Collagenase digestion and mechanical disaggregation as a method to extract and immunophenotype tumour lymphocytes in cutaneous T-cell lymphomas

Rebuilding the microenvironment of primary tumors in humans: a focus on stroma

Conventional tumor models have critical shortcomings in that they lack the complexity of the human stroma. The heterogeneous stroma is a central compartment of the tumor microenvironment (TME) that must be addressed in cancer research and precision medicine. To fully model the human tumor stroma, the deconstruction and reconstruction of tumor tissues have been suggested as new approaches for in vitro tumor modeling. In this review, we summarize the heterogeneity of tumor-associated stromal cells and general deconstruction approaches used to isolate patient-specific stromal cells from tumor tissue; we also address the effect of the deconstruction procedure on the characteristics of primary cells. Finally, perspectives on the future of reconstructed tumor models are discussed, with an emphasis on the essential prerequisites for developing authentic humanized tumor models.

Improving Transcriptome Fidelity Following Synovial Tissue Disaggregation

Objective

To improve the fidelity of the cellular transcriptome of disaggregated synovial tissue for applications such as single-cell RNA sequencing (scRNAseq) by modifying the disaggregation technique.

Methods

Osteoarthritis (OA) and rheumatoid arthritis (RA) synovia were collected at arthroplasty. RNA was extracted from intact or disaggregated replicate pools of tissue fragments. Disaggregation was performed with either a proprietary protease, Liberase TL (Lib) as a reference method, Liberase TL with an RNA polymerase inhibitor flavopyridol (Flavo), or a cold digestion with subtilisin A (SubA). qPCR on selected markers and RNAseq were used to compare disaggregation methods using the original intact tissue as reference.

Results

Disaggregated cell yield and viability were similar for all three methods with some viability improved (SubA). Candidate gene analysis showed that Lib alone dramatically increased expression of several genes involved in inflammation and immunity compared with intact tissue and was unable to differentiate RA from OA. Both alternative methods reduced the disaggregation induced changes. Unbiased analysis using bulk RNAseq and the 3 protocols confirmed the candidate gene studies and showed that disaggregation-induced changes were largely prevented. The resultant data improved the ability to distinguish RA from OA synovial transcriptomes.

Conclusions

Disaggregation of connective tissues such as synovia has complex and selective effects on the transcriptome. We found that disaggregation with an RNA polymerase inhibitor or using a cold enzyme tended to limit induction of some relevant transcripts during tissue processing. The resultant data in the disaggregated transcriptome better represented the in situ transcriptome. The specific method chosen can be tailored to the genes of interest and the hypotheses being tested in order to optimize the fidelity of technique for applications based on cell suspensions such as sorted populations or scRNAseq.

Automated–Mechanical Procedure Compared to Gentle Enzymatic Tissue Dissociation in Cell Function Studies

The first step to obtain a cellular suspension from tissues is the disaggregation procedure. The cell suspension method has to provide a representative sample of the different cellular subpopulations and to maximize the number of viable functional cells. Here, we analyzed specific cell functions in cell suspensions from several rat tissues obtained by two different methods, automated–mechanical and enzymatic disaggregation. Flow cytometric, confocal, and ultrastructural (TEM) analyses were applied to the spleen, testis, liver and other tissues. Samples were treated by an enzymatic trypsin solution or processed by the Medimachine II (MMII). The automated–mechanical and enzymatic disaggregation procedures have shown to work similarly in some tissues, which displayed comparable amounts of apoptotic/necrotic cells. However, cells obtained by the enzyme-free Medimachine II protocols show a better preservation lysosome and mitochondria labeling, whereas the enzymatic gentle dissociation appears to constantly induce a lower amount of intracellular ROS; nevertheless, lightly increased ROS can be recognized as a complimentary signal to promote cell survival. Therefore, MMII represents a simple, fast, and standardized method for tissue processing, which allows to minimize bias arising from the operator’s ability. Our study points out technical issues to be adopted for specific organs and tissues to obtain functional cells.

Establishment and characterization of a new spontaneously immortalized ER-/PR-/HER2+ human breast cancer cell line, DHSF-BR16

Invasive ductal carcinoma (IDC) constitutes the most frequent malignant cancer endangering women’s health. In this study, a new spontaneously immortalized breast cancer cell line, DHSF-BR16 cells, was isolated from the primary IDC of a 74-years old female patient, treated with neoadjuvant chemotherapy and disease-free 5-years after adjuvant chemotherapy. Primary breast cancer tissue surgically removed was classified as ER⁻/PR⁻/HER2⁺, and the same phenotype was maintained by DHSF-BR16 cells. We examined DHSF-BR16 cell morphology and relevant biological and molecular markers, as well as their response to anticancer drugs commonly used for breast cancer treatment. MCF-7 cells were used for comparison purposes. The DHSF-BR16 cells showed the ability to form spheroids and migrate. Furthermore, DHSF-BR16 cells showed a mixed stemness phenotype (i.e. CD44⁺/CD24^−/low), high levels of cytokeratin 7, moderate levels of cytokeratin 8 and 18, EpCAM and E-Cadh. Transcriptome analysis showed 2071 differentially expressed genes between DHSF-BR16 and MCF-7 cells (logFC > 2, p-adj < 0.01). Several genes were highly upregulated or downregulated in the new cell line (log2 scale fold change magnitude within − 9.6 to + 12.13). A spontaneous immortalization signature, mainly represented by extracellular exosomes-, plasma membrane- and endoplasmic reticulum membrane pathways (GO database) as well as by metabolic pathways (KEGG database) was observed in DHSF-BR16 cells. Also, these cells were more resistant to anthracyclines compared with MCF-7 cells. Overall, DHSF-BR16 cell line represents a relevant model useful to investigate cancer biology, to identify both novel prognostic and drug response predictive biomarkers as well as to assess new therapeutic strategies.

Rapid Isolation of Functional ex vivo Human Skin Tissue-Resident Memory T Lymphocytes

Studies in animal models have shown that skin tissue-resident memory T (T_RM) cells provide enhanced and immediate effector function at the site of infection. However, analyses of skin T_RM cells in humans have been hindered by the lack of an optimized isolation protocol. Here, we present a combinatorial strategy-the 6-h collagenase IV digestion and gentle tissue dissociation – for rapid and efficient isolation of skin T_RM cells with skin tissue-specific immune features. In comparison with paired blood circulating memory T cells, these ex vivo isolated skin T cells express typical T_RM cell markers and display higher polyfunctional properties. Moreover, these isolated cells can also be assessed for longer periods of time in ex vivo cultures. Thus, the optimized isolation protocol provides a valuable tool for further understanding of human skin T_RM cells, especially for direct comparison with peripheral blood T cells at the same sample collection time.

Leukotriene B4 licenses inflammasome activation to enhance skin host defense

The initial production of inflammatory mediators dictates host defense as well as tissue injury. Inflammasome activation is a constituent of the inflammatory response by recognizing pathogen and host-derived products and eliciting the production of IL-1β and IL-18 in addition to inducing a type of inflammatory cell death termed "pyroptosis." Leukotriene B4 (LTB4) is a lipid mediator produced quickly (seconds to minutes) by phagocytes and induces chemotaxis, increases cytokine/chemokine production, and enhances antimicrobial effector functions. Whether LTB4 directly activates the inflammasome remains to be determined. Our data show that endogenously produced LTB4 is required for the expression of pro-IL-1β and enhances inflammasome assembly in vivo and in vitro. Furthermore, LTB4-mediated Bruton's tyrosine kinase (BTK) activation is required for inflammasome assembly in vivo as well for IL-1β-enhanced skin host defense. Together, these data unveil a new role for LTB4 in enhancing the expression and assembly of inflammasome components and suggest that while blocking LTB4 actions could be a promising therapeutic strategy to prevent inflammasome-mediated diseases, exogenous LTB4 can be used as an adjuvant to boost inflammasome-dependent host defense.

Quality Control of Immunophenotyping

Applications of immunophenotyping using flow cytometry offer precise and accurate means for providing information used to both diagnose and monitor disease; they serve as a standard platform for many research endeavors that study discrete populations of biological entities. The proper use of this highly sophisticated technology requires daily and ongoing monitoring of both the instrument and the methodology. Best practices for this begin with quality control (QC) procedures designed to set up and monitor the instrument performance, the reagents, and the results to ensure that they are working properly both on the day of use and over time. If the results of those QC procedures are outside of acceptable then recording the corrective action taken must also be included in the quality control records. Quality assurance (QA) is a way to know that the three phases of testing, namely, preanalytic, analytic, and postanalytic procedures, are being followed. This chapter describes the procedures used to assess quality control as it pertains to flow cytometry and immunophenotyping in all three phases of testing.

Identification of an optimal method for extracting RNA from human skin biopsy, using domestic pig as a model system

To evaluate skin tissue gene expression patterns correctly, extracting sufficient quantities of good quality RNA is essential. However, RNA extraction from skin tissue is challenging, as the hyaluronic acid-collagen matrix is extremely difficult to homogenize. Although there are multiple ways to extract RNA from skin, there are no comparative studies that identify the most critical steps, e.g. sample collection, storage and homogenization. We analysed the various steps involved in RNA extraction (i.e. biopsy collection as dry biopsy or into nucleotide stabilizing reagents, different storage conditions, enzymatic digestion, stator-rotor and bead motion-based homogenizing combined with column-based RNA purification). We hypothesised that domestic pig skin is applicable as a model for human skin studies. Altogether twenty different workflows were tested on pig skin and the four most promising workflows were tested on human skin samples. The optimal strategy for extracting human skin RNA was to collect, store and homogenize the sample in RLT lysis buffer from the RNeasy Fibrous Tissue Kit combined with beta-mercaptoethanol. Both stator-rotor and bead motion-based homogenizing were found to result in high quality and quantity of extracted RNA. Our results confirmed that domestic pig skin can be successfully used as a model for human skin RNA studies.

Multiplex staining depicts the immune infiltrate in colitis-induced colon cancer model

Assessment of the host immune response pattern is of increasing importance as highly prognostic and diagnostic, in immune-related diseases and in some types of cancer. Chronic inflammation is a major hallmark in colon cancer formation, but, despite the extent of local inflammatory infiltrate has been demonstrated to be extremely informative, its evaluation is not routinely assessed due to the complexity and limitations of classical immunohistochemistry (IHC). In the last years, technological advance helped in bypassing technical limits, setting up multiplex IHC (mIHC) based on tyramide signal amplification (TSA) method and designing software suited to aid pathologists in cell scoring analysis. Several studies verified the efficacy of this method, but they were restricted to the analysis of human samples. In the era of translational medicine the use of animal models to depict human pathologies, in a more complete and complex approach, is really crucial. Nevertheless, the optimization and validation of this method to species other than human is still poor. We took advantage of Multispectral Imaging System to identify the immunoprofile of Dextran Sulphate Sodium (DSS)-treated mouse colon. We optimized a protocol to sequentially stain formalin fixed paraffin embedded murine colon samples for CD3, CD8a, CD4, and CD4R5B0 antigens. With this approach we obtained a detailed lymphocyte profile, while preserving the morphological tissue context, generally lost with techniques like gene expression profiling or flow cytometry. This study, comparing the results obtained by mIHC with immunophenotyping performed with cytofluorimetric and standard IHC methods validates the potentiality and the applicability of this innovative approach.

Macrophage-derived LTB4 promotes abscess formation and clearance of Staphylococcus aureus skin infection in mice

The early events that shape the innate immune response to restrain pathogens during skin infections remain elusive. Methicillin-resistant Staphylococcus aureus (MRSA) infection engages phagocyte chemotaxis, abscess formation, and microbial clearance. Upon infection, neutrophils and monocytes find a gradient of chemoattractants that influence both phagocyte direction and microbial clearance. The bioactive lipid leukotriene B4 (LTB4) is quickly (seconds to minutes) produced by 5-lipoxygenase (5-LO) and signals through the G protein-coupled receptors LTB4R1 (BLT1) or BLT2 in phagocytes and structural cells. Although it is known that LTB4 enhances antimicrobial effector functions in vitro, whether prompt LTB4 production is required for bacterial clearance and development of an inflammatory milieu necessary for abscess formation to restrain pathogen dissemination is unknown. We found that LTB4 is produced in areas near the abscess and BLT1 deficient mice are unable to form an abscess, elicit neutrophil chemotaxis, generation of neutrophil and monocyte chemokines, as well as reactive oxygen species-dependent bacterial clearance. We also found that an ointment containing LTB4 synergizes with antibiotics to eliminate MRSA potently. Here, we uncovered a heretofore unknown role of macrophage-derived LTB4 in orchestrating the chemoattractant gradient required for abscess formation, while amplifying antimicrobial effector functions.

Topical Prostaglandin E Analog Restores Defective Dendritic Cell-Mediated Th17 Host Defense Against Methicillin-Resistant Staphylococcus Aureus in the Skin of Diabetic Mice

People with diabetes are more prone to Staphylococcus aureus skin infection than healthy individuals. Control of S. aureus infection depends on dendritic cell (DC)-induced T-helper 17 (Th17)-mediated neutrophil recruitment and bacterial clearance. DC ingestion of infected apoptotic cells (IACs) drive prostaglandin E₂ (PGE₂) secretion to generate Th17 cells. We speculated that hyperglycemia inhibits skin DC migration to the lymph nodes and impairs the Th17 differentiation that accounts for poor skin host defense in diabetic mice. Diabetic mice showed increased skin lesion size and bacterial load and decreased PGE₂ secretion and Th17 cells compared with nondiabetic mice after methicillin-resistant S. aureus (MRSA) infection. Bone marrow-derived DCs (BMDCs) cultured in high glucose (25 mmol/L) exhibited decreased Ptges mRNA expression, PGE₂ production, lower CCR7-dependent DC migration, and diminished maturation after recognition of MRSA-IACs than BMDCs cultured in low glucose (5 mmol/L). Similar events were observed in DCs from diabetic mice infected with MRSA. Topical treatment of diabetic mice with the PGE analog misoprostol improved host defense against MRSA skin infection by restoring DC migration to draining lymph nodes, Th17 differentiation, and increased antimicrobial peptide expression. These findings identify a novel mechanism involved in poor skin host defense in diabetes and propose a targeted strategy to restore skin host defense in diabetes.

Dissociation of skeletal muscle for flow cytometric characterization of immune cells in macaques

The majority of vaccines and several treatments are administered by intramuscular injection. The aim is to engage and activate immune cells, although they are rare in normal skeletal muscle. The phenotype and function of resident as well as infiltrating immune cells in the muscle after injection are largely unknown. While methods for obtaining and characterizing murine muscle cell suspensions have been reported, protocols for nonhuman primates (NHPs) have not been well defined. NHPs comprise important in vivo models for studies of immune cell function due to their high degree of resemblance with humans. In this study, we developed and systematically compared methods to collect vaccine-injected muscle tissue to be processed into single cell suspensions for flow cytometric characterization of immune cells. We found that muscle tissue processed by mechanical disruption alone resulted in significantly lower immune cell yields compared to enzymatic digestion using Liberase. Dendritic cell subsets, monocytes, macrophages, neutrophils, B cells, T cells and NK cells were readily detected in the muscle by the classic human markers. The methods for obtaining skeletal muscle cell suspension established here offer opportunities to increase the understanding of immune responses in the muscle, and provide a basis for defining immediate post-injection vaccine responses in primates.

Comparison of enzymatic digestion and mechanical dissociation of human testicular tissues

OBJECTIVE

To compare mechanical dissociation, employing the Medimachine system, and enzymatic digestion of human testicular tissues with respect to the proportion of spermatogonia and somatic cells, with the long-term objective of establishing human spermatogonial cultures.

DESIGN

Experimental basic science study.

SETTING

Reproductive biology laboratory.

PATIENT(S)

Testicular tissues were obtained from patients with gender dysphoria on the day of sex reassignment surgery. On the basis of the histological evaluation, tissue samples with complete spermatogenesis (fresh, n = 6; cryopreserved, n = 7) and with meiotic arrest (cryopreserved, n = 4) were selected.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The composition of testicular cell suspensions was assessed performing quantitative real-time polymerase chain reaction (qPCR) analyses for germ cell-specific (FGFR3, SALL4, UTF1, MAGE-A4) and somatic marker genes (ACTA2 and VIM). Additionally, flow-cytometric analyses were used to evaluate the percentage of SALL4-and vimentin-positive cells.

RESULT(S)

While Medimachine dissociation yielded higher cell numbers in all patient groups, viability of cells was highly variable and correlated with the histological status of the tissue. Interestingly, qPCR analysis revealed a significantly decreased expression of the somatic marker genes ACTA2 and VIM and an increased expression of the spermatogonial marker genes FGFR3 and SALL4 after Medimachine dissociation. These findings were corroborated by flow-cytometric analyses that demonstrated that the proportion of SALL4-positive cells was up to 4 times higher after mechanical dissociation.

CONCLUSION(S)

Medimachine dissociation of human testicular tissues is comparably fast and leads to an enrichment of SALL4-positive spermatogonia. The use of this method may therefore constitute an advantage for the establishment of human spermatogonial cell cultures.

Flow cytometric identification of immunophenotypically aberrant T-cell clusters on skin shave biopsy specimens from patients with mycosis fungoides

OBJECTIVES

To assess the ability of flow cytometry (FC) to detect putative neoplastic T-cell subsets on skin shave biopsy (SSB) specimens from patients with mycosis fungoides (MF) and to study the immunophenotype of skin-infiltrating tumor cells in MF.

METHODS

SSB specimens from patients with suspected MF were bisected and submitted for both FC and routine histopathology. Six-dimensional gating strategies were applied to identify putative neoplastic cells, independently from their expected immunophenotype.

RESULTS

Aberrant T cells were detected by FC in 18 of 33 SBB specimens, of which all had clinicomorphologic features of MF. Of the remaining 15 SSB specimens, six had clinicomorphologic features of MF and nine were diagnosed with benign inflammatory dermatoses. Unexpectedly, CD26 was aberrantly overexpressed in 11 (73%) and lost in three (20%) of 15 SSB specimens from patients with MF where this antigen was evaluated. Other detected aberrancies included CD3 dim- (13/18 [72%]), CD7 dim- (15/18 [83%]), and CD4-/CD8- (3/18 [17%]).

CONCLUSIONS

FC is capable of identifying putative neoplastic cells on SSB specimens from patients with MF. Bright homogeneous CD26 expression is a common and previously undescribed immunophenotypic aberrancy on MF skin infiltrates.

Development and optimization of a non-enzymatic method of leukocyte isolation from macaque tissues

BACKGROUND AND METHODS

Cell isolation from macaque tissues involves laborious enzymatic digestion. The Medimachine provides a simpler, quicker non-enzymatic method, yielding 1.5–5 million cells/g of vaginal or rectal tissue from pigtailed macaques.

RESULTS AND CONCLUSIONS

Flow cytometry analysis of the two methods revealed similar levels of cell viability and most major cell lineage and activation markers.

An optimized disaggregation method for human lung tumors that preserves the phenotype and function of the immune cells

Careful preparation of human tissues is the cornerstone of obtaining accurate data in immunologic studies. Despite the essential importance of tissue processing in tumor immunology and clinical medicine, current methods of tissue disaggregation have not been rigorously tested for data fidelity. Thus, we critically evaluated the current techniques available in the literature that are used to prepare human lung tumors for immunologic studies. We discovered that these approaches are successful at digesting cellular attachments and ECMs; however, these methods frequently alter the immune cell composition and/or expression of surface molecules. We thus developed a novel approach to prepare human lung tumors for immunologic studies by combining gentle mechanical manipulation with an optimized cocktail of enzymes used at low doses. This enzymatic digestion cocktail optimized cell yield and cell viability, retrieved all major tumor-associated cell populations, and maintained the expression of cell-surface markers for lineage definition and in vivo effector functions. To our knowledge, we present the first rigorously tested disaggregation method designed for human lung tumors.

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.

Optimal molecular profiling of tissue and tissue components: defining the best processing and microdissection methods for biomedical applications

Isolation of well-preserved pure cell populations is a prerequisite for sound studies of the molecular basis of any tissue-based biological phenomenon. This updated chapter reviews current methods for obtaining anatomically specific signals from molecules isolated from tissues, a basic requirement for productive linking of phenotype and genotype. The quality of samples isolated from tissue and used for molecular analysis is often glossed over or omitted from publications, making interpretation and replication of data difficult or impossible. Fortunately, recently developed techniques allow life scientists to better document and control the quality of samples used for a given assay, creating a foundation for improvement in this area. Tissue processing for molecular studies usually involves some or all of the following steps: tissue collection, gross dissection/identification, fixation, processing/embedding, storage/archiving, sectioning, staining, microdissection/annotation, and pure analyte labeling/identification and quantification. We provide a detailed comparison of some current tissue microdissection technologies and provide detailed example protocols for tissue component handling upstream and downstream from microdissection. We also discuss some of the physical and chemical issues related to optimal tissue processing and include methods specific to cytology specimens. We encourage each laboratory to use these as a starting point for optimization of their overall process of moving from collected tissue to high-quality, appropriately anatomically tagged scientific results. Improvement in this area will significantly increase life science quality and productivity. The chapter is divided into introduction, materials, protocols, and notes subheadings. Because many protocols are covered in each of these sections, information relating to a single protocol is not contiguous. To get the greatest benefit from this chapter, readers are advised to read through the entire chapter first, identify protocols appropriate to their laboratory for each step in their workflow, and then reread entries in each section pertaining to each of these single protocols.

Phenotypic characterization and functional analysis of human tumor immune infiltration after mechanical and enzymatic disaggregation

Multi-parametric flow cytometry analysis is a reliable method for phenotypic and functional characterization of tumor infiltrating immune cells (TIIC). The isolation of infiltrating leukocytes from solid tumors can be achieved through various methods which can be both enzymatic and mechanical; however, these methods may alter cell biology. The aim of this study was to compare the effects of three tissue disaggregation techniques on TIIC biology in breast, kidney and lung tumor specimens. We therefore compared two enzymatic treatments using either collagenase type IA alone or in combination with collagenase type IV and DNase I type II, and one mechanical system (Medimachine™). We evaluated the impact of treatments on cell viability, surface marker integrity and proliferative capacity. We show that cell viability was not significantly altered by treatments. However, enzymatic treatments decreased cell proliferation; specifically collagenases and DNase provoked a significant decrease in detection of surface markers such as CD4, CD8, CD45RA and CD14, indicating that results of phenotypic studies employing these techniques could be affected. In conclusion, mechanical tissue disaggregation by Medimachine™ appears to be optimal to maintain phenotypic and functional TIIC features.

A practical approach to the flow cytometric detection and diagnosis of T-cell lymphoproliferative disorders

The flow cytometric analysis of T-cell malignancies is difficult due to the heterogeneity of T-cells and the lack of convenient methods to detect T-cell clonality. Neoplastic T-cells are most often detected by their altered level of surface antigen expression, and detection requires an extensive knowledge of the phenotype of normal T-lymphocytes. This review focuses on the methods to distinguish malignant T-cells from their normal counterparts and the phenotypic features of the T-cell lymphoproliferative disorders.

TCRgamma-chain gene rearrangement by PCR-based GeneScan: diagnostic accuracy improvement and clonal heterogeneity analysis in multiple cutaneous T-cell lymphoma samples

Cutaneous T-cell lymphomas are a heterogeneous group of lymphomas where the tumor population emerges within a multiple subclone pattern ("clonal heterogeneity"). PCR analysis has been shown to be useful in the diagnosis of mycosis fungoides (MF) and Sézary Syndrome (SS). Focusing the attention on clonal heterogeneity, the efficacy of the multiplex/heteroduplex (HD) PCR and the GeneScan (GS) capillary electrophoresis analysis was compared in the early diagnosis of MF/SS, using a multiple sample approach. Indeed, GS demonstrated TCRgamma gene rearrangement (GR) in all the 57 SS (100%) and in 123/146 (84%) of the MF samples, whereas the multiplex/HD PCR was less sensitive. An increase in clonality was observed in connection with both a worsening of the cutaneous disease (79% T1/T2; 100% T3/T4) and an increase in the histopathological score (HS < 5, 76%; HS > or = 5, 94%). Clonal heterogeneity with adjunctive reproducible skin TCRgamma-GRs was also observed. "Clonal instability," with different GRs, was present in a small percentage of patients. Therefore, it can be concluded that GS analysis in TCRgamma-GR is able to improve diagnosis in MF/SS patients and the multiple sample approach is helpful for a correct interpretation of clonal patterns in skin lesions, especially in early-stage MF and in SS skin/blood samples.

Expression pattern of chemokine receptors and chemokine release in inflammatory erythroderma and Sézary syndrome

BACKGROUND

Erythroderma can be caused by inflammatory dermatoses or cutaneous T-cell lymphoma. Even if chemokines and their receptors are involved in the skin-selective lymphocyte recruitment, their role in inflammatory erythroderma is yet unclear.

OBJECTIVE

To evaluate the chemokine release (TARC, MDC, IP-10) and to define the expression pattern of Th1- (CCR5, CXCR3) and Th2-related (CCR4) chemokine receptors in inflammatory erythroderma and Sézary syndrome (SS).

MATERIALS AND METHODS

Flow cytometry has been carried out on both circulating and skin-infiltrating T lymphocytes; serum chemokine levels have been evaluated using ELISA techniques.

RESULTS

CCR4, CCR5 and CXCR3 were expressed on about 40% of peripheral blood lymphocytes and on the majority of skin-infiltrating lymphocytes in the inflammatory erythroderma patients, whereas the leukemic CD4+CD26- subpopulation in SS was characterized by a high CCR4 expression without a concurrent increase in CCR5 or CXCR3. TARC, MDC and IP-10 serum levels were significantly increased in both erythrodermic and SS patients.

CONCLUSIONS

Our results confirm that SS is a Th2 disorder with a selective expression of CCR4, whereas inflammatory erythroderma shares an overexpression of both Th1- and Th2-related chemokine receptors, suggesting an activation of different pathways driving reactive lymphocytes to the skin.

Optimal molecular profiling of tissue and tissue components: defining the best processing and microdissection methods for biomedical applications

Isolation of well-preserved pure cell populations is a prerequisite for sound studies of the molecular basis of any tissue-based biological phenomenon. This article reviews current methods for obtaining anatomically specific signals from molecules isolated from tissues, a basic requirement for productive linking of phenotype and genotype. The quality of samples isolated from tissue and used for molecular analysis is often glossed over or omitted from publications, making interpretation and replication of data difficult or impossible. Fortunately, recently developed techniques allow life scientists to better document and control the quality of samples used for a given assay, creating a foundation for improvement in this area. Tissue processing for molecular studies usually involves some or all of the following steps: tissue collection, gross dissection/identification, fixation, processing/embedding, storage/archiving, sectioning, staining, microdissection/annotation, and pure analyte labeling/identification and quantification. We provide a detailed comparison of some current tissue microdissection technologies, and provide detailed example protocols for tissue component handling upstream and downstream from microdissection. We also discuss some of the physical and chemical issues related to optimal tissue processing, and include methods specific to cytology specimens. We encourage each laboratory to use these as a starting point for optimization of their overall process of moving from collected tissue to high quality, appropriately anatomically tagged scientific results. In optimized protocols is a source of inefficiency in current life science research. Improvement in this area will significantly increase life science quality and productivity. The article is divided into introduction, materials, protocols, and notes sections. Because many protocols are covered in each of these sections, information relating to a single protocol is not contiguous. To get the greatest benefit from this article, readers are advised to read through the entire article first, identify protocols appropriate to their laboratory for each step in their workflow, and then reread entries in each section pertaining to each of these single protocols.

Failed or inadequate bone marrow aspiration: a fast, simple and cost-effective method to produce a cell suspension from a core biopsy specimen

Failure to aspirate bone marrow (BM) diminishes diagnostic accuracy and efficiency because BM cell suspensions are crucial for modern haematological diagnostic methods such as cytomorphology, flow cytometric immunophenotyping (FCI), cytogenetics or fluorescent in situ hybridization (FISH). We mechanically disaggregated unfixed BM core biopsies with the Dako Medimachine in 65 cases of macroscopically suspected dry taps. Cytospins, three-colour FCI and in some cases karyotyping and FISH were performed successfully. Most cytospins (34 of 50; 68.0%) were of good quality, while a further 18.0% showed moderate but still informative quality. FCI showed good quality in 36 of 60 (60.0%) cases; in 13.3% quality was moderate, but diagnostically useful results were obtained. Surprisingly, all four cases of formerly undiagnosed BM-carcinosis could be clearly detected on cytospins. Finally, five of seven (71.4%) attempts yielded analysable metaphases mostly in cases where no metaphases could be obtained from BM or peripheral blood. The described method of mechanical disaggregation of unfixed BM core biopsies compares favourably with other published approaches, allowing the application of all techniques where BM cell suspensions are needed. Thus, it can help to establish the underlying diagnosis in patients with abnormalities in peripheral blood and unsuccessful marrow aspirations.

HER-2/neu Overexpression Increases the Viable Hypoxic Cell Population within Solid Tumors without Causing Changes in Tumor Vascularization

The effects of HER-2/neu overexpression on the tumor microenvironment in an aggressive breast cancer xenograft model were investigated. These studies focused on tumors derived following the subcutaneous injection of MDA-MB-435/LCC6 cells transfected with human c-erbB2 (LCC6HER-2) into SCID-Rag2M mice. LCC6HER-2 tumors were more viable (H&E-stained tumor sections) than isogenic vector control tumors (LCC6Vector). Correspondingly, a 2.7-fold increase in trypan blue–excluding cells (P = 0.00056) and a 4.8-fold increase in clonogenic cells (P = 0.00146) were noted in cell suspensions derived from disaggregated LCC6HER-2 versus LCC6Vector tumors. Tumor sections stained with the antibody detecting 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide (EF5), a marker of hypoxia, showed a greater fraction of hypoxic tissue in LCC6HER-2 tumors compared with control tumors. Flow cytometric analyses based on viable tumor cells (DNA content ≥ 2N) in cell suspensions from disaggregated tumors confirmed that there were significantly more EF5-positive cells (i.e., hypoxic) in LCC6HER-2 than in LCC6Vector tumors (16.41 ± 8.1% and 5.96 ± 4.1%, respectively; P = 0.0015). Protein levels of phosphorylated (Ser536) nuclear factor-κB p65 were significantly elevated in LCC6HER-2 tumors (P = 0.00048), and a trend in increased hypoxia-inducible factor-1α protein levels was observed in LCC6HER-2 compared with LCC6Vector tumors. Despite the substantial viable hypoxic cell fraction and a 1.7-fold increase of vascular endothelial growth factor protein (P = 0.05) in LCC6HER-2 tumors, no significant differences were found (P &gt; 0.05) between LCC6HER-2 and LCC6Vector vasculature (CD31 staining and Hoechst 33342 perfusion). These results suggest that HER-2/neu overexpression may be linked with overall increased tumor viability and a significant increase in the population of viable hypoxic cells, which is not due to differences in tumor vascularization.

Comparison of flow cytometry and image morphometry in the quantitative analysis of cell population markers in the lymph node of sheep

Two approaches to the quantitative analysis of cell population markers in tissues are flow cytometry and image morphometry. To compare these methods, sheep lymph nodes were collected and analysed for CD8+ and CD21+ cell populations, which were selected to represent dispersed and concentrated cell populations, respectively. These two populations were measured as a percentage of total cell count (flow) or total tissue area (morphometry). The two populations were also measured as a percentage of respective base populations (CD2+ cells for CD8 and MHC II+ cells for CD21). A simple linear regression analysis showed that when the cell populations were assessed as a percentage of total cell count or total area, measurements obtained with flow and morphometry only correlated significantly with the dispersed CD8+ population and not with the highly concentrated CD21+ population. However, when the cell populations were assessed as a percentage of their base population, measurements obtained with flow and morphometry showed a significant correlation for both the dispersed and concentrated cell populations. This study demonstrates that measurements of lymph node cell populations obtained with the two methods are comparable, but that tissue distribution of cell populations should be considered, when the unit of measurement is chosen.