On the representation of effective stress for computing hemolysis.

Hemolysis is a major concern in blood-circulating devices, which arises due to hydrodynamic loading on red blood cells from ambient flow environment. Hemolysis estimation models have often been used to aid hemocompatibility design. The preponderance of hemolysis models was formulated on the basis of laminar flows. However, flows in blood-circulating devices are rather complex and can be laminar, transitional or turbulent. It is an extrapolation to apply these models to turbulent flows. For the commonly used power-law models, effective stress has often been represented using Reynolds stresses for estimating hemolysis in turbulent flows. This practice tends to overpredict hemolysis. This study focused on the representation of effective stress in power-law models. Through arithmetic manipulations from Navier-Stokes equation, we showed that effective stress can be represented in terms of energy dissipation, which can be readily obtained from CFD simulations. Three cases were tested, including a capillary tube, the FDA benchmark cases of nozzle model and blood pump. The results showed that the representation of effective stress in terms of energy dissipation greatly improved the prediction of hemolysis for a wide range of flow conditions. The improvement increases as Reynolds number increases; the overprediction of hemolysis was reduced by up to two orders of magnitude.

Autocrine growth regulation of CD30 ligand in CD30-expressing Reed-Sternberg cells: distinction between Hodgkin's disease and anaplastic large cell lymphoma.

Persistent expression of high levels of CD30 in Hodgkin's Reed-Sternberg (H-RS) cells and anaplastic large-cell lymphoma (ALCL) cells, but not in most T- or B-cell lymphomas, suggests the presence of an underlying mechanism leading to the abnormality and possible involvement of CD30 in the growth and survival of these two unique types of tumors. In this study, we examined the effect of CD30 ligand (CD30L) on CD30-positive H-RS and ALCL cells in long-term cultures or in primary cultures. CD30L induced various degrees of proliferation in three long-term cultured H-RS cell lines (L428, HDLM-2, and KM-H2) as well as in primary cultures of H-RS cells obtained directly from patients with Hodgkin's disease. In contrast, significant inhibition was observed in one of the ALCL cell lines (SU-DHL-1), but no growth inhibition or promotion in responding to exogenous CD30L was detected in three others (PB-1, JB-6, and McG-2), nor in primary cultures of ALCL cells. Expression of CD30L was determined by polymerase chain reaction in long-term cultured cells and by an immunohistochemical method in H-RS or ALCL cells de novo in tissue sections. None of the H-RS and ALCL cell lines was positive for CD30L. In tissue sections, we noticed that ALCL cells were generally CD30L-negative. In contrast, the anti-CD30L antibody reacted with a majority of H-RS cells with diffuse cytoplasmic staining. Most H-RS cells were CD30-positive, indicating co-expression of CD30 and CD30L in the majority of lymphoma cells. The persistent high levels of CD30 and CD30L expression in H-RS cells suggest that the autocrine CD30L-CD30 cytokine-receptor loop, in addition to having the paracrine activity previously thought to exist, could play important roles in the proliferation of H-RS cells. In contrast, the CD30L-mediated cytotoxicity may participate in the regression or slow progression of ALCL during the early phase of the disease in selected patients. However, when the disease progresses, the ALCL cells are likely to become resistant to exogenous CD30L.

Abundance of heat shock proteins (hsp89, hsp60, and hsp27) in malignant cells of Hodgkin's disease.

Heat shock proteins (HSPs) or stress proteins are synthesized by cells in response to environmental stress. Expression of HSPs by cells may have important physiological or pathological implications. In this study, we carried out an immunohistochemical and biochemical examination of low (hsp27), intermediate (hsp60), and high (hsp89) molecular weight HSP expression in reactive lymph nodes and in lymph nodes of patients with various types of lymphomas. In normal or reactive lymphoid tissues, hsp89 is abundant in large "transformed" lymphoid cells and immunoblasts. Hsp60 is widely distributed in lymphoid tissues, whereas hsp27 is absent in all lymphoid cells and histiocytes. Among lymphomas, the Hodgkin's Reed-Sternberg (H-RS) cells in Hodgkin's disease (HD) had the greatest abundance of hsp89 and hsp60 and, in 20% of cases, hsp27, in contrast to a much weaker staining of anti-hsp89 and -hsp60 in the background reactive lymphoid cells. The large lymphoid cells in small lymphocytic lymphoma are also rich in hsp89, but not hsp60 and hsp27. In contrast, the malignant cells in anaplastic large cell lymphoma and most high-grade tumors, including immunoblastic lymphomas, expressed minimal amounts of hsp89 and hsp60 and virtually no hsp27. Thus, the cellular level of HSPs was neither correlated with the proliferative capacity nor with the aggressiveness of the lymphomas. Hsp89, hsp60, and hsp27, as well, serve critical roles in the chaperoning of cellular proteins (e.g., a Mr 43,000 protein) in H-RS cells. The known interactions of HSPs with Rb, p53, peptide-MHC class II complexes, and cofactors of the glucocorticoid hormone receptor have further broadened the importance of HSPs in cell metabolism and in response to extracellular signals for proliferation, differentiation, or growth suppression (or apoptosis) of H-RS cells. Abundant HSP expression is seen only in HD, but not in other lymphomas. Such expression could have vital roles in the pathogenesis of HD.

Biology and therapy of multiple myeloma in 1996.

Since the introduction of melphalan-prednisone for the treatment of multiple myeloma (MM) three decades ago, the prognosis of patients has not been improved by the addition of other agents, probably due to marked resistance of tumor cells, even at diagnosis, to commonly employed cytotoxic drugs. The biological basis for drug resistance is reviewed and current methods of diagnosis and staging delineated. The overview on treatment focuses on recurrent advances with myeloablative therapy demonstrating, in randomized and historically controlled trials, that high-dose therapy increases the incidence of true complete remission (CR) from 5% to approximately 40%, with an extension of median event-free (EFS) and overall (OS) survival durations to 3.5 and > or = 5 years, respectively. It is concluded that high-dose therapy should be offered to all patients with symptomatic meyloma, and current therapeutic research explores posttransplant immunotherapy.

Absence of T-cell- and B-cell-specific transcription factors TCF-1, GATA-3, and BSAP in Hodgkin's Reed-Sternberg cells.

Based on the presence of T cell receptor-beta (TcR-beta) gene rearrangements in L428 and HDLM-1 cells, the expression of CD2 in HDLM-1 cells, and the presence of immunoglobulin heavy-chain (IgH) gene rearrangement in KM-H2 cells, some researchers have concluded that these long-term cell lines derived from patients with Hodgkin's disease are lymphoid in nature. The information obtained from these cell lines has also been used in arguments for a lymphoid origin of H-RS cells in tissue despite the frequent absence of lymphoid markers and Ig/TcR gene rearrangements in these cells. We questioned whether one can use the limited expression of lymphoid markers or the limited gene rearrangement to conclude that H-RS cells have a lymphoid origin, because these markers may be aberrant in tumor cells. In this study, we examined the expression of two T-cell-specific transcription factors (TCF-1 and GATA-3) and one B-cell-specific transcription factor (BSAP) in cultured H-RS cells by using a gel mobility shift assay. The sensitivity and specificity of this assay for determination of cell lineage have been established in a large number of cultured human and murine cell lines. All three types of H-RS cell lines were consistently negative for BSAP, TCF-1, and GATA-3. The absence of GATA-3 was confirmed in H-RS cells in tissues by an in situ hybridization technique. Virtually all B-cell lines, with the exception of some myeloma cell lines, are positive for BSAP, which is the transcription factor for promoters for several B-cell markers, including VpreB1, lambda 5, CD19, and CD20. All T-cell lines tested were positive for TCF-1 and GATA-3, which are the transcription factors for promoters for several T-cell-restricted markers, including CD2, CD3, TcR, and lck. The absence of BSAP, TCF-1, and GATA-3 clearly indicates an underlying difference between H-RS cells and lymphoid cells.

Hodgkin's Disease and Anaplastic Large Cell Lymphoma Revisited. ii. from cytokines to cell lineage.

The true identity of Hodgkin's mononuclear cells and Reed-Sternberg (H-RS) cells has been a subject of controversy for decades. Those who believe that Hodgkin's disease (HD) is a heterogeneous disease may consider it to constitute lymphomas of various origins. However, this theory seems incompatible with the finding of similar phenotypic, biologic, and immunologic properties among most HD. We believe that, in the majority of cases, HD, except for LP and some LD-type HD, is a homogeneous disease despite differences in the degree of fibrosis and/or cellular reaction. The heterogeneity in cellular reactions is a result of secretion of various cytokines by H-RS cells, which may or may not be influenced by the presence of EBV. H-RS cells, and anaplastic large cell lymphoma (ALCL) cells as well, can express a combination of cytokines and cytokine receptors that is not seen in other types of lymphomas. The unique cytokine/receptor profile (e.g. the expression of c-kit-R/CD117), along with various properties associated with H-RS/ALCL cells, leads to a hypothesis that H-RS/ALCL cells are related to similar lymphohematopoietic progenitor cells with different etiologies and somewhat limited differentiation capacity. A number of H-RS cells may differentiate with limited capacity along the B-cell pathway and may be infected by EBV, which further complicates the biologic and immunologic properties of these cells. The majority of H-RS cells may also, however, differentiate along the antigen-presenting dendritic cell pathway, as indicated by the abundant expression of restin, CD15, CD40, CD54, CD58, CD80, and CD86. The majority of ALCL cells clearly differentiate to T cells, but some may acquire B-cell or histiocyte phenotypes. The progenitor cell hypothesis may explain (1) the variable expression of CD117, CD43, and CD34 as well as the absence of CD27, CD45 and CD45RA in H-RS cells; (2) the inconsistent and irregular patterns of phenotype and genotype and the various, often very limited, degrees of differentiation among these two types of lymphoma cells; (3) the existence of secondary HD or ALCL associated with rare types of lymphomas or leukemias, or vice versa; (4) the absence of recombinase and of the B-specific transcription factors BSAP; and (5) the frequent expression of IL-7 and IL-9 in H-RS cells. Copyright 1996 S. Karger AG, Basel

Hodgkin's Disease and Anaplastic Large Cell Lymphoma Revisited. 1. unique cytokine and cytokine receptor profile distinguished from that of non-hodgkin's lymphomas.

In cultures, and in tissues as well, Hodgkin's and Reed-Sternberg (H-RS) cells and anaplastic large cell lymphoma (ALCL) cells are known to express a variety of cytokines, including IL-1, -5, -6, -8, -9, TNF-alpha, GM-CSF, M-CSF, TGF-beta, CD70, CD80, and CD86. Various numbers of H-RS/ALCL cells may express cytokine receptors (R), such as CD30, CD40, IL-2R (CD25/CD122), IL-6R (CD126), IL-7R (CD127), TNF-R (CD120), TGF-beta-R (CD 105/endoglin), M-CSF-R (CD115), and SCF-R (CD117/c-kit receptor). All of these cytokines and cytokine receptors are implicated in the growth regulation of H-RS/ALCL cells, the histopathologic alterations in tissues, and the clinical manifestations in patients with Hodgkin's disease (HD) or ALCL. Many of these cytokines or cytokine receptors also play an important role in the pathogenesis of other types of lymphomas. In this review, we describe the cytokine or cytokine-receptor expression that is diacritic for H-RS/ALCL cells. The identification of such unique cytokine-cytokine receptor interactions is likely to explain the biologic property that distinguishes HD/ALCL from other types of lymphomas. These interactions include those of CD30L-CD30, CD40L-CD40, CD70-CD27, CD80/CD86- CD28, SCF-CD117, IL-9-IL-9R, and IL-7-IL-7R. The H-RS/ALCL cells express IL-9 and two cytokine receptors, CD30 and CD117, which are observed infrequently in NHLs. Although IL-7 expression is not restricted to H-RS/ALCL cells, the expression of IL-7 in conjunction with IL-9 and/or CD117 may be regarded as unique for HD/ALCL because of an unusual combination and a synergistic activity among these cytokines. The expression of CD70 and CD80/CD86 (as cytokines) may exert a unique effect in HD because of intimate contact between H-RS cells and CD27/CD28-positive T cells. The expression of these costimulators (CD70 and CD80/CD86) and other adhesion/constimulator molecules such as CD54 and CD58, along with the secretion of soluble cytokines such as IL-1, IL-6, IL-7, or TNFs by H-RS/ALCL cells, could result in the profound T-cell proliferation often seen in lymph nodes involved by HD and some ALCL. On the other hand, the expression of CD30L and CD40L by surrounding T cells may affect the proliferation of H-RS/ALCL cells. The cytokine-cytokine receptor interaction between H-RS cells and T cells via direct cell-cell contact is bidirectional, a situation not commonly seen in NHLs. Copyright 1995 S. Karger AG, Basel

The nature of Reed-Sternberg cells: phenotype, genotype, and other properties.

The most recent sophisticated investigations have provided new and revealing but also contradictory and controversial informaiton on the biological nature and the cellular origin of Hodgkin and Reed-Sternberg (H-RS) cells. Immunophenotypic analyses have shown consistent expression of CD15, CD30, CD74, and HLA-Dr antigens, but generally lack of T- or B cell-associated markers in H-RS cells. The H-RS cells are also devoid of many monocyte/macrophage-associated antigens. Molecular genetic studies have demonstrated heterogeneous findings with respect to rearrangements of T-cell receptor and immunoglobulin genes. Only a small percentage of the cases have rearrangements; this cannot always be attributed to the threshold of sensitivity of the method and/or the scarcity of the malignant cells in tissues examined. The H-RS cells do not express transcription factors such as BSAP, TCF-1, and GATA-3, known to be associated with lymphoid cells. It appears that evidence to support a lymphoid origin for H-RS cells is still lacking. On the contrary, the mechanism responsible for the unique clinical and histopathologic alterations associated with this disease has become clear. The H-RS cells have been shown to secrete IL-1, IL-5, IL-6, IL-9, TNF-a, M-CSF, and TGF-b, and, less frequently, IL-4 and G-CSF. These cytokines are likely to be responsible for the increased cellular reaction and fibrosis observed in tissues involved by HD and for the immunosuppression in patients with HD. Like most lymphomas, the etiology or pathogenesis of HD remains unknown. The Epstein-Barr virus (EBV) genomes are clonally integrated in the H-RS cells of about half the cases. The significance of these findings, whether EBV is a causative agent or an epiphenomenon, remains to be elucidated.

Autocrine and paracrine functions of cytokines in malignant lymphomas.

Cytokines play important roles in the pathogenesis of lymphomas via an autocrine or a paracrine mechanism, or both. The characteristic clinical and histopathological features of malignant lymphomas may be due in part to elevated serum or tissue levels of cytokines. Determination of the effects of cytokines on the growth or differentiation of lymphoma cells is often complicated by the fact that more than one cytokine is responsible, and by the failure of anti-cytokine antibodies or antisense oligonucleotides to block the proliferation in vitro of lymphoma cells. However, it appears that IL-6 and/or IL-9 may play a prominent role in the tumor cell proliferation of Hodgkin's disease (HD), anaplastic large-cell lymphoma, or immunoblastic lymphoma. IL-6 may also be responsible for the plasmacytoid differentiation of lymphoma cells in polymorphic immunocytoma. The histopathological changes as a result of paracrine effects are most noticeable in HD. The malignant (H-RS) cells of HD have been shown to express IL-1, IL-5, IL-6, IL-9, TNF-alpha, M-CSF, TGF-beta, and CD80, and, less frequently, IL-4 and G-CSF. These cytokines may be responsible for the increased cellular reaction and fibrosis observed in tissues involved by HD and for the immunosuppression found in patients with HD. In contrast to H-RS cells, most non-HD lymphoma cells do not produce cytokines in excess amounts and reveal only a minimal cellular reaction. Exceptions include T-cell-rich B-cell lymphoma, angiocentric T-cell lymphoma, and angio-immunoblastic lymphadenopathy (AILD-like T-cell lymphoma. IL-4 is responsible for the T-cell reaction in T-cell-rich B-cell lymphoma, whereas IL-6 accounts for the plasma cell reaction in AILD-type T-cell lymphoma. The authors extensively review the role of cytokines in lymphomas because this may lead to major advances in the understanding of the molecular processes involved in the histopathogenesis of lymphomas.

Bacteriophage epitope libraries. The generation of specific binding proteins and peptides in vitro.

New concepts and methodologies that can be used to generate proteins, such as specific variable regions of immunoglobulins and other binding peptides in an in vitro selection system are reviewed. These technologies can also be used to alter the kinetics, affinity and avidity of various binding interactions. The nature of epitopes recognized by specific antibodies or receptors can be delineated using selected epitopes displayed on bacteriophages. The basic principles of the technology is predicted upon the belief that if one has a large enough variety of keys, one can open any given lock. The range of utility of these systems to generate new reagents will impact upon the development of new diagnostic and therapeutic reagents. This technology should allow for a much wider range of probes which may have increased binding capacity and allow the development of more sensitive assays with higher signal to noise ratios. These reagents can be produced more efficiently without the use of animals and will be used in diagnostic and experimental pathology. This brief review presents a concise description of the concepts and uses of this new technology. Selected references and reviews are given as sources for further details.

Delayed hypersensitivity, immune deviation, antigen processing and T-cell subset selection in syphilis pathogenesis and vaccine design.

T-cell mediated delayed-type hypersensitivity (DTH) is the predominant immune mechanism for clearing tissues of infecting organisms in the primary lesion of syphilis. Here, Stewart Sell and Pei-Ling Hsu propose a strategy for vaccination against syphilis in which selective induction of DTH may be accomplished by using BCG vectored vaccines containing selected DNA sequences for T. pallidum antigens.

Cytokines in malignant lymphomas: review and prospective evaluation.

Cytokines play important roles in the pathogenesis of lymphomas. Cytokines either can be produced or exert effects on neoplastic or reactive cells. The secretion of cytokines can provide growth advantages for tumor cells in either an autocrine or a paracrine fashion. An elevated serum or tissue level of cytokines can contribute to the clinical and histopathologic alterations associated with malignant lymphomas. The effects of cytokines on the histopathologic changes are most noticeable in Hodgkin's disease (HD). The malignant (Hodgkin's-Reed-Sternberg) cells in HD have been shown to secrete interleukin-1 (IL-1), IL-5, IL-6, IL-9, tumor necrosis factor-alpha, macrophage colony-stimulating factor, transforming growth factor-beta, and, less frequently, IL-4 and granulocyte colony-stimulating factor. These cytokines may be responsible for the increased cellular reaction and fibrosis observed in tissues involved by HD and for the immunosuppression in patients with HD. In contrast to Hodgkin's-Reed-Sternberg cells, most non-HD lymphoma cells do not produce cytokines in excess amounts. Exceptions include T-cell-rich B-cell lymphoma (IL-4), angioimmunoblastic lymphadenopathy-like T-cell lymphoma with plasmacytosis and hypergammaglobulinemia (IL-6), anaplastic large-cell lymphoma (IL-9), polymorphic immunocytoma (IL-6), and immunoblastic lymphoma (IBL) (IL-6). Some cytokines are involved in the unique cellular reactions in each of these types of lymphoma. For example, IL-4 is responsible for the T-cell reaction in T-cell-rich B-cell lymphoma, while IL-6 is accountable for the plasma cell reaction in angioimmunoblastic lymphadenopathy-type T-cell lymphoma. Others may be directly involved in the tumor cell growth or differentiation. For instance, IL-9 may be important for the autocrine proliferation of anaplastic large cell lymphoma, whereas IL-6 is essential for plasmacytoid differentiation in polymorphic immunocytoma. Further studies of the roles of cytokines in lymphomas may lead to major advances in the understanding of the molecular processes involved in the histopathogenesis of malignant lymphomas. Elucidation of the autocrine or paracrine function of cytokines also may lead to new approaches to a rational intervention in these disease processes.

Abundant expression of transforming growth factor-beta 1 and -beta 2 by Hodgkin's Reed-Sternberg cells and by reactive T lymphocytes in Hodgkin's disease.

The depressed cellular immunity observed in patients with Hodgkin's disease (HD) has been attributed to production of transforming growth factor (TGF)-beta or TGF-beta-like substances by Hodgkin's Reed-Sternberg (H-RS) cells. The TGF-beta produced by L-428 cells (an H-RS cell line) is a 130-kd molecular weight glycoprotein that apparently differs from the TGF-beta (molecular weight, 25 kd) produced by most lymphoid and hematopoietic cells. Among several distinct types of TGF-beta that have been purified, only TGF-beta 1 and TGF-beta 2 have thus far been identified in hematopoietic cells. By using monoclonal antibodies (1D11 and 3C7) and oligonucleotide probes specific for TGF-beta 1 and TGF-beta 2, were confirmed that a cultured H-RS cell line, KM-H2, can produce both TGF-beta types, whereas another line, HDLM-1, produces only TGF-beta 1. Despite the abundance of mRNA in both of these cells, only small amounts of TGF-beta activity were detected, probably because of rapid degradation of TGF-beta 1 mRNA by specific nuclease. No degraded TGF-beta 2 RNA products were observed in KM-H2 cells. The TGF-beta produced by both types of H-RS cells had a molecular weight of approximately 25 kd. In tissues expression of TGF-beta was observed in a small portion (30%) of H-RS cells in 16 of 20 cases examined. A large number of small to medium-sized lymphoid cells (T lymphocytes) in tissues involved by HD also were positive for TGF-beta. These results indicate that there is functional heterogeneity among H-RS cells, and that H-RS cells are not the only source of TGF-beta in tissues involved by HD. Hodgkin's Reed-Sternberg cells are known to secrete several other cytokines, including interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha. These cytokines could be responsible for the increased number of T lymphocytes in tissues involved by HD. Furthermore, T lymphocytes can respond to IL-1 and IL-6 secreted by H-RS cells by increasing their production of TGF-beta. Abundant expression of TGF-beta by T lymphocytes was not observed in lymphoid tissues other than those involved by HD.

Thrombomodulin expression in malignant pleural mesothelioma and pulmonary adenocarcinoma.

Thrombomodulin (TM) is a glycoprotein of molecular weight 75,000 kd that is normally present in restricted numbers of cells, including endothelial and mesothelial cells. In this study, the authors tested the possibility of using anti-TM to facilitate the diagnosis of mesothelioma. All of the 31 mesotheliomas and the two mesothelioma cell lines (MS-1 and MS-2) tested were stained positively with anti-TM. The specificity of anti-TM staining in mesothelioma cells was further confirmed by in situ hybridization of MS-1 cells with a TM-specific probe. The expression of TM in MS-1 cells was increased markedly when these cells were induced by 12-0-tetradecanyl phorbol 13-acetate (TPA) to differentiate. The expression of TM in mesothelioma cells, however, did not correlate with any particular phase of the cell cycle. In an attempt to differentiate pleural mesothelioma from pulmonary adenocarcinoma, the authors compared the expression of TM, carcinoembryonic antigen (CEA), and Leu M1 in these two types of tumors. Only four of 48 (8%) pulmonary adenocarcinomas were stained positively by antibodies to TM. Therefore, immunohistochemical staining with antibodies to TM yielded 100% sensitivity and 92% specificity for diagnosis of mesothelioma. All of the mesotheliomas stained negatively for CEA and Leu M1, except for one, which showed minimal focal positivity for Leu M1. In contrast, 79% and 60% of adenocarcinomas stained positively for CEA and Leu M1, respectively. These findings suggest that immunocytochemical staining with anti-TM should be added to the battery of tests to increase the diagnostic sensitivity and specificity for differentiating mesothelioma from pulmonary adenocarcinoma.

Interleukin-6, but not interleukin-4, is expressed by Reed-Sternberg cells in Hodgkin's disease with or without histologic features of Castleman's disease.

Hodgkin's disease (HD) is a neoplastic disease that is characterized by unbalanced and/or unregulated cytokine production. Information accumulated in our own and other laboratories indicates that the cytokines interleukin-1 (IL-1), IL-5, IL-9, tumor necrosis factor-alpha (TNF-alpha), granulocyte colony-stimulating factor (G-CSF), macrophage CSF (M-CSF), and transforming growth factor-beta (TGF-beta) are secreted by Hodgkin's and Reed-Sternberg (H-RS) cells. These and perhaps additional cytokines are likely to be responsible for the unique histopathologic and clinical alterations seen in patients with HD. In this study, we confirmed that IL-6 is produced by cultured H-RS cells as well as by H-RS cells in tissues. By using an enzyme-linked immunosorbent assay, we found that approximately 2 to 10 ng/ml of IL-6 was secreted by cultured H-RS cells (10(6) cells/ml). In tissues, we were able to immunolocalize IL-6 in the cytoplasm in 10 to 30% of H-RS cells by using rabbit polyclonal and mouse monoclonal anti-IL-6 antibodies. There was no correlation among the IL-6 staining intensity, number of H-RS cells stained, and the degree of plasma cell infiltration. However, in 3 of 17 cases studied, a large number (60%) of H-RS cells were positive for IL-6, and in these patients, abundant plasma cells were present. In one patient, the involved lymph node also showed histologic features similar to those of Castleman's disease. In this patient, we noted abundant IL-6 expression not only in H-RS cells, but also in most reactive histiocytes. The cultured H-RS cells did not express functional receptors for IL-6, and exogenously added IL-6 did not induce proliferation of these cells. We also conducted studies with specific anti-IL-4 antibodies, which did not show IL-4 production by H-RS cells in both cultures and tissues. In tissues, only rare IL-4 positive lymphoid cells or dendritic cells were identified. Thus, the study demonstrated that adequate amounts of IL-6 are required for an abundant plasma cell reaction, and that an additional source of IL-6 from histiocytes is essential for the formation of Castleman's disease-like changes in lymph nodes involved by HD. Furthermore, IL-4 is not likely to be responsible for the T-lymphocyte reaction in tissues, by a mechanism distinct from that in T-cell-rich B-cell lymphomas.

Correlation of c-fos/c-jun expression with histiocytic differentiation in Hodgkin's Reed-Sternberg cells. Examination in HDLM-1 subclones with spontaneous differentiation.

The c-fos proto-oncogene, which is the normal homolog of the transforming gene carried by murine osteogenic sarcoma viruses, interacts with the protein product of another proto-oncogene, c-jun, to form a heterodimer that can recognize and bind to a specific sequence of nucleotides in the DNA. The expression of c-fos and c-jun is linked to the proliferation of certain cells and the differentiation of others, including those of monomyelocyte lineage. The authors used two cultured Hodgkin's Reed-Sternberg (H-RS) cell lines, KM-H2 and HDLM-1, and their single-cell clones to study the correlation of c-fos/c-jun expression with cell differentiation in H-RS cells. Within 48 hours after induction with phorbol ester (TPA), both parent lines exhibited markedly increased expression of c-fos/c-jun. The expression returned to the preinduction level after 96 hours, however, and the cells retained their differentiated status. The transitory increase in c-fos/c-jun expression suggests that binding of these proteins to a specific promoter in the nucleus triggers a cascade of events that result in cell differentiation. Expression of these proteins may not be required for the cells to maintain their differentiation. The authors selected three groups of sublines of HDLM-1 cells based on their degree of spontaneous cytologic differentiation. The first group, without obvious differentiation, showed a c-fos/c-jun expression pattern similar to that of the parent line. The second group, with moderate differentiation, had a high degree of expression, which decreased on treatment with TPA. The third group, which had morphologic features resembling those of histiocytes, expressed minimal amounts of c-fos/c-jun, irrespective of TPA treatment. These findings provide further evidence that c-fos/c-jun expression is related to differentiation of H-RS cells, and that these proteins are not byproducts of TPA induction. Expression of c-fos/c-jun also was noted in a subpopulation of H-RS cells in tissues; and this expression also was enhanced when these cells were treated with TPA in culture. These findings indicate that H-RS cells can differentiate to become mature-appearing cells in tissues.

Expression of macrophage colony-stimulating factor (M-CSF) in two Hodgkin's Reed-Sternberg (H-RS) cell lines, HDLM-1 and KM-H2, and in H-RS cells in tissues.

The authors studied the production of macrophage colony-stimulating factor (M-CSF) and the expression of its receptor (c-fms) in two Hodgkin's Reed-Sternberg (H-RS) cell lines, HDLM-1 and KM-H2 and in H-RS cells in tissues. We found that both types of H-RS cell can produce M-CSF, as was confirmed by the presence of M-CSF mRNA and protein in the cells and by the presence of macrophage colony-stimulating activity in conditioned medium. M-CSF was also expressed by H-RS cells in lymph nodes from patients with Hodgkin's disease. In cultures, KM-H2 cells appeared to produce a lesser amount of M-CSF than did HDLM-1 cells, as indicated by weaker staining with anti-M-CSF in the former cells. In KM-H2 cells, most of the M-CSF was located in the cytoplasm, and in HDLM-1 cells, in the Golgi apparatus and/or on the cell membrane. The two types of cultured H-RS cell either did not express c-fms at all, or expressed it only extremely weakly, perhaps because of the loss of dependence on specific growth factors during culture. The production of M-CSF by H-RS cells may contribute to the clinical and pathologic changes seen in patients with Hodgkin's disease, such as the increased abundance of histiocytes in tissues infiltrated by H-RS cells. Alternatively, the expression of both M-CSF and c-fms could confer a growth advantage to some H-RS cells in an autocrine fashion.

Lymphomas of true histiocytic origin. Expression of different phenotypes in so-called true histiocytic lymphoma and malignant histiocytosis.

The authors determined the phenotypes of neoplastic cells in true histiocytic lymphoma and malignant histiocytosis by using a large panel of monoclonal antibodies and enzyme histochemistry procedures. Although the phenotypes overlapped slightly, the authors noted a distinct pattern in these tumors. The tumor cells of malignant histiocytosis generally expressed the monocyte markers CD11b, CD11c, CD14, and CD45, especially after induction with phorbol ester. In contrast, the tumor cells of true histiocytic lymphoma exhibited a marker expression very similar to that of Reed-Sternberg cells in Hodgkin's disease. These cells expressed markers CD30, 2H9, and 1A2, but rarely expressed CD11b, CD11c, CD14, or CD45. Regardless of their cytologic features, the tumor cells from both types of histiocytic lymphoma exhibited diffuse nonspecific esterase and acid phosphatase activities, and they expressed histiocyte markers CD15, CD68, LN5, 1E9, and M387 to varying degrees. The tumor cells from both lymphomas did not exhibit T- or B-cell markers, T-cell receptor or immunoglobulin gene rearrangements, or gene translation products, even when they were induced with phorbol ester. The phenotypic expression in these two histiocytic malignancies suggests that they are derived from different types of histiocytes, or from histiocytes in different stages of maturation or differentiation, or from histiocytes that have distinct mechanisms of tumorigenic transformation. The expression of circulating monocyte markers in malignant histiocytosis suggests that this tumor originates in monocytes or free histiocytes, whereas the phenotype of true histiocytic lymphoma is compatible with an origin in fixed histiocytes, which generally are devoid of the monocyte markers CD11b and CD14.

Syphilis superinfection activates expression of human immunodeficiency virus I in latently infected rabbits.

Superinfection of latently human immunodeficiency virus (HIV)-infected rabbits with either Treponema pallidum or Shope fibroma virus (SFV) activates HIV expression. In addition, HIV-infected rabbits demonstrate prolonged cutaneous lesions (chancres) after intracutaneous challenge with T. pallidum, the causative agent of syphilis. Rabbits were infected by intravenous inoculation of 3 x 10(7) human T-cell lymphotrophic virus type III (HTLV-III)/B10 (HIV-1)-infected H9 (human) cells. Five weeks after initial infection, integrated HIV-1-specific DNA sequences were detected in the DNA of the peripheral blood lymphocytes of only one of eight rabbits using polymerase chain reactions (PCR); human DNA could not be detected at this time. Furthermore HIV infection could not be demonstrated by either seroconversion or PCR during the next 6 months. All HIV-infected rabbits remained clinically healthy and had normal white blood cell counts. Six months after HIV infection, four HIV-infected and two noninfected controls were superinfected with 10(6) T. pallidum in eight skin sites in the shaved skin of the back, and four infected and two control animals were challenged with an intradermal injection with SFV. After infection with either syphilis or SFV, the DNA from the white blood cells of all eight HIV-infected rabbits contained HIV sequences, and HIV sequences were demonstrated in dermal mononuclear cells of the syphilitic lesions by in situ hybridization. The SFV-induced tumors were rejected normally in the HIV-infected rabbits, but four of the four rabbits challenged with T. pallidum had delayed development of cutaneous lesions and three of four demonstrated larger and more prolonged lesions. White blood counts, mitogen responses, and interleukin-2 production remained within normal limits, and seroconversion for HIV was not detected. Three of four rabbits in a second group, challenged with T. pallidum 4 months after HIV-inoculation, also had delayed healing of syphilitic lesions. These results indicate that latent HIV-infection of rabbits may be activated by immunostimulation and that latently HIV-infected rabbits have impaired delayed hypersensitivity reactions. It is hypothesized that true latent HIV-infection in the rabbits is in monocytes and postulated that further immunostimulation may produce infection of lymphocytes and activation of disease.

Lymphocyte functional antigens stabilize agglutination between Reed-Sternberg cells and T cells, but are not responsible for homotypic binding of Hodgkin's Reed-Sternberg cells.

The neoplastic (Hodgkin's Reed-Sternberg [H-RS]) cells in Hodgkin's disease (HD) are known for their unique capacity to form rosettes with unprimed T cells. Recently, a family of leukocyte-adherence molecules (LFA-1 and LFA-2) has been identified on T lymphocytes. The molecules bind to intercellular-adhesion molecules (ICAMs) and to LFA-3, respectively, which are associated with antigen-presenting cells. In this study, the authors examined whether these molecules are responsible for the homotypic and heterotypic agglutination that occurs in the cultured H-RS cells HDLM-1, HDLM-1d, and KM-H2. Despite their similar expressions of LFA-3 and ICAM-1, the different H-RS cells tested showed different growth patterns in culture. HDLM-1 cells grew singly, whereas HDLM-1d and KM-H2 cells grew in clumps. The HDLM-1 cells formed clumps when mixed with peripheral-blood T lymphocytes, cells of two lymphoblastic T-cell lines (MOLT-3 and MOLT-4), and cells of two monocyte lines (ML-1 and U-937). The addition of anti-LFA and ICAM-1 antibodies to cultures did not result in disassembly of the homotypic clusters of HDLM-1d or KM-H2 cells and it did not cause any significant changes in the size of heterotypic clusters or in the timing of cluster formation of HDLM-1 cells with other types of cells. In all studies, the cell clusters formed during homotypic and heterotypic aggregation were disassembled only minimally by cell shearing with pipetting. The disaggregation by pipetting was slightly more prominent in the presence of antibodies than was that of control cultures. However, in no case did the use of monoclonal antibodies (MAbs) and cell shearing cause complete disaggregation of homotypic and heterotypic clusters. The result seems to suggest that binding between H-RS cells and T cells and between H-RS cells and monocytes is not mediated primarily by LFAs and ICAMs, but that the binding may be strengthened in the presence of these molecules.