Applications of Flow Cytometry and Immunohistochemistry to Diagnostic Hematopathology

Validation of Artificial Intelligence (AI)-Assisted Flow Cytometry Analysis for Immunological Disorders

Flow cytometry is a vital diagnostic tool for hematologic and immunologic disorders, but manual analysis is prone to variation and time-consuming. Over the last decade, artificial intelligence (AI) has advanced significantly. In this study, we developed and validated an AI-assisted flow cytometry workflow using 379 clinical cases from 2021, employing a 3-tube, 10-color flow panel with 21 antibodies for primary immunodeficiency diseases and related immunological disorders. The AI software (DeepFlow™, version 2.1.1) is fully automated, reducing analysis time to under 5 min per case. It interacts with hematopatholoists for manual gating adjustments when necessary. Using proprietary multidimensional density-phenotype coupling algorithm, the AI model accurately classifies and enumerates T, B, and NK cells, along with important immune cell subsets, including CD4+ helper T cells, CD8+ cytotoxic T cells, CD3+/CD4-/CD8- double-negative T cells, and class-switched or non-switched B cells. Compared to manual analysis with hematopathologist-determined lymphocyte subset percentages as the gold standard, the AI model exhibited a strong correlation (r > 0.9) across lymphocyte subsets. This study highlights the accuracy and efficiency of AI-assisted flow cytometry in diagnosing immunological disorders in a clinical setting, providing a transformative approach within a concise timeframe.

Review of flow cytometry as a tool for cell and gene therapy

Quality control testing and analytics are critical for the development and manufacture of cell and gene therapies, and flow cytometry is a key quality control and analytical assay that is used extensively. However, the technical scope of characterization assays and safety assays must keep apace as the breadth of cell therapy products continues to expand beyond hematopoietic stem cell products into producing novel adoptive immune therapies and gene therapy products.  Flow cytometry services are uniquely positioned to support the evolving needs of cell therapy facilities, as access to flow cytometers, new antibody clones and improved fluorochrome reagents becomes more egalitarian. This report will outline the features, logistics, limitations and the current state of flow cytometry within the context of cellular therapy.

Sulfoxaflor insecticide exhibits cytotoxic or genotoxic and apoptotic potential via oxidative stress-associated DNA damage in human blood lymphocytes cell cultures

The need for foodstuff that emerged with the rapidly increasing world population made fertilizers and pesticides inevitable to obtain maximum efficiency from existing agricultural areas. Sulfoxaflor is currently the only member of the new sulfoximine insecticide subclass of nicotinic acetylcholine receptor agonists. In the study, it was aimed to determine the in vitro genetic, oxidative damage potential, genotoxic and apoptotic effects of three different concentrations (10 µg/mL, 20 µg/mL and 40 µg/mL) of sulfoxaflor insecticide in the cultures of blood lymphocytes. In this study, the single-cell gel electrophoresis (comet), Cytokinesis Block Micronuclues Test (MN test), flow cytometry and measurement of Catalase (CAT) enzyme activity were used to determine genotoxic, apoptotic effects and oxidative damage potential, respectively. It found that there is a decrease in CPBI values and Live cell numbers. It was observed an increase in late apoptotic and necrotic cell numbers, Micronucleus frequency, and Comet analysis parameters (GDI and DCP). There is a significant difference between negative control and all concentration of insecticide for Cytokinesis Block Proliferation Index (CBPI) values and late apoptotic, necrotic and viable cell counts. An increase in CAT enzyme levels was observed at 10 and 20 µg/mL concentrations compared to control., It is found that CAT enzyme activity was inhibited at concentrations of 40 µg/mL. This study is crucial as it is the first study to investigate the impact of Sulfoxaflor insecticide on peripheral blood lymphocyte cells. The genotoxic, oxidative damage, and apoptotic effects of Sulfoxafluor insecticide on the results obtained and its adverse effects on other organisms raise concerns about health and safety.

Cell projection plots: A novel visualization of bone marrow aspirate cytology

Deep models for cell detection have demonstrated utility in bone marrow cytology, showing impressive results in terms of accuracy and computational efficiency. However, these models have yet to be implemented in the clinical diagnostic workflow. Additionally, the metrics used to evaluate cell detection models are not necessarily aligned with clinical goals and targets. In order to address these issues, we introduce novel, automatically generated visual summaries of bone marrow aspirate specimens called cell projection plots (CPPs). Encompassing relevant biological patterns such as neutrophil maturation, CPPs provide a compact summary of bone marrow aspirate cytology. To gauge clinical relevance, CPPs were inspected by 3 hematopathologists, who decided whether corresponding diagnostic synopses matched with generated CPPs. Pathologists were able to match CPPs to the correct synopsis with a matching degree of 85%. Our finding suggests CPPs can represent clinically relevant information from bone marrow aspirate specimens and may be used to efficiently summarize bone marrow cytology to pathologists. CPPs could be a step toward human-centered implementation of artificial intelligence (AI) in hematopathology, and a basis for a diagnostic-support tool for digital pathology workflows.

Radiomics for characterization of the glioma immune microenvironment

Increasing evidence suggests that besides mutational and molecular alterations, the immune component of the tumor microenvironment also substantially impacts tumor behavior and complicates treatment response, particularly to immunotherapies. Although the standard method for characterizing tumor immune profile is through performing integrated genomic analysis on tissue biopsies, the dynamic change in the immune composition of the tumor microenvironment makes this approach not feasible, especially for brain tumors. Radiomics is a rapidly growing field that uses advanced imaging techniques and computational algorithms to extract numerous quantitative features from medical images. Recent advances in machine learning methods are facilitating biological validation of radiomic signatures and allowing them to "mine" for a variety of significant correlates, including genetic, immunologic, and histologic data. Radiomics has the potential to be used as a non-invasive approach to predict the presence and density of immune cells within the microenvironment, as well as to assess the expression of immune-related genes and pathways. This information can be essential for patient stratification, informing treatment decisions and predicting patients' response to immunotherapies. This is particularly important for tumors with difficult surgical access such as gliomas. In this review, we provide an overview of the glioma microenvironment, describe novel approaches for clustering patients based on their tumor immune profile, and discuss the latest progress on utilization of radiomics for immune profiling of glioma based on current literature.

Distinct cellular composition between normal surgical margins and tumor tissues in oral squamous cell carcinoma

BACKGROUND

Adequate resection of normal surgical margins is important. However, the clear distinction between the normal surgical margins and tumor tissues is still difficult.

OBJECTIVE

Here, this study analyzed the variety of cell types in tumors and the normal surgical margins using a computational approach.

METHODS

The composition of cell types was compared between the two tissues by statistical and machine learning approaches.

RESULTS

The results showed the distinct cellular composition between tumor-adjacent and tumor tissues. In particular, endothelial cells were highly represented and macrophages were underrepresented at the normal surgical margin. Moreover, the normal surgical margin and tumor tissues could be discriminated using a machine learning algorithm.

CONCLUSION

The results will help to understand cellular differences between normal surgical margins and tumor tissues and to provide potentials for tumor detection and treatment.

Incorporation of ultrasound-guided core biopsy with flow cytometry to assist the diagnosis of cervical lymphoma

PURPOSE

The main purpose of surgery for cervical lymphoma is only for tissue sampling. To establish a patient-friendly diagnostic approach, we investigated the feasibility of ultrasound-guided core biopsy with flow cytometry in the patients with suspected cervical lymphoma.

METHODS

We prospectively recruited patients with suspected cervical lymphoma from Nov 2017 till Jan 2021 in a referral medical center and performed retrospective interpretation of the prospectively acquired data. Ultrasound-guided core biopsy as the tissue sampling approach for the targeted lesions was performed in all patients. The ultrasound-guided core biopsy samples were analyzed by immunohistochemical stains and flow cytometry. The sample quality and the rate of definite and decisive diagnosis obtained by ultrasound-guided core biopsy alone and ultrasound-guided core biopsy with flow cytometry were evaluated.

RESULTS

Total 81 consecutive patients were recruited for analysis. All ultrasound-guided core biopsy samples were qualified for analysis of pathology and flow cytometry. Pathologically, the diagnoses were definite and compatible with their flow cytometry results in 70 patients (86.42%). Either newly-diagnosed or recurrent cervical lymphoma/lymphoproliferative disorders with histologic transformation could be diagnosed by ultrasound-guided core biopsy with flow cytometry. Nine of the 11 patients with pathologically indefinite diagnosis became clinically decisive when flow cytometry was incorporated into the process, which improved the rate of decisive diagnosis to 98.77% (Odds ratio [95% CI]: 6.21 [1.28, 58.96]).

CONCLUSION

Ultrasound-guided core biopsy combined with flow cytometry is suggested to serve as the first-line and patient-friendly diagnostic approach for the patients with suspected cervical lymphoma.

Amyloid Deposits and Fibrosis on Left Ventricular Endomyocardial Biopsy Correlate With Extracellular Volume in Cardiac Amyloidosis

Background The relative contribution of amyloid and fibrosis to extracellular volume expansion in cardiac amyloidosis (CA) has never been defined. Methods and Results We included all patients diagnosed with amyloid light-chain (AL) or transthyretin cardiac amyloidosis at a tertiary referral center between 2014 to 2020 and undergoing a left ventricular endomyocardial biopsy. Patients (n=37) were more often men (92%), with a median age of 72 years (interquartile range, 68-81). Lambda-positive AL was found in 14 of 19 AL cases (38%) and kappa-positive AL in 5 of 19 (14%), while transthyretin was detected in the other 18 cases (48%). Amyloid deposits accounted for 15% of tissue sample area (10%-30%), without significant differences between AL and transthyretin amyloidosis. All patients displayed myocardial fibrosis, with a median extent of 15% of tissue samples (10%-23%; range, 5%-60%), in the absence of spatial overlap with amyloid deposits. Interstitial fibrosis was often associated with mild and focal subendocardial fibrosis. The extent of fibrosis or the combination of amyloidosis and fibrosis did not differ significantly between transthyretin amyloidosis and AL subgroups. In 20 patients with myocardial T1 mapping at cardiac magnetic resonance, the combined amyloid and fibrosis extent displayed a modest correlation with extracellular volume (r=0.661, P=0.001). The combined amyloid and fibrosis extent correlated with high-sensitivity troponin T (P=0.035) and N-terminal pro-B-type natriuretic peptide (P=0.002) serum levels. Conclusions Extracellular spaces in cardiac amyloidosis are enlarged to a similar extent by amyloid deposits and fibrotic tissue. Their combination can better explain the increased extracellular volume at cardiac magnetic resonance and circulating biomarkers than amyloid extent alone.

O-GlcNAcylation in early stages of chronic lymphocytic leukemia; protocol development for flow cytometry

BACKGROUND

Recent studies proved that metabolic changes in malignant disorders have an impact on protein glycosylation, however, only a few attempts have been made so far to use O-GlcNAc analysis as a prognostic tool. Glucose metabolism is reported to be altered in hematological malignancies thus, we hypothesized that monitoring intracellular O-GlcNAc levels in Rai stage 0-I (Binet A) CLL patients could give deeper insights regarding subtle metabolic changes of progression which are not completely detected by the routine follow-up procedures.

OBJECTIVE

In this proof of concept study we established a flow cytometric detection method for the assessment of O-GlcNAcylation as a possible prognostic marker in CLL malignancy which was supported by fluorescence microscopy.

METHODS

Healthy volunteers and CLL patients were recruited for this study. Lymphocytes were isolated, fixed and permeabilised by various methods to find the optimal experimental condition for O-GlcNAc detection by flow cytometry. O-GlcNAc levels were measured and compared to lymphocyte count and various blood parameters including plasma glucose level.

RESULTS

The protocol we developed includes red blood cell lysis, formalin fixation, 0.1% Tween 20 permeabilisation and employs standardized cell number per sample and unstained controls. We have found significant correlation between O-GlcNAc levels and WBC (R2= 0.8535, p< 0.0029) and lymphocyte count (R2= 0.9225, p< 0.0006) in CLL patients. Interestingly, there was no such correlation in healthy individuals (R2= 0.05664 for O-GlcNAc vs WBC and R2= 0.04379 for O-GlcNAc vs lymphocytes).

CONCLUSION

Analyzing O-GlcNAc changes in malignant disorders, specifically in malignant hematologic diseases such as CLL, could be a useful tool to monitor the progression of the disease.

Multicentric MFI30 study: Standardization of flow cytometry analysis of CD30 expression in non-Hodgkin lymphoma

CD30 transmembrane receptor, a member of the tumor necrosis factor receptor family, is expressed in different lymphomas. Brentuximab vedotin (BV), a CD30 monoclonal antibody (Ab)-drug conjugate, is effective in CD30-positive lymphomas. However, the response to BV is not always correlated to CD30 expression detected by immunohistochemistry (IHC). The objectives of this study were to standardize and evaluate CD30 intensity by flow cytometry (FCM) in non-Hodgkin's lymphomas. Twelve centers analyzed 161 cases on standardized cytometers using normalized median fluorescence intensity (nMFI30) of three different Abs, of which one clone can recognize the same epitope as BV. FCM distinguished four groups of cases: negative group (n = 110) which showed no expression with the three clones; high positive group (n = 13) which gave nMFI30 > 5% with all tested clones; dim positive group (n = 17) which showed nMFI30 > 1% with all tested clones and <5% for at least one; discordant group (n = 21) with positive and negative expression of the different clones. In consistency with the literature, CD30 was positive in all anaplastic large cell lymphomas, in some diffuse large B-cell lymphomas (DLBCL), and in other rare lymphomas. FCM results were concordant with those of IHC in 77% of cases. Discrepancies could be explained by clones-related differences, microenvironment, or intracytoplasmic staining. Interestingly, FCM was more sensitive than IHC in 11% of cases, especially in DLBCL. Multicenter standardized FCM of specific CD30 could improve case detection and extend the treatment of BV to various CD30-positive lymphomas.

Practical Approaches on CD30 Detection and Reporting in Lymphoma Diagnosis

While our understanding of the biology of CD30 in lymphoma continues to evolve, our need to detect and measure its expression at the protein level remains critically important for diagnosis and patient care. In addition to its diagnostic and prognostic utility, CD30 has emerged as a vehicle for drug targeting through the antibody-drug conjugate brentuximab-vedotin (BV). Given the numerous ways that CD30 is utilized and its emergence as a predictive/prognostic biomarker, pathologists must come to a general consensus on the best reporting structure and methodology to ensure appropriate patient care. In this manuscript, we review the indications for testing, various modalities for testing, technical challenges, pitfalls, and potential standards of reporting. The following questions will try to be addressed in the current review article: What defines a "POSITIVE" level of CD30 expression?; How do we evaluate and report CD30 expression?; What are the caveats in the evaluation of CD30 expression?

Current applications of molecular testing on body cavity fluids

INTRODUCTION

Effusion cytology has a high sensitivity for the diagnosis of malignancy and provides abundant material for molecular testing. Effusion draining is a minimally invasive procedure with few complications.

MATERIALS AND METHODS

We performed a review of publications regarding the use of molecular testing in serous effusions.

RESULTS

In diagnostics, BAP-1 IHC and CDKN2A FISH are powerful tools for the diagnosis of malignant mesothelioma. FISH, PCR, and EBER-ISH work well in lymphomas. RT-PCR may enhance the diagnosis of secondary epithelial malignancies. In theranostics, molecular testing on serous effusions is widely reported for the detection of alterations in genes related to lung carcinomas, such as EGFR, ALK, ROS1, and BRAF. PD-L1 expression testing by immunohistochemistry (IHC) also seems to be viable in this type of sample. HER2 FISH and IHC provide actionable results in the context of breast malignancies. Results in serous effusions seem to be equivalent to tissue biopsies for most applications and across different molecular techniques. The most interesting technology is next-generation sequencing (NGS), given its ability to sequence multiple genes on a single sample and the decreasing costs that have closely followed increasing throughputs. Cell-free DNA from effusion supernatants might be the most promising area for future research, showing superiority to serum and even to cell-block samples in limited studies.

CONCLUSIONS

Molecular tests are viable in serous effusion specimens when sufficient material is available. Given the rising importance of molecular testing we expect this to be an active field of research in the near future.

CD163 is a predictive biomarker for prognosis of classical Hodgkin's lymphoma in Saudi patients

Hodgkin's lymphoma (HL) is a hematological malignancy characterized by a minority of neoplastic cells outnumbered by tumor-associated macrophages (TAMs). The overexpression of the CD163 antigen by TAMs is considered to be a significant predictive biomarker for risk stratification. This is likely caused by a genetic single-nucleotide polymorphism (SNP) at the gene promoter. The aim of the present retrospective case-control study was to establish a gene expression profile of a specific biomarker for classical HL (CHL) in order to predict the outcome and survival of CHL patients in Saudi Arabia. The protein expression of CD163 on TAMs was studied using immunohistochemistry (IHC). A prognosis index was calculated for the CD163 protein to assess the risk stratification of CHL. Genotyping of selected SNPs of this antigen was performed for 100 CHL cases and controls. The analysis revealed that the CD163 protein expression level was significantly correlated with disease relapse (DR) and overall survival (OS). In addition, the CD163 index threshold (15.0) was found to be significantly correlated with the relapse rate. Among the studied CD163 SNPs, rs75608120 exhibited a significant correlation with the DR rate of CHL patients, but not with OS. The findings of the present study confirmed that CD163 is a specific marker for TAMs, and its overexpression by TAMs is significantly associated with relapse and reduced survival post-therapy. In addition, a new methodology of indexing CD163 protein expression for HL risk stratification was proposed. Thus, the present study identified a specific predictive molecular and antigenic biomarker for CHL prognosis.

Chronic Inflammation in Response to Injury: Retention of Myeloid Cells in Injured Tissue Is Driven by Myeloid Cell Intrinsic Factors

Chronic inflammation is a hallmark of impaired healing in a plethora of tissues, including skin, and is associated with aging and diseases such as diabetes. Diabetic chronic skin wounds are characterized by excessive myeloid cells that display an aberrant phenotype, partially mediated by stable intrinsic changes induced during hematopoietic development. However, the relative contribution of myeloid cell-intrinsic factors to chronic inflammation versus aberrant signals from the local environmental was unknown. Moreover, identification of myeloid cell intrinsic factors that contribute to chronic inflammation in diabetic wounds remained elusive. Here we show that Gr-1⁺CD11b⁺ myeloid cells are retained specifically within the presumptive granulation tissue region of the wound at a higher density in diabetic mice and associate with endothelial cells at the site of injury with a higher frequency than in nondiabetic mice. Adoptive transfer of myeloid cells demonstrated that aberrant wound retention is due to myeloid cell intrinsic factors and not the local environment. RNA sequencing of bone marrow and wound-derived myeloid cells identified Selplg as a myeloid cell intrinsic factor that is deregulated in chronic wounds. In vivo blockade of this protein significantly accelerated wound healing in diabetic mice and may be a potential therapeutic target in chronic wounds and other chronic inflammatory diseases.

Acute monocytic leukemia diagnosed by flow cytometry includes acute myeloid leukemias with weakly or faintly positive non-specific esterase staining

A diagnosis of acute monocytic leukemia (AML-M5) based on α-naphthyl butyrate esterase (α-NB) staining has some problems, because AML-M5 leukemic cells often show weak or faint positivity on α-NB staining. In these situations, some cases of AML-M5 tend to be misdiagnosed as AML-M0. Therefore, we evaluated the significance of weak or faint α-NB staining in AML-M5 diagnosed by flow cytometry (FCM). Nineteen AML cases in which leukemic cells were negative for naphthol AS-D chloroacetate esterase staining were studied. For FCM, we defined leukemic cells as having a monocytic nature when more than 10% of the leukemic cells were positive for at least one of the following antigens: CD4, CD11c, CD14, and CD64. The monocytic nature determined by FCM was consistent with positive or weak positivity on α-NB staining. Five of 6 cases in which leukemic cells exhibited faint positivity for α-NB staining could be diagnosed as AML-M5 by FCM, while negative α-NB staining was consistent with a diagnosis of AML-M0. These results suggest that AML-M5 should be taken into consideration even when leukemic cells are faintly positive for α-NB staining.

Methods and Study Designs for Characterizing the Pharmacokinetics and Pharmacodynamics of Carrier-Mediated Agents

Major advances in carrier-mediated agents (CMAs), which include nanoparticles, nanosomes, and conjugates, have revolutionized drug delivery capabilities over the past decade. While providing numerous advantages, such as greater solubility, duration of exposure, and delivery to the site of action over their small molecule counterparts, there is substantial variability in systemic clearance and distribution, tumor delivery, and pharmacologic effects (efficacy and toxicity) of these agents. In this chapter, we focus on the analytical and phenotypic methods required to design a study that characterizes the pharmacokinetics (PK) and pharmacodynamics (PD) of all forms of these nanoparticle-based drug agents. These methods include separation of encapsulated and released drugs, ultrafiltration for measurement of non-protein bound active drug, microdialysis to measure intra-tumor drug concentrations, immunomagnetic separation and flow cytometry for sorting cell types, and evaluation of spatial distribution of drug forms relative to tissue architecture by mass spectrometry imaging and immunohistochemistry.

HLA and Histo-Blood Group Antigen Expression in Human Pluripotent Stem Cells and their Derivatives

One prerequisite for a successful clinical outcome of human pluripotent stem cell (hPSC) based therapies is immune compatibility between grafted cells/tissue and recipient. This study explores immune determinants of human embryonic stem cell lines (hESC) and induced human pluripotent stem cell (hiPSC) lines and hepatocyte- and cardiomyocyte-like cells derived from these cells. HLA class I was expressed on all pluripotent hPSC lines which upon differentiation into hepatocyte-like cells was considerably reduced in contrast to cardiomyocyte-like cells which retained class I antigens. No HLA class II antigens were found in the pluripotent or differentiated cells. Histo-blood group carbohydrate antigens SSEA-3/SSEA-4/SSEA-5, Globo H, A, Le^x/Le^y and sialyl-lactotetra were expressed on all hPSC lines. Blood group AB(O)H antigen expression was in accordance with ABO genotype. Interestingly, only a subpopulation of A1O1 cells expressed A. During differentiation of hPSC, some histo-blood group antigens showed congruent alteration patterns while expression of other antigens differed between the cell lines. No systematic difference in the hPSC cell surface tissue antigen expression was detected. In conclusion, hPSC and their derivatives express cell surface antigens that may cause an immune rejection. Furthermore, tissue antigen expression must be established for each individual stem cell line prior to clinical application.

Increased SYK activity is associated with unfavorable outcome among patients with acute myeloid leukemia

Recent discoveries have led to the testing of novel targeted therapies for the treatment of acute myeloid leukemia (AML). To better inform the results of clinical trials, there is a need to identify and systematically assess biomarkers of response and pharmacodynamic markers of successful target engagement. Spleen tyrosine kinase (SYK) is a candidate therapeutic target in AML. Small-molecule inhibitors of SYK induce AML differentiation and impair leukemia progression in preclinical studies. However, tools to predict response to SYK inhibition and to routinely evaluate SYK activation in primary patient samples have been lacking. In this study we quantified phosphorylated SYK (P-SYK) in AML cell lines and establish that increasing levels of baseline P-SYK are correlated with an increasing sensitivity to small-molecule inhibitors targeting SYK. In addition, we found that pharmacological inhibition of SYK activity extinguishes P-SYK expression as detected by an immunohistochemical (IHC) test. Quantitative analysis of P-SYK expression by the IHC test in a series of 70 primary bone marrow biopsy specimens revealed a spectrum of P-SYK expression across AML cases and that high P-SYK expression is associated with unfavourable outcome independent of age, cytogenetics, and white blood cell count. This study thus establishes P-SYK as a critical biomarker in AML that identifies tumors sensitive to SYK inhibition, identifies an at-risk patient population, and allows for the monitoring of target inhibition during treatment.

Secondary B-cell lymphoma diagnosed by fine-needle aspiration cytology and flow cytometry following penile carcinoma: A case report

The number of studies reporting lymphoma as a secondary tumor has gradually increased. However, few studies have reported that occurrence of lymphoma as a secondary tumor following treatment for penile carcinoma, particularly cases in which the lymphoma was diagnosed by fine-needle aspiration cytology and flow cytometry. The present study reports the case of a 62-year-old male patient who was troubled with frequent urination and repeated chest tightness for 5 years. The diagnosis upon admission was penile carcinoma. Two months subsequent to the tumor removal surgery, enlarged lymph nodes were extracted from the patient using fine-needle biopsy, to be analyzed using light microscopy and flow cytometry. Smear results indicated a large number of abnormal cells scattered in the right axillary lymph node. Flow cytometry immunophenotyping of fine-needle aspiration samples indicated the increased expression of cluster of differentiation (CD)79a, CD19, CD20, CD38, κ chain and human leukocyte antigen-DR, which supported a diagnosis of B-cell lymphoma. Thus, the patient was diagnosed with B-cell lymphoma based on the results of the fine-needle aspiration biopsy and flow cytometry. The method of diagnosis and causes of therapy-related leukemia are discussed in the present report.

Clonality assessment of cutaneous B-cell lymphoid proliferations: a comparison of flow cytometry immunophenotyping, molecular studies, and immunohistochemistry/in situ hybridization and review of the literature

Cutaneous lymphoid infiltrates are diagnostically challenging. Although ancillary techniques to assess clonality can help distinguish between reactive lymphoid hyperplasia and lymphoma, one of the most widely used techniques in hematopathology, flow cytometry immunophenotyping (FCI), has not been routinely applied to skin specimens. We performed FCI on 73 skin specimens from 67 patients clinically suspected of having a cutaneous B-cell lymphoma (CBCL) and compared the results with those obtained from immunoglobulin heavy chain (IGH) gene molecular studies (58 cases, primarily by polymerase chain reaction) and either immunohistochemistry (IHC) or in situ hybridization to evaluate for light chain restriction (22 and 2 cases, respectively). Sufficient quantity of CD45 (leukocyte common antigen)-positive cells and staining quality were achieved in 88% of cases by FCI, and clonality was detected in 68% of CBCLs versus molecular studies showing sufficient DNA quality in 74% and only 39% clonality detection, and interpretable/contributory IHC results in 84% of cases with 55% clonality detection. Clonality was documented more frequently in secondary rather than primary CBCLs by all 3 techniques. Therefore, FCI is feasible and appears to be more reliable than molecular studies or IHC/in situ hybridization for detecting clonality in CBCLs and can provide additional prognostically and therapeutically relevant information. The exception is cases with plasmacytic differentiation such as marginal zone lymphoma for which IHC might be a superior tool. We have also shown that a large subset of primary cutaneous follicle center lymphomas express CD10 and/or BCL2 by FCI. Recent advances in FCI beg the question of applicability to cutaneous T-cell and NK-cell lymphomas.

Lymphomas in Ile-Ife, Nigeria: Immunohistochemical Characterization and Detection of Epstein-Barr virus Encoded RNA

BACKGROUND

The proper histopathological characterization of malignant lymphomas requires the use of immunohistochemistry along with other molecular pathology techniques.

MATERIALS AND METHODS

Malignant lymphomas histologically diagnosed in our hospital were reclassified according to the WHO scheme using immunohistochemistry while in-situ hybridization was performed for the detection of Epstein-Barr virus encoded RNA.

RESULTS

There were 83 cases of lymphoma. The male to female ratio was 1.9:1 while the overall mean age was 41.7 years. Non-Hodgkin lymphomas (NHL) constituted about 79.5% of cases. The majority of cases (98.8%) were B-cell lymphomas. Nine subtypes of lymphomas were identified with diffuse large B-cell lymphomas (56.4% of which were of the germinal centre type) constituting the largest group (47.0%). Intermediate and high grade subtypes were more common. The majority of cases (72.3%) were nodal lymphomas with cervical lymph node being the commonest site (48.2%). Only classical Hodgkin lymphoma (HL) (20.5%) was seen of which the mixed cellularity subtype was the most common. Epstein Barr virus (EBV) encoded ribonucleic acid was detected in 7 cases (8.4%) including 4 cases of HL, 2 cases of Burkitt lymphoma and the only case of plasmablastic lymphoma. About five cases were reclassified as non-lymphoid malignant lesions.

CONCLUSION

Immunohistochemistry is vital to the proper classification of lymphomas even in a resource poor environment. Although nine subtypes of lymphomas were identified, diffuse large B-cell lymphomas formed the largest single group. Epstein-Barr virus probably plays an important role in lymphomatogenesis in this environment. A larger multicentre study is required to prove this.

Standardization of Diagnostic Immunohistochemistry: Literature Review and Geisinger Experience

Context

Immunohistochemistry has become an indispensable ancillary technique in anatomic pathology laboratories. Standardization of every step in preanalytic, analytic, and postanalytic phases is crucial to achieve reproducible and reliable immunohistochemistry test results.

Objective

To standardize immunohistochemistry tests from preanalytic, analytic, to postanalytic phases.

Data Sources

Literature review and Geisinger (Geisinger Medical Center, Danville, Pennsylvania) experience.

Conclusions

This review article delineates some critical points in preanalytic, analytic, and postanalytic phases; reiterates some important questions, which may or may not have a consensus at this time; and updates the newly proposed guidelines on antibody validation from the College of American Pathologists Pathology and Laboratory Quality Center. Additionally, the article intends to share Geisinger's experience with (1) testing/optimizing a new antibody and troubleshooting; (2) interpreting and reporting immunohistochemistry assay results; (3) improving and implementing a total immunohistochemistry quality management program; and (4) developing best practices in immunohistochemistry.

A quality improvement assessment of multiple, concurrent flow cytometry analyses at a tertiary care center

INTRODUCTION

The utility of flow cytometry (FC) in diagnosis and staging of hematologic malignancy is controversial. Often, multiple specimens from the same patient are processed concurrently for FC analyses, alongside tissue for histomorphologic diagnosis.

METHODS

To assess the diagnostic utility of multiple, concurrent FC analyses, a 10-year retrospective review of cases with ≥2 concurrent specimens (from the same patient) submitted for FC was conducted. Light microscopic (LM) diagnoses were compared to FC findings, and the contribution of FC results to final diagnoses was examined.

RESULTS

Of 4058 specimens (predominantly lymph nodes, bone marrows, and oropharyngeal tissues) submitted for FC analyses, 129 (3.2%) represented cases with multiple (average: 2.19) concurrent FC analyses. All were accompanied by tissues and/or aspirates for LM examination. In 115 (89.1%) cases, multiple FC analyses were performed prior to morphologic examination. In 87.0% of those cases, ≥1 FC result(s) aligned with LM findings. In 15 (13.0%) cases where FC results differed from morphologic diagnoses, 86.7% (13/15) failed to detect an abnormal cell population by FC in the presence of a hematologic malignancy by LM. In one case (0.9%), FC detected a lymphoma, without morphologic evidence by LM.

CONCLUSIONS

Overall, multipart FC failed to demonstrate a significant contribution in initial diagnoses of hematologic malignancies compared with analysis of a single specimen.

The Diagnostic Value of Flow Cytometry Imunophenotyping in an Albanian Patient Population with a Preliminary Clinical Diagnosis of Chronic Lymphocytic Leukemia

Objective: Based on the flow cytometry multiparametric immunophenotyping methodology we studied some useful cell marker criteria needed for the practical differentiation of the chronic lymphocytic leukemia from other chronic limphoproliferative diseases with a leukemic component.Materials and Methods: The applied methodology is a four color flow cytometry multiparametric immunophenotyping technique using EDTA blood samples taken from 84 consecutive patients diagnosed with CLL through a preliminary clinical and white blood cell examination. The following fluorescent stained monoclonal antibodies were used: CD3, CD4, CD5, CD8, CD11c, CD19, CD20, CD23, CD25, FMC7 and kappa/lambda light chains.Results: From the 84 individuals tested, 2 out of them (2.4%) resulted with a abnormal T-cell population while 82 (97.6%) showed a pathological B cell line. 58 (69.1%) patients resulted with typical CLL markers (CD19+CD5+CD23+) while 5 (5.9%) of them presented a non typical chronic lymphocytic leukemia profile (CD19+CD5+CD23-). 19 (22.6%) out of patients displayed an abnormal CD19+CD5- B cell population. A statistically significant correlation was found between the clinical stage of CLL and the positivity for the CD38 marker (p=0.04).Conclusion: Flow cytometry immunophenotyping is a fundamental examination for the final diagnosis of chronic lymphocytic leukemia. The expression of CD38+ in CLL patients stands for a more advanced clinical stage.

Early T-cell Precursor Acute Lymphoblastic Leukemia/Lymphoma

Discrete diagnostic subtypes of T lymphoblastic leukemia/lymphoma (T-cell acute lymphoblastic leukemia/lymphoma, T-ALL) have historically not been widely recognized. Recently, a novel subset with distinctive immunophenotypic, molecular, and clinical features has been proposed. Termed early T-cell precursor acute lymphoblastic leukemia (ETP-ALL), these cases seem to correspond to a very early stage of T-cell development. ETP-ALL is associated with a poor prognosis using standard protocols, and patients with ETP-ALL may benefit from intensified, alternative, or targeted therapies. Recognizing ETP-ALL and distinguishing it from other forms of acute leukemia are important elements of an up-to-date diagnostic approach to precursor T-cell neoplasms.

Neoplastic and Nonneoplastic Lesions in Aging Mice of Unique and Common Inbred Strains Contribution to Modeling of Human Neoplastic Diseases

The evaluation of spontaneous lesions in classical inbred strains of mice has become increasingly important because genetically engineered mice (GEMs) are created on these backgrounds. Novel inbred strains—genetically diverse from classic strains—are valuable both as a new background for GEM mice and to increase the genetic variation found in laboratory mice. Newly arising spontaneous genetic alterations in commonly used strains may also lead to new and valuable mouse models of disease. This report evaluates gross and histological lesions in relatively new, classic, and rarely explored mouse inbred strains. Pathological lesions of 1273 mice from 12 inbred strains (129S1/SvW, A.CA- H2f/W, AKR/W, BALB/cW, BN/aW, C57BL/6 W, C57BL/10 W, C3H/W, C3H wad/W, CBA/W, DBA/2 W, and WOM/W) are reported. BN/aW, WOM/W, and C3H wad/W are novel inbred strains produced and maintained in the Department of Genetics and Laboratory Animal Breeding at the Center of Oncology, Warsaw, Poland. Both neoplastic and nonneoplastic lesions were examined. The prevalence of lung neoplasms was significantly higher in A.CA- H2f/W (33.3%) and BALB/cW (33.8%) mice ( P < .01). The prevalence of liver neoplasms was significantly higher in the CBA/W strain ( P < .01). Mammary gland neoplasms arose at a greater frequency in C3H/W mice ( P < .01). The occurrence of uterine neoplasms was higher in DBA/W and 129S1/SvW mice. AKR/W and WOM/W mice developed T-cell lymphoblastic lymphoma with high frequency (110/121 [90.9%] and 159/175 [90.9%], respectively) before 1 year of age. The occurrence of nonneoplastic lesions in the kidneys of BN/aW mice was increased ( P < .01).

Developments in the immunophenotypic analysis of haematological malignancies

Immunophenotyping is the method by which antibodies are used to detect cellular antigens in clinical samples. Although the major role is in the diagnosis and classification of haematological malignancies, applications have expanded over the past decade. Immunophenotyping is now used extensively for disease staging and monitoring, to detect surrogate markers of genetic aberrations, to identify potential immuno-therapeutic targets and to aid prognostic prediction. This expansion in applications has resulted from developments in antibodies, methodology, automation and data handling. In this review we describe recent advances in both the technology and applications for the analysis of haematological malignancies. We highlight the importance of the expanding repertoire of testing capability for diagnostic, prognostic and therapeutic applications. The impact and significance of immunophenotyping in the assessment of haematological neoplasms are evident.

Tissue flow cytometry immunophenotyping in the diagnosis and classification of non-Hodgkin's lymphomas: a retrospective evaluation of 1,792 cases

A retrospective analysis of 1,792 solid tissues suggestive of lymphoma, submitted over a 12-year period, was carried out and flow cytometry (FC) results were compared with histologic findings. The final histologic diagnosis of cases documented in this report is as follows: 1,270 non-Hodgkin's lymphomas (NHL); 17 composite lymphomas; four NHL plus carcinomas; five post-transplant lymphoproliferative disorders; 105 Hodgkin's lymphomas (HL); eight acute leukemias; 42 tissue cancers; and 341 non-neoplastic diseases. A strong correlation between morphology and FC data was observed among hematological malignancies (1,268/1,304, 97.2%) with the exception of HL. Among B-NHL, FC detection of clonally restricted B-cell allowed the identification of lymphomas that were not histologically clear and the differential diagnosis between follicular lymphoma and reactive hyperplasia. A high correlation level (r = 0.83; P < 0.0001) was obtained in comparing proliferation results obtained by FC and immunohistochemistry. Among T-NHL, FC detection of an aberrant phenotype direct histologic diagnosis in cases having less than 20% of neoplastic cells. In nine cases, FC suggested the need to evaluate a neoplastic population, not morphologically evident. Results show that FC routinely performed on tissue samples suspected of lymphomas is a fundamental adjunct to morphology in the diagnosis of NHL and may enhance the performance of the histologic evaluation so as to achieve the final diagnosis. To the best of our knowledge, this is the first report in the literature of a wide series of tissues also studied by FC.

Immunophenotyping of chronic B-cell neoplasms: flow cytometry versus immunohistochemistry

Morphological differentiation between benign and malignant lymphoproliferative disorders (LPDs) can be challenging. Immunophenotyping (IPT) by either technique, flow cytometry or immunohistochemistry (IHC), is an important step in solving such difficulty. Thirty-five newly diagnosed patients with chronic B-cell neoplasms (11 chronic lymphocytic leukemia, 22 non Hodgkin lymphoma and 2 hairy cell leukemia) were included in this study with age range from 20 to 70 years. Monoclonal antibodies surface expression using lymphoproliferative disorders panel (CD45, CD19, CD5, CD10, CD11c, CD20, CD22, CD23, CD38, CD79b, FMC7, CD103, CD25, kappa and lambda light chains) by flow cytometry was done on bone marrow samples. CD20, CD5, CD23, Bcl-2, Bcl-6, kappa and lambda light chain immunostaining were performed on fixed bone marrow trephine biopsy specimen. The sensitivity of IHC was 81.8% in chronic lymphocytic leukemia (CLL) and 100% in non Hodgkin lymphoma (NHL) as regards CD20, 100% in both groups as regards CD5, 46% in CLL and 66.7% in NHL as regards CD23, 33.3% in CLL and 50% in NHL as regards kappa chain, 20% in CLL and 33.3% in NHL as regards lambda chain. We found that IHC and flow cytometry are equally effective in diagnosing CLL; however, IHC might be slightly more sensitive than flow cytometry in detecting bone marrow infiltration in NHL and hairy cell leukemia (HCL).

Usefulness of multiparametric flow cytometry in detecting composite lymphoma: study of 17 cases in a 12-year period

Composite lymphoma (CL) is a rare occurrence of 2 or more morphologically and immunophenotypically distinct lymphoma clones in a single anatomic site. A retrospective analysis of 1,722 solid tissue samples clinically suggestive of lymphoma was carried out in our institute during a 12-year period to evaluate the efficacy of flow cytometry (FC) in identifying CL. We report 17 CL cases. A strong correlation between morphologic findings and FC was observed in 13 cases (76%). In the 4 cases diagnosed as non-Hodgkin lymphoma plus Hodgkin lymphoma, although FC did not detect Reed-Sternberg cells, it accurately identified the neoplastic B- or T-cell component. In 3 cases, FC indicated the need to evaluate an additional neoplastic component that was not morphologically evident. Our data demonstrate that FC immunophenotyping of tissues may enhance the performance of the diagnostic morphologic evaluation of CL. To the best of our knowledge, this is the first report in the literature of a wide series of CL studied also by FC.

Automated leukocyte recognition using fuzzy divergence

This paper aims at introducing an automated approach to leukocyte recognition using fuzzy divergence and modified thresholding techniques. The recognition is done through the segmentation of nuclei where Gamma, Gaussian and Cauchy type of fuzzy membership functions are studied for the image pixels. It is in fact found that Cauchy leads better segmentation as compared to others. In addition, image thresholding is modified for better recognition. Results are studied and discussed.

Flowcytometric immunophenotyping in the diagnosis of pediatric lymphoma: how reliable is it and how can we optimize its use?

We aimed to evaluate the role of flowcytometric immunophenotyping (FCI) as an adjunct to histologic examination in pediatric lymphoma. We conducted a retrospective review of 39 fresh tissue samples and 2 pleural fluids submitted to the histopathology department with a clinical suspicion of lymphoma during a 4-year period, where FCI was performed. The FCI results were correlated with the final histologic diagnosis. The study comprised 38 lymphoid lesions and 3 nonlymphoid tumors. The concordance of FCI for all lesions was 71% and that for non-Hodgkin lymphoma was 75%. When Hodgkin lymphoma was excluded, the correlation was 93.1%. In 3 cases of nonhematologic tumors, FCI was useful in excluding a lymphoma. In one of them, FCI supported the diagnosis of neuroblastoma when CD81, CD9, GD2, and CD56 were added to the FCI panel. FCI produced rapid same-day results with a high sensitivity for benign lymphoid lesions and non-Hodgkin lymphoma. It was not helpful for Hodgkin lymphoma. Although the main application of FCI was to assess lymphoid lesions, it was also useful in the identification of nonlymphoid tumors, especially neuroblastoma. As the prevalence of lymphomas in children differ from that in adults, we believe that the algorithm proposed by us to triage specimens using imprint cytology can optimize the use of FCI in routine pediatric pathology practice.

WebFlow: a software package for high-throughput analysis of flow cytometry data

Flow cytometry has emerged as a powerful tool for quantitative, single-cell analysis of both surface markers and intracellular antigens, including phosphoproteins and kinase signaling cascades, with the flexibility to process hundreds of samples in multiwell plate format. Quantitative flow cytometric analysis is being applied in many areas of biology, from the study of immunology in animal models or human patients to high-content drug screening of pharmacologically active compounds. However, these experiments generate thousands of data points per sample, each with multiple measured parameters, leading to data management and analysis challenges. We developed WebFlow (http://webflow.stanford.edu), a web server-based software package to manage, analyze, and visualize data from flow cytometry experiments. WebFlow is accessible via standard web browsers and does not require users to install software on their personal computers. The software enables plate-based annotation of large data sets, which provides the basis for exploratory data analysis tools and rapid visualization of multiple different parameters. These tools include custom user-defined statistics to normalize data to other wells or other channels, as well as interactive, user-selectable heat maps for viewing the underlying single-cell data. The web-based approach of WebFlow allows for sharing of data with collaborators or the general public. WebFlow provides a novel platform for quantitative analysis of flow cytometric data from high-throughput drug screening or disease profiling experiments.

Flow cytometric immunophenotyping (FCI) of lymphoma: correlation with histopathology and immunohistochemistry

BACKGROUND

To evaluate the role of flow cytometric immunophenotyping (FCI) in diagnosis and characterization of lymphoma tissue specimens from Egyptian patients.

METHODS

FCI using 2 and 3 color staining approaches, was performed on 50 fresh lymph nodes specimen from Cairo NCI patients with suspected lymphoma presenting with either localized or generalized lymphadenopathy.FCI results were correlated with histopathologic as well as immunophenotypic[by immunohistochemistry (IHC)] findings.

RESULTS

By FCI, cases were diagnosed as follows: 9(18%) reactive hyperplasia (RH), 32(64%) B-cell non-Hodgkin's lymphoma (B-NHL) [24 diffuse large (DLBCL), 2 follicular, 3 small lymphocytic, 2 mantle cell lymphoma and a case of T cell rich B cell lymphoma], 3 (6%) T cell NHL [2 peripheral T cell lymphoma and a case of anaplastic large cell lymphoma], 2(4%) Hodgkin's lymphoma (HL) while 4 (8%) were non-lymphomatous tumors (NLT). Light chain restriction (LCR) was detected in the 32 FCI diagnosed B-NHL. The overall concordance between FCI versus histopathology and IHC was 88%. The sensitivity and specificity of FCI in diagnosis of NHL was 94.9% and 100% respectively; in HL they were 40% and 100% respectively and in NLT, both sensitivity and specificity were 100% while for RH were 100% and 89.1% respectively.

CONCLUSION

FCI is a sensitive and specific method in diagnosis and classification of NHL as well as in detection of monoclonality. False negative results could be due to the presence of heterogeneous populations of lymphocytes in special types of lymphoma.

Methods for simultaneous measurement of apoptosis and cell surface phenotype of epithelial cells in effusions by flow cytometry

We describe here a protocol for the detection of epithelial cells in effusions combined with quantification of apoptosis by flow cytometry (FCM). The procedure described consists of the following stages: culturing and induction of apoptosis by staurosporine in control ovarian carcinoma cell lines (SKOV-3 and OVCAR-8); preparation of effusion specimens and cell lines for staining; staining of cancer cells in effusions and cell lines for cell surface markers (Ber-EP4, EpCAM and CD45) and intracellular/nuclear markers of apoptosis (cleaved caspase-3 and caspase-8, and incorporated deoxyuridine triphosphates); and FCM analysis of stained cell lines and effusions. This protocol identifies a specific cell population in cytologically heterogeneous clinical specimens and applies two methods to measure different aspects of apoptosis in the cell population of interest. The cleaved caspase and deoxyuridine triphosphate incorporation FCM assays are run in parallel and require (including sample preparation, staining, instrument adjustment and data acquisition) 8 h. The culturing of cell lines requires 2-3 days and induction of apoptosis requires 16 h.

Ex vivo simulation of IgG Fc and T-cell receptor functions: an application to inflammatory bowel disease

BACKGROUND

Human leukocyte IgG Fc receptors (FcgammaR) and T-cell receptors (TCR) are primary molecules involved in inflammatory and immune pathways.

METHODS

These 2 receptors were stimulated in whole blood for 2-4 hours with immune complex and specific agonistic antibody, respectively, and various mRNAs were quantified by a method we developed previously.

RESULTS

FcgammaR stimulation induced tumor necrosis factor superfamily 2 (TNFSF2), TNFSF8, TNFSF15, interleukin 1B (IL1B), IL8, CCL chemokine 2 (CCL2), CCL3, CCL4, CCL11, CCL20, CXCL chemokine 1 (CXCL1), CXCL2, and CXCL3 mRNA, whereas TCR stimulation induced different subsets of mRNA such as TNFSF1, TNFSF2, TNFSF5, TNFSF6, TNFSF9, TNFSF14, IL6, CCL2, CCL8, CCL20, and CXCL10. Interestingly, respondents and nonrespondents were identified for each mRNA. When we applied this method to inflammatory bowel disease, the respondent populations of TCR-induced TNFSF2 (= TNFalpha), TNFSF5, TNFSF14, CCL2, CCL8, and CCL20 mRNA were significantly higher in Crohn's disease (CD) patients than in healthy controls or those with ulcerative colitis (UC). No difference was found for FcgammaR-mediated responses. The respondent population of TCR-induced TNFSF2 showed significantly (P = 0.05) higher incidence of multiple surgeries than did nonrespondents.

CONCLUSIONS

These data demonstrate an underlining hyperfunction of TCR in peripheral-blood leukocytes in CD patients. The ex vivo simulation demonstrates an underlining hyperfunction of TCR in peripheral-blood leukocytes in CD patients and may form the basis of a relatively noninvasive test for distinguishing these IBDs.

Application of Immunohistochemistry in the Diagnosis of Non-Hodgkin and Hodgkin Lymphoma

Context.—Beginning with the immunologic classifications of Lukes and Collins and Kiel and culminating in the Revised European-American Lymphoma and World Health Organization classifications, the diagnosis of lymphoid tumors relies heavily on the determination of cell lineage, maturation, and function, based on antigen expression in addition to morphology and clinical features. Technologic advances in immunology, antibody production, genetic analysis, cloning, and the identification of new genes and proteins by microarray and proteomics have provided pathologists with many antibodies to use in routine diagnosis.

Objective.—To provide guidance to the practicing pathologist in the appropriate selection of an antibody panel for the diagnosis of lymphoma based on morphology and relevant clinical data and to avoid pitfalls in the interpretation of immunohistochemical data. Attention is given to some of the newer antibodies, particularly against transcription factors, that are diagnostically and prognostically useful.

Data Sources.—The information presented in this article is based on review of the literature using the OVID database (Ovid MEDLINE 1950 to present with daily update) and 20 years of experience in diagnostic hematopathology.

Conclusions.—Immunophenotyping is required for the diagnosis and classification of lymphoid malignancies. Many paraffin-reactive antibodies are available to the pathologist but most are not specific. To avoid diagnostic pitfalls, interpretation of marker studies must be based on a panel and knowledge of a particular antigen's expression in normal, reactive, and neoplastic conditions.

Lymphocyte subpopulations in human exposure to metals (IUPAC Technical Report)

Numerous species of metal ions cause immunosensitization in humans. Possible approaches to determine those occupational and environmental exposures to metals that result in immunological changes include lymphocyte transformation assay, cytokine profiling, and measurement of lymphocyte subpopulations. In two previous papers, we considered lymphocyte transformation assay [1] and cytokine profiling [2]. Here we review the effects of exposures to metals on lymphocyte subpopulations. Specific consideration is given to beryllium, chromium, cobalt, nickel, palladium and platinum, cadmium, gold, mercury, and lead. Analysis of the scientific literature shows that immunosensitizing metals may have influences on the lymphocyte subset composition, but only in a few instances does exposure to metals cause reproducible shifts of lymphocyte subpopulations. If lymphocyte subpopulations are analyzed, each diagnostic step, including indication, sample handling, analytic procedure, and data interpretation, should adhere to good quality assurance and quality control.

Grading of follicular lymphoma: comparison of routine histology with immunohistochemistry

CONTEXT

Follicular lymphoma (FL) grading is based on the average number of large transformed cells in 10 neoplastic follicles at x40 high-power field (x10-40 high-power field) examination (grade 1, 0-5 centroblasts per high-power field; grade 2, 6-15 centroblasts per high-power field; grade 3, >15 centroblasts per high-power field).

OBJECTIVE

Since there may be significant interobserver variability, we analyzed the usefulness of immunohistochemical stains in grading FLs more reliably.

DESIGN

Forty-three FLs initially graded by World Health Organization criteria (grade 1, 12; grade 2, 18; grade 3, 13) were reviewed and stained with CD3, CD20, Ki-67, CD30, CD68, PAX-5, and BCL-6. Retrospective review was performed for the average number of large cells, of large lymphoid cells, of large cells staining with CD3, CD20, BCL-6 (40 cases), and PAX-5, and of all cells staining with CD68, Ki-67, and CD30.

RESULTS

By histologic review, 8 of 43 FLs had a significant grade change (4 cases upgraded and 4 cases downgraded). CD3 and CD30 stained only 0 to 3 large cells and 0 to 3 cells, respectively, in neoplastic follicles. CD68+ cells represented the large nonlymphoid cells. Increasing FL grades demonstrated increases in Ki-67+ cells. The original grade showed substantial agreement with CD20 and moderate agreement with PAX-5 and BCL-6. The original histologic grade agreed with immunohistochemical-based grade using 2 or more antibodies in 5 of 8 discordant cases (4 by CD20 or BCL-6 and PAX-5; 1 by CD20, PAX-5, and BCL-6).

CONCLUSIONS

Interobserver variability of histologic FL grading may be significant; we showed low-end "substantial agreement." Immunohistochemical stains (ie, CD20, PAX-5, and BCL-6) may more reliably determine the number of large transformed cells in neoplastic follicles; Ki-67 staining correlates with higher FL grades. Immunohistochemical stains may be evaluated in clinical trials of FL patients to determine prognostic significance.

The Value of CD64 Expression in Distinguishing Acute Myeloid Leukemia With Monocytic Differentiation From Other Subtypes of Acute Myeloid Leukemia: A Flow Cytometric Analysis of 64 Cases

Context.—Flow cytometric immunophenotyping is a useful ancillary tool in the diagnosis and subclassification of acute myeloid leukemias (AMLs). A recent study concluded that CD64 is sensitive and specific for distinguishing AMLs with a monocytic component (ie, AML M4 and AML M5) from other AML subtypes. However, in that study, the intensity of CD64 was not well defined and the number of non-M4/non-M5 AMLs was small.

Objective.—To evaluate the usefulness of CD64 by flow cytometric immunophenotyping in distinguishing AMLs with monocytic differentiation from other AML subtypes.

Design.—Sixty-four AMLs subclassified based on the French-American-British and World Health Organization classifications on pretreatment bone marrows were retrieved from our files (7 M0s, 11 M1s, 17 M2s, 7 M3s, 9 M4s, 7 M5s, 4 M6s, and 2 M7s). A standard panel of markers, including CD2, CD3, CD5, CD7, CD10, CD11b, CD13, CD14, CD15, CD19, CD20, CD33, CD34, CD45, CD56, CD64, CD117, and HLA-DR, were analyzed by flow cytometric immunophenotyping in all AMLs (52 bone marrow samples; 12 peripheral blood samples).

Results.—CD64 was expressed in AML subtypes M0 to M5 in varying intensities: heterogeneously expressed in 1 of 7 M0s; dimly expressed in 3 of 11 M1s; dimly and moderately expressed in 6 and 2 of 17 M2s, respectively; dimly and moderately expressed in 5 and 1 of 7 M3s, respectively; dimly expressed in 4 of 9 M4s; and heterogeneously, moderately, and strongly expressed in 1, 3, and 3 of 7 M5s, respectively.

Conclusions.—Strong CD64 expression distinguishes AML M5; however, heterogeneous, dim, or moderate expression in itself does not distinguish M0 through M4 subtypes from M5 with dim to moderate CD64 expression. However, any CD64 expression associated with strong CD15 expression distinguishes AML M4 or M5, from other AML subtypes.

Morphological Granulometric Features of Nucleus in Automatic Bone Marrow White Blood Cell Classification

The proportion of counts of different types of white blood cells in the bone marrow, called differential counts, provides invaluable information to doctors for diagnosis. Due to the tedious nature of the differential white blood cell counting process, an automatic system is preferable. In this paper, we investigate whether information about the nucleus alone is adequate to classify white blood cells. This is important because segmentation of nucleus is much easier than the segmentation of the entire cell, especially in the bone marrow where the white blood cell density is very high. In the experiments, a set of manually segmented images of the nucleus are used to decouple segmentation errors. We analyze a set of white-blood-cell-nucleus-based features using mathematical morphology. Fivefold cross validation is used in the experiments in which Bayes' classifiers and artificial neural networks are applied as classifiers. The classification performances are evaluated by two evaluation measures: traditional and classwise classification rates. Furthermore, we compare our results with other classifiers and previously proposed nucleus-based features. The results show that the features using nucleus alone can be utilized to achieve a classification rate of 77% on the test sets. Moreover, the classification performance is better in the classwise sense when the a priori information is suppressed in both the classifiers.

High-content flow cytometry and temporal data analysis for defining a cellular signature of graft-versus-host disease

Acute graft-versus-host disease (GVHD) is diagnosed by clinical and histologic criteria that are often nonspecific and typically apparent only after the disease is well established. Because GvHD is mediated by donor T cells and other immune effector cells, we sought to determine whether changes within a wide array of peripheral blood lymphocyte populations could predict the development of GvHD. Peripheral blood samples from 31 patients undergoing allogeneic blood and marrow transplant were analyzed for the proportion of 121 different subpopulations defined by 4-color combinations of lymphocyte phenotypic and activation markers at progressive time points posttransplant. Samples were processed using a newly developed high content flow cytometry technique and subjected to a spline- and functional linear discriminant analysis (FLDA)-based temporal analysis technique. This strategy identified a consistent posttransplant increase in the proportion and extent of fluctuation of CD3+CD4+CD8beta+ cells in patients who developed GVHD compared to those that did not. Although larger prospective clinical studies will be necessary to validate these results, this study demonstrates that high-content flow cytometry coupled with temporal analysis is a powerful approach for developing new diagnostic tools, and may be useful for developing a sensitive and specific predictive test for GVHD.

Polychromatic flow cytometry: a rapid method for the reduction and analysis of complex multiparameter data

BACKGROUND

Recent advances in flow cytometry have resulted in the development of reliable techniques for performing polychromatic (5-17 color) flow cytometry analysis. However, the data reduction and analysis involved in the resolution of hundreds of possible cellular subphenotypes identified, using a single polychromatic flow cytometry staining panel, presents a major obstacle to the successful application of this technology.

METHODS

To generate two distinct collections of T cell populations with differentially expressed surface markers, cryopreserved lymph node cells from 5 melanoma patients vaccinated with the modified gp100(209-2M) melanoma peptide were stimulated with cognate peptide and cultured in either IL-21 + low-dose IL-2 or IL-15 + low-dose IL-2. In vitro stimulated (IVS) cells were interrogated using 8-color flow cytometry. Data were analyzed using Winlist Hyperlog and FCOM software, and 32 T cell subsets were resolved for each culture condition. Hierarchical clustering analysis was applied to the relative percentages of each subphenotype for both IVS conditions to determine if unique cell surface marker expression signatures were produced for each IVS culture.

RESULTS

Sequential data analysis using Hyperlog and FCOM demonstrated that lymphocytes cultured in IL-21 + IL-2 had a distinctively different set of subphenotype signatures compared to cells grown in IL-15 + IL-2 for all 5 patients. Importantly, subsequent cluster analysis of all 32 subphenotype frequencies in each IVS test condition for all 5 patients reproducibly demonstrated that cellular subphenotypes produced after IL-21 + IL-2 IVS partitioned separately from subphenotypes produced by IL-15 + IL-2 IVS.

CONCLUSIONS

The integrated sequential use of Hyperlog and FCOM software with cluster analysis algorithms for the reduction and analysis of polychromatic flow cytometry data produces an effective, rapid technique for the assessment of complex patterns of subphenotype expression between and within multiple test samples. This approach to data analysis may enhance the use of polychromatic flow cytometry for both research and clinical applications.

Flow cytometric immunophenotyping of cancer cells in effusion specimens: Diagnostic and research applications

Flow cytometry (FCM) immunophenotyping is frequently used as an ancillary technique for the diagnosis of hematological malignancies or for measurement of DNA content. In recent years, we applied FCM to the diagnosis of metastatic adenocarcinoma and malignant mesothelioma in effusions. We established a panel of antibodies that allows for rapid and effective differentiation between epithelial cells, mesothelial cells, and leukocytes. FCM was subsequently used for quantitative analysis of integrin subunits. Recently, we studied different parameters of the immune response, including HLA molecules and chemokine receptors, using this method. Our data suggest that FCM is an effective method for the characterization of cancer cells in clinical effusion specimens in both the diagnostic and research setting, and that this method is comparable to immunohistochemistry in terms of sensitivity and specificity, with the additional advantage of providing quantitative data. This review discusses previous work in this area and the future potential of this method in the characterization of tumor cells in serous effusions.

Flow cytometric immunphenotyping of epithelial cancer cells in effusions—Technical considerations and pitfalls

BACKGROUND

Data regarding the role of flow cytometry (FCM) in the characterization of malignant effusions are limited to date. In the present study, we optimized the conditions for FCM immunphenotyping of effusions using a four-color analysis and investigated aspects related to the advantages and limitations of this method in this setting.

METHODS

FCM analysis optimization for the study of epithelial cells was undertaken using five carcinoma cell lines, and subsequently applied to malignant pleural and peritoneal effusions using antibodies against epithelial and mesothelial markers (Ber-EP4 and EMA), CD138, and integrin subunits. FCM of frozen versus fresh specimens and the performance of FCM compared to immunhistochemistry were evaluated.

RESULTS

FCM optimization was achieved and applied to clinical specimens, with resulting detection of epithelial markers and adhesion molecules on cancer cells. Frozen clinical specimens and cell lines showed reduced CD138 expression compared to fresh specimens, with conservation of the remaining epitopes. FCM generally showed comparable performance to immunhistochemistry.

CONCLUSIONS

FCM is an effective method for characterization of cancer cells in clinical effusion specimens in both the diagnostic and research setting, and is comparable to immunhistochemistry in terms of sensitivity and specificity, with the additional advantage of providing quantitative data. The majority of epitopes are conserved in frozen cells, but a minority may be lost, suggesting that the thorough testing of each antibody in both conditions is mandatory.