Differential DNA methylation patterns of small B-cell lymphoma subclasses with different clinical behavior

Non-Hodgkin's lymphoma (NHL) is a group of malignancies of the immune system with variable clinical behaviors and diverse molecular features. Despite the progress made in classification of NHLs based on classical methods, molecular classifications are a work in progress. Toward this goal, we used an array-based technique called differential methylation hybridization (DMH) to study small B-cell lymphoma (SBCL) subtypes. A total of 43 genomic DMH experiments were performed. From these results, several statistical methods were used to generate a set of differentially methylated genes for further validation. Methylation of LHX2, POU3F3, HOXC10, NRP2, PRKCE, RAMP, MLLT2, NKX6.1, LRP1B and ARF4 was validated in cell lines and patient samples and demonstrated subtype-related preferential methylation patterns. For LHX2 and LRP1B, bisulfite sequencing, real-time reverse transcriptase-polymerase chain reaction and induction of gene expression following treatment with the demethylating agent, 5'-aza-2'-deoxycytidine, were confirmed. This new epigenetic information is helping to define molecular portraits of distinct subtypes of SBCL that are not recognized by current classification systems and provides valuable potential insights into the biology of these tumors.

Microarray image spot segmentation using the method of projections

Microarray technology is increasingly used as a means of high throughput analysis of human, non-human and plant genomes. Manual methods of array production using this technology lead to many inherent problems in the microarray image produced. The density of the spots in the images produced is very high, such that neighboring spots can overlap. The image background is often not uniform, containing noise that is often difficult to distinguish from actual spots. In this research, a projections-based approach is investigated for spot segmentation in paired radio probe microarray images. An important aspect of spot segmentation is the capability to perform corresponding spot-to-spot comparisons between the paired images. Experimental results are presented for spot segmentation in isolated and paired microarray images.

Dissecting complex epigenetic alterations in breast cancer using CpG island microarrays

It is now clear that aberrant DNA methylation observed in cancer cells is not restricted to a few CpG islands, but affects multiple loci. When this epigenetic event occurs at the 5'-end of the regulatory region of genes, it is frequently associated with transcriptional silencing. To investigate further this widespread event in the tumor genome, we developed a novel microarray containing 7776 short GC-rich tags tethered to glass slide surfaces. This DNA chip was used to study 17 paired tissues of breast tumors and normal controls. Amplicons, representing differential pools of methylated DNA fragments between tumors and normal controls, were cohybridized to the microarray panel. Hypermethylation of multiple CpG island loci was then detected in a two-color fluorescence system. Approximately 1% (on average, 83 loci) of these CpG islands examined were hypermethylated in this patient group. Hierarchical clustering segregated these tumors based on their methylation profiles and identified a group of CpG island loci that corresponds to the hormone-receptor status of breast cancer. This observation was independently confirmed by examining a single locus, the promoter of the human glypican 3 gene, which was predominately hypermethylated in the hormone receptor-negative tumors. Our findings support the notion that hypermethylation of critical CpG island loci influences cancer development and produces distinct epigenetic signatures for particular tumor subtypes.

Structural analysis of TCRalpha and beta chains from human T-Cell clones specific for small nuclear ribonucleoprotein polypeptides Sm-D, Sm-B and U1-70 kDa: TCR complementarity determining region 3 usage appears highly conserved

Systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) are systemic autoimmune diseases that are characterized by the presence of autoantibodies reactive with U small nuclear RNP (snRNP) autoantigens. Both B and T cells are important in the pathogenesis of the disease, and T- and B-cell immunity against snRNP polypeptides have been shown to be linked in vivo. Currently, several alternative hypotheses for the pathogenesis of these diseases have been proposed. These include loss of tolerance, modified self-antigens, molecular mimicry and nondirected immune activation. To help distinguish between the various models of disease pathogenesis, we have characterized the T-cell receptor (TCR) CDR3 from a large panel of well-characterized human T-cell clones and lines specific for individual snRNP polypeptides. The results presented here reveal highly restricted TCR usage across patients by the snRNP-reactive T cells based on the deduced amino acid sequence of the CDR3 loop. These data support the hypothesis that T-cell responses against self antigens in SLE and MCTD are antigen driven and that there are a limited number of T-cell epitopes present on the snRNP autoantigens.

CpG island arrays: an application toward deciphering epigenetic signatures of breast cancer

CpG island hypermethylation is a frequent epigenetic event in cancer. We have recently developed an array-based method, called differential methylation hybridization (DMH), allowing for a genome-wide screening of CpG island hypermethylation in breast cancer cell lines (T. H-M. Huang et al., Hum. Mol. Genet., 8: 459-470, 1999). In the present study, DMH was applied to screen 28 paired primary breast tumor and normal samples and to determine whether patterns of specific epigenetic alterations correlate with pathological parameters in the patients analyzed. Amplicons, representing a pool of methylated CpG DNA derived from these samples, were used as hybridization probes in an array panel containing 1104 CpG island tags. Close to 9% of these tags exhibited extensive hypermethylation in the majority of breast tumors relative to their normal controls, whereas others had little or no detectable changes. Pattern analysis in a subset of CpG island tags revealed that CpG island hypermethylation is associated with histological grades of breast tumors. Poorly differentiated tumors appeared to exhibit more hypermethylated CpG islands than their moderately or well-differentiated counterparts (P = 0.041). This early finding lays the groundwork for a population-based DMH study and demonstrates the need to develop a database for examining large-scale methylation data and for associating specific epigenetic signatures with clinical parameters in breast cancer.

An information system for improving clinical laboratory outcomes

Laboratories performing clinical molecular diagnostic and cytogenetic testing require improved information systems to address their specialized data processing needs. We developed an application that automates result reporting, documents quality assurance information, and tracks specimens. While similar functionality was implemented in both the molecular diagnostic and cytogenetic modules, we present an outcome assessment of the cytogenetic laboratory's use of the system since it maintained a relatively constant number of personnel, test procedures, and samples over a three-year period. Upon implementation, significant reductions occurred in the time taken from receipt of sample to the release of the final report by 44% (P < 0.001) and 48% (P < 0.001) for peripheral blood and bone marrow samples, respectively. The number of cases processed per technologist increased by 26% (P = 0.017). We attribute these gains in quality improvement to the automation of clerical tasks and decision support provided by the information system.

Analysis of T cell receptors specific for U1-70kD small nuclear ribonucleoprotein autoantigen: the alpha chain complementarity determining region three is highly conserved among connective tissue disease patients

The U1-70kD autoantigen is a major target of B cell responses in patients with connective tissue diseases (CTD). T cell responses are important in the pathogenesis of CTD, however little is known about autoantigen-specific T cells in these diseases. We have recently proven that U1-70kD-reactive human T cells exist. To further characterize these autoreactive T cells, U1-70kD-reactive T cell clones have been generated from patients with CTD using either a recombinant fusion protein or synthetic peptides spanning the U1-70kD polypeptide. T cell receptors (TCR) isolated from the U1-70kD-reactive T cell clones were sequenced and the third complementarity-determining region (CDR3) compared to determine if a common motif was present. mAb blocking of antigen-induced proliferation was done to determine the HLA restriction element used in recognition of the U1-70kD autoantigen by T cells. The results presented here indicate that TCRAV CDR3 usage is highly restricted among U1-70kD autoantigen-specific human T cells clones derived from CTD patients with distinctive structural features. Furthermore, the recognition of the U1-70kD autoantigen occurs in the context of HLA-DR.

The effects of image manipulation on automated karyotyping

Karyotyping is one of the standard tools for human genetic investigations. Karyotyping involves the classification and interpretation of chromosomes found in a metaphase spread. As part of the automated karyotyping process, image manipulation is required for appropriately positioning metaphase spread chromosomes in their corresponding karyotype. Image manipulation, specifically image rotation, reorganizes the grey-level information within chromosomes to facilitate analysis. Statistical tests are performed to compare features related to banding pattern and length between unmanipulated chromosomes and corresponding rotated chromosomes. Based on experimental results, reorganizing the grey-level information yields statistically different chromosome features. Depending on the purpose of chromosome image analysis, the interpretation process of karyotyping could be impaired with chromosome feature distortion due to image rotation.

Data-driven homologue matching for chromosome identification

Karyotyping involves the visualization and classification of chromosomes into standard classes. In "normal" human metaphase spreads, chromosomes occur in homologous pairs for the autosomal classes 1-22, and X chromosome for females. Many existing approaches for performing automated human chromosome image analysis presuppose cell normalcy, containing 46 chromosomes within a metaphase spread with two chromosomes per class. This is an acceptable assumption for routine automated chromosome image analysis. However, many genetic abnormalities are directly linked to structural or numerical aberrations of chromosomes within the metaphase spread. Thus, two chromosomes per class cannot be assumed for anomaly analysis. This paper presents the development of image analysis techniques which are extendible to detecting numerical aberrations evolving from structural abnormalities. Specifically, an approach to identifying "normal" chromosomes from selected class(es) within a metaphase spread is presented. Chromosome assignment to a specific class is initially based on neural networks, followed by banding pattern and centromeric index criteria checking, and concluding with homologue matching. Experimental results are presented comparing neural networks as the sole classifier to our homologue matcher for identifying class 17 within normal and abnormal metaphase spreads.

Homologue matching using the Choquet integral

Automated Giemsa-banded chromosome image research has been largely restricted to classification schemes associated with isolated chromosomes within metaphase spreads. In normal human metaphase spreads, there are 46 chromosomes occurring in homologous pairs for the autosomal classes, 1-22, and X chromosome for females. For optimizing automated human chromosome image analysis, many existing techniques assume cell normalcy. With many genetic abnormalities directly linked to structural and numerical aberrations of chromosomes within the metaphase spread, the two chromosome per class assumption may not be appropriate for anomaly analysis. At the University of Missouri, a data-driven homologue matching approach has been developed to identify all normal chromosomes within a metaphase spread from a selected class. Chromosome assignment to a specific class is initially based on neural networks, followed by banding pattern and centromeric index criteria checking, and concluding with homologue matching utilizing a density profile-based classifier, a shape profile-based classifier, and a binary band profile-based classifier. Based on preliminary results for the profile-based classifiers assigning chromosome 17, the Choquet integral is presented as an extension to the homologue matching approach. Experimental results are presented comparing the extended homologue matching approach to the transportation algorithm for identifying chromosome 21 within normal metaphase spreads.

Integrating molecular diagnostic and flow cytometric reporting for improved longitudinal monitoring of HIV patients

Studies have shown that monitoring HIV-infected patients undergoing antiretroviral therapy is best represented by combined measurement of plasma HIV-1 RNA and CD4+ T-lymphocytes [1]. This pilot study at the University of Missouri-Columbia integrates molecular diagnostic and flow cytometric data reporting to provide current and historical HIV-1 RNA levels and CD4+ T-cell counts. The development of a single database for storage and retrieval of these values facilitates composite report generation that includes longitudinal HIV-1 RNA levels and CD4+ T-cell counts for all patients. Results are displayed in tables and plotted graphically within a web browser. This method of data presentation converts individual data points to more useful medical information and could provide clinicians with decision support for improved monitoring of HIV patients undergoing antiretroviral therapy.

Central nervous system manifestations of human ehrlichiosis

Since 1989, we have confirmed the diagnosis of human ehrlichiosis in 57 patients. Although routine radiological studies of the central nervous system (CNS) or analyses of cerebrospinal fluid (CSF) samples were not done for these patients, primary care physicians detected symptoms or signs that prompted them to perform such studies. CSF samples were examined for 15 of the 57 patients. Findings in eight of the 15 CSF samples were abnormal, and the most common abnormalities were lymphocytic pleocytosis and elevated protein levels. A search of the English-language literature revealed 21 additional cases in which CSF examinations were performed; in 13 of these cases, CSF findings were abnormal. The most common clinical finding that predicted CSF abnormalities was a change in mental status. A total of 14 patients underwent computerized tomographic studies, and none of these studies showed abnormalities. Four (19%) of the 21 patients with CNS manifestations of ehrlichiosis and abnormal CSF findings died.

Effects of altered prenatal hormonal environment on expression of autoimmune disease in NZB/NZW mice

F1 hybrid New Zealand Black (NZB) x New Zealand White (NZM) (NZB/NZW) mice spontaneously develop an autoimmune disease analogous to systemic lupus erythematosus (SLE). Testosterone experts a powerful suppressive effect on this disorder in adult NZB/NZW mice. A series of experiments was designed to determine if disease would also be suppressed by exposing fetal NZB/NZW mice to increased testosterone. A model was developed in which NZB dams carrying NZB/NZW fetuses were treated with testosterone in a dose adequate to masculinize the external genitalia in female fetuses. NZB/NZW mice that were derived from testosterone-treated dams and control NZB/NZW offspring were followed in a longevity study and had serial assays to assess development of SLE. Additional experiments were carried out to measure lymphocyte subsets and responses to mitogens. Results were compared with F1 hybrid offspring of C57BL/6 dams crossed with DBA/2 males, which are not autoimmune and do not develop SLE. Spleen cells from these groups were tested for Thy 1.2, CD4, CD8, and IgM receptors, and for responses to the mitogens Concanavalin A (ConA) and lipopolysaccharide. Control male NZB/NZW fetuses had unexpectedly high serum estradiol, which decreased significantly with maternal testosterone treatment. The testosterone-exposed male NZB/NZW fetuses developed into adults that lived longer than male NZB/NZW controls. Testosterone treatment of the dam was associated with elevated terminal anti-DNA levels but did not alter markers of renal diseases in adult NZB/NZW mice of either sex. Testosterone-exposed NZB/NZW females had altered T-lymphocyte subsets and testosterone-exposed males had increased response to ConA compared to controls. In male NZB/NZW fetuses whose mothers were administered testosterone, the naturally high level of circulating estradiol observed in untreated male fetuses was decreased significantly. This decrease was associated with an increase in longevity. This unique observation has important implications for fetal exposure to endocrine disruptors in the environment.

Apoptosis of gamma/delta T cells in human ehrlichiosis

Expansion of activated T cells expressing the T-cell receptor (TCR) gamma/delta, CD45RO, and HLA-DR antigens is a prominent feature of acute infection with Ehrlichia chaffeensis in humans. The fate of these activated cells and the resolution of the gamma/delta T-cell response with return to the usual alpha/beta T-cell populations in this disease are not clearly understood. At a morphologic level, apoptotic cells are present in the peripheral blood during the acute and resolution phases of the infection. Simple culture of density gradient-separated lymphocytes from the blood of patients with acute ehrlichiosis produced cell death rapidly in the media compared to alpha/beta T cells. This loss of viability after incubation was apparently mediated by apoptosis, based on flow cytometric and morphologic analyses. The results suggest that most primed (CD45RO+) and activated (HLA-DR+) gamma/delta T cells in acute ehrlichiosis might be subject to removal from the body by programmed or apoptotic cell death.

Centromere attribute integration based chromosome polarity assignment

Automated karyotyping involves evaluating quantified chromosome attributes for proper classification. Chromosome attributes derived from the banding pattern require the correct chromosome polarity for correct banding sequence interpretation. Chromosome polarity is defined in terms of determining the short and long arms of the chromosome using the centromere as the reference point for measuring the chromosome length on both sides of the centromere. In addition to banding sequence interpretation, polarity is used in the chromosome orientation for chromosome repositioning from the metaphase spread to the karyotype. Automated polarity determination is often not performed for classifying chromosomes in the metaphase spread image. Polarity may be determined user interactively, by the system, or not at all. In order to reduce the computational complexity of evaluating banding sequence features using both chromosome ends as reference points, there is a need to improve chromosome polarity determination in automated karyotyping. A centromere attribute integration approach has been developed at the University of Missouri-Columbia which performs correct chromosome polarity assessment at a rate comparable to other studies of 96.1% on a diversified data set.

Lymphocytosis of gamma/delta T cells in human ehrlichiosis

The majority of T cells in peripheral blood express a T-cell receptor (TCR) comprised of alpha and beta chains. An alternate form of the TCR is comprised of gamma and delta chains. These gamma/delta T cells are associated with certain infectious lesions, and modestly elevated in peripheral blood in certain disease states. Human ehrlichiosis is characterized by hematologic abnormalities including multi-lineage cytopenias. In most cases reported, a lymphocytopenia has been present either at diagnosis, or at some time during the illness. Early in the course of antibiotic treatment (48-72 hours), the lymphocytopenia corrects itself and is rapidly followed by a lymphocytosis of T cells that express CD3, but are negative for CD4 and CD8, as well as the major form of the TCR formed by the alpha/beta heterodimer. Instead, these CD3+4-8- T cells express the gamma/delta heterodimer associated with V gamma 9 and V delta 2 chains, a population of cells usually the distinctive minority of peripheral blood T cells, but constituting the major phenotype of peripheral gamma/delta T cells.

Ehrlichiosis--a cause of prolonged fever

Human ehrlichiosis is a recently described illness that is thought to be tick-borne. Most recognized cases of human ehrlichiosis manifest as an acute nonspecific febrile illness. The natural history of untreated symptomatic disease is largely unknown. Over a 4-year period, we identified 41 cases of human ehrlichiosis by serological testing, polymerase chain reaction analysis, or both methods. The principal finding for six of the patients was protracted fever. The duration of their fevers ranged from 17 to 51 days. At the time of presentation, all six patients had clinical features, laboratory features, or both consistent with a diagnosis of ehrlichiosis. Polymerase chain reaction analysis helped to rapidly confirm the diagnosis for four of five patients tested. The diagnosis of human ehrlichiosis should be considered for patients with prolonged fever who live in an area of endemicity.

Genetic alterations of microsatellites on chromosome 18 in human breast carcinoma

Allelic alterations of chromosome 18 microsatellites were determined using normal and tumor DNA pairs from 29 patients with infiltrating ductal carcinoma of the breast. Loss of heterozygosity was detected in 62% (18 of 29 patients) of the tumors at one or more of these microsatellites. Eight of the 18 patients exhibited deletions in the region at 18q21.1. This chromosomal band is known to contain a tumor suppressor gene (DCC) whose expression is frequently inactivated in several types of cancer. Ten other patients had deletions in regions not included in the DCC locus. Five of these patients revealed a common deletion at the D18S50 locus (18q23), and the other five patients had deletions in various other regions of the chromosome. No apparent correlation between loss of heterozygosity of chromosome 18 microsatellites and the clinical stage was found in this series. The results indicate that, in addition to the DCC locus, the 18q23 region is likely to contain a second tumor suppressor gene relevant to breast carcinogenesis. Four percent of all microsatellites tested in these patients showed allelic differences in the sizes of repeat units between tumor and the corresponding constitutional DNAs. The pattern of allele instability observed in breast carcinoma differed from that originally reported in a hereditary type of colorectal carcinoma. The observation suggests that this phenomenon is not a mechanism specific to neoplastic processes in breast carcinoma.

Familial translocation t(10;14) (q26.1;q32.3): report of three offspring with 10q deletion and 14q duplication

We describe two brothers and a cousin with common clinical features, including mild mental retardation, motor delays, hypotonia with truncal ataxia, esotropia, and mild facial and hand dysmorphia. The initial routine chromosome study failed to detect any abnormality in the proband. Based on a high index of clinical suspicion, high-resolution chromosome studies were performed on the proband's parents. A small reciprocal translocation t(10;14) (q26.1;q32.3) was detected in the father. The breakpoint on the derivative chromosome 14 was further placed telomeric to the immunoglobulin heavy-chain gene cluster at the band q32.33 by fluorescence in situ hybridization. Studies of the proband and two affected paternal cousins revealed that each had inherited the same derivative chromosome 10 from their carrier parents. This unbalanced karyotype resulted from an adjacent-1 segregation of the 10;14 translocation.

Preservation of B-cell-associated surface antigens by chemical fixation

Usual methods of chemical fixation preclude examination of cells with most monoclonal antibodies due to alteration or destruction of the surface antigen itself. A method of chemical stabilization and preservation of human B-cell-associated surface antigens is described which facilitates retrospective flow cytometric analysis. This method involves pretreatment of the cells with protease enzyme inhibitors, followed by chemical cross-linking of surface proteins with 2% formalin, and finally blockade of non-specific reactive groups with excess glycine. Once prepared, the expression of pertinent cellular antigens is stable on the cell surface for as long as 4 years. Such methodology could conceivably be used for preparation of cells for longitudinal quality control of monoclonal antibodies or archival storage of patient specimens for retrospective flow cytometric analysis.

Human T cell clones reactive against U-small nuclear ribonucleoprotein autoantigens from connective tissue disease patients and healthy individuals

SLE and mixed connective tissue disease (MCTD) are characterized by the presence of high titers of autoantibodies against uridine-rich RNA-small nuclear ribonucleoprotein (snRNP) Ag. Because the presence of such snRNP-reactive autoantibodies has recently been shown to be associated with polymorphisms of HLA, this study was undertaken to determine whether snRNP-reactive T cells could be identified and characterized from patients. PBMC were stimulated with affinity-purified snRNP Ag and cloned by limiting dilution in the presence of rIL-2 and rIL-4, snRNP-reactive human T cell clones were generated from three patients and two healthy blood donors who possessed disease-associated HLA genotypes. The cell surface phenotype of clones determined by flow cytometry was CD3+, CD4+, CD45RO+, TCR V alpha beta+. TCR V beta analysis, performed using V beta-specific primers and polymerase chain reaction, revealed that the T cell lines generated were clonal; a limited number of TCR V beta genes were expressed among the clones tested. All clones tested by mAb blocking of Ag-induced proliferation were restricted by HLA-DR. Several T cell clones were identified that were specific for B'/B or D polypeptides. These results demonstrate that snRNP-reactive T cells can be isolated from SLE and MCTD patients in vitro, and that Ag-driven expansion of such T cells could play a role in the immunopathogenesis of these diseases in vivo.

Human T cell clones reactive against U-small nuclear ribonucleoprotein autoantigens from connective tissue disease patients and healthy individuals

SLE and mixed connective tissue disease (MCTD) are characterized by the presence of high titers of autoantibodies against uridine-rich RNA-small nuclear ribonucleoprotein (snRNP) Ag. Because the presence of such snRNP-reactive autoantibodies has recently been shown to be associated with polymorphisms of HLA, this study was undertaken to determine whether snRNP-reactive T cells could be identified and characterized from patients. PBMC were stimulated with affinity-purified snRNP Ag and cloned by limiting dilution in the presence of rIL-2 and rIL-4, snRNP-reactive human T cell clones were generated from three patients and two healthy blood donors who possessed disease-associated HLA genotypes. The cell surface phenotype of clones determined by flow cytometry was CD3+, CD4+, CD45RO+, TCR V alpha beta+. TCR V beta analysis, performed using V beta-specific primers and polymerase chain reaction, revealed that the T cell lines generated were clonal; a limited number of TCR V beta genes were expressed among the clones tested. All clones tested by mAb blocking of Ag-induced proliferation were restricted by HLA-DR. Several T cell clones were identified that were specific for B'/B or D polypeptides. These results demonstrate that snRNP-reactive T cells can be isolated from SLE and MCTD patients in vitro, and that Ag-driven expansion of such T cells could play a role in the immunopathogenesis of these diseases in vivo.

In vivo upregulation of CD45RA in neutrophils of acutely infected patients

The CD45 family of high relative molecular mass (M(r)) cell surface antigens is expressed on all lymphohematopoietic cells. Different cell types express various M(r) isoforms in a precisely programmed fashion. The cytoplasmic domain of the CD45 family possesses protein tyrosine phosphatase activity and is involved in transmembrane signaling. Under normal conditions, the major CD45 isoform on neutrophils is CD45RO, the low M(r) isoform. We recently demonstrated a cytoplasmic granule-associated pool of CD45RA, the highest M(r) isoform, in mature neutrophils that is generally absent from the cell surface under nonstimulatory conditions. Calcium ionophore A23187 induced translocation of cytoplasmic CD45RA to the cell surface and increased the cell surface expression of CD45RO and CD45. The present study demonstrates that without in vitro stimulation, there is an increase in expression of CD45RA on the surface of neutrophils from patients with systemic, acute infections, while those of patients with localized infections are only slightly increased compared to normal controls. Although the exact functions of the various isoforms of CD45 are not known, this increased expression of CD45RA suggests a role for this high M(r) isoform during in vitro neutrophil activation.

Psychological factors, immunologic activation, and disease activity in rheumatoid arthritis

The purpose of this study was to use structural equation modeling techniques to examine potential interrelationships among psychological factors, immunologic activation, and disease activity in rheumatoid arthritis (RA). The subjects were 80 male patients with a diagnosis of classic or definite RA. Measures included the Beck Depression Inventory, the Arthritis Helplessness Index, and the Arthritis Impact Measurement Scales (AIMS) pain score. Joint counts and immunophenotypic analyses of peripheral blood lymphocytes also were collected. Path analysis showed that percentage of HLA-DR+ cells in the peripheral blood and helplessness were related to join count. In addition, joint count had an effect upon depression. Depression had an effect upon pain, but there was no reciprocal effect of pain upon depression. This study describes a preliminary path model of interrelationships among psychological factors, immunologic activation, and disease activity in RA.

A controlled study of lymphocyte subsets in rheumatoid arthritis

The purpose of this study was to determine if patients with rheumatoid arthritis (RA) exhibited unique patterns of peripheral blood lymphocyte (PBL) subsets in comparison to patients with osteoarthritis (OA) and, further, if such differences related to disease activity or nondisease factors. Data from 63 RA patients and 47 OA patients revealed that the RA patients had lower absolute numbers of CD2+ and CD4+ lymphocytes. Small differences also were found in selected B-cell subsets and subsets of lymphocytes expressing CD16 and/or CD57 antigens. Further analysis revealed that these differences were due primarily to the effects of cytotoxic medications in the RA group. However, there were also alterations in some subsets independent of medication groups. PBL subsets in RA patients did not relate to chronic low-dose prednisone or measures of disease activity. This study demonstrated the need to control carefully for variables such as age and medication in immunophenotypic investigations of RA.

Flow cytometry, morphometry and histopathology as biomarkers of benzo[a]pyrene exposure in brown bullheads (Ameiurus nebulosus)

Brown bullheads were given a single intraperitoneal dose of 0, 5, 25 or 125 mg kg-1 benzo[a]pyrene (BaP), a carcinogenic polycyclic aromatic hydrocarbon, and evaluated over 18 months. Flow cytometric analyses of hepatocyte DNA content indicated an increase in DNA synthesis in BaP-exposed fish prior to day 14 post-exposure. Thereafter, all flow cytometric variables returned to initial levels. Histopathological evaluation of livers from fish sampled at 18 months revealed significant differences among treatments in the amount of hepatic macrophage ceroid pigmentation and basophilic staining intensity. No neoplasms or changes in blood cell DNA content were detected. Significant morphometric variations existed among fish, but differences between sexes overshadowed differences attributable to dose. Flow cytometry yielded no evidence of long-term DNA alterations from a single exposure to BaP; however, the differences detected by DNA analysis shortly after the toxic event suggest that flow cytometric cell cycle analysis may be useful for documenting continuing exposures.

Expression of CD45 isoforms by Epstein-Barr virus-transformed human B lymphocytes

CD45 is the most common protein tyrosine phosphatase (PTPase) in the membrane of white blood cells, serving as a potent regulator of lymphocyte activation and signal transduction. While the amino acid sequence of the intracellular domain of the molecule is conserved, that of the extracellular domain occurs in multiple isoforms, each of the result of alternative mRNA splicing. In T lymphocytes, the lowest relative molecular mass (Mr) form, CD45RO, is associated with acquisition of memory function, whereas the highest Mr isoform, CD45RA, occurs in "naive" T cells. Recently, B cells were also found to express CD45RO following in vitro activation. In order to more fully characterize the expression of CD45 on activated B cells, we have studied its appearance on Epstein-Barr virus-transformed (EBV-t) cells and have found heterogeneous expression of CD45RO and CD45RA. CD45RO expression was unstable with eventual loss by some EBV-t lines, and loss followed by reappearance in others. CD45RA and CD45RO varied independently whereas CD45 remained stable and high, suggesting a fluctuation in other CD45 isoforms. Immunostaining for CD45RB indicates that a probable 190-kDa isoform may be responsible for this observation. A similar bidirectional reversible shifting between CD45RA and CD45RO on T-cell lines has also been reported by Rothstein et al. In contrast to some reports on normal B cells, neither CD45RA nor CD45RO expression was associated with PCA-1 expression. Further evidence that these EBV-t lines may not correspond to a well-defined stage of B-cell differentiation is provided by the observation that a disproportionate loss of CD20 compared to CD19 was noted for several lines. The basis for the CD45 isoform switching, or any functional difference(s) in the expressed isoforms, is not yet known for human B cells.

B-cell precursors in normal pediatric bone marrow

A number of studies have been published pertaining to "normal" lymphocyte subsets in bone marrow. However, these studies are based on normal adult marrow or marrows of children with leukemia in remission or other systemic illness. Data on hematologically normal children are lacking. This study demonstrates that, compared with that of adults, bone marrow of hematologically normal children has an increased percentage of B cells and B-cell precursors. Dual-parameter flow cytometric methods demonstrated subpopulations of B cells at various stages of differentiation; the percentage of cells in these subsets is highest in the very young and decreases with increasing age. Caution must be exercised when searching for early leukemic relapse in pediatric marrows because these normal immature B-cell precursors immunophenotypically resemble leukemic blasts.

Expansion of immature thymic precursor cells in peripheral blood after acute marrow suppression

Leukemoid reactions occur in response to a number of infectious agents and sometimes may be associated with bone marrow suppression. After acute suppression of the bone marrow, a resurgent hyperplasia occurs that may appear as synchronous maturation of a single cell type. The authors describe the case of a 13-year-old child in whom a remarkable lymphocytosis developed during a period of pancytopenia associated with a febrile syndrome resembling Ehrlichiosis. Most of these lymphoid cells were morphologically similar to large granular lymphocytes (LGLs), but many appeared to be less mature. Immunophenotypic studies demonstrated most of these lymphoid cells to be immature T cells at an "intermediate" or "transitional" stage of thymocyte differentiation characterized by the CD1-CD3+CD4-CD8- phenotype, as well as positivity for nuclear terminal deoxynucleotidyl transferase. In T-cell ontogeny, this stage represents a transition between thymic precursors and mature thymocytes. Their presence in the peripheral blood of this child is thought to represent a lymphocytic leukemoid response to his infection. Cases such as this may be confused with malignancy.

Biopsychosocial parameters of disease activity in rheumatoid arthritis

The purpose of this study was to examine the applicability of a biopsychosocial model for estimating disease activity in rheumatoid arthritis (RA). Sixty-three patients with RA were evaluated at baseline, 3 months, and 6 months. Joint counts were collected as the measure of disease activity. Peripheral blood immunophenotypic subsets, demographic characteristics, and psychological measures were obtained and entered into hierarchical regression analyses, with the joint count as the dependent variable. Immunophenotypic subsets (that is, CD57+/CD16-, HLA-DR+) were predictive of disease activity at all three time intervals. At baseline and 3 months, psychological variables (that is, helplessness and depression) were significantly related to joint counts, and the full model was highly significant. The conclusion was that the biopsychosocial perspective is useful for estimating RA disease activity.

Translocation of CD45RA in neutrophils

The CD45 family of high-Mr glycoprotein antigens is expressed in some molecular form on all lymphohematopoietic cells. Different cell types express various isoforms in a precisely programmed fashion. In addition to cell surface CD45 antigens, we recently demonstrated a cytoplasmic granule-associated pool of CD45RA, the highest Mr isoform, in mature neutrophils that is generally absent from the cell surface under nonstimulatory conditions. Under such conditions, the major cell surface form is CD45RO, the low-Mr isoform. In the present study, we demonstrate the ability of calcium ionophore A23187 to induce translocation of cytoplasmic CD45RA to the cell surface as well as to increase the cell surface expression of CD45RO and CD45. This process was calcium dependent and rapid, occurring within 5 min. A series of experiments using chemical antagonists of protein kinases suggest that this up-regulation may be mediated via the calmodulin system rather than via protein kinase C. Although the exact function(s) of the various isoforms of CD45 is not known, this translocation suggests a role for CD45RA in neutrophil activation.

Expression of the low Mr isoform of CD45 (CD45RO) in B-cell non-Hodgkin's lymphomas

The CD45 antigen family consists of multiple molecular isoforms ranging from 180 to 220 relative molecular mass (Mr). The highest Mr isoforms are recognized by monoclonal antibodies (MoAbs) designated CD45RA, while those recognizing the low Mr isoform are designated CD45RO. About half of the T-cells in peripheral blood express CD45RA while the remainder express CD45RO. A switch from the high to the low Mr isoform of CD45 has been found in association with the process of T-cell stimulation and acquisition of "memory." B-cells normally express CD45RA, but not CD45RO. However, under stimulatory conditions, B-cells may be capable of undergoing an isoform switch and expressing CD45RO. The expression of this low Mr isoform of CD45 was investigated in lymphomas composed of monoclonal B-cells to determine if such a switch occurs in malignant B-cell populations. The vast majority (110/117 cases) of B-cell lymphomas expressed only CD45RA, while a very small number (7/117 cases) expressed CD45RO, but not CD45RA. There was no relationship between the CD45RO expression and the histologic subtype. The physiological significance of this unusual expression of CD45RO in a subpopulation of B-cell lymphomas is not clear. In that CD45RO, as defined by the MoAb UCHL 1, is typically used as a marker of T-cells in tissue sections, caution must be exercised in interpretation, since not all T-cells are reactive and some B-cell lymphomas are reactive.

Surface and cytoplasmic expression of CD45 antigen isoforms in normal and malignant myeloid cell differentiation

The CD45 family contains protein tyrosine phosphatase (PTPase) activity and is expressed in one or more of its isoforms on all lymphohematopoietic cells. Considerable work has focused on CD45 expression by lymphoid cells, but minimal work has involved granulocytes. Granulocytic, or myeloid, cell differentiation is accompanied by a number of morphologic and immunophenotypic changes. This study used flow cytometric and immunocytochemical methods in conjunction with morphologic assessment to investigate the expression of CD45 isoforms during differentiation of normal and malignant granulocytic cells. On normal bone marrow cells, the quantity of surface CD45 did not change during earlier stages but did increase significantly at the terminal stages (bands and polymorphonuclear leukocytes [PMNs]). CD45RO (the low relative molecular mass [Mr] isoform) was very dimly expressed on immature cells but became increasingly brighter beginning at approximately the myelocyte stage. The high Mr isoform (CD45RA) was virtually absent from the cell surface at all stages. Only a small percentage (3-15%) of PMNs expressed surface CD45RA. However, there was a cytoplasmic pool of each isoform associated with membrane-bound granules found throughout differentiation, with remarkable increases in expression at the terminal stages. In the case of acute myeloid leukemias (AMLs), most cases expressed surface CD45RA with, or without, CD45RO, regardless of their French-American-British (FAB) classification. This appeared to be a stable process at diagnosis and relapse in individual patients and may therefore serve as a diagnostic aid. The biologic significance of this aberrant expression of CD45RA by malignant cells is unknown but raises important questions regarding the cellular processes of phosphorylation/dephosphorylation in normal and malignant cells.

Relationship between CD45 antigen expression and putative stages of differentiation in B-cell malignancies

The cell-surface antigen CD45 is a complex family of high-molecular-weight glycoproteins expressed on all lymphohematopoietic cells, but not in the same molecular isoform. This antigen complex is known to exhibit protein tyrosine phosphatase (PTPase) activity and appears to have a role in regulation of cell differentiation. In that CD45 expression parallels stages of differentiation in normal bone marrow B cells, it was of interest to evaluate this process in malignant B cells. Monoclonal antibodies (MoAbs) were used to investigate the quantitative expression of CD45 and CD45RA on the B cells of lymphoid leukemias. Employing standardized flow cytometric methods, it was found that the fluorescence intensity (FI) of immunostained malignant B cells, as a reflection of the antigen content, demonstrated correlations with the putative stage of cell differentiation for malignancies at the earlier stages, but at the later stages, a progressive loss of CD45 was observed. Since this antigen family has been found to display PTPase activity, further investigation of CD45 alterations in malignancies may provide insight into potential regulatory disturbances.

Acute leukemia/lymphoma of plasmacytoid T-cell type

Plasmacytic morphologic characteristics are usually associated with cells of B-lymphocyte origin. Recently, plasmacytoid T-cells have been described in reactive lymph nodes and a rare form of lymphoma characteristically associated with myeloproliferative disorders. This report documents a case of plasmacytoid T-cell malignancy that initially presented as an acute leukemia in an elderly man with a longstanding myelodysplastic syndrome. The tumor replaced bone marrow and involved lymph nodes. Despite aggressive therapy, he died quickly of his leukemia/lymphoma. This case illustrates the need for complete cellular analysis in the diagnosis of morphologically plasmacytic malignancies and raises additional questions about the relationship of this peculiar type of T-cell to the hematopoietic marrow.

Expression of CD45 isoforms in lymph node reactive hyperplasia

The CD45 antigen family consists of multiple molecular isoforms ranging from 180 to 220 kDa. The highest Mr isoforms are recognized by monoclonal antibodies (MoAbs) designated CD45RA, while those recognizing the low Mr isoforms are designated CD45RO. T cells expressing CD45RA are "naive" or unprimed, while those expressing CD45RO have "memory." Further, stimulation of CD45RA+ T cells induces an isoform switch to the CD45RA-/CD45RO+ phenotype. The present study examined this in vitro process by determining the in vivo CD45 isoform expression of T cells from human hyperplastic lymph nodes. Hyperplastic, as opposed to nonhyperplastic, lymph nodes exhibited the expected CD45 isoform switch from CD45RA+ to CD45RO+ T cells that has been described in vitro. The percentage of CD45RO+ T cells did not correlate with other parameters of lymphoid activation. Thus, CD45RO expression probably represents a marker of differentiation and acquisition of "memory" or late cellular activation.

Myelodysplastic syndrome: prospective evaluation of fifty-one patients using the Dutcher scoring system

Fifty-one patients with primary myelodysplastic syndrome were prospectively evaluated using a scoring system based on the presentation blood and bone marrow findings. Twenty-four patients (47%) evolved to acute nonlymphocytic leukemia. Stepwise regression model showed that the scoring system was the only significant variable for predicting transformation to acute leukemia (p = 0.0007, sensitivity 70.8%, specificity 77.8%). Seventy-six percent of patients with a score of 14 or greater developed acute leukemia compared to 19% with a score of 13 or less. Median survival of the entire group was 10 months. The most important prognostic factor for predicting survival was the scoring system (p = 0.0001). Survival correlated inversely with the score. This scoring system may be useful in the management of patients with myelodysplasia.

Fluorescence intensity as a quality control parameter in clinical flow cytometry

The fluorescence intensity (FI) and percentage of immunostained peripheral blood lymphocytes (PBLs) were tested as parameters for monitoring quality control of monoclonal antibodies (MoAbs) and the staining procedure. Several potential variables were addressed, including optimal dilutions of MoAbs, standardization of instrument functions with fluorescent microspheres, stability of day-to-day fluorescence detection with fluorescent fixed cells, and effects of separation method and storage conditions on FI and PBL antigens. Although some small (but statistically significant) changes were found in certain tests, in general the FI and percentages of MoAB-positive human PBLs provided information useful in a standardized flow cytometry quality control program. This type of standardization and quality control facilities early discovery of methodologic and reagent problems in the clinical laboratory, as well as the ability to routinely evaluate disease states associated with abnormal antigen density.

Relationship between T200 antigen expression and stages of B cell differentiation in resurgent hyperplasia of bone marrow

Using monoclonal antibodies (MoAbs) and dual-parameter flow cytometric techniques, bone marrow mononuclear cells (MMC) from patients with resurgent hyperplasia were analyzed for their coexpression of HLe-1 (T200) and antigens normally associated with particular stages of B cell differentiation. The marrow from those with resurgent hyperplasia contained increased numbers of B cell precursors in multiple stages of differentiation compared to controls, thus providing a useful model system for studies of B cell differentiation. These studies indicate that the quantitative expression of T200 is differentiation-related on normal and malignant B cells and B cell precursors. Immature cells express low amounts of T200, while increasing levels of maturity correlated with increasing amounts of the antigen. This study increases the understanding of relationships between B cell surface antigens and T200 and further demonstrates that B cell hyperplasia occurs commonly in association with bone marrow reactive or resurgent processes. The quantitative, rather than only the qualitative, expression of T200 is therefore a useful marker of B cell differentiation in reactive hyperplasia and in further investigation of B cell malignancy.

Alterations of HLe-1 (T200) fluorescence intensity on acute lymphoblastic leukemia cells may relate to therapeutic outcome

Quantitative differences in HLe-1 expression were studied on normal lymphocytes and lymphoblasts of patients with acute lymphoblastic leukemia (ALL). A relationship was found between quantitative antigen expression and therapeutic outcome. Alterations in fluorescence intensity (FI) were demonstrated using quantitative flow cytometric methods and the monoclonal antibody (MoAb) anti HLe-1 (T200). Lymphoblasts from patients with ALL produced FI peaks ranging form channel 17 to 112 (mean 68; n = 28), while normal lymphoid cells were at FI channel 127 +/- 3 (n = 121). Patients with the dimmest-staining lymphoblasts (channels 17-50) responded better to therapy than those with brighter-staining cells (channels 50-100). Data from this pilot study suggests that the FI of malignant lymphoblasts has implications in the clinical response to therapy.