Aberrant T-cell antigen expression in B lymphoblastic leukaemia

Synthesis of an Anti-CD7 Recombinant Immunotoxin Based on PE24 in CHO and E. coli Cell-Free Systems

Recombinant immunotoxins (RITs) are an effective class of agents for targeted therapy in cancer treatment. In this article, we demonstrate the straight-forward production and testing of an anti-CD7 RIT based on PE24 in a prokaryotic and a eukaryotic cell-free system. The prokaryotic cell-free system was derived from Escherichia coli BL21 StarTM (DE3) cells transformed with a plasmid encoding the chaperones groEL/groES. The eukaryotic cell-free system was prepared from Chinese hamster ovary (CHO) cells that leave intact endoplasmic reticulum-derived microsomes in the cell-free reaction mix from which the RIT was extracted. The investigated RIT was built by fusing an anti-CD7 single-chain variable fragment (scFv) with the toxin domain PE24, a shortened variant of Pseudomonas Exotoxin A. The RIT was produced in both cell-free systems and tested for antigen binding against CD7 and cell killing on CD7-positive Jurkat, HSB-2, and ALL-SIL cells. CD7-positive cells were effectively killed by the anti-CD7 scFv-PE24 RIT with an IC50 value of 15 pM to 40 pM for CHO and 42 pM to 156 pM for E. coli cell-free-produced RIT. CD7-negative Raji cells were unaffected by the RIT. Toxin and antibody domain alone did not show cytotoxic effects on either CD7-positive or CD7-negative cells. To our knowledge, this report describes the production of an active RIT in E. coli and CHO cell-free systems for the first time. We provide the proof-of-concept that cell-free protein synthesis allows for on-demand testing of antibody−toxin conjugate activity in a time-efficient workflow without cell lysis or purification required.

B-Lymphoblastic Leukemia With Aberrant CD5 Expression

OBJECTIVES

B-acute lymphoblastic leukemia (B-ALL) is a neoplasm of precursor lymphoid cells committed to the B-lineage. Expression of CD5 is rare in B-ALL.

METHODS

We studied the clinicopathologic, immunophenotypic, and molecular genetic features of 10 cases of B-ALL with aberrant CD5 expression, and compared with CD5-B-ALL.

RESULTS

B-ALL with aberrant CD5 expression is rare and predominantly affects men. Patients with CD5+ B-ALL had shorter median overall survival (21 vs 45 months, P = .0003). Expression of CD5 imposed a challenge in the differential diagnoses between B-ALL and other CD5+ B-cell lymphomas with blastic morphology. Dim CD20 and CD45, lack of surface immunoglobulin, expression of CD34 and TdT, negative immunostain for cyclin D1, and absence of t(11;14)(q13;q32) support a diagnosis of B-ALL.

CONCLUSIONS

CD5 expression is rare in B-ALL and associated with poor clinical outcome. CD5+ B-ALL represents a distinct entity that needs to be considered in the differential diagnoses of CD5+ B-cell lymphoproliferative disorders.

CD34 is not Expressed by Blasts in a Third of B-ALL Patients and its Negativity is associated with Aberrant Marker Expression: A Retrospective Analysis

BACKGROUND

CD34 antigen is expressed by early hematopoietic progenitor cells and acute leukemia cells. Its expression is associated with good prognosis in acute myeloid leukemia. Literature is sparse on its prognostic significance in B- acute lymphoblastic leukemia (B-ALL) especially from India. Hence the present study was undertaken to analyse the frequency of CD34 expression in B-ALL in Indian patients and determine its prognostic significance by associating with other prognostic markers and aberrant antigen expression.

METHODS

Seventy-five B-ALL patients diagnosed by flow cytometry over a period of 3½ year were studied. Correlation of CD34 expression was studied with gender, age, total leucocyte count (TLC), French-American-British (FAB) morphological type, immuno-phenotypic markers, cytogenetics and minimal residual disease. Differences between groups were evaluated using Student's T-test for quantitative data and Chi-square test/Fishers exact T-test for qualitative variables. P value.

Precursor B-lineage acute lymphoblastic leukemia patients with aberrant natural killer cell and T cell - lineage antigen expression: experience from a tertiary cancer care center

Introduction

Flow cytometric immunophenotyping (FCI) plays a major role in diagnosing hematologic malignancies. In patients diagnosed with precursor B-lineage acute lymphoblastic leukemia (B-ALL), expression of certain non-lineage/cross lineage antigens is of prognostic and cytogenetic relevance. There is a paucity of studies that have comprehensively analyzed the clinical and laboratory profiles of B-ALL patients showing aberrant T/natural killer (NK) cell antigen expression.

Materials and methods

This is a prospective study where 152 consecutive B-ALL patients were analyzed for aberrant expression of T/NK cell antigens (CD1a, CD5, CD4, CD7, CD8 and CD56) by FCI. The clinical and laboratory profile of these T/NK-cell antigen-expressing B-ALL patients was statistically analyzed against conventional B-ALL patients.

Results

In our B-ALL cohort, CD5, CD7 and CD56 expression were observed in one, six and nine patients, respectively. CD56-expressing B-ALL patients were predominantly children (89%) and presented as standard clinical risk (p = 0.010) disease with frequent ETV6-RUNX1 fusion (p = 0.021) positivity. On the contrary, CD7-expressing B-ALL patients were adolescent-young adult/adult-age skewed (83%) and had an adverse cytogenetic profile (p = 0.001), especially for the frequent presence of BCR-ABL1 fusion (p = 0.004) and KMT2A rearrangement (p = 0.045). CD7-expressing B-ALL patients had inferior event-free survival (p = 0.040) than their CD56-expressing counterparts, but there was no significant difference in the overall survival (p = 0.317).

Conclusion

In comparison to conventional B-ALL patients, there are significant differences in the age, cytogenetic profile and event-free survival of T/NK-cell antigen-expressing B-ALL patients.

Characterization of Immunophenotypic Aberrancies in Adult and Childhood Acute Lymphoblastic Leukemia: Lessons from Regional Variation

Background & Objective:

Although the antigen expression patterns of acute lymphoblastic leukemia (ALL) are well known, this study attempted to evaluate commonly used immune markers for immunophenotyping of acute leukemia to set the minimum of necessary diagnostic panels by flow cytometry.

Methods:

This study evaluated 89 patients referred from all over the country to the Iranian Blood Transfusion Organization (IBTO) in Tehran from 2013 to 2015. We compared the immunophenotype patterns of childhood and adult ALLs including 69(77.5%) B-cell lymphoblastic lymphoma (B-LBL), 2(2.2%) Burkitt’s lymphoma (BL), and 18(20.2%) T-cell lymphoblastic lymphoma (T-LBL) cases using flowcytometry with broad antibody panel.

Results:

CD19 and CD79a were the most frequent markers for B-LBL while CD7 was the most sensitive marker in T-LBL; the frequency of CD7, CD3, and CD5 antigens were 100%, 38.9%, and 88.9%, respectively. TdT+/CD34+ was significantly higher in adult B-LBLs than children, which indicates blast cells are more immature in adults. In addition, CD10 and cCD79a were significantly higher in children with B-LBL like as CD5 and CD8 in children with T-LBL. Aberrant phenotypes including CD13, CD33, CD7, and CD117 were found in 7(10.1%) cases of B-LBL. These phenotypes were CD117, HLA-DR, and CD33 in 7(38/9%) cases of T-LBL. Expression of CD117 aberrant myeloid antigen was significantly more associated with T-LBL than with B-lineage ALL.

Conclusion:

Significant differences were observed in antigen-expression patterns between adult and childhood ALLs. Further studies are needed to correlate specific markers with recurrent cytogenetic abnormalities and prognosis with therapeutic response.

Relative safety of various spermatogenic stem cell purification methods for application in spermatogenic stem cell transplantation

Background

Spermatogonial stem cell (SSC) transplantation technology as a promising option for male fertility preservation has received increasing attention, along with efficient SSC purification technology as a necessary technical support; however, the safety of such application in patients with tumors remains controversial.

Methods

In this study, we used a green fluorescent protein mouse xenograft model of B cell acute lymphocytic leukemia. We isolated and purified SSCs from the testicular tissue of model mice using density gradient centrifugation, immune cell magnetic bead separation, and flow cytometry. The purified SSCs were transplanted into convoluted seminiferous tubules of the nude mice and C57BL/6 male mice subjected to busulfan. The development and proliferation of SSCs in the recipient testis were periodically tested, along with whether B cell acute lymphocytic leukemia was induced following SSC implantation. The genetic characteristics of the offspring obtained from natural mating were also observed.

Results

In testicular leukemia model mice, a large number of BALL cells infiltrated into the seminiferous tubule, spermatogenic cells, and sperm cells in the testis tissue decreased. After spermatogonial stem cell transplantation, the transplanted SSCs purified by immunomagnetic beads and flow cytometry methods colonized and proliferated extensively in the basement of the seminiferous tubules of mice; a large number of spermatogenic cells and sperm were found in recipient testicular tissue after 12 weeks of SSC transplantation. In leukemia detection in nude mice after transplantation in the three SSC purification groups, a large number of BALL cells could be detected in the blood of recipient mice 2–3 weeks after transplantation in the density gradient centrifugation group, but not in the blood of the flow cytometry sorting group and the immunomagnetic bead group after 16 weeks of observation.

Conclusions

In this study, we confirmed that immunomagnetic beads and flow cytometry methods of purifying SSCs from the testicular tissue of the testicular leukemia mouse model could be safely applied to the SSC transplantation technology without concomitant tumor implantation. The results thus provide a theoretical basis for the application of tumor SSC cryopreservation for fertility preservation in patients with tumors.

Prognostic significance of aberrant CD5 expression in B-cell leukemia

Aberrant expression of CD5 (as a T-cell marker) is seen in some leukemia and lymphoma of B lineage origin. Given that the signaling resulting from the expression of this marker plays an essential role in the development of leukemia and lymphoma, evaluating the expression of this marker is of paramount importance. Therefore, our goal in this study was to investigate the prognostic importance of CD5 expression in B-cell leukemia and lymphoma. We evaluate CD5 expression in normal and leukemic B-cells by identifying relevant literature through a PubMed search (1998-2018) of English language papers using the terms: ‘CD5,’ ‘B-cell,’ ‘Leukemia,’ and ‘Lymphoma.’ We are doing this thorough comparison of results from CD5 positive and negative cases to make a correct decision about prognostic importance of CD5 expression in these malignancies. In a number of B-cell malignancies, CD5 is expressed in varying degrees. Due to the different origins and characteristics of these malignancies, the results of CD5 expression evaluations are heterogeneous and impossible to generalize. However, CD5 expression is sometimes associated with clinicopathologic findings, more invasive clinical course, and even resistance to treatment (specifically in DLBCL) among CD5- positive patients, which appears to be a function of CD5 signaling and its downstream factors such as STAT3. Depending on the type of malignancy, CD5 expression is associated with good or bad prognosis, which can be used as an auxiliary prognostic factor to assess the clinical course of B-cell malignancies. Moreover, the difference in expression levels of CD5 in a variety of B-cell malignancies allows for differential diagnosis of these malignancies, which can be helpful when diagnosis is difficult.

MLL rearranged acute lymphoblastic leukaemia presenting as a maxillary sinus mass with a discordant immunophenotypic profile from the bone marrow

We describe an unusual case of pre-B lymphoblastic leukaemia presenting with a unilateral maxillary sinus mass in which biopsies of the primary mass and the bone marrow demonstrated conflicting immunophenotyping results. The extramedullary mass was consistent with a precursor B-cell malignancy, while the bone marrow was initially reported as a possible mature B-cell malignancy. The treatments for the two are fundamentally different, which necessitated a delay in the initiation of his chemotherapy until a clear diagnosis was made. Mixed lineage leukaemia gene rearrangement was confirmed by fluorescence in situ hybridisation in both the primary mass and bone marrow, which unified the diagnosis as pre-B acute lymphoblastic leukaemia given the common cytogenetic feature.

CD5 positive B-ALL, a uniquely aggressive subcategory of B-ALL? A case report and brief review of the literature

CD5 antigen expression in B-cell acute lymphoblastic leukemia (B-ALL) is exceptionally rare. There are six detailed case reports in the literature, with only 16 cases described. Case series analyzing the frequency of aberrant B-ALL immunophenotypes suggest that this variant may occur in as little as 2-4.5% of all B-ALL cases, with one series having no CD5⁺ positive cases. Herein we report a case of CD5⁺ B-ALL in a 15-year-old female, and review the previously reported cases. As limited information is available, more data from prospective clinical trials are required to determine whether CD5 positivity portends a poorer prognosis.

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

Background and Objective

Aberrant phenotype is a phenomenon of abnormal expression or loss of expression of cell specific lineage marker not associated with specific cell type. Aberrant phenotype expression due to genetic defects may be associated with unfavorable outcome. It can be used to determine minimal residual disease status. The purpose of the study was to find out the occurrence of aberrant phenotypes in leukemia/lymphoma patients.

Methods

One milliliter peripheral blood or bone marrow samples were analyzed on FACS Calibur flowcytometer. The cells were lysed and stained following standard protocol. Data was acquired and analyzed by CellQuest-Pro software. The Antigenic expression was rated as positive when the percentage of positive blast cells was ≥ 20%. In that manner, aberrant phenotype was considered positive when 20% of blast cells show expression of markers.

Results

Of a total 145 cases analyzed, 26 were acute myeloid leukemia, 71 of acute lymphoblastic leukaemia, 48 were of Chronic Lymphoid leukemia on the basis of morphological features and confirmed by flow cytometry. Overall, 19% (28) cases showed aberrant expression of antigens. In 32% (9/28) AML patients, CD5, CD7, CD64dim, CD10, CD117, CD25 and TdT were expressed while in 25% (7/28) ALL patients CD33, CD13, HLA-DR and CD3 were detected. Among chronic leukemia, all aberrant expressions were seen in cases of B-CLL (10/28) only; with CD11c, CD3 and CD10 as the aberrantly expressed markers.

Conclusion

Variability in aberrant phenotype expression was observed in different types of acute and chronic leukemia patients with no prognostic implications on treatment response.

Prognostic impact of CD200 and CD56 expression in adult acute lymphoblastic leukemia patients

BACKGROUND

The aim of the study is to determine the prognostic relevance of CD200/ CD56 expression in adult acute lymphoblastic leukemia patients.

METHODS

The expression of CD200 and CD56 by blast cells was assessed by flow cytometry before the start of chemotherapy in 70 B-ALL patients.

RESULTS

Positive expression of CD200 was detected in forty-six patients (66%) and CD56 was detected in 7 patients (10%) out of 70 patients, respectively. Only three patients (4.3%) had co-expression for CD200⁺ and CD56⁺. Splenomegaly and thrombocytopenia were frequently observed more in CD200⁺ patients. Increased frequency of CD34⁺ was associated with CD200⁺and CD56⁺ patients. The CD200⁺ and CD56⁺ subgroups of B-ALL patients had inferior OS and disease free survival compared to CD 200^- and CD 56^- patients.

CONCLUSIONS

CD200⁺ and/or CD56⁺ positive expression in B-ALL patients at diagnosis is a poor prognostic biomarker. Identification of CD200⁺ and CD56⁺ expression at diagnosis is recommended for a better stratification of adult B-ALL patients.

Prognostic impact of CD200 and CD56 expression in pediatric B-cell acute lymphoblastic leukemia patients

This study aimed to determine the prognostic impact of CD200 and CD56 expression in pediatric B cell acute lymphoblastic leukemia (B-ALL) patients, both of which have been implicated in immune tolerance and previously suggested as independent risk factors. CD200 has a central role in immune tolerance that protects stem cells and other critical tissues from immune damage. The expression of CD200/CD56 in leukemic blasts were assessed in leukemic blasts before chemotherapy in 43 bone marrow (BM) and/or peripheral blood (PB) samples by flow cytometry. Twenty eight of 43 B-ALL cases (65%) showed CD200 positive expression, 5 of 43 cases (11.6%) showed CD56 expression, and only 2 patients (4.7%) expressed both CD200 and CD56. Patients with CD200⁺ and CD56⁺ were significantly associated with lower platelet count; less tendency for induction of remission response as compared to negative ones (p = .01 for both). The overall survival (OS) and DFS were significantly shorter in CD200⁺ and CD56⁺ cases as compared to those with CD200^- and CD56^- expression. In conclusion, CD200 and/or CD56 positive expression in B-ALL at diagnosis suggest a poor prognosis and may be associated with biological aggressiveness.

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.

CD7 aberrant expression led to a lineage switch at relapsed childhood acute pre-B lymphoblastic leukemia

Immunophenotypic changes and lineage switch between diagnosis and relapse in acute lymphoblastic leukemia are uncommon and accompanied by poor outcomes. In this report, a 12-year-old boy with diagnosis of pre-B ALL with an aberrant expression of CD 7 is described. Patient was treated with the ALL-BFM 2000 protocol and suffered an episode of relapse with a lineage switch from pre-B ALL to T cell ALL. This report concludes that presence of aberrant expression of CD7 at diagnosis of pre-B ALL can have prognostic value of lineage switch to T cell ALL at relapse.

CD5 Positive B Lymphoblastic Leukemia: Report of a Case with Review of Literature

We report a rare CD5 positive B cell acute lymphoblastic leukemia (B-ALL) with a review of the clinopathological features and prognosis of previously reported cases in the literature. The aberrant expression of CD 5 antigen is uncommon in B-ALL; the morphological differential diagnosis includes blastic mantle cell lymphoma, denovo CD5(+) diffuse large B cell lymphoma and secondary diffuse large cell lymphoma/Richter's transformation. CD5(+) B cell ALL is commonly reported in younger patients (<18 years). Though the expression of T cell antigens is reported to have poor prognosis, the experience with CD5(+) B-ALL is limited to draw any firm conclusion regarding its prognosis.

CD7 promotes extramedullary involvement of the B-cell acute lymphoblastic leukemia line Tanoue by enhancing integrin β2-dependent cell adhesiveness

Extramedullary involvement (EMI) is a factor that defines prognosis of acute lymphoblastic leukemia; however, the molecular mechanism(s) remain elusive. Here, we show that CD7 promotes EMI of the human B-cell acute lymphoblastic leukemia cell line Tanoue. The Tanoue cell line expressing firefly luciferase, Luc-Tanoue, was transplanted into non-obese diabetic/severe combined immunodeficient mice, and cells infiltrated into the brain were cultured ex vivo. This process was repeated 4 times to obtain the highly invasive line Luc-Tanoue-F4. Comparison of the global gene expression signatures of Luc-Tanoue-F4 and Luc-Tanoue indicated that the CD7 gene showed the largest increase in expression among EMI-related genes in Luc-Tanoue-F4 cells. Overexpression of CD7 in Tanoue enhanced cell invasiveness. Among cell migration, proliferation, adhesion and protease activity, only cell adhesiveness showed enhancement in Luc-Tanoue-F4. Expression of the intracellular domain, but not the extracellular domain, of CD7 enhanced cell adhesiveness. Luc-Tanoue-F4 showed a higher level of integrin β2 expression; overexpression of CD7 induced the expression of integrin β2 in Luc-Tanoue. These results show that CD7 induces integrin β2 and enhances cell adhesiveness and invasiveness in Tanoue cells. This study highlights the role of the CD7/integrin β2 axis as a critical pathway in the process of EMI of human B-cell acute lymphoblastic leukemia.

Aberrant Immunophenotypic Expression of CD5 in a Case of B Acute Lymphoblastic Leukemia: A Case Report

Aberrant expression of CD5 has rarely been reported in B cell lineage acute lymphoblastic leukemia (B-ALL). We report the rare immunophenotypic expression of CD5 in a 20-year-old male who was diagnosed to have B-ALL on bone marrow examination. Cytogenetic analysis revealed a mosaic supernumerary marker chromosome. The patient died due to acute pancreatitis after admission. CD5 positive B-ALL may represent a distinct clinicopathologic subcategory of B-ALL with an aggressive clinical course.