Molecular subtyping of gastric cancer according to ACRG using immunohistochemistry - Correlation with clinical parameters.

BACKGROUND: Gastric cancer (GC) is a very heterogenous disease necessitating further stratification for prognostic and therapeutic aspects. Based on the recommendation of The Asisan Cancer Research Group (ACRG) recently established four molecular subtypes (MSI, MSS/EMT, MSS/TP53+, MSS/TP53-) which require molecular expression analysis. The technology required for comprehensive molecular analysis is expensive and not applicable for routine diagnostics. Thus, in this study we established a classification system utilizing immunohistochemistry and morphology-based analyses as surrogate markers in order to reproduce the ACRG molecular subtypes of gastric cancer. To clarify the clinical relevance of the novel classification system, we performed a correlation with established clinical parameters. METHODS: The study cohort consisted of 189 patients with GC (UICC III and IV). Using immunohistochemistry, the following markers were analysed: MLH1, MSH2, MSH6, PMS2 (as a surrogate for microsatellite status), p53, SOX9. We assessed tumor budding as a surrogate for EMT to distinguish between MSS/EMT and MSS/non-EMT groups. RESULTS: Immunohistochemical and morphologic subtyping classified cases as follows: 10% MSI, 35% MSS/EMT, 16% MSS/TP53 + and 39% MSS/TP53-. Subtypes significantly correlated with the Lauren classification, tumor stage, venous invasion and SOX9 expression (p < .05). There was no significant correlation between molecular subtype and lymph node growth pattern. CONCLUSION: We propose a simple algorithm for molecular subtyping of GC using universally available immunohistochemistry, which correlates with clinical parameters and is cost-effective and applicable in diagnostic routine. This classification might prospectively help to determine patient prognosis, optimize patient care and homogenize patient cohorts for clinical trials.

Deep phenotyping of T cell populations under long-term treatment of tacrolimus and rapamycin in patients receiving renal transplantations by mass cytometry.

Tacrolimus (FK506) and rapamycin (RAPA) are widely used to maintain long-term immunosuppression after organ transplantation. However, the impact of accumulative drug administration on the recipients' immune systems remains unclear. We investigated the impact of 3-year FK506 or RAPA treatment after renal transplantation on the human immune systems. A discovery cohort of 30 patients was first recruited, and we discovered two distinctive T lineage suppressive regulatory patterns induced by chronic treatment of FK506 and RAPA. The increased percentage of senescent CD8+ CD57+ T lineages and less responsive T cell receptor (TCR) pathway in the FK506 group indicate better graft acceptance. Meanwhile, percentages of regulatory T cells (Tregs) and expression of CTLA-4 were both up to two-fold higher in the RAPA group, suggesting the inconsistent reactivation potential of the FK506 and RAPA groups when an anti-tumour or anti-infection immune response is concerned. Additionally, up-regulation of phosphorylated signaling proteins in T lineages after in vitro CD3/CD28 stimulation suggested more sensitive TCR-signaling pathways reserved in the RAPA group. An independent validation cohort of 100 renal transplantation patients was further investigated for the hypothesis that long-term RAPA administration mitigates the development of tumours and infections during long-term intake of immunosuppressants. Our results indicate that RAPA administration indeed results in less clinical oncogenesis and infection. The deep phenotyping of T-cell lineages, as educated by the long-term treatment of different immunosuppressants, provides new evidence for personalized precision medicine after renal transplantations.

CytoPy: An autonomous cytometry analysis framework.

Cytometry analysis has seen a considerable expansion in recent years in the maximum number of parameters that can be acquired in a single experiment. In response to this technological advance there has been an increased effort to develop new computational methodologies for handling high-dimensional single cell data acquired by flow or mass cytometry. Despite the success of numerous algorithms and published packages to replicate and outperform traditional manual analysis, widespread adoption of these techniques has yet to be realised in the field of immunology. Here we present CytoPy, a Python framework for automated analysis of cytometry data that integrates a document-based database for a data-centric and iterative analytical environment. In addition, our algorithm-agnostic design provides a platform for open-source cytometry bioinformatics in the Python ecosystem. We demonstrate the ability of CytoPy to phenotype T cell subsets in whole blood samples even in the presence of significant batch effects due to technical and user variation. The complete analytical pipeline was then used to immunophenotype the local inflammatory infiltrate in individuals with and without acute bacterial infection. CytoPy is open-source and licensed under the MIT license. CytoPy is available at https://github.com/burtonrj/CytoPy, with notebooks accompanying this manuscript (https://github.com/burtonrj/CytoPyManuscript) and software documentation at https://cytopy.readthedocs.io/.

Immune and gene expression profiling during tacrolimus to everolimus conversion early after liver transplantation.

Early elimination of tacrolimus in favor of everolimus can improve renal function in liver transplant recipients. However, as this approach increases the risk of acute rejection, it may benefit from predictive biomarkers guiding weaning. We enrolled 20 recipients on stable tacrolimus + everolimus to undergo tacrolimus withdrawal early post-liver transplant. Blood samples were collected at month 3 (withdrawal initiation), 4 (withdrawal completion), 4.5 and 6 (both everolimus alone). 15 patients did not reject and 5 had mild rejection responding to tacrolimus resumption. Before tacrolimus withdrawal, eventual rejecters had higher percentages of CD56+ NK cells and CD19+CD27+CD24+ memory B cells, and lower levels of T cells expressing the exhaustion marker PD-1. Over time, memory B cells, Ki-67+CD3+ (proliferating) cells and CD4+CD127-CD25HIGH FOXP3+ Tregs increased in rejecters. Tregs also increased in non-rejecters over time. The number of differentially expressed genes progressively increased in rejecters, particularly in mTOR, Eukaryotic Initiation Factor 2, and Neuroinflammation signaling pathways. There was no difference in anti-HLA antibodies between the groups. In summary, blood mononuclear cell and gene expression may predict successful vs. failed early tacrolimus withdrawal in liver transplant recipients. While needing validation, these preliminary findings highlight the potential for cellular and molecular biomarkers to guide decision-making during tacrolimus weaning.

Invasive Fungal Disease in Critically Ill Patients at High Risk: Usefulness of Lymphocyte Subtyping.

OBJECTIVES: This study aimed to investigate the distinguishing ability of lymphocyte subtyping for diagnosis and prognosis of invasive fungal disease (IFD). METHODS: We assessed lymphocyte subtyping and evaluated the quantitative changes in key immunological parameters at intensive care unit (ICU) admission in critically ill patients at high risk and their potential influence on diagnosis and outcome of IFD. The primary outcome was 28-day mortality. RESULTS: Among the 124 critically ill patients with mean Candida score 3.89 (0.76), 19 (15.3%) were in the IFD group. CD28+CD8+ T-cell counts (area under the curve [AUC] 0.899, 95% confidence interval [CI], 0.834-0.964, P < .001) had better distinguishing ability than other immune parameters for IFD diagnosis. The cutoff value of CD28+CD8+ T-cell counts at ICU admission for IFD diagnosis was 59.5 cells/mm3, with 83.3% sensitivity and 86.4% specificity. Multivariate logistic regression analysis identified CD28+CD8+ T-cell count <59.5 cells/mm3 (odds ratio 59.7, 95% CI, 7.33-486.9, P < .001) as an independent predictor for IFD diagnosis. CD28+CD8+ T-cell counts could also predict 28-day mortality (AUC 0.656, 95% CI, 0.525-0.788, P = .045). Kaplan-Meier survival analysis provided evidence that natural killer cell count <76.0 cells/mm3 (log-rank test; P = .001), CD8+ T-cell count <321.5 cells/mm3 (log-rank test; P = .04), and CD28+CD8+ T-cell count <129.0 cells/mm3 (log-rank test; P = .02) at ICU admission were associated with lower survival probabilities. CONCLUSION: CD28+CD8+ T-cell counts play an important role in early diagnosis of IFD. Low counts are associated with early mortality in critically ill patients at high risk of IFD. Our findings add evidence to the utility of lymphocyte subtyping in a diagnostic algorithm to better define IFD in critically ill patients at high risk.

Peripheral blood lymphocyte subset repertoires are biased and reflect clinical features in patients with dermatomyositis.

OBJECTIVE: Dermatomyositis (DM) is an idiopathic inflammatory myopathy which often involves the lungs. DM is likely to be associated with aberrant T- and B-cell activation in the pathogenesis because of the proven effectiveness of T- and B-cell-targeted treatments. Assuming that the aberrant activation is reflected by biases in the lymphocyte subset repertoires, we aimed to elucidate these biases, especially in relation to clinical features of DM. METHOD: Based on the immunophenotyping standardized by the Human Immunology Project Consortium, untreated 13 DM patients, including seven patients with interstitial lung disease (ILD), and 18 age-matched healthy donors (HDs) were examined for proportions of peripheral blood lymphocyte subsets. Six DM patients were examined before and after successful induction of remission. RESULTS: Naïve CD4+ T cells and naïve B cells were more abundant, while there were fewer naïve CD8+ T cells, central memory CD8+ T cells, effector memory CD4+ T cells, Th1 cells, Tfh cells, and memory B cells in DM patients than in HDs. When the patients were subgrouped according to the presence of ILD, the lymphocyte subset repertoires in the patients with ILD contributed to the statistical differences in all the biased lymphocyte subset proportions. After treatment, transitional B cells vanished and there was an increase in memory B cells. CONCLUSION: The lymphocyte subset repertoires in the DM patients were biased, and were associated with the presence of ILD and disease activity of DM.

High throughput automated analysis of big flow cytometry data.

The rapid expansion of flow cytometry applications has outpaced the functionality of traditional manual analysis tools used to interpret flow cytometry data. Scientists are faced with the daunting prospect of manually identifying interesting cell populations in 50-dimensional datasets, equalling the complexity previously only reached in mass cytometry. Data can no longer be analyzed or interpreted fully by manual approaches. While automated gating has been the focus of intense efforts, there are many significant additional steps to the analytical pipeline (e.g., cleaning the raw files, event outlier detection, extracting immunophenotypes). We review the components of a customized automated analysis pipeline that can be generally applied to large scale flow cytometry data. We demonstrate these methodologies on data collected by the International Mouse Phenotyping Consortium (IMPC).

Clinical Aspects, Immunophenotypic Analysis and Survival Rate of Chronic Lymphocytic Leukaemia Patients in Erbil City, Iraq.

OBJECTIVES: Chronic lymphocytic leukaemia (CLL) is characterised by an accumulation of clonal B cells in the blood, bone marrow and lymphatic tissue. This study aimed to evaluate the clinical and immunophenotypic characteristics and survival rate of CLL patients. METHODS: This retrospective study was conducted at the Nanakaly Hospital for Blood Diseases & Oncology in Erbil, Iraq, between January 2011 and December 2017. A total of 105 CLL patients were assessed to determine clinical presentation and staging, immunophenotype and survival rate. RESULTS: The median age of the patients was 65 years and 63.8% were male. The main clinical presentations were splenomegaly (64.8%), pallor (61.9%) and lymphadenopathy (60%). More than half of the patients presented at an advanced clinical stage according to the Rai and Binet staging systems (59.1% and 55.2%, respectively). All CLL cases expressed both cluster of differentiation (CD)19 and CD5, 67.6% had monoclonal kappa light chains and 21% expressed CD38. The five-year overall survival (OS) rate was 61.3%. The mean duration of five-year survival was 41.3 months (95% confidence interval: 36.4-46.3 months). There were no correlations between survival and sociodemographic, clinical or laboratory characteristics. CONCLUSION: In comparison to the existing Western literature, Iraqi CLL patients more frequently presented with hepatosplenomegaly and at a more advanced clinical stage. In addition, the five-year OS rate was much lower.

Multi-parametric cytometry from a complex cellular sample: Improvements and limits of manual versus computational-based interactive analyses.

The wide possibilities opened by the developments of multi-parametric cytometry are limited by the inadequacy of the classical methods of analysis to the multi-dimensional characteristics of the data. While new computational tools seemed ideally adapted and were applied successfully, their adoption is still low among the flow cytometrists. In the purpose to integrate unsupervised computational tools for the management of multi-stained samples, we investigated their advantages and limits by comparison to manual gating on a typical sample analyzed in immunomonitoring routine. A single tube of PBMC, containing 11 populations characterized by different sizes and stained with 9 fluorescent markers, was used. We investigated the impact of the strategy choice on manual gating variability, an undocumented pitfall of the analysis process, and we identified rules to optimize it. While assessing automatic gating as an alternate, we introduced the Multi-Experiment Viewer software (MeV) and validated it for merging clusters and annotating interactively populations. This procedure allowed the finding of both targeted and unexpected populations. However, the careful examination of computed clusters in standard dot plots revealed some heterogeneity, often below 10%, that was overcome by increasing the number of clusters to be computed. MeV facilitated the identification of populations by displaying both the MFI and the marker signature of the dataset simultaneously. The procedure described here appears fully adapted to manage homogeneously high number of multi-stained samples and allows improving multi-parametric analyses in a way close to the classic approach. © 2016 International Society for Advancement of Cytometry.

The Immunology Quality Assessment Proficiency Testing Program for CD3⁺4⁺ and CD3⁺8⁺ lymphocyte subsets: a ten year review via longitudinal mixed effects modeling.

Since 1999, the National Institute of Allergy and Infectious Diseases Division of AIDS (NIAID DAIDS) has funded the Immunology Quality Assessment (IQA) Program with the goal of assessing proficiency in basic lymphocyte subset immunophenotyping for each North American laboratory supporting the NIAID DAIDS HIV clinical trial networks. Further, the purpose of this program is to facilitate an increase in the consistency of interlaboratory T-cell subset measurement (CD3(+)4(+)/CD3(+)8(+) percentages and absolute counts) and likewise, a decrease in intralaboratory variability. IQA T-cell subset measurement proficiency testing was performed over a ten-year period (January 2003-July 2012), and the results were analyzed via longitudinal analysis using mixed effects models. The goal of this analysis was to describe how a typical laboratory (a statistical modeling construct) participating in the IQA Program performed over time. Specifically, these models were utilized to examine trends in interlaboratory agreement, as well as successful passing of proficiency testing. Intralaboratory variability (i.e., precision) was determined by the repeated measures variance, while fixed and random effects were taken into account for changes in interlaboratory agreement (i.e., accuracy) over time. A flow cytometer (single-platform technology, SPT) or a flow cytometer/hematology analyzer (dual-platform technology, DPT) was also examined as a factor for accuracy and precision. The principal finding of this analysis was a significant (p<0.001) increase in accuracy of T-cell subset measurements over time, regardless of technology type (SPT or DPT). Greater precision was found in SPT measurements of all T-cell subset measurements (p<0.001), as well as greater accuracy of SPT on CD3(+)4(+)% and CD3(+)8(+)% assessments (p<0.05 and p<0.001, respectively). However, the interlaboratory random effects variance in DPT results indicates that for some cases DPT can have increased accuracy compared to SPT. Overall, these findings demonstrate that proficiency in and among IQA laboratories have, in general, improved over time and that platform type differences in performance do exist.

Clinical relevance of differential lymphocyte recovery after alemtuzumab therapy for multiple sclerosis.

OBJECTIVE: Alemtuzumab is potentially a highly effective treatment for relapsing multiple sclerosis (MS) acting via complement-mediated lysis of circulating lymphocytes. Variability in posttreatment lymphocyte recovery time is observed, with some patients showing striking durability in the efficacy of treatment. This study aims to establish whether this observed variation affects clinical and imaging parameters of disease activity. METHODS: A total of 56 patients were followed for a median of 39.5 months post alemtuzumab treatment with interval clinical assessments, lymphocyte immunophenotyping, and MRI. Timing and degree of CD4+, CD8+, and CD19+ recovery were correlated with the re-emergence of disease activity defined as clinical relapse, increasing disability, and new T2/enhancing lesions on MRI. RESULTS: New disease activity was recorded in 14% of patients. Mean time to CD19+, CD8+, and CD4+ reconstitution was 6, 10, and 36 months. No differences were observed in CD8+ and CD19+ reconstitution between patients with active disease and those in remission. Patients with active disease showed an accelerated recovery of CD4+ cells (p = 0.001) with a difference in absolute CD4+ counts at 24 months (p = 0.009). CD4+ counts <388.5 × 10(6) cells/mL predicted MRI stability. CONCLUSIONS: Differential lymphocyte recovery in MS following alemtuzumab may be a biomarker for relapse and also inform monitoring and treatment protocols. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that differential lymphocyte reconstitution after alemtuzumab treatment may be a biomarker for relapse.

ACUTE LEUKEMIAS IMMUNOPHENOTYPES AT AGAKHAN UNIVERSITY HOSPITAL, NAIROBI.

OBJECTIVE: The aim was to determine relative frequencies of acute leukemia immunophenotypes using commonly expressed markers and to describe the clinicopathological characteristics. Design: This was a prospective cross-sectional study. SETTING: The study was based at Aga khan clinical laboratory department. SUBJECTS: One hundred and thirty two (132) consecutive blood and bone marrow specimens from patients suspected to have acute leukemia were analysed for cytomorphological characteristics and immunophenotyping. The clinical-pathological characteristics were also recorded. Immunological category was assigned using the EGIL criteria. RESULTS: There were 88 AML and 42 ALL patients analysed for immunophenotypes. Only tw cases of biphenotypic leukemia were found. The commonest overall AML morphological sub-type was AML-M2, 26 (29.5%). Majority of ALL cases were B-cell immunological sub-type (96.6%). Early pre-B phenotype constituted 62.07% and Common B-cell ALL 37.93%. There were only 4 cases of T-cell ALL. Majority of patients presented with anaemia with a median hemoglobin of 7.5g/dl (range 2-15g/dl). The median platelet count was 55 (range 4-462 x 10(9)/L). CONCLUSION: Immunophenotyping of acute leukemia is beneficial in accurate diagnosis of patients with these malignancies in this setup. T-cell ALL, AML-M6 and M7 are less frequent than what has been reported in most studies in Africa.

Mixture modeling approach to flow cytometry data.

Flow Cytometry has become a mainstay technique for measuring fluorescent and physical attributes of single cells in a suspended mixture. These data are reduced during analysis using a manual or semiautomated process of gating. Despite the need to gate data for traditional analyses, it is well recognized that analyst-to-analyst variability can impact the dataset. Moreover, cells of interest can be inadvertently excluded from the gate, and relationships between collected variables may go unappreciated because they were not included in the original analysis plan. A multivariate non-gating technique was developed and implemented that accomplished the same goal as traditional gating while eliminating many weaknesses. The procedure was validated against traditional gating for analysis of circulating B cells in normal donors (n = 20) and persons with Systemic Lupus Erythematosus (n = 42). The method recapitulated relationships in the dataset while providing for an automated and objective assessment of the data. Flow cytometry analyses are amenable to automated analytical techniques that are not predicated on discrete operator-generated gates. Such alternative approaches can remove subjectivity in data analysis, improve efficiency and may ultimately enable construction of large bioinformatics data systems for more sophisticated approaches to hypothesis testing.

Nine-color flow cytometry for accurate measurement of T cell subsets and cytokine responses. Part I: Panel design by an empiric approach.

Polychromatic flow cytometry offers the unprecedented ability to investigate multiple antigens per cell. Unfortunately, unwanted spectral overlaps and compensation problems increase when more than four colors are used, but these problems can be minimized if staining combinations are chosen carefully. We used an empiric approach to design, test and identify six-color T cell immunophenotyping reagent panels that can be expanded to include three or more functional or other markers in the FITC, PE, and APC channels without significant spectral limitations. Thirty different six-color T cell surface antigen reagent panels were constructed to identify major T cell subsets and maturational subtypes as defined by CCR7 and CD45RA expression, while excluding monocytes, B and non-viable cells. Staining performance of each panel was compared on cryopreserved cells from a single healthy donor recorded on a multiparameter cell sorter. Ten of the thirty reagent panels offered reliable resolution of T cell major and maturational surface markers. Of these, two panels were selected that showed the least spectral overlap and resulting background increase in the FITC, PE, and APC channels. These channels were left unoccupied for inclusion of additional phenotypic or functional markers, such as cytokines. Careful reagent titration and testing of multiple candidate panels are necessary to ensure quality results in multiparametric measurements.

Transfer of maternal colostral leukocytes promotes development of the neonatal immune system Part II. Effects on neonatal lymphocytes.

It has been established that maternal leukocytes, conditioned by the mammary environment, cross the neonatal gut and circulate in the newborn calf. However, the impact of these cells on the development of neonatal immunity remains to be determined. This study examined the effects of maternal colostral leukocytes on development and maturation of neonatal adaptive immunity by examining the expression of surface markers on neonatal lymphocytes. At birth, neonatal calves were fed whole colostrum, or colostrum that had the maternal cells removed (cell-free colostrum), from their respective dams. Peripheral blood samples were collected at regular intervals over the first 4 weeks of life and lymphocytes were evaluated for surface expression of cellular markers. The results of these studies demonstrated that calves receiving whole colostrum had fewer CD11a positive lymphocytes in circulation during the first 2 weeks of life and this marker was expressed at a lower density than calves receiving cell-free colostrum. In addition, calves receiving whole colostrum also had a higher percentage of lymphocytes expressing the activation markers CD25 and CD26 by 7 days after birth. During the first week of life, lymphocytes from calves receiving whole colostrum had a higher density of MHC class I expression on their surfaces than cells from calves receiving cell-free colostrum. In general, these results indicate that transfer of maternal cells with colostrum allows for more rapid development of lymphocytes and maternal cells appeared to enhance their activation.

Immunophenotypic profiles of peripheral blood lymphocytes on the day of embryo transfer in women undergoing in vitro fertilization.

UNLABELLED: Evaluation of different types of lymphocyte subpopulations in the peripheral blood has unknown and controversial significance in diagnosis of infertility. The aim of the study was to evaluate selected blood lymphocytes in patients treated with intracytoplasmic sperm injection (ICSI). MATERIALS AND METHODS: women were divided into three groups: (1) control fertile group (n=18), (2) infertile women that achieved (n=32), and (3) did not achieve a pregnancy after ICSI (n=26). The following types of leukocytes were analyzed by three-colour flow cytometry by detection of specific CD antigens: lymphocytes T (CD3+), B (CD19+ and CD5+CD19+), T and B (CD5+), NK cells (CD56+CD16-, CD56-CD16+, CD56+CD16+, CD56brightCD16-, CD56dimCD16+). Additionally, the antigen of early activation (CD69) was evaluated on T, B and NK cells. The results were presented as a percentage and total counts of all lymphocytes. RESULTS: The percentage of total NK cells (CD56+CD16+, CD56+CD16- and CD56-CD16+) did not differ between pregnant and non pregnant women and was lower comparing to control group. Fractions of CD56-CD16+ cells were higher in pregnant vs. non-pregnant women. The percentages of CD56brightCD16- NK cells were higher in control group comparing to both ICSI treated groups. Other fractions of lymphocyte subpopulations, including activated cells (with CD69 expression) did not differ between the analyzed groups. Total counts of CD56-CD16+ cells were higher in pregnant vs. non-pregnant group, and the CD56brightCD16- cells was more abundant in control group vs. women with unsuccessful ICSI. CONCLUSIONS: Testing of peripheral blood NK cells and the others lymphocytes has limited value as a prognostic factor in ICSI treated patients. The antigen of early lymphocytic activation (CD69) has not any predictive value in prognosis of ICSI outcome.

A new automated flow cytometry data analysis approach for the diagnostic screening of neoplastic B-cell disorders in peripheral blood samples with absolute lymphocytosis.

Currently, multiparameter flow cytometry immunophenotyping is the selected method for the differential diagnostic screening between reactive lymphocytosis and neoplastic B-cell chronic lymphoproliferative disorders (B-CLPD). Despite this, current multiparameter flow cytometry data analysis approaches still remain subjective due to the need of experienced personnel for both data analysis and interpretation of the results. In this study, we describe and validate a new automated method based on vector quantization algorithms to analyze multiparameter flow cytometry immunophenotyping data in a series of 307 peripheral blood (PB) samples. Our results show that the automated method of analysis proposed compares well with currently used manual approach and significantly improves semiautomated approaches and, that by using it, a highly efficient discrimination with 100% specificity and 100% sensitivity can be made between normal/reactive PB samples and cases with B-CLPD based on the total B-cell number and/or the sIgkappa+/sIglambda+ B-cell ratio. In addition, the method proved to be able to detect the presence of pathologic neoplastic B-cells even when these are present at low frequencies (<5% of all lymphocytes in the sample) and in poor-quality samples enriched in 'noise' events.

A scoring system based on the expression of six surface molecules allows the identification of three prognostic risk groups in B-cell chronic lymphocytic leukemia.

We have previously identified 12 surface antigens whose differential expression represented the signature of B-cell chronic lymphocytic leukemia (B-CLL) subsets with different prognosis. In the present study, expression data for these antigens, as determined in 137 B-CLL cases, all with survivals, were utilized to devise a comprehensive immunophenotypic scoring system of prognostic relevance for B-CLL patients. In particular, univariate z score was employed to identify the markers with greater prognostic impact, while maximally selected log-rank statistics were chosen to define the optimal cut-off points capable to split patients into two groups with different survivals. A weighted immunophenotypic scoring system was developed by integrating results from these analyses. Six antigens were selected: three positive prognosticators (CD62L, CD54, CD49c) and three negative prognosticators (CD49d, CD38, CD79b), with cut-off values ranging from 30% to 50% of positive cells. By weighing the expression of each marker according to its statistical power, a complete scoring system, with point values comprised between 0 (complete absence of phenotypic conditions associated with good prognosis) and 9 (all the phenotypic conditions associated with good prognosis fulfilled), allowed to split the whole set of B-CLL patients, into three distinctive prognostic groups (P = 4.78 x 10(-11)) with high- (score 0-3), intermediate- (score 4-6), and low- (score 7-9) risk of death. The three risk groups showed different distribution of cases as for Rai's stages, IgVH mutations, and ZAP-70 expression. The proposed immunophenotypic scoring system may be an additional useful tool in routine diagnostic/prognostic procedures for B-CLL.

Ultrasensitive detection and phenotyping of CD4+ T cells with optimized HLA class II tetramer staining.

HLA class I tetramers have revolutionized the study of Ag-specific CD8+ T cell responses. Technical problems and the rarity of Ag-specific CD4+ Th cells have not allowed the potential of HLA class II tetramers to be fully realized. Here, we optimize HLA class II tetramer staining methods through the use of a comprehensive panel of HIV-, influenza-, CMV-, and tetanus toxoid-specific tetramers. We find rapid and efficient staining of DR1- and DR4-restricted CD4+ cell lines and clones and show that TCR internalization is not a requirement for immunological staining. We combine tetramer staining with magnetic bead enrichment to detect rare Ag-specific CD4+ T cells with frequencies as low as 1 in 250,000 (0.0004% of CD4+ cells) in human PBLs analyzed directly ex vivo. This ultrasensitive detection allowed phenotypic analysis of rare CD4+ T lymphocytes that had experienced diverse exposure to Ag during the course of viral infections. These cells would not be detectable with normal flow-cytometric techniques.

Immunophenotypic analysis of peripheral blood stem cell harvests from patients with multiple myeloma.

BACKGROUND AND OBJECTIVES: Four-color multiparameter immunophenotyping has recently proven to be an attractive technique for evaluating the plasma cell (PC) compartment since it allows discrimination between myelomatous and normal PC. This study was designed to investigate: i) whether peripheral blood is less contaminated than bone marrow as a source for an autologous transplant; ii) the effect of growth factors on mobilizing myelomatous PC into peripheral blood; iii) the degree of contamination by myelomatous PC in apheresis samples; and iv) whether the number of PC increases during the last days of apheresis. DESIGN AND METHODS: Using 4-color antigen staining we investigated the composition of the PC compartment in 90 apheresis products from 40 patients with MM; in 17 cases bone marrow and peripheral blood samples were also simultaneously evaluated. RESULTS: (i) All pre-mobilization bone marrow samples analyzed were always contaminated with myelomatous PC whereas only 41% of the post-mobilization peripheral blood samples were contaminated. Moreover, the use of peripheral blood would lead to a reduction of >5x10(5) infused myelomatous PC; (ii) mobilization with cytokines increased the number of circulating PC, generally because of an expansion of the normal PC population; (iii) forty-eight percent of all peripheral blood stem cell harvests were contaminated with myelomatous PC, although normal PC usually represented the predominant population; (iv) no significant changes were observed in the amount of contaminating myelomatous PC during the first three days of apheresis. INTERPRETATION AND CONCLUSIONS: Multiparameter immunophenotyping is a useful approach for investigating the PC compartment in apheresis products.