Diagnosis of human lymphoma with monoclonal antileukocyte antibodies

Of drills and bones: Giovanni Ghedini and the origin of bone marrow biopsy

Bone marrow (BM) studies are pivotal for the diagnosis of haematological disorders. Their introduction into clinical haematology dates back to the work of Giovanni Ghedini (1877-1959), an Italian physician who first conceived BM sampling in 1908. Ghedini's proposal stemmed from his clinical experience and from the scientific developments that characterised his epoch. By presenting selected passages of Ghedini's publications, this report considers the theoretical and historical bases of his work and analyses its practical implications for modern haematology.

Developing Monoclonal Antibodies for Immunohistochemistry

The experiences of a laboratory which pioneered the application of monoclonal antibodies to diagnostic histochemistry is described. This was achieved in four key steps: (1) Monoclonal antibodies were successfully produced to replace the difficult-to-produce and limited polyclonal antibodies available for immunohistochemistry. (2) Monoclonal antibodies were produced to improve the immunoenzymatic detection of bound antibodies, using immunoperoxidase or alkaline phosphatase, increasing sensitivity and allowing the use of two chromogens when applied together. The availability of a reliable alkaline phosphatase-based detection allowed the detection of antigens in tissues with high endogenous peroxidase. (3) Methodologies were developed to unmask antigens not detected in routinely processed paraffin-embedded tissue. (4) Synthetic peptides were used as immunising antigens for the direct production of specific molecules of diagnostic interest. This was expanded to include recombinant proteins. Many reacted with fixed tissue and recognised homologous molecules in other species. In addition to these developments, the laboratory promoted the collaboration and training of researchers to spread the expertise of monoclonal production for diagnosis.

Lymphoma versus Carcinoma and Other Collaborations

David Mason started his research career at a time when lymphoma diagnosis was based primarily on cellular morphology, clinical symptoms and special cytochemical stains using formalin fixed tissue sections. There were occasions, however, where the morphology was unhelpful, such as in the case of anaplastic or poorly differentiated tumours, where a distinction between lymphoma and a non-haematopoietic tumour was often problematical. Accurate diagnosis became even more important with the developments in the clinical staging of lymphoma and the availability of more effective treatments. One way forward to improve diagnosis was to use immunohistochemistry to study the antigens expressed by the tumor cells.

The Value of Immunohistological Techniques in Undifferentiated Cancers

From 1980 to 1984, we observed 144 undifferentiated cancers, of which 116 (0.9% of all cancers treated during this period) were treated in our center. Immunohistochemical study classified 130 tumors (90%), which comprised 82 non-Hodgkin's lymphomas (57%), 32 carcinomas (22%), 7 melanomas (5%), 7 sarcomas (5%) and 2 others (1%). Sixty-nine patients, with the diagnostic problem of non-Hodgkin's lymphoma versus carcinoma, which was solved by immunohistology, were followed up for 44 ± 20 months. Lymphomas (57 cases) had a better clinical course than carcinomas (11 cases), and a clinical course similar to high-grade lymphomas identified by conventional histology. For 66 patients with the same problem, the treatment was started before the immunohistochemical diagnosis. This treatment was inappropriate in the light of the correct diagnosis in 16 of 66 cases (24% of all cases).

Burkitt-Like Lymphoid Malignancy Presenting as a Breast Tumor

The authors describe a case of a female patient, who presented with a rapidly expanding mass of the right breast as the first clinical sign of a Burkitt-like lymphoproliferative disorder. Massive bone marrow infiltration with leukemic spillover and limited lymph node involvement were subsequently detected. The difficulties encountered in classifying, according to current schemes, the observed lymphoid neoplasm are emphasized. Moreover, an evaluation of the true rarity of mammary localizations at the onset of lymphoid malignancies, based on a review of the literature, suggests, especially for the most malignant varieties, a higher frequency than supposed.

The Microscope as a Tool for Disease Discovery-A Personal Voyage

This review reflects the trajectory of my career in hematopathology, and my personal reflections on scientific advances in the field. During the course of more than 40 years, the approach to classification of hematological malignancies has evolved from descriptive approaches, based on either cytological or clinical features, to a modern approach, which incorporates cutting-edge technologies. My philosophy has focused on defining individual diseases, an approach that can best lead to an understanding of molecular pathogenesis. To quote Carolus Linnaeus ( 1 , p. 19), the father of taxonomy, "The first step in wisdom is to know the things themselves; this notion consists in having a true idea of the objects; objects are distinguished and known by classifying them methodically and giving them appropriate names. Therefore, classification and name-giving will be the foundation of our science."

Squamous cell carcinoma variants of the upper aerodigestive tract: a comprehensive review with a focus on genetic alterations

CONTEXT

Squamous cell carcinoma of the upper aerodigestive tract is a heterogenous entity. Although conventional squamous cell carcinomas are easily recognized, the morphologic variants of squamous cell carcinoma can present a diagnostic challenge. Familiarity with these variants is necessary because many are associated with unique risk factors and are characterized by specific molecular alterations (eg, nuclear protein in testis midline carcinomas). Perhaps the most important distinction is in identifying viral-related from nonviral-related carcinomas. The accurate diagnosis of these variants is necessary for prognostic and therapeutic reasons.

OBJECTIVES

To provide a clinicopathologic overview and summary of the molecular alterations of the common squamous cell carcinoma variants, including verrucous, spindle cell, acantholytic, adenosquamous, basaloid, and papillary squamous cell carcinoma, as well as nuclear protein in testis midline carcinoma, and to discuss the distinguishing features of human papillomavirus- and Epstein-Barr virus-related squamous cell carcinomas.

DATA SOURCES

Published peer-reviewed literature.

CONCLUSIONS

Familiarity with squamous cell carcinoma variants is essential for proper diagnosis and to guide appropriate clinical management. Further insight into the molecular alterations underlying those variants may lead to alterations in existing treatment approaches and to evolution of novel treatment modalities.

Integration of genomic medicine into pathology residency training: the stanford open curriculum

Next-generation sequencing methods provide an opportunity for molecular pathology laboratories to perform genomic testing that is far more comprehensive than single-gene analyses. Genome-based test results are expected to develop into an integral component of diagnostic clinical medicine and to provide the basis for individually tailored health care. To achieve these goals, rigorous interpretation of high-quality data must be informed by the medical history and the phenotype of the patient. The discipline of pathology is well positioned to implement genome-based testing and to interpret its results, but new knowledge and skills must be included in the training of pathologists to develop expertise in this area. Pathology residents should be trained in emerging technologies to integrate genomic test results appropriately with more traditional testing, to accelerate clinical studies using genomic data, and to help develop appropriate standards of data quality and evidence-based interpretation of these test results. We have created a genomic pathology curriculum as a first step in helping pathology residents build a foundation for the understanding of genomic medicine and its implications for clinical practice. This curriculum is freely accessible online.

Expression profiling in soft tissue sarcomas with emphasis on synovial sarcoma, gastrointestinal stromal tumor, and leiomyosarcoma

Sarcomas are defined as malignant neoplasms derived from mesenchymal tissues. A variety of different molecular approaches, including gene expression profiling, have identified candidate biomarkers and insights into sarcoma biology that will aid in the diagnosis and treatment of these tumors. Many gene expression profiling findings have been translated into immunohistochemical tests for diagnostic, prognostic, or predictive purposes. This review details gene expression studies done in 3 sarcomas, synovial sarcoma, gastrointestinal stromal tumor, and leiomyosarcoma.

Histology and immunohistology of bone marrow biopsy in multiple myeloma

B5-fixed/paraffin-embedded Jamshidi needle biopsies from 125 multiple myeloma patients were reviewed according to both morphological and immunohistological criteria. At microscopic examination, the following parameters were evaluated: i) grade of malignancy (low = 56; intermediate = 50; high = 19); ii) growth pattern (interstitial +/- sheets/nodules = 90; nodular = 13; packed marrow = 18; sarcomatous = 4); III) histological stage (I = 64; II = 35; III = 26). Comparison of the findings in trephine biopsies and aspirates showed that in 30% of the cases the latter led to an underestimation of the tumor burden. Immunohistochemical determination of Ig easily allowed: i) differential diagnosis from exuberant reactive plasmacytosis; ii) recognition and counting of neoplastic plasma cells; iii) detection of minimal residual disease after treatment. Immunohistochemistry also confirmed phenotypic aberration of neoplastic plasma cells, showing positivity for CD45, EMA, and cytokeratins in 14%, 59%, and 25% of the cases, respectively. Furthermore, it displayed expression of the P-glycoprotein in 4/8 resistant cases. These findings underline that routinely processed Jamshidi needle biopsies can be of great value in the study of patients with multiple myeloma.

Primary lymphomas of the breast: a report on 5 cases studied in a period of 5 years at the Hospital General de México

Breast lymphomas can be primary or secondary. Among the primary lymphomas, the most common histologic types are the large B-cell diffuse lymphomas and the extranodal B mucosa-associated lymphatic tissue lymphomas. We studied 5 cases of primary breast lymphoma in female patients. The criteria for the diagnosis were based on the proposal of Wiseman and Liao: (1) in the biopsy or surgical specimen, the lymphoma involves the breast parenchyma, and (2) nonsystemic disease at diagnosis. Clinical data, histologic findings, immunohistochemical reactions, treatment, and clinical follow-up were reviewed. The 5 patients were young women with average age of 27 years; the youngest was 20 years old, and the oldest was 44 years old. The right breast was the most affected, and 1 patient was HIV positive. The most common symptoms were the presence of nodes, progressive increase of volume, collateral venous network, and hemorrhagic discharge from the nipple. The clinical course was of 1 to 14 months before diagnosis. Three patients died because of central nervous system infiltration, one is still alive, and the other was lost during follow-up. Histologically, all primary breast lymphomas were large B-cell lymphomas; one had focal starry sky pattern, and the other 3 were centroblastic. All were positive to CD20 and CD79(a), 3 expressed bcl2, and 2 expressed bcl6. The proliferation index was between 60% and 80%. Primary breast lymphomas are rare. The average age of our patients was 27 years, and their clinical course was aggressive with central nervous system infiltration. The most common histologic type was the large B-cell diffuse lymphoma. Differential diagnosis must be established in the presence of poorly differentiated lobules and ductal carcinoma.

Leucocyte-specific protein (LSP1) in malignant lymphoma and Hodgkin's disease

Biopsies from 319 haematopoietic neoplasms were immunostained for intracellular leucocyte-specific protein 1 (LSP1) to assess its distribution and to compare its diagnostic value with that of CD45 (leucocyte common antigen: LCA). Most small B-cell neoplasms expressed LSP1, but one third of diffuse large B-cell lymphomas (DLBCL) were LSP1 negative. Among the cases with DLBCL (76 samples) tested for both LSP1 and CD45, one fifth expressed only CD45, but five samples were LSP1-positive and negative for CD45. The latter pattern was also seen in four of nine myelomas. Five out of 14 T-lymphoblastic lymphomas co-expressed LSP1 and CD45, and three cases were LSP1 negative and CD45-positive. Most peripheral T-cell lymphomas co-expressed LSP1 and CD45. All anaplastic lymphoma kinase (ALK)-negative lymphomas of anaplastic large cell morphology (T and null phenotype) expressed LSP1 although the percentage of LSP1-positive tumour cells was variable, however, only seven out of 30 cases with ALK-positive lymphoma were LSP1 positive. LSP1 was expressed on Reed-Sternberg cells in 60 out of 66 cases with classic Hodgkin's disease but neoplastic cells were usually negative in lymphocyte predominant Hodgkin's. This study confirms the wide expression of LSP1 within haematopoietic neoplasms and its diagnostic value for a minority of lymphoid tumours that have lost CD45 expression. Furthermore, the strong expression of LSP1 in classic Hodgkin's disease, contrasting with its heterogeneous expression in ALK-negative anaplastic lymphomas, may help to distinguish the latter lymphomas from patients with tumour cell-rich Hodgkin's disease.

Immunophenotypic analysis of the inflammatory infiltrates in herniated intervertebral discs

STUDY DESIGN

The herniated portion of the lumbar disc was analyzed immunohistochemically for inflammatory infiltrates to determine their immunophenotype.

OBJECTIVE

To investigate the pathomechanism behind spontaneous regression of herniated discs.

SUMMARY OF BACKGROUND DATA

Spontaneous regression of herniated intervertebral discs has been increasingly reported. The inflammatory response of the host has been suggested as a factor in this phenomenon. However, whether the inflammation is induced from direct chemical irritation of the nucleus pulposus material or whether it is secondary to an autoimmune response to the nucleus pulposus remains controversial.

METHODS

The herniated portion of the disc was collected from 38 patients who underwent surgery for lumbar disc herniation. Thin cryostat sections were made, and the extent to which inflammatory cells had infiltrated the disc specimen was defined. Then the immunophenotype of cellular infiltrates in the herniated disc specimens was assessed by immunostaining using a series of antibodies for lymphocyte, monocyte, macrophage, and dendritic cell markers.

RESULTS

The inflammatory infiltrates in 14 of the 38 herniated discs were subjected to immunohistochemical analysis. None of them expressed the immunophenotypic markers of the lymphocyte (CD20, CD45RO, CD4, CD8, TCRgammadelta), mature monocyte (CD33), or dendritic cell (CD1a, CD80, CD86, S100). Abundant infiltration of CD68-positive cells that lacked CD33 but had a variable amount of CD11b, CD11c, and CD40 likely represents a process of differentiation from monocytes to macrophages.

CONCLUSIONS

These findings are consistent with an immunophenotype of inflammatory responses to tissue injury or chemical irritation rather than antigen-specific immune responses. Therefore, understanding the mechanism of tissue repair is fundamentally important in the management of patients with disc herniations.

The cost-effectiveness of immunohistochemistry

OBJECTIVE

To evaluate the cost-effectiveness of immunohistochemistry.

DESIGN

Using a theoretical decision analytic model, the cost-effectiveness of immunohistochemistry was evaluated in different scenarios depicting the beneficial use of immunohistochemistry. Data regarding the effectiveness of immunohistochemistry were obtained from the medical literature and costs were obtained from Allegheny General Hospital.

SETTINGS

The scenarios depicted both private practice and university patients from which anatomic pathology specimens were obtained. Immunohistochemistry was subsequently performed on these specimens.

MAIN OUTCOME MEASURES

Cost, life expectancy, diagnostic certainty, ability to predict prognosis, and cost-effectiveness were evaluated.

RESULTS

In all scenarios, immunohistochemistry was cost-effective at very low efficacies. Assuming a per-antibody cost of $50 and use of a 5-antibody panel, immunohistochemistry was cost-effective if it resulted in a 1-year gain of population life expectancy in 1 or more of every 200 cases in which it was applied. Alternatively, if the gain in diagnostic certainty by using immunohistochemistry was 10% and the value placed on a percentage gain in diagnostic certainty was $1000, immunohistochemistry was cost-effective if it produced this increase in certainty in 1 of every 40 tests. If a life-year was valued at $50 000, immunohistochemistry was cost-effective if it resulted in a change in patient prognosis of 0.5 years in 1 of every 100 tests.

CONCLUSIONS

Using theoretical modeling, immunohistochemistry is extremely cost-effective. These data have implications in an era of managed care when providers attempt to trim laboratory services. Additional studies are needed to evaluate the actual practice efficacy of immunohistochemistry.

Expression of the stem cell factor receptor c-kit in normal and diseased pediatric liver: identification of a human hepatic progenitor cell?

The stem cell factor (SCF)/c-kit ligand/receptor system has been implicated in stem (oval) cell activation following liver injury in the rat. The aim of this study was to determine the role of the SCF/c-kit system in pediatric human liver during acute and chronic liver injury. Tissue was obtained from hepatectomy specimens of patients undergoing liver transplantation for extrahepatic biliary atresia (EHBA) and fulminant hepatic failure (FHF). Specific expression of mRNA for c-kit and beta-actin was measured by ribonuclease protection and by immunohistochemistry to localize c-kit in tissue sections. Expression of c-kit was detected at relatively consistent levels in normal and cirrhotic (EHBA) livers. However, in FHF, c-kit mRNA levels were elevated in 3 of 6 specimens. Immunolocalization highlighted the presence of small numbers of c-kit-positive cells in the portal tracts of normal livers with increased numbers in cirrhotic livers. The highest c-kit staining, however, was observed in FHF, in which, in addition to the cells in the portal tracts, discrete c-kit-positive cells were also found integrated into bile ducts. Colocalization studies demonstrated some of the c-kit-positive cells to be of mast cell, leukocyte, and hematopoietic cell origin. However, there remained a subset that was also negative for these markers. The up-regulation of c-kit receptor expression in diseased livers suggests an involvement of this receptor/ligand system in hepatic repair mechanisms, and we speculate that c-kit-positive cells may represent a hepatic progenitor cell population. The origin and growth/differentiation potential of these c-kit-positive cells is under investigation.

Localization of ubiquitin and ubiquitin cross-reactive protein in human and baboon endometrium and decidua during the menstrual cycle and early pregnancy

We have examined the distribution of ubiquitin and the related ubiquitin cross-reactive protein (UCRP) in paraffin-embedded sections of human and baboon endometrium and decidua by immunoperoxidase or immunofluorescence cytochemistry with antibodies raised against ubiquitin, UCRP, CD45, and insulin-like growth factor-binding protein-1. Anti-ubiquitin immunoreactivity was present in the nonpregnant endometrium, particularly in the glandular epithelial cells, and up-regulated in endometrial stromal cells as they decidualized at the beginning of pregnancy. Anti-UCRP immunoreactivity was absent from nonpregnant tissue but accumulated to high levels in decidual cells during pregnancy. Western blotting indicated that immunoreactivity was primarily due to the presence of ubiquitin and UCRP conjugated to other proteins, and that although levels of ubiquitin-protein conjugates do not change substantially during pregnancy, decidualization is accompanied by the appearance of conjugates of UCRP. Baboon uterine tissues demonstrated a similar distribution of the two proteins, which indicates that the baboon may be a useful model for study of the role of the ubiquitin system and UCRP in the establishment of pregnancy in humans.

Practical applications of immunohistochemistry in hematolymphoid neoplasms

Immunohistochemistry plays a key role in the diagnosis and classification of hematolymphoid neoplasms. New cell and lineage markers are constantly being discovered and added to the existing long list of antibodies. In this review article we provide general information and new applications of the commonly used hematolymphoid markers. We also discuss the features and applications of some newly discovered markers, such as ALK, fascin, granzyme/perforin, and tryptase. There is no universal "panel" for the diagnosis of hematolymphoid neoplasms. However, in this review article, we provide suggested panels for a given hematolymphoid neoplasm that is based on our experience and that reported in the literature.

Skin as the primary site of Hodgkin's disease: a case report of primary cutaneous Hodgkin's disease and review of its relationship with non-Hodgkin's lymphoma

We report an elderly patient who presented with a single cutaneous nodule of primary cutaneous Hodgkin's disease (PCHD). Reed-Sternberg cells, expressing CD30 and CD15, but not leukocyte common antigen (CD45RB), were identified in the neoplastic cells. Southern blot analysis failed to detect T-cell receptor or immunoglobulin gene rearrangement. A work-up for systemic disease at the time of presentation was negative, supporting the diagnosis of PCHD. Nevertheless, 1 year later, the disease course was complicated by the development of nodal HD and nonHodgkin's lymphoma (NHL). This case report supports the existence of this rare, but distinct, cutaneous tumor.

Hemopoiesis in human fetal and embryonic liver

In this review, we describe the topographic distribution of hemopoietic cells of the lymphoid, myeloid, and erythroid lineages in the human fetal and embryonic liver. The data are based on studies of frozen tissue, allowing the determination of a broad range of hemopoietic antigens, and studies on paraffin-embedded tissue, allowing the combination of optimal morphology and immunodetection of lineage-specific antigens. The different hemopoietic lineages each show their own immunophenotype and distribution; intercellular and microenvironmental relationships were easily determined. In a few cases, some scarce CD34-positive early progenitor cells were seen. The number of proliferating cells, identified by monoclonal antibody (MAb) Ki-67, varied from 350 to 2500 (median = 1,500) per square millimeter of tissue. Erythroid cells reacted with antisera to glycophorin A, CDw75, and CD43 and partly surround a central macrophage, whereas the myelomonocytic cells reacted with CD45, CD43, CD74, and antilysozyme serum, and with LN3 from 14 weeks onward. Myelopoietic (CD15 positive) cells were localized mainly around portal triad vessels and increased in number with gestational age. The lymphoid cells showed CD45, CD43, CD45RA/MT2, CD45RA/MB1, MB2, and CD74 reactivity. B cells and their precursors were scattered among the hepatocytes without any sign of focal development in the age range studied. We seldom found cells positive for delta-H chain or C3bR (CD35); C3dR (CD21)-positive cells were even more scarce. Cells reactive with MAb WT1 (CD7) were present in a scattered single pattern (< or = 20/mm2) among the parenchymal cells; cells expressing mature T-cell markers (CD2, CD3, CD5) were rare. Large (> 15 mu) CD43-positive hemopoietic cells in the fetal liver were distinguished that exclusively expressed CD43, probably representing early hemopoietic progenitor cells.

Immunohistochemical and ultrastructural investigation of the human vestibular dark cell area: roles of subepithelial capillaries and T lymphocyte-melanophage interaction in an immune surveillance system

BACKGROUND

The aim of the present study was to morphologically characterize the structure of the subepithelial blood vessels in the dark cell area of the human vestibular organs, and to determine whether immunocompetent cells such as macrophages and lymphocytes could be found around these small blood vessels.

MATERIALS AND METHODS

All 31 surgical specimens (semicircular canals and utricles) were obtained from patients with vestibular schwannoma. Formalin fixed specimens were stained with hematoxylin and eosin (H&E), and with antibodies to von Willebrand Factor (vWF), leukocyte common antigen (LCA), and UCHL-1, and were examined with light microscope. Specimens fixed with glutaraldehyde were examined with a transmission electron microscope (TEM).

OBJECTIVES

Subepithelial blood vessels stained positive for vWF. By TEM observation, these blood vessels were observed to be capillaries that consisted of non-fenestrated endothelium, occasional pericytes, and a basement membrane. They were usually accompanied by melanophages with a number of secondary lysosomes containing phagocytosed degraded melanosomes and lipid droplets. Moreover, melanocytes and their cell processes directly surrounded these subepithelial capillaries. The fact that cells which were positively stained with LCA and UCHL-1 were present both in the intra- and subepithelial layer of the specimens, and that by TEM the intra- and subepithelial mononuclear cells with a lymphoid appearance had clustered dense bodies in their cytoplasm, suggested that they were a population of T lymphocytes.

CONCLUSIONS

Results suggested the possibility of a T lymphocyte-melanophage (macrophage) interaction, both originating from and harbored around subepithelial capillaries, which suggests the presence of an immune surveillance system in the human vestibular organs.

Nasal mucosa inflammation induced by oxygen administration in humans

BACKGROUND

The effect of oxygen toxicity in human airways is still poorly documented. We prospectively evaluated the inflammatory reaction induced by nasal oxygen exposure in an experimental setting.

METHODS

Healthy subjects without nasal symptoms were exposed to high FIO2 during 5 h. Oxygen was delivered from a tank at a flow of 4 l/min to one nostril of each subject and both nostrils were studied. Mucociliary clearance was measured as saccharine nasal transit time (SNTT). Nasal lavage was performed with 5 ml normal saline and the fluid recovered was processed for cytology and measurements of cytokines concentrations: TNF alpha, IL-6, IL-8 and soluble ICAM-1. Under local anaesthesia, biopsies were performed for immunochemistry and electron microscopy.

RESULTS

After oxygen exposure mucociliary clearance decreased and SNTT increased from 16 [9-21] to 20.5 [14-32] min (median and extremes; P < 0.1). In the lavage fluid, concentration of IL-6 was higher in the oxygen-exposed nostril (40.5 [11-128] pg/ml) than in the non-exposed one (7 [0-34] pg/ml; P < 0.05). There was also a trend for a higher IL-8 in the exposed than in the non-exposed nostril, (respectively 501 [214-587] pg/ml and 214 [122-616] pg/ml, P < 0.08), and for a higher number of polymorphonuclear cells in exposed nostril. In the mucosal biopsies substance P was not found, but ICAM-1 expression was higher in the mucosa and submucosa of the exposed nostrils where mast cells were also more abundant and showed piecemeal degranulation.

CONCLUSION

In summary, we found clinical, functional and biological evidence of ongoing nasal inflammation following high FIO2 inhalation for 5 h. Since the histology and behaviour of nasal and bronchi mucosa are very similar, the same inflammatory events are likely to be occurring in the bronchi upon high concentrations of inhaled oxygen.

Differential expression of 92-kDa gelatinase in primary atherosclerotic versus restenotic coronary lesions

Rupture of atherosclerotic plaque resulting in intravascular thrombosis and myocardial infarction (MI), while a common sequelae of de novo atherosclerotic lesions, is an uncommon consequence of restenosis. We hypothesize that the rarity of MI associated with restenotic lesions is a result of cellular and biochemical modifications induced by the local response to mechanical injury rendering the site resistant to rupture. Clinical and angiographic features of patients presenting with symptomatic primary (n = 24) or restenotic coronary lesions (n = 12) who underwent directional atherectomy were compared. Histologic analysis and immunostaining for 92-kDa gelatinase were performed on each atherectomy specimen. There was no significant difference between the 2 groups regarding age, gender, incidence of diabetes, smoking, hypertension, hypercholesterolemia, or previous MI. Lesion length, extent, and distribution of disease and percent stenosis were not significantly different between groups. However, 8% of primary lesions were hypercellular compared with 75% of restenotic specimens (p = 0.0001). Hypercellularity in restenotic specimens was shown by adjacent section staining to be composed of smooth muscle cells. Ninety-two kDa gelatinase was expressed in 79% of primary lesions versus 0% of restenotic specimens (p = 0.0001). Thrombus was identified in 54% of primary lesions versus 22% of restenotic lesions (p <0.05). These findings suggest that, independent of clinical or angiographic influences, balloon injury induces increased lesion cellularity and reduced expression of 92-kDa gelatinase, possibly resulting in a reduced propensity for plaque rupture and thrombosis.

Comparative immunocytochemical study of MHC class II expression in human donor pancreas and isolated islets

Expression of major histocompatibility complex (MHC) molecules by pancreatic islets may influence the survival of pancreas or islet grafts in allogeneic recipients. This study compares the presence of MHC class II (HLA-DP, DQ, DX and DR)-positive cells in 27 pancreases and in 10 isolated islet preparations from human donors. Cells expressing MHC class II were present in all tissues examined as histiocytes located in interstitial areas in both the endocrine and nonendocrine components and as endothelial cells in the nonendocrine part. Endocrine, acinar and duct cells were MHC class II negative. In pancreases from donors under the age of 7 years the frequency of MHC class II-positive histiocytes was only one third of that in adults, and they rarely contained MHC class II-positive endothelial cells. The MHC class II-positive histiocytes were further phenotyped as macrophages positive for LCA and acid phosphatase, or dendritic cells negative for the latter markers. Dendritic cells were frequent in adult organs but rare in organs from donors under 7 years of age. In freshly isolated islet preparations from adult donors, less than 1% of the cells were MHC class II positive. These were identified as resident macrophages and dendritic cells. No MHC class II positive cells were encountered in the islet capillaries. The putative role of MHC class II-positive donor cells in allograft rejection suggests that these differences in MHC class II expression influence the immunogenicity of pancreatic and islet grafts in an age-dependent manner.

Immunohistochemistry in diagnostic dermatopathology

Immunopathology continues to be important in diagnostic dermatopathology. Immunopathology is an invaluable tool for assessing the tissue of origin or direction of differentiation of cells. In some cases this can result in a more precise diagnosis. This article reviews the role of immunopathology in determining the biologic behavior of hematolymphoid infiltrates. It explores the methodology of immunoperoxidase, discusses the most commonly used antibody reagents, and presents a series of diagnostic dilemmas in which immunopathology can be useful. In each case a strategy is established that maximizes the likelihood of making a definitive diagnosis.

CD45 (leucocyte common antigen) expression in T and B lymphocyte subsets

CD45 is the dominant tyrosine phosphatase in haematopoietic cells and can modulate the effects of many other signaling molecules by dephosphorylation. The extracellular portion of CD45 has considerable variability due to differential splicing and glycosylation. This may allow for interactions with a variety of ligands expressed on interacting cells or on the same cell surface. Monoclonal anti CD45 antibodies that are reactive with epitopes that result from differential splicing and glycosylation can distinguish between cell populations that differ in maturation and function. These reagents can be used in the immunophenotyping of hematopoietic malignancies as well as in immunodeficiencies and autoimmune diseases. Several studies have shown that different anti CD45 reagents have different activating or inhibiting effects in vitro on a variety of T and B cell activation events. There are some indications that anti CD45 reagents can also selectively modify lymphocyte function in vivo. Such applications could potentially allow for the selective upregulation and down regulation of lymphocyte functions in a variety of immunologically mediated diseases.

Identification of 92-kD gelatinase in human coronary atherosclerotic lesions. Association of active enzyme synthesis with unstable angina

BACKGROUND

Acute coronary ischemia is usually initiated by rupture of atherosclerotic plaque, leading to intracoronary thrombosis and clinical sequelae. The proximate cause of plaque rupture is unknown. Accordingly, we investigated the potential role of the 92-kD gelatinase member of the matrix metalloproteinase family in acute coronary ischemia.

METHODS AND RESULTS

Coronary atherectomy specimens from patients with atherosclerosis and an acute ischemic syndrome consistent with recent plaque rupture (unstable angina) (n = 12) were immunostained for the presence of 92-kD gelatinase; the results were compared with those obtained by identical study of atherectomy specimens from patients with atherosclerosis and angina but without acute ischemia (stable angina) (n = 12). Positive immunostaining for 92-kD gelatinase was present in 83% of specimens from both unstable and stable angina patients. However, intracellular localization of enzyme (indicating active synthesis) was documented in 10 of 10 positively stained specimens from patients with unstable angina compared with 3 of 10 positively stained specimens from patients with stable angina. Macrophages and smooth muscle cells were the major sources of 92-kD gelatinase in all specimens examined by immunostaining of adjacent sections.

CONCLUSIONS

92-kD gelatinase is commonly expressed in coronary arterial atherosclerotic lesions. Active synthesis of 92-kD gelatinase by macrophages and smooth muscle cells in atherosclerotic lesions may play a pathogenic role in the development of acute coronary ischemia.

Mediastinal large B-cell lymphoma: clinical and immunohistological findings in 18 patients treated with different third-generation regimens

We report on the immunophenotype, clinical findings and response to aggressive chemotherapy of 18 patients with mediastinal large B-cell lymphoma (MLCL). Cases were collected from a series of 286 high-grade non-Hodgkin's lymphomas (HG-NHL) which, in the period September 1988 to August 1991, were enrolled in a prospective multicentre trial designed to compare the MACOP-B and F-MACHOP regimens. Immunostaining on frozen sections revealed a previously unrecognized phenotype, i.e. co-expression of B-cell (CD19, CD20, CD22, Ig-associated dimer) and activation-associated antigens (CD30 and CDw70) in about 60% of MLCL cases; in contrast, the activation-associated antigens CD25 and Ki-27 (unclustered) were consistently negative. This peculiar phenotype may reflect a derivation of the tumour from a subset of thymic activated B cells. Clinically, the patients (median age 31 years; F/M ratio 2.6) presented with bulky mediastinal mass (72%) associated with mediastinal syndrome in > 50% cases; disease was stage IIA in most cases. All 18 patients received aggressive chemotherapy (F-MACHOP 11; MACOP-B 7). Complete response (CR) was achieved in 57.1% of cases treated with MACOP-B. In contrast, the response of the 11 MLCL treated with F-MACHOP was poor (CR 18.2%) as compared to that of the 135 HG-NHL treated with the same regimen during the trial (CR 69.6%). This difference was still statistically significant after adjusting for negative prognostic factors (mediastinal mass > 10 cm plus increased LDH) and suggests that F-MACHOP might not be the most appropriate regimen for this kind of lymphoma.

Human thymic epithelial cells express an endogenous lectin, galectin-1, which binds to core 2 O-glycans on thymocytes and T lymphoblastoid cells

Thymic epithelial cells play a crucial role in the selection of developing thymocytes. Thymocyte-epithelial cell interactions involve a number of adhesion molecules, including members of the integrin and immunoglobulin superfamilies. We found that human thymic epithelial cells synthesize an endogenous lectin, galectin-1, which binds to oligosaccharide ligands on the surface of thymocytes and T lymphoblastoid cells. Binding of T lymphoblastoid cells to thymic epithelial cells was inhibited by antibody to galectin-1 on the epithelial cells, and by two antibodies, T305 and 2B11, that recognize carbohydrate epitopes on the T cell surface glycoproteins CD43 and CD45, respectively. T lymphoblastoid cells and thymocytes bound recombinant galectin-1, as demonstrated by flow cytometric analysis, and lectin binding was completely inhibited in the presence of lactose. The degree of galectin-1 binding to thymocytes correlated with the maturation stage of the cells, as immature thymocytes bound more galectin-1 than did mature thymocytes. Preferential binding of galectin-1 to immature thymocytes may result from regulated expression of preferred oligosaccharide ligands on those cells, since we found that the epitope recognized by the T305 antibody, the core 2 O-glycan structure on CD43, was expressed on cortical, but not medullary cells. The level of expression of the UDP-GlcNAc:Gal beta 1,3GalNAc-R beta 1, 6GlcNAc transferase (core 2 beta 1, 6 GlcNAc transferase, or C2GnT), which creates the core 2 O-glycan structure, correlated with the glycosylation change between cortical and medullary cells. Expression of mRNA encoding the C2GnT was high in subcapsular and cortical thymocytes and low in medullary thymocytes, as demonstrated by in situ hybridization. These results suggest that galectin-1 participates in thymocyte-thymic epithelial cell interactions, and that this interaction may be regulated by expression of relevant oligosaccharide ligands on the thymocyte cell surface.

Peripheral giant cell granuloma. An immunohistochemical and ultrastructural study

OBJECTIVE

To study the nature of multinucleated and mononuclear cells from peripheral giant cell granuloma (PGCG).

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded sections of 40 cases of PGCG were immunohistochemically stained for vimentin, alpha I-antichymotrypsin, CD68, S-100 protein, lysozyme, leucocyte common antigen (LCA), factor VIII-related antigen and muscle cell actin. Six cases of PGCG were also studied by transmission electron microscopy.

RESULTS

Vimentin, alpha I-antichymotrypsin and CD68 were expressed in both the mononuclear and multinucleated giant cells. Dendritic mononuclear cells, positive for S-100 protein, were noted in 67.5% of the lesions, whereas lysozyme and leucocyte common antigen were detected in occasional mononuclear cells. Ultrastructural examination showed mononuclear cells with signs of phagocytosis and sometimes interdigitations with similar cells. Others presented non-specific characteristics and the third type exhibited cytoplasmic processes and occasional Birbeck granules. Some multinucleated giant cells showed oval nuclei, abundant mitochondria and granular endoplasmic reticulum whereas others presented with irregular nuclei and a great number of cytoplasmic vacuoles.

CONCLUSIONS

Immunohistochemical and ultrastructural results suggest that PGCGs of the jaws are composed mainly of cells of the mononuclear phagocyte system and that Langerhans cells are present in two thirds of the lesions.

Characterization of the mononuclear infiltrate involved in regression of halo nevi

Halo nevi are characterized by progressive degeneration of nevus cells surrounded by a mononuclear cell infiltrate. We studied the morphological features of the nevus cells and the composition of the mononuclear cell infiltrate in 15 cases of halo nevi using immunohistochemical techniques and a battery of antibodies to different subsets of lymphocytes and histiocytes. Regression could be divided into four more or less identifiable stages, associated with different subsets of lymphocytes and monocyte-macrophage lineage cells. Stage I (preregression): nests of unremarkable nevus cells were surrounded by a moderate number of T lymphocytes (relatively small percentage of helper inducer T cells), occasional B cells and macrophages. Stage II (early regression): large number of T lymphocytes and FXIIIa-positive cells were in close contact with nevus cell clusters which showed ragged edges. Lysozyme-positive cells and epidermal Langerhans cells were mildly increased. Stage III (late regression): single nevomelanocytes showing mild atypia were present. Numerous T lymphocytes and macrophages positive for lysozyme, KP1 and/or FXIIIa were interspersed between the nevus cells. Increased numbers of epidermal Langerhans cells were present. Stage IV (complete regression): no nevus cells were observed and moderate numbers of T lymphocytes only remained. These results suggest that T cells, especially T-suppressor cells, and different subsets of macrophages participate in the regression of the nevi.

A rapid immunostaining method for frozen sections

A simple and rapid one-step method for demonstrating immunohistochemical markers (leukocyte common antigen, cytokeratin, etc.) is described, which can help define the nature of poorly differentiated neoplasms for diagnosis using frozen section. Microwave irradiation was used to speed immunohistochemical analysis using "Enhanced Polymer One-step Staining" (EPOS) reagents on cryostat sections from a variety of pathologic samples. Reproducible results were obtained using EPOS reagents for leukocyte common antigen and cytokeratin. The overall procedure takes less than 10 min and can be completed during surgery.

Characterization of platelet aggregation induced by human colon adenocarcinoma cells and its inhibition by snake venom peptides, trigramin and rhodostomin

SW-480 cells, derived from a primary human colon adenocarcinoma, caused dose-dependent platelet aggregation in heparinized human platelet-rich plasma. SW-480 tumour cell-induced platelet aggregation (TCIPA) was completely inhibited by hirudin (5 U/ml) but unaffected by apyrase (10 U/ml). This TCIPA was also unaffected by cysteine proteinase inhibition with E-64 (10 microM) but was limited by cell pretreatment with phospholipase A2. SW-480 cell suspension caused marked dose-dependent decreases in plasma recalcification times using normal, factor VIII-deficient and factor IX-deficient human plasma. This effect was potentiated with cell lysates but inhibited in intact cells pretreated with sphingosine. SW-480 cell suspension did not affect the recalcification time of factor VII-deficient plasma. Moreover, monoclonal antibody against human tissue factor completely abolished SW-480 TCIPA. Taken together, these data suggest that SW-480 TCIPA arises from SW-480 tissue factor activity expression. Trigramin and rhodostomin, RGD-containing snake venom peptides, which antagonize the binding of fibrinogen to platelet membrane glycogen IIb/IIIa, prevented SW-480 TCIPA. Likewise, synthetic peptide GRGDS as well as monoclonal antibodies against platelet membrane glycoprotein IIb/IIIa and Ib prevent SW-480 TCIPA, which was unaffected by control peptide GRGES. On a molar basis, trigramin (IC50 0.09 microM) and rhodostomin (IC50 0.03 microM) were about 6000 and 18,000 times, respectively, more potent than GRGDS (IC50 0.56 mM).

Neuronophagia in the motor cortex in amyotrophic lateral sclerosis

This study was designed to identify which phagocytic cells in the cerebral cortex of amyotrophic lateral sclerosis (ALS) patients are involved in the process of neuronophagia. For this purpose a number of single and double immunocytochemical stains were carried out on five ALS cases which were selected on the basis of the presence of degenerative and phagocytic phenomena in the cerebral cortex. The cortical degenerative process is mainly present in the third and fifth layers and is not restricted to the fifth layer which contains the cell bodies of the Betz cells. The present study indicates that a number of cells are involved in the process of phagocytosis in ALS. Resident macrophages (from microglial or perivascular origin) and astrocytes seem to play an immunologically-mediated role in the disappearance of neurons. Some of the cells involved in the degenerative process, i.e. rounded macrophages and microglia, expressed major histocompatibility class II antigen. The phagocytic cells in neuronophagia were phenotypically identical to perivascular macrophages and not to microglia. Therefore, the process of phagocytosis of neurons appears to be primarily the task of the perivascularly located macrophage.

Hematopoietic precursor cells within the yolk sac tumor component are the source of secondary hematopoietic malignancies in patients with mediastinal germ cell tumors

BACKGROUND

Patients with mediastinal germ cell tumors (MGCT) have a high incidence of hematologic malignancies unrelated to cytotoxic chemotherapy. It has been suggested that these leukemic conditions originate from a MGCT progenitor cell capable of undergoing non-germ cell (hematopoietic) differentiation.

METHODS

To assess this hypothesis, histologic material from six patients with MGCTs associated with leukemia was examined using monoclonal and polyclonal antibodies capable of labeling cells of the different marrow cell lineages.

RESULTS

Morphologically identifiable hematologic cells were found within the yolk sac tumor component of the MGCT in four of these patients. In three of the four cases, the cells consisted of poorly differentiated blast cells, whereas in the fourth, clusters of erythroblasts were identified. The leukemic cells within the MGCT and in the bone marrow had similar morphology, constant expression of the early progenitor cell marker CD34, and variable expression of more mature myeloid, monocytic, erythroid, and megakaryocytic markers. Three cases expressed p53, a nuclear protein associated with neoplastic transformation in a wide range of malignancies, including testicular cancers, but which rarely is reported in leukemias. Karyotype of the leukemia was assessed in five cases: two showed an i(12p), a cytogenetic marker of GCT not identified in the usual cases of leukemia.

CONCLUSIONS

The results support the hypothesis that these leukemic conditions originate in the MGCT through a mechanism of differentiation from a yolk sac tumor-derived progenitor cell, with subsequent homing to the marrow.

Classification of Hodgkin's disease biopsies by a panel of four histopathologists. Report of 1,140 patients from the German National Trial

First results from reviewing the diagnostic biopsies of Hodgkin's lymphomas (HL) are reported. Biopsies from 1,140 patients were evaluated by consensus diagnoses according to an extended classification of the British National Lymphoma Investigation. 95 of the recruited cases (8.3%) were omitted and not approved as Hodgkin's lymphoma. The remaining 1,045 biopsies were classified as follows: Lymphocytic predominance 31 (2.7%); Nodular sclerosis (NS) 660 (57.9%), Mixed cellularity (MC) 159 (13.9%); Lymphocytic depletion 8 (0.7%); unclassifiable Hodgkin's 148 (13.0%). The unproved Hodgkin's cases [95 (8.3%)] were divided into non-Hodgkin's lymphomas 32 (1.9%), uncertain due to inadequate techniques 32 (2.8%), borderline between Hodgkin's- and Non-Hodgkin's lymphoma 23 (2.0%). Major dissent on this question involved 17 cases (1.5%) and 1 case which was non-malignant. All unclassifiable, borderline or dissent cases were reassessed after the histologic techniques were improved, and immunophenotyping and clinical data reevaluated. The rate of agreement among the observers was about 81.6%, varying between 23.8% in grade 2 NS to 85.0% in both NS groups. Only 62.8% of all primary diagnoses were approved by the final diagnoses of the panel. Important differences in the classification of the British National Lymphoma Investigation concerns the NS-group and mainly its grade 2 subtype. MC was identical in both classifications. Clinico-pathologic correlation of actuarial survival times revealed a significantly worse outcome of MC vs NS, < 20% after 80 months observation. Only slightly significant better survivals were found in grade 1 vs grade 2 NS. Significant differences in unclear compared to all Hodgkin's, were found and the worst survival was in the NHL group.

Breast lymphomas: a clinicopathologic review

Primary lymphoma is an uncommon tumor in the breast. Review of the literature shows two distinct clinicopathologic groups. One, which affects young women, is frequently bilateral, is often associated with pregnancy, and is a Burkitt-type lymphoma. The second group affects older women, is usually B-cell non-Hodgkins-type lymphoma, and presents clinical features identical to carcinoma of the breast. Three recent studies have suggested that up to half of the cases in the latter group belong to the category of lymphomas arising from the mucosa-associated lymphoid tissues. We have identified nine cases of primary lymphoma from the files of Guys Hospital Clinical Oncology Breast Unit in the 16-year period from 1974 to 1990. The clinical features have been reviewed and the tumors have been evaluated both on a morphologic and an immunohistochemical basis, and seven of nine of the cases have been screened for t[14;18] translocation using the polymerase chain reaction. All the tumors occurred in women older than 50 years and who presented with features of mammary carcinoma. One tumor was true histiocytic lymphoma; the remaining eight cases were B-cell lymphomas. Seven of the latter cases were high-grade B-cell lymphomas and one was a true follicular lymphoma. None of our cases showed the features of lymphoma arising in mucosa-associated lymphoid tissue.