Higher rate of central nervous system involvement by flow cytometry than morphology in acute lymphoblastic leukemia

Patterns and prognostic impact of CNS infiltration in adults with newly diagnosed acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is highly associated with central nervous system (CNS) infiltration and can be associated with higher risk of relapse. Conventional cytology (CC) is the traditional method for diagnosing CNS infiltration, although the use of immunophenotyping by flow cytometry (FC) has gained prominence in recent years due to its higher sensitivity. Also, some authors have proposed that CSF contamination by a traumatic lumbar puncture (TLP) could have a clinical impact. This retrospective study accessed the impact of CNS infiltration by CC or FC on overall survival, event-free survival, and relapse rate. In a cohort of 105 newly diagnosed ALL patients, CNS1, CNS2, and CNS3 status were found in 84%, 14%, and 2%, respectively. We found that extramedullary disease at the diagnosis, higher leukocyte counts, and higher blast percentage were associated with a positive CC. Sensitivity and specificity of CC were 53% and 98%, respectively. Three-year overall survival was 42.5%. Conversely, TLP was not associated with a positive CC nor had an impact on relapse rates. In multivariate analysis, a positive CC was associated with an increased relapse rate (HR 2.074, p = 0.037), while its detection by FC did not associate with this endpoint. Survival rates seem to be increasing over the last years by the adoption of a stratified CNS prophylaxis risk strategy. CSF contamination does not represent a major concern according to our report, as it did not increase CNS involvement or relapse rates.

Diagnostic significance of cerebrospinal fluid flow cytometry in Chinese children with B lineage acute lymphoblastic leukemia

BACKGROUND

Central nervous system leukemia (CNSL) is one of the major causes of the poor prognosis of childhood leukemia. We aimed to compare the sensitivity of cytomorphology (CM) and flow cytometry (FCM) in diagnosing CNSL, emphasizing the importance of FCM in the diagnosis process.

METHODS

One-hundred-sixty-five children with newly diagnosed B-cell Acute Lymphoblastic Leukemia (B-cell ALL) were included in this study. Cerebrospinal fluid (CSF) samples were taken for routine CSF analysis, CM analysis, and FCM examination. Computed tomography scans and/or magnetic resonance imaging were performed at diagnosis. Patients with CNS2, CNS3, and traumatic lumbar puncture (TLP) at diagnosis received two additional courses of triple intrathecal injections during induction treatment. We compared the sensitivity of FCM and CM in the diagnosis of children with CNSL.

RESULTS

One hundred and twenty-eight (77.58%) CSF samples were negative by either CM or FCM (CM-/FCM-), four (2.42%) were positive by both CM and FCM (CM+/FCM+), and thirty-three (20%) displayed a single positive finding by FCM (CM-/FCM+) (p = 0.044). By adding two intrathecal injections in the induction treatment, ten children with TLP+ had no CNS relapse, like those with TLP-. However, compared to CNS1 and TLP, the event-free survival (EFS) did not significantly improve in patients with CNS2 and CNS3. Moreover, CNSL status was associated with worse 3-year EFS (p < 0.05).

CONCLUSIONS

We have validated that FCM is more accurate in stratifying the status of the CNS compared to CM analysis. However, to improve the EFS rate of childhood leukemia, it is necessary to combine CM examination, FCM, and cranial imaging for the early diagnosis of CNSL.

Technological features of blast identification in the cerebrospinal fluid: A systematic review of flow cytometry and laboratory haematology methods

BACKGROUND

Involvement of the central nervous system (CNS) by acute leukemias (ALs) has important implications for risk stratification and disease outcome. The clinical laboratory plays an essential role in assessment of cerebrospinal fluid (CSF) specimens from patients with ALs at initial diagnosis, at the end of treatment, and when CNS involvement is clinically suspected. The two challenges for the laboratory are 1) to accurately provide a cell count of the CSF and 2) to successfully distinguish blasts from other cell types. These tasks are classically performed using manual techniques, which suffer from suboptimal turnaround time, imprecision, and inconsistent inter-operator performance. Technological innovations in flow cytometry and hematology analyzer technology have provided useful complements and/or alternatives to conventional manual techniques.

AIMS

We performed a PRISMA-compliant systematic review to address the medical literature regarding the development and current state of the art of CSF blast identification using flow cytometry and laboratory hematology technologies.

MATERIALS AND METHODS

We searched the peer reviewed medical literature using MEDLINE (PubMed interface), Web of Science, and Embase using the keywords "CSF or cerebrospinal" AND "blasts(s)".

RESULTS

108 articles were suitable for inclusion in our systematic review. These articles covered 1) clinical rationale for CSF blast identification; 2) morphology-based CSF blast identification; 3) the role of flow cytometry; 4) use of hematology analyzers for CSF blast identification; and 5) quality issues. 9 /L, which is much lower than the original machine count and platelet transfusion was warranted.

DISCUSSION

1) Clinical laboratory testing plays a central role in risk stratification and clinical management of patients with acute leukemias, most clearly in pediatric ALs; 2) studies focused on other patient populations, including adults and patients with AML are less prevalent in the literature; 3) improvements in instrumentation may provide better performance for the classification of CSF specimens.

CONCLUSION

Current challenges include: 1) more precisely characterizing the natural history of AL involvement of the CNS, 2) improvements in automated cell count technology of low cellularity specimens, 3) defining the role of flow MRD testing of CSF specimens and 4) improved recognition of specimen quality by clinicians and laboratory personnel.

Central Nervous System Prophylaxis and Treatment in Acute Leukemias

OPINION STATEMENT

Improvements in systemic therapy in the treatment of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) have improved patient outcomes and reduced the incidence of CNS relapse. However, management of patients with CNS disease remains challenging, and relapses in the CNS can be difficult to salvage. In addition to treatment with CNS-penetrant systemic therapy (high-dose methotrexate and cytarabine), intrathecal prophylaxis is indicated in all patients with ALL, however is not uniformly administered in patients with AML without high-risk features. There is a limited role for radiation treatment in CNS prophylaxis; however, radiation should be considered for consolidative treatment in patients with CNS disease, or as an option for palliation of symptoms. Re-examining the role of established treatment paradigms and investigating the role of radiation as bridging therapy in the era of cellular therapy, particularly in chemotherapy refractory patients, is warranted.

Isolated CNS Relapse in Acute Lymphoblastic Leukemia (ALL): An Experience from a Tertiary Care Center

Aims and Objectives  In this study the various parameters of acute lymphoblastic leukemia (ALL), including the clinical features, peripheral blood and bone marrow (BM) findings, immunophenotypic and cytogenetic details in ALL cases who had isolated relapse involving the central nervous system (CNS), were studied.

Patients/Materials and Methods  Duration of the study is from 2015 to 2019 in which 5 ALL cases were presented to this tertiary care center. The presenting symptoms varied from headache, fever, and distension of abdomen. These cases were either on therapy or post completion of chemotherapy. The diagnosis of CNS relapse followed after the examination of cerebrospinal fluid (CSF). Patients also underwent BM examination to rule out systemic relapse.

Results  Age of patients ranged from 7 months to 42 years. There were three female patients. Two patients had isolated CNS relapse 3.5 years after completing therapy and succumbed to their illness. Two patients had t(9;22) while one patient had t(1;14) cytogenetic abnormality at diagnosis. One patient was diagnosed as T-ALL. Treatment offered was German Multicentre ALL protocol for induction along with 10 cycles of maintenance.

Conclusion  The most common hematolymphoid malignancy in children namely ALL accounts for 75% of childhood leukemias. Complete remission rates reach up to 70 to 80%. CNS involvement is known to occur in these cases. CNS relapse may occur alone or with systemic relapse. Advances in therapeutic protocols along with CNS prophylaxis have drastically brought down the rates of CNS relapse. It is essential to maintain a high degree of suspicion so that these cases of isolated CNS relapse can be identified at the earliest and definitive therapy can be offered.

Initial Diagnostic Work-Up of Acute Leukemia: ASCO Clinical Practice Guideline Endorsement of the College of American Pathologists and American Society of Hematology Guideline

PURPOSE

The College of American Pathologists (CAP) and the American Society of Hematology (ASH) developed an evidence-based guideline on the initial diagnostic work-up of acute leukemia (AL). Because of the relevance of this topic to the ASCO membership, ASCO reviewed the guideline and applied a set of procedures and policies for endorsing clinical practice guidelines that have been developed by other professional organizations.

METHODS

The CAP-ASH guideline on initial diagnostic work-up of AL was reviewed for developmental rigor by methodologists. Then, an ASCO Endorsement Expert Panel updated the literature search and reviewed the content and recommendations.

RESULTS

The ASCO Expert Panel determined that the recommendations from the guideline, published in 2016, are clear, thorough, and based on the most relevant scientific evidence. ASCO fully endorsed the CAP-ASH guideline on initial diagnostic work-up of AL and included some discussion points according to clinical practice and updated literature.

CONCLUSION

Twenty-seven guideline statements were reviewed. Some discussion points were included to better assess CNS involvement in leukemia and to provide novel insights into molecular diagnosis and potential markers for risk stratification and target therapy. These discussions are categorized into four sections: (1) initial diagnosis focusing on basic diagnostics and determination of risk parameters, (2) molecular markers and minimal residual disease detection, (3) context of referral to another institution with expertise in the management of AL, and (4) reporting and record keeping for better outlining and follow-up discussion. Additional information is available at: www.asco.org/hematologic-malignancies-guidelines .

Pediatric acute lymphoblastic leukemia-Conquering the CNS across the choroid plexus

Despite the high prevalence of central nervous system (CNS) involvement in relapsing pediatric acute lymphoblastic leukemia (ALL), our understanding of CNS invasion is still vague. As lymphoblasts have to overcome the physiological blood-CNS barriers to enter the CNS, we investigated the cellular interactions of lymphoblasts with the choroid plexus (CP) epithelium of the blood-cerebrospinal fluid barrier (BCSFB). Both a precurser B cell ALL (pB-ALL) cell line (SD-1) and a T cell ALL (T-ALL) cell line (P12-Ishikawa) were able to actively cross the CP epithelium in a human in vitro model. We could illustrate a transcellular and (supposedly) paracellular transmigration by 3-dimensional immunofluorescence microscopy as well as electron microscopy. Chemotactic stimulation with CXCL12 during this process led to a significantly increased transmigration and blocking CXCL12/CXCR4-signaling by the CXCR4-inhibitor AMD3100 inhibited this effect. However, CXCR4 expression in primary ALL samples did not correlate to CNS disease, indicating that CXCR4-driven CNS invasion across the BCSFB might be a general property of pediatric ALL. Notably, we present a unique in vitro BCSFB model suitable to study CNS invasion of lymphoblasts in a human setting, providing the opportunity to investigate experimental variables, which may determine CNS disease childhood ALL.

Prolonged Survival of Acute Lymphoblastic Leukemia with Intrathecal Treatments for Isolated Central Nervous System Relapse

Acute lymphoblastic leukemia is commonly cured when diagnosed in the pediatric population. It portends a poorer prognosis if present in adult patients. Although adults frequently achieve complete remission, relapse rates are substantial, particularly among the elderly and high-risk populations. In the absence of prophylactic intrathecal chemotherapy, more than half of patients may develop CNS involvement or relapse, which is associated with significant risk for systemic illness. This report describes a patient with acute lymphoblastic leukemia with repeated isolated CNS relapses. This case should remind clinicians that isolated CNS disease in the absence of systemic recurrence could successfully respond to intrathecal therapy and offer patients a favorable quality of life.

Comparison of conventional cytomorphology, flow cytometry immunophenotyping, and automated cell counting of CSF for detection of CNS involvement in acute lymphoblastic leukemia

BACKGROUND AND OBJECTIVE

Cytospin conventional cytomorphology (CCC) is the standard method for detecting lymphoblasts in cerebrospinal fluid (CSF) of patients with acute lymphoblastic leukemia (ALL) and for guiding treatment decisions. We evaluated flow cytometry immunophenotyping (FCI) performance for improving detection of central nervous system (CNS) involvement in ALL.

METHODS

This prospective study included analysis of consecutive CSF samples of patients of all ages with ALL at 3 clinical stages: new diagnosis, relapse suspicion, and after relapse treatment. Manual, cytospin, automated, and FCI methods were compared and their performance statistically assessed. Using FCI as the reference method, optimal CSF cutoff cell count that better correlated with presence of lymphoblasts was established by receiver operating characteristic (ROC) curve analysis.

RESULTS

Seventy-seven CSF samples were investigated, 35 (45.4%) from newly diagnosed cases, 30 (39%) suspicion of relapse, and 12 (15.6%) after treatment for relapse. Median manual WBC count in patients with CNS involvement detected by FCI was 3.75 cells/μL (0.0-1280), and this was also the count that best correlated with CNS infiltration (sensitivity, 50.0%; specificity, 82.2%). Compared with FCI, CCC sensitivity and specificity were 28.6% and 100%. Automated CSF WBC count in patients with CNS involvement detected by FCI was 5 (0.0-1578). For automated count, optimal WBC cutoff was 4.5 cells/μL (sensitivity, 62.5%; specificity, 70.5%).

CONCLUSION

Flow cytometry immunophenotyping complements conventional cytospin analysis for detection of lymphoblasts in the CSF of ALL patients at any clinical stage.