cell lines (5/7) and patient-derived primary osteosarcoma cultures (4/6) as measured by flow cytometry. In contrast, CD70 was detected on few Ewing sarcoma cell lines (5/15) and was virtually absent from neuroblastoma (1/7) and rhabdomyosarcoma cell lines (0/5). CD70(+) primary cultures were derived from CD70(+) osteosarcoma lesions. CD70 expression in osteosarcoma cryosections was heterogeneous, restricted to tumor cells and not attributed to infiltrating CD3(+) T cells as assessed by immunohistochemistry/immunofluorescence. CD70 was detected in primary (1/5) but also recurrent (2/4) and metastatic (1/3) tumors. CD27, the receptor for CD70, was neither detected on tumor cells nor on T cells in CD70(+) or CD70(-) tumors, suggesting that CD70 on tumor cells is not involved in CD27-dependent tumor-immune cell interactions in osteosarcoma. CD70 gene expression in diagnostic biopsies of osteosarcoma patients did not correlate with the occurrence of metastasis and survival (n = 70). Our data illustrate that CD70 is expressed in a subset of osteosarcoma patients. In patients with CD70(+) tumors, CD70 may represent a novel candidate for antibody-based targeted immunotherapy.

Histologic patterns of thymic involvement in Langerhans cell proliferations: a clinicopathologic study and review of the literature

Thymic involvement by Langerhans cell histiocytosis (LCH) has been described mainly in isolated case reports. A description of the histopathologic patterns of LCH proliferations in the thymus, together with therapeutic implications, has not, to our knowledge, been previously addressed. The pathology consultation files at Children's Hospital of Pittsburgh of the University of Pennsylvania Medical Center were reviewed for cases of thymic involvement by LCH. Relevant cases in the literature were also reviewed, and the histopathology and clinical course of those cases were collected. Nine consultation cases of thymic involvement were reviewed, together with 23 cases in the literature, which provided adequate pathologic description and ancillary confirmation (n  =  32), revealing 4 distinct pathologic groups. Group 1 showed microscopic collection of hyperplastic LCH-like cells in incidental thymectomies of patients without LCH disease, requiring no further treatment (n  =  7; 22%). Group 2 showed solitary and/or cystic LCH of the thymus with gland disruption, and at least 3 cases resolved without systemic therapy (n  =  10; 31%). Group 3 showed more variable thymic involvement in multisystemic LCH disease, with either a medullary restricted pattern or more diffuse gland involvement, requiring adjuvant therapy and having a higher mortality rate (n  =  13; 41%). Group 4 showed a mixed histiocytic lesion with a concurrent LCH and juvenile xanthogranuloma-like proliferation (n  =  2; 6%). Thymic involvement in LCH is quite rare. Based on our cases and those in the literature, we propose 4 distinct pathologic groups of thymic involvement in Langerhans cell proliferations with relevance for diagnosis and treatment.

Despite differential gene expression profiles pediatric MDS derived mesenchymal stromal cells display functionality in vitro

Pediatric myelodysplastic syndrome (MDS) is a heterogeneous disease covering a spectrum ranging from aplasia (RCC) to myeloproliferation (RAEB(t)). In adult-type MDS there is increasing evidence for abnormal function of the bone-marrow microenvironment. Here, we extensively studied the mesenchymal stromal cells (MSCs) derived from children with MDS. MSCs were expanded from the bone-marrow of 17 MDS patients (RCC: n=10 and advanced MDS: n=7) and pediatric controls (n=10). No differences were observed with respect to phenotype, differentiation capacity, immunomodulatory capacity or hematopoietic support. mRNA expression analysis by Deep-SAGE revealed increased IL-6 expression in RCC- and RAEB(t)-MDS. RCC-MDS MSC expressed increased levels of DKK3, a protein associated with decreased apoptosis. RAEB(t)-MDS revealed increased CRLF1 and decreased DAPK1 expressions. This pattern has been associated with transformation in hematopoietic malignancies. Genes reported to be differentially expressed in adult MDS-MSC did not differ between MSC of pediatric MDS and controls. An altered mRNA expression profile, associated with cell survival and malignant transformation, of MSC derived from children with MDS strengthens the hypothesis that the micro-environment is of importance in this disease. Our data support the understanding that pediatric and adult MDS are two different diseases. Further evaluation of the pathways involved might reveal additional therapy targets.

Major ABO incompatible BMT in children: determining what residual volume of donor red cells can safely be infused following red cell depletion

Major ABO incompatible BM transplantation carries a risk of acute haemolysis. Red cell depletion reduces this risk but not all incompatible RBC (iRBCs) are removed and in children the residual volume can be significant relative to body weight. We sought to determine the volume of iRBCs that can be safely given to children. All patients receiving fresh BM from a donor with a major ABO blood group mismatch between January 2000 and July 2013 at the Hospital for Sick Children, Toronto, were included. Seventy-eight patients were identified. The median volume of iRBCs transfused was 1.6 mL/kg (range 0.1-10.6 mL/kg). Thirty-five patients had minor haemolytic events and five patients had clinically significant adverse events. Two patients, who received 3.66 and 3.9 mL iRBCs/kg, developed renal impairment and in one case hypoxia and hyperbilirubinaemia. One patient had mild hypotension that resolved with i.v. fluid. Two patients developed hypotension secondary to sepsis and unrelated to BM infusion. Although signs of haemolysis occur, with appropriate hydration and monitoring of renal function, clinically significant adverse events related to the infusion of ABO incompatible BM are rare, and, in this study, were only seen in patients receiving >3 mL/kg of iRBCs per kg.

Patient reported outcomes in pediatric oncology practice: suggestions for future usage by parents and pediatric oncologists

Several studies in adults have shown patient reported outcomes (PROs) to be effective in enhancing patient-physician communication and discussion of Health Related Quality of Life outcomes. Although less studied, positive results have been demonstrated in children. A PRO-intervention needs to be feasible in clinical practice to be successful. In the current study, 74 parents of children who successfully completed their cancer treatment and 21 pediatric oncologists (POs) evaluated a PRO-intervention and gave recommendations for future use in their practice. Most parents and POs suggested PROs to be an important part of standard care, starting during treatment, with an assessment frequency of every 3 months.

Sustained Engraftment of Cryopreserved Human Bone Marrow CD34(+) Cells in Young Adult NSG Mice

Hematopoietic stem cells (HSCs) are defined by their ability to repopulate the bone marrow of myeloablative conditioned and/or (lethally) irradiated recipients. To study the repopulating potential of human HSCs, murine models have been developed that rely on the use of immunodeficient mice that allow engraftment of human cells. The NSG xenograft model has emerged as the current standard for this purpose allowing for engraftment and study of human T cells. Here, we describe adaptations to the original NSG xenograft model that can be readily implemented. These adaptations encompass use of adult mice instead of newborns and a short ex vivo culture. This protocol results in robust and reproducible high levels of lympho-myeloid engraftment. Immunization of recipient mice with relevant antigen resulted in specific antibody formation, showing that both T cells and B cells were functional. In addition, bone marrow cells from primary recipients exhibited repopulating ability following transplantation into secondary recipients. Similar results were obtained with cryopreserved human bone marrow samples, thus circumventing the need for fresh cells and allowing the use of patient derived bio-bank samples. Our findings have implications for use of this model in fundamental stem cell research, immunological studies in vivo and preclinical evaluations for HSC transplantation, expansion, and genetic modification.

Mesenchymal stromal cell therapy is associated with increased adenovirus-associated but not cytomegalovirus-associated mortality in children with severe acute graft-versus-host disease

Beneficial effects of mesenchymal stromal cells (MSCs) in patients with severe steroid-refractory acute graft-versus-host disease (aGvHD) have been reported. However, controversy exists about the effect of MSCs on virus-specific T cells. We evaluated 56 patients with grade II-IV aGvHD who responded to steroids (n = 21) or were steroid refractory receiving either MSCs (n = 22) or other second-line therapy (n = 13). Although the overall incidence of cytomegalovirus (CMV), Epstein-Barr virus, and human adenovirus (HAdV) infections was not significantly increased, HAdV infection was associated with decreased survival in children treated with MSCs. Thus, we investigated in vitro the effects of MSCs on virus-specific T cells. Both CMV-specific and, to a lesser extent, HAdV-specific T-cell activation and proliferation were negatively affected by MSCs either after induction of a response in peripheral blood mononuclear cells (PBMCs) or after restimulation of virus-specific T-cell lines. In patient-derived PBMCs, CMV-specific proliferative responses were greatly decreased on first-line treatment of aGvHD with systemic steroids and slowly recovered after MSC administration and tapering of steroids. HAdV-specific T-cell proliferation could not be detected. In contrast, the proportion of CMV- and HAdV-specific effector T cells, measured as interferon-γ-secreting cells, remained stable or increased after treatment with MSCs. In conclusion, although in vitro experimental conditions indicated a negative impact of MSCs on CMV- and HAdV-specific T-cell responses, no solid evidence was obtained to support such an effect of MSCs on T-cell responses in vivo. Still, the susceptibility of steroid-refractory severe aGvHD patients to viral reactivation warrants critical viral monitoring during randomized controlled trials on second-line treatment including MSCs.

Macrophages inhibit human osteosarcoma cell growth after activation with the bacterial cell wall derivative liposomal muramyl tripeptide in combination with interferon-γ

Background

In osteosarcoma, the presence of tumor-infiltrating macrophages positively correlates with patient survival in contrast to the negative effect of tumor-associated macrophages in patients with other tumors. Liposome-encapsulated muramyl tripeptide (L-MTP-PE) has been introduced in the treatment of osteosarcoma patients, which may enhance the potential anti-tumor activity of macrophages. Direct anti-tumor activity of human macrophages against human osteosarcoma cells has not been described so far. Hence, we assessed osteosarcoma cell growth after co-culture with human macrophages.

Methods

Monocyte-derived M1-like and M2-like macrophages were polarized with LPS + IFN-γ, L-MTP-PE +/− IFN-γ or IL-10 and incubated with osteosarcoma cells. Two days later, viable tumor cell numbers were analyzed. Antibody-dependent effects were investigated using the therapeutic anti-EGFR antibody cetuximab.

Results

M1-like macrophages inhibited osteosarcoma cell growth when activated with LPS + IFN-γ. Likewise, stimulation of M1-like macrophages with liposomal muramyl tripeptide (L-MTP-PE) inhibited tumor growth, but only when combined with IFN-γ. Addition of the tumor-reactive anti-EGFR antibody cetuximab did not further improve the anti-tumor activity of activated M1-like macrophages. The inhibition was mediated by supernatants of activated M1-like macrophages, containing TNF-α and IL-1β. However, specific blockage of these cytokines, nitric oxide or reactive oxygen species did not inhibit the anti-tumor effect, suggesting the involvement of other soluble factors released upon macrophage activation. While LPS + IFN-γ–activated M2-like macrophages had low anti-tumor activity, IL-10–polarized M2-like macrophages were able to reduce osteosarcoma cell growth in the presence of the anti-EGFR cetuximab involving antibody-dependent tumor cell phagocytosis.

Conclusion

This study demonstrates that human macrophages can be induced to exert direct anti-tumor activity against osteosarcoma cells. Our observation that the induction of macrophage anti-tumor activity by L-MTP-PE required IFN-γ may be of relevance for the optimization of L-MTP-PE therapy in osteosarcoma patients.

Intact IFN-γR1 expression and function distinguishes Langerhans cell histiocytosis from mendelian susceptibility to mycobacterial disease

PURPOSE

Poly-ostotic Langerhans Cell Histiocytosis (LCH) can be difficult to distinguish clinically and histologically from disseminated infection in manifesting specific subtypes of Mendelian Susceptibility to Mycobacterial Disease (MSMD). In MSMD-patients, dominant negative germline mutations in the IFN-γR1 gene, in particular in exon 6, lead to autosomal dominant IFN-γ receptor 1 deficiency (ADIFNGR1) and can mimic LCH. We hypothesized that similar defects might underlie the pathogenesis of LCH.

METHODS

IFN-γR1 expression was immunohistochemically determined at disease onset in biopsies from 11 LCH-patients and four ADIFNGR1-patients. IFN-γR1 function was analyzed in 18 LCH-patients and 13 healthy controls by assessing the IFN-γ-induced upregulation of Fc-gamma-receptor I (FcγRI) expression on monocytes. Pro-inflammatory cytokine production was measured after stimulation of whole blood with LPS and IFN-γ. Exon 6 of the IFN-γR1 gene was sequenced in 67 LCH-patients to determine whether mutations were present.

RESULTS

IFN-γR1 expression was high in three LCH-affected biopsies, similar to ADIFNGR1-affected biopsies, but varied from negative to moderate in eight other LCH-affected biopsies. No functional differences in IFN-γ signaling were detected between LCH-patients with active or non-active disease and healthy controls. No germline mutations in exon 6 of the IFN-γR1 gene were detected in any of the 67 LCH-patients.

CONCLUSIONS

In contrast to ADIFNGR1-patients, IFN-γ signaling is fully functional in LCH-patients. Either performed before, during or after treatment, these non-invasive functional assays can distinguish LCH-patients from ADIFNGR1-patients and thereby facilitate correct therapy regimens for patients with recurrent osteolytic lesions.

Gastrointestinal acute graft-versus-host disease in children: histology for diagnosis, mesenchymal stromal cells for treatment, and biomarkers for prediction of response

Steroid-nonresponsive acute graft-versus-host disease (aGVHD) after hematopoietic stem cell transplantation carries a poor prognosis. Various groups have reported beneficial effects of mesenchymal stromal cell (MSC) infusion as salvage treatment. Response to treatment is typically evaluated using the diagnostic clinical criteria for aGVHD. In this study, we evaluated the usefulness of additional gastrointestinal biopsy specimens paired with serum biomarkers. In a cohort of 22 pediatric patients, persistent or recurrent diarrhea was seen in 18 children treated with MSC infusion for steroid-refractory aGVHD. To exclude other causes of gastrointestinal pathology, patients were biopsied for histological analysis. Eight of 12 patients exhibited residual tissue damage and villous atrophy, but no active aGVHD. Serum biomarkers have been identified as an alternative tool for monitoring the response to aGVHD treatment. The value of biomarkers for inflammation, tissue, and endothelial cell damage was evaluated in our cohort. Although predictive of response to treatment and survival, these markers lack the necessary specificity and sensitivity to predict response to MSC therapy. Objective endpoints for clinical trials on the treatment of steroid-refractory aGVHD remain to be defined. Thus, we recommend including biopsies and biomarkers to discriminate between ongoing aGVHD and postinflammatory malabsorption.

High-risk childhood acute lymphoblastic leukemia in first remission treated with novel intensive chemotherapy and allogeneic transplantation

Children with acute lymphoblastic leukemia (ALL) and high minimal residual disease (MRD) levels after initial chemotherapy have a poor clinical outcome. In this prospective, single arm, Phase 2 trial, 111 Dutch and Australian children aged 1-18 years with newly diagnosed, t(9;22)-negative ALL, were identified among 1041 consecutively enrolled patients as high risk (HR) based on clinical features or high MRD. The HR cohort received the AIEOP-BFM (Associazione Italiana di Ematologia ed Oncologia Pediatrica (Italy)-Berlin-Frankfurt-Münster ALL Study Group) 2000 ALL Protocol I, then three novel HR chemotherapy blocks, followed by allogeneic transplant or chemotherapy. Of the 111 HR patients, 91 began HR treatment blocks, while 79 completed the protocol. There were 3 remission failures, 12 relapses, 7 toxic deaths in remission and 10 patients who changed protocol due to toxicity or clinician/parent preference. For the 111 HR patients, 5-year event-free survival (EFS) was 66.8% (±5.5) and overall survival (OS) was 75.6% (±4.3). The 30 patients treated as HR solely on the basis of high MRD levels had a 5-year EFS of 63% (±9.4%). All patients experienced grade 3 or 4 toxicities during HR block therapy. Although cure rates were improved compared with previous studies, high treatment toxicity suggested that novel agents are needed to achieve further improvement.

Langerhans cell histiocytosis (LCH): guidelines for diagnosis, clinical work-up, and treatment for patients till the age of 18 years

These guidelines for the management of patients up to 18 years with Langerhans cell histiocytosis (LCH) have been set up by a group of experts involved in the Euro Histio Net project who participated in national or international studies and in peer reviewed publications. Existing guidelines were reviewed and changed where new evidence was available in the literature up to 2012. Data and publications have been ranked according to evidence based medicine and when there was a lack of published data, consensus between experts was sought. Guidelines for diagnosis, initial clinical work-up, and treatment and long-term follow-up of LCH patients are presented.

Prediction of area under the cyclosporine concentration versus time curve in children undergoing hematopoietic stem cell transplantation

This prospective study aimed to validate a previously developed first-dose limited sampling strategy (LSS) to predict the area under the cyclosporine concentration-versus-time curve (AUC) and to develop and then validate an LSS to predict cyclosporine AUC at steady state. This two-center Canadian study included children (ages .4 to 17.2 years) undergoing myeloablative allogeneic hematopoietic stem cell transplantation receiving cyclosporine for acute graft-versus-host disease prophylaxis. There were three cohorts, each incorporating 24 AUC determinations: first-dose LSS validation, steady-state LSS development, and steady-state LSS validation. Patients contributing data to either of the development cohorts were excluded from the corresponding validation group. Cyclosporine was given every 12 hours as a 2-hour infusion. Cyclosporine AUC was determined after administration of the first cyclosporine dose (8 samples) and then once weekly (9 samples) until engraftment. Steady-state LSSs were developed using stepwise multiple linear regression. An LSS was considered to provide an acceptable estimate of AUC if the lower limit of the 95% confidence limit (CL) of the intraclass coefficient was .8 or higher and both bias and precision were 15% or less. Fifty-three children age .4 to 18 years participated. Cyclosporine concentrations drawn up to 4 hours from the start of the infusion correlated most strongly with AUC. The previously developed first-dose LSSs and three steady-state LSSs met criteria for acceptability. The intraclass coefficients of the three-point first-dose LSS validation cohort, three-point steady-state LSS development cohort, and three-point steady-state LSS validation cohort were .974 (95% CL: .941 to .988), .984 (95% CL: .965 to .993), and .993 (95% CL: .984 to .997), respectively. The three-point first-dose (2, 6, and 8 hours) and steady-state (2, 2.5, and 8 hours) LSSs are valid measures of cyclosporine AUC after intravenous administration over 2 hours. Their use in a prospective evaluation of the relationship between cyclosporine AUC and hematopoietic stem cell transplantation clinical outcomes in children is suggested.

Phage display generation of a novel human anti-CD1A monoclonal antibody with potent cytolytic activity

CD1A is a cell surface protein expressed on Langerhans cells and cortical thymocytes that could potentially be used as an immunotherapeutic target in Langerhans Cell Histiocytosis (LCH), the cortical subtype of T-cell acute lymphocytic leukaemia (T-ALL) and other CD1A-positive tumours. The monoclonal antibody (mAb) CR2113 was selected from a panel of six fully human mAbs isolated from a semi-synthetic phage display library, based on specificity and avidity against cells expressing CD1 antigen variants. CR2113 recognized CD1A in T-ALL cell lines and patient samples. Confocal microscopy revealed that the CR2113-CD1A complex was internalized at 37°C. Furthermore, while CR2113 induced moderate complement-dependent cytotoxicity (CDC), potent antibody-dependent cell cytotoxicity (ADCC) activity was observed against CD1A expressing cell lines as well as T-ALL cell lines and T-ALL patient samples. In vivo experiments showed that CR2113 as a naked antibody has modest but specific anti-tumour activity against CD1A-expressing tumours. CR2113 is a high-affinity human anti-CD1A mAb with significant ADCC activity. These properties make CR2113 a candidate for clinical diagnostic imaging and therapeutic targeting of LCH as well as potential use in other clinical applications.

Reporting health-related quality of life scores to physicians during routine follow-up visits of pediatric oncology patients: is it effective?

BACKGROUND

The aim of the current study is to investigate the effectiveness of an intervention that provides health-related quality of life (HRQOL) scores of the patient (the QLIC-ON PROfile) to the pediatric oncologist.

PROCEDURE

Children with cancer participated in a sequential cohort intervention study: intervention N = 94, control N = 99. Primary outcomes of effectiveness were communication about HRQOL domains (t-test, Mann-Whitney U-test) and identification of HRQOL problems (chi-squared test). Secondary outcomes were satisfaction (multilevel analysis), referrals (chi-squared test), and HRQOL (multilevel analysis).

RESULTS

The QLIC-ON PROfile increased discussion of emotional functioning (control M = 32.9 vs. intervention M = 47.4, P < 0.05) and psychosocial functioning (M = 56.9 vs. M = 63.8, P < 0.05). Additionally more emotional problems remained unidentified in the control compared to the intervention group, for example, anger (control 26% vs. intervention 3%, P < 0.01), fear (14% vs. 0%, P < 0.01), and sadness (26% vs. 0%, P < 0.001). The intervention had no effect on satisfaction and referrals, but did improve HRQOL of patients 5-7 years of age with respect to self-esteem (P < 0.05), family activities (P < 0.05), and psychosocial functioning (P < 0.01).

CONCLUSIONS

We conclude that a PRO is a helpful tool for systematic monitoring HRQOL of children with cancer, without lengthening the duration of the consultation. It is recommended to be implemented in clinical practice.

Histone deacetylase inhibitors enhance expression of NKG2D ligands in Ewing sarcoma and sensitize for natural killer cell-mediated cytolysis

Background

Ewing sarcoma patients have a poor prognosis despite multimodal therapy. Integration of combination immunotherapeutic strategies into first-/second-line regimens represents promising treatment options, particularly for patients with intrinsic or acquired resistance to conventional therapies. We evaluated the susceptibility of Ewing sarcoma to natural killer cell-based combination immunotherapy, by assessing the capacity of histone deacetylase inhibitors to improve immune recognition and sensitize for natural killer cell cytotoxicity.

Methods

Using flow cytometry, ELISA and immunohistochemistry, expression of natural killer cell receptor ligands was assessed in chemotherapy-sensitive/-resistant Ewing sarcoma cell lines, plasma and tumours. Natural killer cell cytotoxicity was evaluated in Chromium release assays. Using ATM/ATR inhibitor caffeine, the contribution of the DNA damage response pathway to histone deacetylase inhibitor-induced ligand expression was assessed.

Results

Despite comparable expression of natural killer cell receptor ligands, chemotherapy-resistant Ewing sarcoma exhibited reduced susceptibility to resting natural killer cells. Interleukin-15-activation of natural killer cells overcame this reduced sensitivity. Histone deacetylase inhibitor-pretreatment induced NKG2D-ligand expression in an ATM/ATR-dependent manner and sensitized for NKG2D-dependent cytotoxicity (2/4 cell lines). NKG2D-ligands were expressed in vivo, regardless of chemotherapy-response and disease stage. Soluble NKG2D-ligand plasma concentrations did not differ between patients and controls.

Conclusion

Our data provide a rationale for combination immunotherapy involving immune effector and target cell manipulation in first-/second-line treatment regimens for Ewing sarcoma.

Prospective Study on Incidence, Risk Factors, and Long-Term Outcome of Osteonecrosis in Pediatric Acute Lymphoblastic Leukemia

Purpose

We studied cumulative incidence, risk factors, therapeutic strategies, and outcome of symptomatic osteonecrosis in pediatric patients with acute lymphoblastic leukemia (ALL).

Patients and Methods

Cumulative incidence of osteonecrosis was assessed prospectively in 694 patients treated with the dexamethasone-based Dutch Child Oncology Group–ALL9 protocol. Osteonecrosis was defined by development of symptoms (National Cancer Institute grade 2 to 4) during treatment or within 1 year after treatment discontinuation, confirmed by magnetic resonance imaging. We evaluated risk factors for osteonecrosis using logistic multivariate regression. To describe outcome, we reviewed clinical and radiologic information after antileukemic treatment 1 year or more after osteonecrosis diagnosis.

Results

Cumulative incidence of osteonecrosis at 3 years was 6.1%. After adjustment for treatment center, logistic multivariate regression identified age (odds ratio [OR], 1.47; P < .01) and female sex (OR, 2.23; P = .04) as independent risk factors. Median age at diagnosis of ALL in patients with osteonecrosis was 13.5 years, compared with 4.7 years in those without. In 21 (55%) of 38 patients with osteonecrosis, chemotherapy was adjusted. Seven patients (18%) underwent surgery: five joint-preserving procedures and two total-hip arthroplasties. Clinical follow-up of 35 patients was evaluated; median follow-up was 4.9 years. In 14 patients (40%), symptoms completely resolved; 14 (40%) had symptoms interfering with function but not with activities of daily living (ADLs; grade 2); seven (20%) had symptoms interfering with ADLs (grade 3). In 24 patients, radiologic follow-up was available; in six (25%), lesions improved/disappeared; in 13 (54%), lesions remained stable; five (21%) had progressive lesions.

Conclusion

Six percent of pediatric patients with ALL developed symptomatic osteonecrosis during or shortly after treatment. Older age and female sex were risk factors. After a median follow-up of 5 years, 60% of patients had persistent symptoms.

IgG antibodies to ATG early after pediatric hematopoietic SCT increase the risk of acute GVHD

Anti-thymocyte globulin (ATG), raised in rabbits, is frequently used in allogeneic hematopoietic SCT (HSCT), to prevent graft rejection and acute GVHD. In solid organ transplant patients, antibodies to rabbit IgG result in an enhanced clearance of ATG. The occurrence of such antibodies in HSCT recipients and their clinical impact is unknown. Concentrations of ATG and anti-ATG antibodies were measured in 72 pediatric HSCT recipients treated with ATG as part of the conditioning. Anti-ATG antibodies were detected in 20 children (28%), all transplanted with a non-depleted graft. IgG anti-ATG, alone or combined with IgM and/or IgA anti-ATG, appeared in 10 children. Four patients developed IgG anti-ATG antibodies early (before day 22) post-HSCT. They had steep drops in ATG levels and showed rapid T-cell recovery, which was associated with a significantly increased risk of acute GVHD. In six patients IgG anti-ATG responses occurred later (range 28-46 days) after HSCT without an increased risk of GVHD. A total of 10 children only mounted an IgM (and IgA) anti-ATG response, which was without major impact on ATG levels. These results indicate that early development of IgG anti-ATG antibodies has a major impact on acute GVHD. Routine analysis ATG/anti-ATG Ab measurement should be considered.

Chemotherapeutic adjuvant treatment for osteosarcoma: where do we stand?

AIM

Since the introduction of chemotherapy, survival in localised high-grade osteosarcoma has improved considerably. However, there is still no worldwide consensus on a standard chemotherapy approach. In this systematic review evidence for effectiveness of each single drug and the role of response guided salvage treatment of adjuvant chemotherapy are addressed, whereas in a meta-analysis the number of drugs in current protocols is considered.

METHODS

A systematic literature search for clinical studies in localised high-grade osteosarcoma was undertaken, including both randomised and non-randomised trials. Historical clinical studies from the pre-chemotherapy era were included for comparison purposes.

RESULTS

Nine historical studies showed a long-term survival of 16% after only local treatment. Fifty single agent phase II studies showed high response rates for adriamycin (A, 43%), ifosfamide (Ifo, 33%), methotrexate (M, 32%), cisplatin (P, 26%) but only 4% for etposide (E). In 19 neo-adjuvant studies the mean 5-year event free survival (EFS) was 48% for 2-drug regimens and 58% for ⩾3 drug regimens, with a 5-year overall survival (OAS) of 62% and 70%, respectively. Meta-analysis showed that ⩾3 drug regimens including methotrexate plus adriamycin plus cisplatin (plus ifosfamide) (MAP(Ifo)) had significant better outcome (EFS: HR=0.701 (95% confidence interval [95% CI]: 0.615-0.799); OAS: HR=0.792 (95% CI: 0.677-0.926) than 2-drug regimens, but there was no significant difference between MAP and MAPIfo (or plus etoposide). Salvage of poor responders by changing drugs, or intensifying treatment postoperatively has not proven to be useful in this analysis.

CONCLUSION

Meta-analysis in patients with localised high-grade osteosarcoma shows that 3-drug regimens, for example MAP are the most efficacious drug regimens.

Impaired sleep affects quality of life in children during maintenance treatment for acute lymphoblastic leukemia: an exploratory study

Background

With the increase of pediatric cancer survival rates, late effects and quality of life (QoL) have received more attention. Disturbed sleep in pediatric cancer is a common clinical observation, but research on this subject is sparse. In general, sleep problems can lead to significant morbidity and are associated with impaired QoL. Information on sleep is essential to develop interventions to improve QoL.

Methods

Children (2-18 years) with acute lymphoblastic leukemia (ALL) were eligible for this multi-center study. The Children's Sleep Habits Questionnaire (CSHQ), Child Health Questionnaire (CHQ) and Pediatric Quality of Life Inventory 3.0™ Acute Cancer Version (PedsQL) were used to assess sleep and QoL halfway through maintenance therapy. Sleep and QoL were measured during and after dexamethasone treatment (on-dex and off-dex).

Results

Seventeen children participated (age 6.7 ± 3.3 years, 44% boys). Children with ALL had more sleep problems and a lower QoL compared to the norm. There were no differences on-dex and off-dex. Pain (r = -0.6; p = 0.029) and worry (r = -0.5; p = 0.034) showed a moderate negative association with sleep. Reduced overall QoL was moderately associated with impaired overall sleep (r = -0.6; p = 0.014) and more problems with sleep anxiety (r = -0.8; p = 0.003), sleep onset delay (r = -0.5; p = 0.037), daytime sleepiness (r = -0.5; p = 0.044) and night wakenings (r = -0.6; p = 0.017).

Conclusion

QoL is impaired in children during cancer treatment. The results of this study suggest that impaired sleep may be a contributing determinant. Consequently, enhanced counseling and treatment of sleep problems might improve QoL. It is important to conduct more extensive studies to confirm these findings and provide more detailed information on the relationship between sleep and QoL, and on factors affecting sleep in pediatric ALL and in children with cancer in general.

Chemotherapy-resistant osteosarcoma is highly susceptible to IL-15-activated allogeneic and autologous NK cells

High-grade osteosarcoma occurs predominantly in adolescents and young adults and has an overall survival rate of about 60%, despite chemotherapy and surgery. Therefore, novel treatment modalities are needed to prevent or treat recurrent disease. Natural killer (NK) cells are lymphocytes with cytotoxic activity toward virus-infected or malignant cells. We explored the feasibility of autologous and allogeneic NK cell-mediated therapies for chemotherapy-resistant and chemotherapy-sensitive high-grade osteosarcoma. The expression by osteosarcoma cells of ligands for activating NK cell receptors was studied in vitro and in vivo, and their contribution to NK cell-mediated cytolysis was studied by specific antibody blockade. Chromium release cytotoxicity assays revealed chemotherapy-sensitive and chemotherapy-resistant osteosarcoma cell lines and osteosarcoma primary cultures to be sensitive to NK cell-mediated cytolysis. Cytolytic activity was strongly enhanced by IL-15 activation and was dependent on DNAM-1 and NKG2D pathways. Autologous and allogeneic activated NK cells lysed osteosarcoma primary cultures equally well. Osteosarcoma patient-derived NK cells were functionally and phenotypically unimpaired. In conclusion, osteosarcoma cells, including chemoresistant variants, are highly susceptible to lysis by IL-15-induced NK cells from both allogeneic and autologous origin. Our data support the exploitation of NK cells or NK cell-activating agents in patients with high-grade osteosarcoma.