The histopathology of splenic lymphoma with villous lymphocytes

Whereas the hematologic, immunophenotypic, and molecular characteristics of splenic lymphoma with villous lymphocytes (SLVL) have been well documented, the histologic features of the spleen and lymph nodes remain uncharacterized. We have reviewed the histopathology of the spleen in 37 cases of SLVL and of involved splenic hilar lymph nodes in 6 cases. Tissue immunophenotyping was performed in 24 cases, 6 of which had frozen tissue available, and the results were compared with the membrane immunophenotype of the circulating villous lymphocytes and cells extracted from spleen and lymph nodes. In the spleen, SLVL is characterized by involvement of the white pulp follicles, which may be surrounded or replaced by the lymphoma cells. In the red pulp, the cells form small nodules and infiltrate diffusely with sinusoidal invasion. The cytologic appearance of the neoplastic cells varies from a resemblance to small mantle-zone--like lymphocytes to that of marginal-zone cells and there are scattered blast forms. In involved lymph nodes, the infiltrate again centers on the follicles that are usually replaced, but occasionally show preservation of follicle centers; sinuses are often preserved. The tissue immunophenotype is similar to that of marginal-zone B cells. Membrane immunophenotyping may give different results in some cases and may vary depending on the compartment from which the cells are obtained. SLVL in the peripheral blood is a histologically homogeneous entity identical to the condition previously characterised by histopathologists as splenic marginal-zone lymphoma.     

Human hepatic sinusoidal endothelial cells in culture produce von Willebrand factor and contain Weibel-Palade bodies

Human hepatic sinusoidal endothelial cells were derived from cadaveric human livers. Cells were grown in culture for several weeks to produce small patches of confluent endothelial cells. The ultrastructure of sinusoidal endothelial cells was examined, cell monolayers were stained immunocytochemically for von Willebrand factor antigen, and antigen in cell culture media was measured by enzyme-linked immunosorbent assay. Human hepatic sinusoidal endothelial cells contained von Willebrand factor antigen and Weibel-Palade bodies, were fenestrated, and released von Willebrand factor antigen into media in a time-dependent manner. Although in some respects human hepatic endothelial cells were different from vascular cells, there was no evidence that there were qualitative differences in their capacity to produce von Willebrand factor.     

DC-SIGNR, a DC-SIGN homologue expressed in endothelial cells, binds to human and simian immunodeficiency viruses and activates infection in trans

DC-SIGN, a C-type lectin expressed on the surface of dendritic cells (DCs), efficiently binds and transmits HIVs and simian immunodeficiency viruses to susceptible cells in trans. A DC-SIGN homologue, termed DC-SIGNR, has recently been described. Herein we show that DC-SIGNR, like DC-SIGN, can bind to multiple strains of HIV-1, HIV-2, and simian immunodeficiency virus and transmit these viruses to both T cell lines and human peripheral blood mononuclear cells. Binding of virus to DC-SIGNR was dependent on carbohydrate recognition. Immunostaining with a DC-SIGNR-specific antiserum showed that DC-SIGNR was expressed on sinusoidal endothelial cells in the liver and on endothelial cells in lymph node sinuses and placental villi. The presence of this efficient virus attachment factor on multiple endothelial cell types indicates that DC-SIGNR could play a role in the vertical transmission of primate lentiviruses, in the enabling of HIV to traverse the capillary endothelium in some organs, and in the presentation of virus to CD4-positive cells in multiple locations including lymph nodes.     

严重急性呼吸综合征的肺组织损伤病理改变

目的 观察严重急性呼吸综合征(SARS)死亡患者的肺部病变特点。方法 采用光镜、组织特殊染色对3例SARS死亡患者的肺组织进行了重点观察。采用兔抗-Fas、鼠抗-PCNA、鼠抗-CD83、CD4、CD8单克隆抗体，经免疫组织化学法对肺及肺门淋巴结等组织进行了检测。结果 肺脏的外观多呈红色或紫红色，镜下显示不同程度的间质渗出性或漏出性炎症和肺泡损伤，肺泡间隔内单个核细胞浸润，肺泡腔内有透明膜形成及凋亡脱落的Ⅱ型肺泡上皮细胞。一些肺泡毛细血管腔内可见纤维素性血栓形成，支气管动脉腔内有血栓栓塞。增宽的肺泡间隔内有纤维素沉积。3例肺泡腔内未见明显地巨细胞浸润。免疫组织化学检测显示，增殖细胞核抗原阳性细胞少见，Ⅱ型肺泡上皮细胞及肺泡间隔、肺门淋巴结内的单个核细胞有较多的Fas抗原表达；与慢性炎性淋巴结相比，SARS患者的肺门淋巴结内淋巴细胞结构破坏、淋巴细胞稀疏、数量明显减少，但CD83及CD8阳性细胞仍较多见，而CD4阳性淋巴细胞少见。脾脏也可观察到淋巴细胞数量的减少，白髓萎缩，出血坏死，表达CD4的阳性细胞减少。结论 严重的肺组织及免疫系统损伤可能导致SARS患者的死亡。     

Murine spleen and lymph node cellular composition and function during cyclophosphamide and splenectomy induced resistance to Toxoplasma gondii

Murine toxoplasmosis caused by a low virulence, cyst-forming strain of Toxcoplasma gondii (Pe strain) is characterized by splenomegaly, lymphadenopathy, decreased delayed-type hypersensitivity (DTH), and the presence of toxoplasma cysts in brain tissue. Cyclophosphamide (CY) in a single dose of 100 mg/kg injected 3 days before infection, or splenectomy 3 weeks before infection, augmented DTH and decreased the number of toxoplasma brain cysts. CY-induced augmentation of resistance during the first 3 weeks of murine toxoplasmosis was associated with: (1) an increase in mononuclear phagocytes and a decrease in T lymphocytes (including Lyt2+ cells) in spleens and lymph nodes; (2) suppressed toxoplasma antigen induced proliferation of cultured spleen cells: (3) augmentation of antigen induced proliferation of cultured lymph node cells; and (4) low levels of interferon-gamma production in both spleen and lymph node cultures. The best correlate of the enhanced in-vivo effects of CY was proliferation of nylon wool-purified lymph node cells to toxoplasma antigen. The presence of Lyt2+ cells in lymph nodes of toxoplasma infected mice inhibited maximal proliferation.     

Simultaneous multiorgan presence of human herpesvirus 8 and restricted lymphotropism of Epstein-Barr virus DNA sequences in a human immunodeficiency virus-negative immunodeficient infant

Because a profound dysregulation of the immune system occurs in primary immunodeficiencies, viral infections are not uncommon. Human herpesvirus (HHV)-8 DNA was detected by polymerase chain reaction (PCR) analysis, Southern blotting, and in situ hybridization (ISH) in peripheral blood mononuclear cells and lymphoid organs (bone marrow, spleen, and lymph nodes) and endothelial and epithelial cells and macrophages from several organs (skin, lung, esophagus, intestine, choroid plexus [but not in brain or cerebellum], heart, striated muscle, liver, and kidney) of a human immunodeficiency virus-negative infant with DiGeorge anomaly who died of disseminated infection. Epstein-Barr virus DNA sequences were detected in the spleen and lymph nodes (by PCR and ISH) and in bone marrow (only by ISH) but not in blood or nonlymphoid organs. This report is believed to be the first of multiorgan dissemination of HHV-8 in a primary immunodeficiency.     

LYVE-1 expression on high endothelial venules (HEVs) of lymph nodes

LYVE-1 (lymphatic endothelium hyaluronan receptor) has been identified as a powerful marker for lymphatic endothelium. Apart from lymphatic endothelium, LYVE-1 is expressed in normal liver blood sinusoids, spleen endothelium and activated tissue macrophages. LYVE-1 has not been detected in blood vascular endothelium with the exception of blood vessels in the lung. High endothelial venules (HEVs) belong to the vascular compartment of lymph nodes. They are the major site of entry for circulating lymphocytes into the node. HEVs are characterized by cuboidal endothelial cells, the existence of discontinuous junctions between these endothelial cells, and the presence of large numbers of lymphocytes within their walls. 40 paraffin-embedded lymph node biopsy specimens from newly diagnosed patients with non-Hodgkin lymphoma were evaluated as well as 10 lymph node biopsy specimens from adult patients with reactive lymphadenitis, and 10 normal, non-metastatic lymph nodes obtained from adult patients during cancer surgery served as controls. Samples were fixed in 10% buffered formalin, paraffin embedded, and stained with hematoxylin and eosin for histopathological evaluation. Sections were also evaluated with mouse monoclonal antibodies against LYVE-1 and CD34, and expression of both LYVE-1 and CD34 was demonstrated in HEVs. LYVE-1 expression was also found on the endothelial cells of the lymphatic sinus and in reticular cells in the lymph nodes.     

The Immunological Localization of Factor V in Human Tissue

Antibody to factor V was produced by immunizing rabbits with purified factor V from human plasma. Various tissues were examined for the presence of factor-V antigen using this antiserum. It was consistently demonstrated in homogenates of liver and spleen by means of an antibody (coagulation inhibitor) neutralization technique. The antigen was further localized histologically by the indirect fluorescent antiglobulin technique. It was present on the endothelium of normal blood vessels in all organs examined. In the liver it was detected in hepatic parenchymal cells and a distinctive pattern of fluorescence in the spleen suggested that it was being detected on platelets. Results were negative in all other tissues examined. The findings confirm the presence of factor V in hepatic parenchymal cells and support the suggestion that endothelial coagulation factors may play a role in haemostasis and thrombosis.     

Viral Load and Patterns of SARS-CoV-2 Dissemination to the Lungs,Mediastinal Lymph Nodes,and Spleen of Patients with COVID-19 Associated Lymphopenia

Lymphopenia is a frequent hematological manifestation, associated with a severe course of COVID-19, with an insufficiently understood pathogenesis. We present molecular genetic immunohistochemical, and electron microscopic data on SARS-CoV-2 dissemination and viral load (VL) in lungs, mediastinum lymph nodes, and the spleen of 36 patients who died from COVID-19. Lymphopenia <1 × 10⁹/L was observed in 23 of 36 (63.8%) patients. In 12 of 36 cases (33%) SARS-CoV-2 was found in lung tissues only with a median VL of 239 copies (range 18–1952) SARS-CoV-2 cDNA per 100 copies of ABL1. Histomorphological changes corresponding to bronchopneumonia and the proliferative phase of DAD were observed in these cases. SARS-CoV-2 dissemination into the lungs, lymph nodes, and spleen was detected in 23 of 36 patients (58.4%) and was associated with the exudative phase of DAD in most of these cases. The median VL in the lungs was 12,116 copies (range 810–250281), lymph nodes—832 copies (range 96–11586), and spleen—71.5 copies (range 0–2899). SARS-CoV-2 in all cases belonged to the 19A strain. A immunohistochemical study revealed SARS-CoV-2 proteins in pneumocytes, alveolar macrophages, and bronchiolar epithelial cells in lung tissue, sinus histiocytes of lymph nodes, as well as cells of the Billroth pulp cords and spleen capsule. SARS-CoV-2 particles were detected by transmission electron microscopy in the cytoplasm of the endothelial cell, macrophages, and lymphocytes. The infection of lymphocytes with SARS-CoV-2 that we discovered for the first time may indicate a possible link between lymphopenia and SARS-CoV-2-mediated cytotoxic effect.     

The immune response of regional lymph nodes during the early stages of Fasciola hepatica infection in cattle

In this study we examined regional immune responses to Fasciola hepatica infection in the natural ruminant host. Naïve cattle and those pre‐exposed to a drug‐abbreviated infection were subsequently challenged and lymph nodes extracted at slaughter. In vitro proliferation and cytokine production by mononuclear cells isolated from hepatic and mesenteric lymph nodes were measured after culture with whole fluke antigen (WFA). Hepatic lymph node cells had a significantly greater response to parasite antigen than mesenteric lymph node cells (P < 0·02), although there was no difference in the magnitude of the proliferative response between naïve and pre‐exposed challenged cattle. Mononuclear cells from hepatic lymph nodes produced interferon gamma, interleukin 2 and interleukin 4 after culture with parasite antigen, indicative of a mixed, T helper type 0, response. Comparison of the hepatic node response to a variety of F. hepatica antigens showed that proliferation was lower after culture with cathepsin‐L, than with a high molecular weight fraction, WFA or excretory–secretory antigen. Cell culture supernatant fluid from unstimulated hepatic lymph node cells showed an IgG1 response to antigens of 48, 52–70, 82, 96 and 120–190 kDa on Western blot in pre‐exposed, but not naïve, challenged animals.     

On the Origin of Foà-Kurloff Cells

The thymic and splenic release of Foà-Kurloff cells into the blood was studied in estradiol-treated male guinea pigs by comparison between the cellular content in afferent and efferent blood. The amount and distribution of such cells in thymus, spleen, lymph nodes, and bone marrow was investigated. The treatment with estradiol caused involution of the thymus and splenomegaly. An abundance of Foà-Kurloff cells was found in the red splenic pulp and a considerable release of such cells from the spleen into the blood was demonstrated. At the same time the output of lymphocytes from the spleen was reduced, suggesting that the Foà-Kurloff cells are transformed lymphocytes. The spleen contained an increased amount of erythroblasts, indicating a stimulation of splenic erythropoiesis by estradiol. In the bone marrow and the thymus the number of Foà-Kurloff cells was much smaller than in the spleen and no emigration of such cells from the thymus into the blood was demonstrated. A very small amount of Foà-Kurloff cells was found in the lymph nodes and very few occurred in the thoracic duct lymph. Thus, the Foà-Kurloff cells of the blood do not originate in the lymph nodes and do not recirculate between blood and lymph. It is concluded that the spleen is the major producer of Foà-Kurloff cells and that they are released from the spleen into the blood.     

Sinusoidal endothelial cells from normal guinea pig liver: isolation, culture and characterization

Guinea pig nonparenchymal hepatic cells were isolated by enzymatic digestion and subsequent separation on a 17.5% metrizamide gradient. Endothelial cell and Kupffer cell-enriched fractions were separated by centrifugal elutriation. Viability of both cell fractions was approximately 80%. Endothelial cells were cultured on a substratum of guinea pig liver collagen and 1% gelatin (1:1). Freshly isolated and cultured sinusoidal endothelial cells contained Factor VIII R:antigen, angiotensin I converting enzyme activity, and they synthesized prostaglandins characteristic of other endothelial cells. Sieve plates were identified in both freshly isolated and cultured cells. Fresh endothelial cells and Kupffer cells formed Fc receptor-mediated rosettes with IgG-opsonized sheep red blood cells, but cultured endothelial cells did not. Only Kupffer cells demonstrated Fc and C3 receptor-mediated phagocytosis. These methods for isolating and culturing sinusoidal endothelial cells should permit further functional assessment of endothelial cells and their interrelationship with other sinusoidal lining cells.     

Red cell autoantibody production by colonic mononuclear cells from a patient with ulcerative colitis and autoimmune haemolytic anaemia

We have studied the ability of mononuclear cells extracted from the colon (CMC), draining lymph nodes (LNMC), peripheral blood (PBMC) and spleen (SMC) of a patient with ulcerative colitis and severe autoimmune haemolytic anaemia to produce red cell autoantibodies. The LNMC, PBMC and SMC secreted immunoglobulin in vitro in pokeweed mitogen culture but not spontaneously. They also produced immunoglobulin when transferred to severe combined immunodeficient (SCID) mice but no anti-red cell activity was demonstrable. In contrast, in vitro cultures of CMC produced immunoglobulin spontaneously, showing the presence of activated B-cells and plasma cells, but anti-red cell activity could not be demonstrated. However, CMC transferred to SCID mice were able to produce IgG with anti-red cell activity. These results concur with clinical observations suggesting that the colon is the source of red cell autoantibodies in these patients.     

Spontaneous rupture of the spleen and liver in amyloidosis--a case report and review of the literature

A 52 year-old woman with systemic amyloidosis complicated with multiple myeloma died suddenly of intraperitoneal hemorrhage due to spontaneous rupture of the spleen and liver. Autopsy revealed multiple myeloma involving the bone marrow and diffuse amyloidosis involving the liver, spleen, kidneys, heart, bone marrow, lymph nodes, lungs, gastrointestinal tract, thyroid, skin and adrenal glands. The splenic red pulp and the hepatic parenchyma were replaced by masses of amyloid. Amyloid deposits were also numerous in the walls of blood vessels and linearly in the intracapsular regions of both the liver and spleen. This is the eighth case of spontaneous rupture of the spleen and the second case of spontaneous rupture of the liver in association with systemic amyloidosis.     

Immunohistochemical Studies on Structural Changes of the Hepatic Lobules in Chronic Liver Diseases

Liver biopsy specimens were examined immunohistochemically to clarify structural changes of the hepatic lobules in chronic liver diseases. In normal liver carbohydrate antigen 19-9 was located in the biliary ductular epithelium, whereas factor VIII-related antigen was observed in the endothelium of portal veins, hepatic arteries, and central veins. This antigen was not detected in the sinusoidal endothelium. In contrasts, monoclonal antibody OKM5 was reactive with the sinusoidal endothelium but was unreactive with the endothelium of the portal blood vessels or central veins. In chronic active hepatitis and liver cirrhosis, both carbohydrate antigen 19-9 positive biliary ductular cells and factor VIII-related antigen positive endothelial cells were not only observed in the enlarged portal area but also extended into the parenchyma. They were occasionally accompanied by fibers. These findings suggest that fibrosis, ductular epithelial, and blood vascular proliferation in the portal space and their invasion into the parenchyma might gradually cause structural changes of the hepatic lobules in chronic liver disease.     

Localization of hyaluronan in human liver sinusoids: a histochemical study using hyaluronan-binding protein

Abstract: Circulating hyaluronan is mostly derived from lymph, fibroblast and Ito cells in the liver, and more than 90% of hyaluronan is degraded in hepatic sinusoidal endothelial cells. Thus, elevated serum hyaluronan is regarded as an indication of hepatic fibrosis with activated Ito cells and dysfunctional sinusoidal endothelial cells. We studied the distribution of hyaluronan in human liver sinusoids to determine the influences on elevated hyaluronan levels in sera. Histochemical examination was made using hyaluronan-binding protein (HABP) and serial sections of liver tissue for staining of alpha-smooth muscle actin (ASMA) (an indicator of activated Ito cells) and of ulex europaeus agglutinin I lectin (UEA-1) (closely related to hepatic sinusoidal capillarization). Positive staining, indicating the presence of hyaluronan, was noted in fibrous regions around the portal tracts, areas of focal necrosis in the liver parenchyma, and walls of the sinusoids in chronic hepatitis. In this group, hyaluronan-positive areas corresponded to positive ASMA staining and faint staining of UEA-1. On the contrary, in liver cirrhosis, UEA-1-positive areas were essentially identical to hyaluronan-positive areas and to ASMA-negative areas in sinusoidal walls. Hyaluronan and ASMA could be detected in the same areas of sinusoidal walls in chronic hepatitis, but not in liver cirrhosis. Hyaluronan appears to be mainly related to the staining of activated Ito cells in chronic hepatitis. Therefore, we concluded that in chronic hepatitis, the production of hyaluronan was accelerated in Ito cells; however, degradation of hyaluronan by sinusoidal endothelial cells continued. On the contrary, in liver cirrhosis, hyaluronan production decreased in Ito cells, and a marked transformation of sinusoidal endothelial cells with hepatic sinusoidal capillarization indicated loss of the ability to degrade hyaluronan. These different mechanisms in chronic hepatitis and liver cirrhosis may operate in the sinusoidal walls and may cause the elevation of hyaluronan in sera.     

Spleen and lymph node cell populations, In vitro cell proliferation and interferon-y production during the primary immune response to Toxoplasma gondii

An animal model for the study of transient lymphadenopathy-splenomegaly during toxoplasmosis is presented. Injection of CBA/J mice with the low virulent, cyst-forming strain of Toxoplasma gondii (Pe strain) induces a three to four fold increase in weight and cellularity of spleen and lymph nodes with peak changes at 30-50 days after infection. The spleen displays marked haemopoiesis, a 30 fold increase in mononuclear phagocytes, and a two fold increase in Lyt2+ lymphocytes. Lymph nodes show a five fold increase in mononuclear phagocytes and a four and a half fold increase in Lyt2+ T cells. The increase in mononuclear phagocytes significantly alters T cell/macrophage ratios and this is associated with decreases in in vitro cell proliferation to mitogen and toxoplasma antigen. The relationship between alterations in cell balance of mononuclear phagocytes and T cell subsets and the expression of transient immune dysfunction can now be examined by modulating changes in these cell types.     

从组织病理学角度探讨慢性乙型肝炎肝纤维化的发生

目的 探讨窦内皮细胞在肝纤维化发生中的作用,以及肝脏微循环障碍、肝窦毛细血管化与肝纤维化发生的关系. 方法对56例慢性乙型肝炎患者进行肝活组织枪查,将肝组织分成两部分,分别通过HE染色进行光学显微镜观察,以及常规制作电子显微镜标本在透射电子显微镜下进行超微结构观察.结果 56例慢性乙型肝炎患者中,轻度39例,中度10例,重度7例.慢性乙型肝炎患者肝星状细胞的形态类似成纤维细胞,周围有胶原纤维形成.窦内皮细胞与肝星状细胞间有电子致密物沉积.其中53例窦内皮细胞窗孔有不同程度的减少,减小,20例见窦内皮细胞下有连续或不连续的膜样物质形成,15例狄氏腔内有胶原纤维沉积.15例肝功能正常患者有的肝窦腔内有红细胞聚集,严重者有微血栓形成. 结论窦内皮细胞通过与肝星状细胞作用,从而参与肝纤维化的发生.肝脏微循环障碍、肝窦毛细血管化是肝纤维化的早期重要病理改变.     

从组织病理学角度探讨慢性乙型肝炎肝纤维化的发生

目的 探讨窦内皮细胞在肝纤维化发生中的作用,以及肝脏微循环障碍、肝窦毛细血管化与肝纤维化发生的关系. 方法对56例慢性乙型肝炎患者进行肝活组织枪查,将肝组织分成两部分,分别通过HE染色进行光学显微镜观察,以及常规制作电子显微镜标本在透射电子显微镜下进行超微结构观察.结果 56例慢性乙型肝炎患者中,轻度39例,中度10例,重度7例.慢性乙型肝炎患者肝星状细胞的形态类似成纤维细胞,周围有胶原纤维形成.窦内皮细胞与肝星状细胞间有电子致密物沉积.其中53例窦内皮细胞窗孔有不同程度的减少,减小,20例见窦内皮细胞下有连续或不连续的膜样物质形成,15例狄氏腔内有胶原纤维沉积.15例肝功能正常患者有的肝窦腔内有红细胞聚集,严重者有微血栓形成. 结论窦内皮细胞通过与肝星状细胞作用,从而参与肝纤维化的发生.肝脏微循环障碍、肝窦毛细血管化是肝纤维化的早期重要病理改变.