Expression of aberrant antigens in hematological malignancies: A single center experience

Secondary acute myeloid leukemia and de novo acute myeloid leukemia with myelodysplasia-related changes - close or complete strangers?

AIM

To compare the main features of patients with secondary acute myeloid leukemias (AMLs) after post-myelodysplastic syndrome (AML-post-MDS) or post-myeloproliferative neoplasms (AML-post-MPN) and myeloid blast crisis of chronic myeloid leukemia (CML-BC) vs. de novoAMLs with myelodysplastic characteristics (dn-AML-MDS).

Leukemia-associated aberrant immunophenotype: A flow cytometry-based experience of 110 cases from a tertiary care center in Northern India

Background

Leukemic cells express a characteristic set of "cluster of differentiation" (CD) markers, which forms the basis of the current WHO classification. Leukemia-associated aberrant immunophenotype (LAIP) refers to expression of unusual CD markers by leukemic cells, which are not normally expressed by their respective lineage. The incidence of LAIP varies considerably, and its clinical implications, prognostic relevance, and sensitivity to therapy are still debatable. This study was conducted to identify the immunophenotypic aberrancies in newly diagnosed leukemias in our Institute.

Method

This was an observational study, which included newly diagnosed leukemias on flow cytometry. Aberrant immunophenotypic expressions were recorded whenever present and were correlated with prognostic factors like age, gender, and total leucocyte count (TLC).

Results

The study included 110 newly diagnosed cases of leukemias (85 acute and 25 chronic) over 1.5 years. Immunophenotypic aberrancies were detected in 40.4% of the cases. The highest incidence of aberrations was detected in acute myeloid leukemia (60.7%). LAIPs were detected in 50% of T-acute lymphoblastic leukemia and 25% cases of in B-cell acute lymphoblastic leukemia (B-ALL). Aberrant CD33 and CD56 expression in B-ALL correlated with poor prognostic factors like higher age and higher TLC, respectively. Immunophenotypic aberrancies were present in 28% cases of chronic lymphocytic leukemia.

Conclusion

The results of this study have generated valuable baseline data on the incidence of LAIPs in this region. This information is vital because establishing LAIPs at the time of diagnosis is crucial for disease monitoring. Some LAIPs are associated with underlying cytogenetic abnormalities and hence impact the management and prognosis.

Multi-targeted immunotherapeutics to treat B cell malignancies

The concept of multi-targeted immunotherapeutic systems has propelled the field of cancer immunotherapy into an exciting new era. Multi-effector molecules can be designed to engage with, and alter, the patient's immune system in a plethora of ways. The outcomes can vary from effector cell recruitment and activation upon recognition of a cancer cell, to a multipronged immune checkpoint blockade strategy disallowing evasion of the cancer cells by immune cells, or to direct cancer cell death upon engaging multiple cell surface receptors simultaneously. Here, we review the field of multi-specific immunotherapeutics implemented to treat B cell malignancies. The mechanistically diverse strategies are outlined and discussed; common B cell receptor antigen targeting strategies are outlined and summarized; and the challenges of the field are presented along with optimistic insights for the future.

A Defucosylated Mouse Anti-CD10 Monoclonal Antibody (31-mG2a-f) Exerts Antitumor Activity in a Mouse Xenograft Model of Renal Cell Cancers

CD10 is a cell surface metalloendopeptidase that cleaves and degrades many secreted physiologically active peptides by its enzymatic activity. Although CD10 expression has been found in various types of cells, its expression is increased in several cancers, including renal cancer. In this study, the antitumor activity of a novel anti-human CD10 monoclonal antibody (mAb) was investigated. A defucosylated mouse IgG_2a version of C₁₀Mab-31 (31-mG_2a-f) was created from an anti-CD10 mAb, C₁₀Mab-31 (IgG₁, kappa). Both C₁₀Mab-31 and 31-mG_2a-f specifically reacted with endogenous CD10 in renal cancer cells, VMRC-RCW, with the dissociation constant (K_D) values of 6.3 × 10^-9 M and 1.1 × 10^-9 M, respectively, indicating high binding affinity. To further examine the anti-CD10 mAb-mediated effector functions, the antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) were examined. The 31-mG_2a-f significantly exhibited ADCC and CDC against VMRC-RCW cells in vitro. Furthermore, 31-mG_2a-f exhibited antitumor activities in mouse xenografts of VMRC-RCW cells. These results suggest that 31-mG_2a-f exerts antitumor activities against CD10-expressing renal cancers and could be a valuable therapeutic candidate for treating them.

Negative value of CD10-/CD34- immunophenotype in pediatric leukemia and development of a related cell line model for investigating drug resistance

PURPOSE

Appropriate sub-classification of leukemia according to the immunophenotypic characteristics of the malignant cells may improve therapeutic strategies. The aim of this study was to investigate the prognostic value of CD10/CD34 surface markers in pediatric acute lymphoblastic leukemia (pALL).

PATIENTS AND METHODS

A retrospective cohort study was performed in 79 children with ALL. Possible correlation between leukemia prognosis and CD10 CD34 immunophenotype was assessed using Kaplan-Meier and Cox regression analyses. A CD10- CD34- pre-B-ALL cell line was generated from a patient with resistant ALL. RN95 was characterized using light microscopy, immunophenotyping, karyotyping, and Western blotting. Drug sensitivity and resistant genes' expression profile were assessed using MTT and RT-PCR assays.

RESULTS

Kaplan-Meier analysis showed negative correlation between CD10/CD34 double negativity and patients' 2- and 5-year disease-free survival (DFS). Multivariate analysis indicated that the absence of CD10 and CD34 expression in the ALL patients was an independent negative prognostic marker for 2- and 5-year DFS. A novel cell line model, RN95, was developed with similar immunophenotype from a primary relapsed sample. Cells showed p53 positive functionality and demonstrated partial sensitivity to Vincristine, but complete resistance to Cytarabine. Overexpression of ABCB1, ABCA2, and ABCA3 was detected.

CONCLUSION

In the current study, simultaneous absence of CD10 and CD34 cell surface markers was introduced as an unfavorable prognostic factor in pediatric B-ALL. Moreover, a special cell line was established to help delineation of novel therapeutics for B-ALL drug resistance.

The Frequency of Aberrant CD7 Antigen Expression in Acute Myeloid Leukaemia Patients

Background

Aberrant phenotype expression in acute myeloid leukemia (AML) may be due to genetic defects and is associated with a poor prognosis. CD7 is the first T-cell-associated antigen to be expressed during T-lymphocyte maturation. Aberrant expression of CD7 in AML influences clinical response, remission rate, and overall survival in these patients.

Objective

To determine the frequency of aberrant CD7 expression in patients with AML.

Materials and methods

This cross-sectional study was performed over a period of 12 months from July 2020 to June 2021 in the Hematology Department, Chughtai Lab, Lahore. This study included 120 patients who were newly diagnosed with AML. The following tests were performed for included patients: complete blood count (CBC), peripheral blood smear analysis, and flow cytometric analysis using a blood sample or bone marrow aspirate. Blast cells were analyzed for aberrant CD7 expression. Calculation of the sample size was performed by using the Select Statistics calculator. All statistical analyses were performed using SPSS ver. 23 software (IBM Corp., Armonk, NY). Data were expressed as frequencies, means ± standard deviation (SD), and percentages.

Results

Of 120 patients newly diagnosed with AML, the CD7 antigen was aberrantly expressed in 36 cases (30%). Of these patients, the AML2 subtype was the most common type of AML with aberrant CD7 expression, followed by AML M4, AML M1, M3, AML M5, and AML M0, respectively.

Conclusion

In our study, aberrant CD7 expression occurred at a high frequency in acute myeloid leukemia. Thus, this marker should be added to the current flow cytometry panels.

Clinical and Prognostic Significance of Cell Sensitivity to Chemotherapy Detected in vitro on Treatment Response and Survival of Leukemia Patients

Multidrug resistance (MDR) is a major challenge in leukemia treatment. The objective of this study was to identity predictors of MDR to allow for rapid and economical assessment of the efficacy of planned antitumor therapy for leukemia patients. The study included 113 patients with acute and chronic leukemias. Prior to antitumor therapy, we measured the sensitivity of tumor cells of patients to the panel of chemotherapeutic drugs, together with MDR1 mRNA and P-glycoprotein (P-gp) expression as one of the mechanisms of MDR, and compared these data with the response to therapy. The scales for leukemia patients according to therapy response, drug sensitivity of tumor cells, MDR1 mRNA and P-gp levels, and the presence of unfavorable immunological and cytogenetic markers were introduced for subsequent correlation analysis. We show that the drug resistance of tumor cells of leukemia patients estimated in vitro at diagnosis correlates with a poor response to chemotherapy and is usually combined with aberrant and immature immunological markers, cytogenetic abnormalities, and a high expression of MDR1 mRNA and P-gp. All together, these factors indicate unfavorable prognosis and low survival of leukemia patients. Thus, the sensitivity of tumor cells to chemotherapeutic drugs measured in vitro at diagnosis may have prognostic value for individual types of leukemia.