Immunophenotypic markers in adult acute lymphoblastic leukemia: the prognostic significance of CD20 and TdT expression

Transcriptome Analysis in Mexican Adults with Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) represents around 25% of adult acute leukemias. Despite the increasing improvement in the survival rate of ALL patients during the last decade, the heterogeneous clinical and molecular features of this malignancy still represent a major challenge for treatment and achieving better outcomes. To identify aberrantly expressed genes in bone marrow (BM) samples from adults with ALL, transcriptomic analysis was performed using Affymetrix Human Transcriptome Array 2.0 (HTA 2.0). Differentially expressed genes (DEGs) (±2-fold change, p-value < 0.05, and FDR < 0.05) were detected using the Transcriptome Analysis Console. Gene Ontology (GO), Database for Annotation, Visualization, and Integrated Discovery (DAVID), and Ingenuity Pathway Analysis (IPA) were employed to identify gene function and define the enriched pathways of DEGs. The protein-protein interactions (PPIs) of DEGs were constructed. A total of 871 genes were differentially expressed, and DNTT, MYB, EBF1, SOX4, and ERG were the top five up-regulated genes. Meanwhile, the top five down-regulated genes were PTGS2, PPBP, ADGRE3, LUCAT1, and VCAN. An association between ERG, CDK6, and SOX4 expression levels and the probability of relapse and death was observed. Regulation of the immune system, immune response, cellular response to stimulus, as well as apoptosis signaling, inflammation mediated by chemokines and cytokines, and T cell activation were among the most altered biological processes and pathways, respectively. Transcriptome analysis of ALL in adults reveals a group of genes consistently associated with hematological malignancies and underscores their relevance in the development of ALL in adults.

High CD34 surface expression in BCP-ALL predicts poor induction therapy response and is associated with altered expression of genes related to cell migration and adhesion

Minimal residual disease (MRD) constitutes the most important prognostic factor in B‐cell precursor acute lymphoblastic leukemia (BCP‐ALL). Flow cytometry is widely used in MRD assessment, yet little is known regarding the effect of different immunophenotypic subsets on outcome. In this study of 200 BCP‐ALL patients, we found that a CD34‐positive, CD38 dim‐positive, nTdT dim‐positive immunophenotype on the leukemic blasts was associated with poor induction therapy response and predicted an MRD level at the end of induction therapy (EOI) of ≥ 0.001. CD34 expression was strongly and positively associated with EOI MRD, whereas CD34‐negative patients had a low relapse risk. Further, CD34 expression increased from diagnosis to relapse. CD34 is a stemness‐associated cell‐surface molecule, possibly involved in cell adhesion/migration or survival. Accordingly, genes associated with stemness were overrepresented among the most upregulated genes in CD34‐positive leukemias, and protein–protein interaction networks showed an overrepresentation of genes associated with cell migration, cell adhesion, and negative regulation of apoptosis. The present work is the first to demonstrate a CD34‐negative immunophenotype as a good prognostic factor in ALL, whereas high CD34 expression is associated with poor therapy response and an altered gene expression profile reminiscent of migrating cancer stem‐like cells.

The Outcome of Acute Lymphoblastic Leukemia in 109 Adult Iraqi Patients

While many studies addressed the outcome of adult ALL in developed Western countries, there is paucity of such prospective studies from developing Mediterranean ones. This is a prospective cohort study conducted at Hiwa Cancer Hospital in Sulaimani city and Nanakali Hospital in Erbil city-Kurdistan Iraq from March 2012 to August 2017. The main characteristics of adult ALL patients, type of therapy and risk factors were analyzed to assess their impact on treatment outcome and survival status. A total of 109 adult ALL patients were included with a median age of 24 years and male to female ratio of 1.7:1. B-ALL accounted for 76.1% of the cases, while the rest were T-ALL. BCR-ABL rearrangement was encountered in 12% of B-ALL. Complete remission (CR) rate was 81.7%, the overall 5 year survival (OS) was 38%, Relapse Free 5 year Survival (RFS) was 49%. Younger adults (< 35 years) had significantly higher CR rates and OS compared to the older group (P < 0.001 each). On the other hand, gender, high leucocyte count ≥ 50×109/L, immunophenotype (including B and T ALL subtypes), and clinical risk status did not predict a poor outcome. Multivariate analysis revealed that only age < 35 years and BCR-ABL rearrangement were significantly associated with better OS. Despite some limitations, the outcomes of Iraqi adult ALL is comparable to those reported in Western developed countries, with particularly favorable outcomes in younger patients. The need to improve outcome in adult ALL remains an important priority in our country as it is throughout the world.

Terminal deoxynucleotidyl transferase-mediated formation of protein binding polynucleotides

Terminal deoxynucleotidyl transferase (TdT) enzyme plays an integral part in the V(D)J recombination, allowing for the huge diversity in expression of immunoglobulins and T-cell receptors within lymphocytes, through their unique ability to incorporate single nucleotides into oligonucleotides without the need of a template. The role played by TdT in lymphocytes precursors found in early vertebrates is not known. In this paper, we demonstrated a new screening method that utilises TdT to form libraries of variable sized (vsDNA) libraries of polynucleotides that displayed binding towards protein targets. The extent of binding and size distribution of each vsDNA library towards their respective protein target can be controlled through the alteration of different reaction conditions such as time of reaction, nucleotide ratio and initiator concentration raising the possibility for the rational design of aptamers prior to screening. The new approach, allows for the screening of aptamers based on size as well as sequence in a single round, which minimises PCR bias. We converted the protein bound sequences to dsDNA using rapid amplification of variable ends assays (RAVE) and sequenced them using next generation sequencing. The resultant aptamers demonstrated low nanomolar binding and high selectivity towards their respective targets.

[CD20 is not a poor prognostic factor for childhood B-lineage acute lymphoblastic leukemia with high white blood cell count]

OBJECTIVE

To study the significance of CD20 combined with white blood cell (WBC) count at diagnosis in the prognosis assessment in children with B-lineage acute lymphoblastic leukemia (ALL).

METHODS

A retrospective analysis was performed on the medical data of 821 B-ALL children who were treated with CCLG-ALL2008 regimen from April 2008 to April 2015. Their survival status was followed up.

RESULTS

Among the 821 children, 547 (66.6%) were negative, while 274 (33.4%) were positive for CD20 expression. Among 694 children with WBC<50×10⁹/L (lower WBC count), the 5-year EFS rates were 65.9%±3.2% and 77.3%±2.0% for CD20 positive and negative patients respectively (P=0.001); the 5-year OS rates were 78.3%±2.9% and 87.5%±1.6% for CD20 positive and negative patients respectively (P=0.005); CD20 positive expression was an independent risk factor for EFS (HR=1.634, P=0.001) and OS (HR=1.761, P=0.005). Among 127 children with WBC>50×10⁹/L (higher WBC count), the 5-year EFS rates was 64.3%±7.7% and 53.7%±5.5% for CD20 positive and negative patients respectively (P=0.135); the 5-year OS rate was 81.4%±6.4% and 58.6%±5.6% for CD20 positive and negative patients respectively (P=0.022); CD20 positive expression was an independent protective factor for OS (HR=0.367, P=0.016).

CONCLUSIONS

In children with B-ALL who are treated with CCLG-ALL2008 regimen, those with CD20 positive expression in lower WBC count at diagnosis have a poor prognosis; however, those with CD20 positive expression in higher WBC count at diagnosis have a better long-time survival.

[CD20 is not a poor prognostic factor for childhood B-lineage acute lymphoblastic leukemia with high white blood cell count]

OBJECTIVE

To study the significance of CD20 combined with white blood cell (WBC) count at diagnosis in the prognosis assessment in children with B-lineage acute lymphoblastic leukemia (ALL).

METHODS

A retrospective analysis was performed on the medical data of 821 B-ALL children who were treated with CCLG-ALL2008 regimen from April 2008 to April 2015. Their survival status was followed up.

RESULTS

Among the 821 children, 547 (66.6%) were negative, while 274 (33.4%) were positive for CD20 expression. Among 694 children with WBC<50×109/L (lower WBC count), the 5-year EFS rates were 65.9%±3.2% and 77.3%±2.0% for CD20 positive and negative patients respectively (P=0.001); the 5-year OS rates were 78.3%±2.9% and 87.5%±1.6% for CD20 positive and negative patients respectively (P=0.005); CD20 positive expression was an independent risk factor for EFS (HR=1.634, P=0.001) and OS (HR=1.761, P=0.005). Among 127 children with WBC>50×109/L (higher WBC count), the 5-year EFS rates was 64.3%±7.7% and 53.7%±5.5% for CD20 positive and negative patients respectively (P=0.135); the 5-year OS rate was 81.4%±6.4% and 58.6%±5.6% for CD20 positive and negative patients respectively (P=0.022); CD20 positive expression was an independent protective factor for OS (HR=0.367, P=0.016).

CONCLUSIONS

In children with B-ALL who are treated with CCLG-ALL2008 regimen, those with CD20 positive expression in lower WBC count at diagnosis have a poor prognosis; however, those with CD20 positive expression in higher WBC count at diagnosis have a better long-time survival.

[Value of S100A8 in evaluating the prognosis of children with acute lymphoblastic leukemia]

OBJECTIVE

To study the association between S100A8 expression and prognosis in children with acute lymphoblastic leukemia (ALL).

METHODS

The clinical data of 377 children with ALL who were treated with the CCLG-2008-ALL regimen were retrospectively reviewed. ELISA and PCR were used to measure serum protein levels and mRNA expression of S100A8. The Kaplan-Meier method was used for survival analysis and a Cox regression analysis was also performed.

RESULTS

The children were followed up for 56 months, and the overall survival rate of the 377 children was 89.1%. The prednisone good response group had significantly lower S100A8 protein and mRNA levels than the prednisone poor response group (P<0.01). In the children with standard or median risk, both S100A8 protein and mRNA levels were associated with event-free survival rate (P<0.05). There were significant differences in S100A8 protein and mRNA levels between the children with different risk stratifications (P<0.01). The children who experienced events had significantly higher S100A8 protein and mRNA levels than those who did not (P<0.01). The Kaplan-Meier survival analysis and the Cox regression model suggested that S100A8 overexpression was an independent risk factor for the prognosis of children with ALL.

CONCLUSIONS

High S100A8 expression may be associated with the poor prognosis of children with ALL and is promising as a new marker for individualized precise treatment of children with ALL.

Immature Terminal Deoxynucleotidyl Transferase Positive B Cells are Detected in a Subset of Adult and Pediatric Liver Biopsies

Terminal deoxynucleotidyl transferase (TdT) is a nuclear enzyme restricted to precursor lymphoid cells and their malignant counterparts; immunohistochemical TdT labeling is helpful in recognition of lymphoblasts, which can resemble mature lymphocytes. The diagnosis of B-lymphoblastic leukemia/lymphoma (B-ALL) is occasionally first encountered on liver core biopsy, but TdT immunostain specificity for B-ALL is not clearly established in this setting, which can be problematic when only a few TdT-positive cells are identified. In this study, we evaluated the incidence and distribution of immature B lymphocytes coexpressing TdT and PAX-5, in pediatric and adult liver biopsies, to determine whether a normal complement of hepatic immature B cells can be detected, which must be recognized in a workup to exclude B-ALL. We selected 41 pediatric and adult liver biopsies with a significant portal and/or sinusoidal hematolymphoid infiltrate and performed immunohistochemical stains for TdT and PAX-5 to identify and categorize distribution of immature B cells. TdT-positive cells were detected in 40% of pediatric liver biopsies with a significant hematolymphoid infiltrate (4/10), which included all biopsies from neonates (and infants under 9 wk of age). In adults, immature B-cell infiltrates were less common (6%, 2/31). Dual immunostaining was performed on 2 cases of neonatal hepatitis, which documented B-cell lineage in at least a subset of TdT-positive cells and there was no colabeling with CD3. Immature B cells can be detected in liver biopsies in a variety of clinical settings, most commonly in children, and presence of a few TdT-positive cells cannot be considered entirely specific for involvement by B-ALL. Further workup for B-ALL can be warranted if there is more extensive multifocal portal and/or sinusoidal involvement by blasts with TdT labeling.

Immunophenotypic aberrancies in acute lymphoblastic leukemia from 282 Iraqi patients

INTRODUCTION

The identification of aberrancies in leukemia-associated immunophenotype (LAIP) of acute lymphoblastic leukemia (ALL) is quite important in the assessment of minimal residual disease (MRD). This study, the first from Iraq, aimed to assess the frequency and patterns of LAIP among Iraqi patients with ALL, to establish future strategies for evaluating MRD.

METHODS

A total of 282 newly diagnosed Iraqi ALL cases were analyzed with six-parameter flow cytometry using a panel of 29 monoclonal antibodies.

RESULTS

Immunological subtyping revealed that 85.5% of cases were B-ALL and the remainder T-ALL. LAIP was detected in 97.1% of B-ALL, and in 26.8% of T-ALL. The asynchronous maturation-associated antigen patterns in B-ALL were CD10^strong+ /TdT^dim+ , CD38^dim+ /CD34⁺ , CD10^dim+ /CD34⁺ , CD10^strong /CD20^strong+ , CD20^strong+ /CD34^+, and CD45^dim+ /CD20^strong+ in 84.6%, while the cross-lineage myeloid expression was seen in 81.3% and aberrant T-cell antigen expression in 6.2%. For T-ALL, asynchronous maturation-associated antigen patterns included the following: CD1a⁺ /CD5⁺ /sCD3⁺ and CD34⁺ /sCD3⁺ in 12.2%. Myeloid and B-cell antigen expression were each identified in 7.3% of T-ALL. No significant differences in LAIP were found between children and adults.

CONCLUSION

The high rates and the patterns of LAIP particularly in Iraqi B-ALL patients may allow the development of more cost-effective strategies for MRD monitoring.

In vitro and in vivo assessment of direct effects of simulated solar and galactic cosmic radiation on human hematopoietic stem/progenitor cells

Future deep space missions to Mars and near-Earth asteroids will expose astronauts to chronic solar energetic particles (SEP) and galactic cosmic ray (GCR) radiation, and likely one or more solar particle events (SPEs). Given the inherent radiosensitivity of hematopoietic cells and short latency period of leukemias, space radiation-induced hematopoietic damage poses a particular threat to astronauts on extended missions. We show that exposing human hematopoietic stem/progenitor cells (HSC) to extended mission-relevant doses of accelerated high-energy protons and iron ions leads to the following: (1) introduces mutations that are frequently located within genes involved in hematopoiesis and are distinct from those induced by γ-radiation; (2) markedly reduces in vitro colony formation; (3) markedly alters engraftment and lineage commitment in vivo; and (4) leads to the development, in vivo, of what appears to be T-ALL. Sequential exposure to protons and iron ions (as typically occurs in deep space) proved far more deleterious to HSC genome integrity and function than either particle species alone. Our results represent a critical step for more accurately estimating risks to the human hematopoietic system from space radiation, identifying and better defining molecular mechanisms by which space radiation impairs hematopoiesis and induces leukemogenesis, as well as for developing appropriately targeted countermeasures.