Seropositivity in Dutch Crohn's disease patients against primed nude mouse lymph nodes, and the difference with lymphocytotoxic antibodies.

Sera from patients with Crohn's disease have been reported to show positive immunofluorescence with lymph nodes of nude mice primed with a filtrate of intestinal tissue affected with Crohn's disease. An indirect immunofluorescence assay was used to test sera of 63 unrelated patients with Crohn's disease, 21 with ulcerative colitis and 36 control subjects against lymph nodes of athymic nude (nu/nu) mice which had been injected with Crohn's disease and ulcerative colitis intestinal tissue filtrates. Forty nine per cent of Crohn's disease patients, 10% of ulcerative colitis patients and 3% of control sera reacted against lymph nodes of mice injected injected with ulcerative colitis intestinal tissue filtrates, 18% of Crohn's disease sera were with intestinal tissue homogenate from Dutch Crohn's patients. With the lymph nodes of mice injected with ulcerative colitis intestinal tissue filtrates, 18% of Crohn's disease sera were positive, whereas all ulcerative colitis and control sera were negative. Lymph nodes from 18 of the 19 mice injected with Crohn's disease tissue filtrates reacted with Crohn's disease sera, whereas only three of these 19 mice reacted with ulcerative colitis sera. A comparative study, carried out in parallel with Crohn's disease filtrate induced hyperplastic lymph nodes from the Bilthoven colony (W2) and from the New York colony (E671) using sera from 54 Crohn's disease patients from Leiden, showed immunoreactivity with 44 and 57% of the Crohn's disease sera against the two hyperplastic lymph nodes. Thirty six of the 54 Crohn's disease sera (67%) reacted with either or both lymph nodes. Only 11% of the Crohn's disease sera which were examined for immunofluorescence and lymphocytotoxic antibodies had lymphocytotoxic antibodies, whereas 40% and 46% of the same sera showed positive immunofluorescence against E671 and W2, respectively. Absorption studies indicated that lymphocytotoxic antibodies activity and the immunofluorescence against the primed nude mouse lymph node are mediated by different serum antibodies in Crohn's disease. The reproducibility of the nude mouse immunofluorescence test system for a preferential immunoreactivity of Crohn's disease sera against Crohn's disease tissue primed murine lymph nodes has been confirmed by the present study. Further studies are necessary to find out whether crossreactive antigen(s) as recognised by some of the Crohn's disease sera in mice injected with ulcerative colitis tissue filtrate is similar to the antigen(s) detected by Crohn's disease sera in mice injected with Crohn's disease tissue filtrates.     

Of mice and men: lessons on Crohn's disease and the spirit of scientific inquiry

Over the past 10 years, Kiron Das and his associates have developed an animal model for the study of a putative Crohn's disease (CD)-specific antigen. Athymic T-cell deficient nu/nu mice inoculated with intestinal and lymph node tissue filtrates from patients with CD sometimes develop lymphomas and/or lymph node plasma cell hyperplasia. Patients with CD often have an antibody that reacts with an antigen contained in these murine lymphomas and hyperplastic lymph nodes. This antibody is found in the sera of about one-third to one-half of CD patients, but it is rarely found in ulcerative colitis (UC) patients and almost never in other controls. This issue of the Journal of Clinical Gastro-enterology contains Das's most recent clinical study on the subject, indicating that this serum antibody was present in 11 of 29 CD patients (38%), in only 4 of 25 UC patients (16%), and in almost no disease controls or normal subjects. Das's immunofluorescent assay is not yet sufficiently sensitive, specific, or convenient to be widely applicable as a routine serodiagnostic tool in clinical practice, but it could be enormously important if it proved in fact to be a marker for a CD-specific antigen. Other laboratories, however, have sharply questioned the specificity of this antigen, whose pathogenetic significance therefore remains controversial.     

Application of an immunofluorescence assay for Crohn's disease using primed nude mouse lymph nodes to a United States/Mexican border population

Previous studies using an indirect immunofluorescence (IF) technique found that sera from patients with Crohn's disease (CD) frequently contained antibody that recognized an antigen(s) in CD tissue filtrate-primed lymphoid tissue from athymic nude (nu/nu) mice. The present study examined the reproducibility of this IF assay in a different laboratory setting and used patients with infectious diarrhea. We examined the immunoreactivity of 113 sera from eight patients with Crohn's disease, 11 with ulcerative colitis, 62 patients with infectious diarrhea, 22 nondiarrheal disease controls, and ten normal adults. Sera were absorbed with nu/+BALB/c mouse serum proteins coupled to Sepharose 4B to remove nonspecific binding. All sera were coded and tested against at least 2 of 4 lymph nodes from nu/nu mice that were previously inoculated with either CD tissue filtrate or with a passaged CD-induced nu/nu lymphoma. Reference positive CD sera and negative control sera were run in parallel during each assay. Sera from three CD patients consistently showed positive IF. None of the sera from patients with infectious diarrhea, other disease controls, or normals were positive. These results demonstrate the reproducibility of the IF assay using CD tissue-primed nude mouse lymph nodes and the preferential immunoreactivity of CD sera.     

Sera-reactivity in inflammatory bowel disease: frequency of recognition of Crohn's disease tissue primed nude mouse lymphoid tissue in an interinstitutional blinded study

We used a double-blinded interinstitutional study with an indirect immunofluorescence assay to evaluate the immunoreactivity of Crohn's disease (CD) sera against hyperplastic and malignant lymph nodes from nude mice primed with CD tissue filtrates. We assessed the reactivity for potential usefulness as a serodiagnostic test by using sera from different clinical subgroups of patients with inflammatory bowel disease. The immunoreactivity of 86 coded sera from ambulatory patients treated at the Mount Sinai Medical Center were examined-29 from patients with CD, 25 from patients with ulcerative colitis (UC), 21 from disease controls, and 11 from normal controls. Each serum was tested at the Albert Einstein College of Medicine against lymph nodes from at least two of six nude mice inoculated with CD tissue filtrates or CD filtrate-induced lymphoma. There was positive immunofluorescent staining in 11 of 29 (38%) CD patients, 4 of 25 (16%) UC patients, 1 of 21 (4.8%) disease controls, and 0 of 11 normal volunteers. Statistically significant differences in immunoreactivity were seen between CD patients compared to non-inflammatory-bowel-disease controls (p = 0.007) and to normals (p = 0.02).     

Cell-Wall Defective Bacteria and Crohn''s Disease: Studies Using Athymic Nude Mice

Indirect immunofluorescence studies were performed to determine whether the antigenic recognition by Crohn's disease (CD) sera of lymphoid tissue from nude (nu/nu) mice injected with CD filtrate is related to cell wall defective pseudomonas-like bacterial revertant forms (CWD-RF). Antisera raised in rabbits against two CWD-RF isolates from CD tissues did not stain lymphomas or hyperplastic lymph nodes produced by CD filtrates, although these tissues demonstrated positive immunofluorescence with CD sera. Pre-absorption of reactive CD sera with CWD-RF did not block this immunofluorescence. Formalinized suspensions of CWD-RF were injected into 36 nu/nu, 12 nu/+, and 31 conventional mice. Thirty other mice were fed suspensions of bacteria. Several nu/nu injected with CWD-RF developed lymphoma (n = 2) and plasma cell hyperplasia (n = 5), none of which reacted with CD sera. Mice fed bacteria did not show intestinal pathology. These studies demonstrate that CWD-RF are not directly related to lymphomagenesis in nu/nu induced by CD filtrates and that different CD serum antibodies are involved in recognition of CWD-RF and lymphoid tissues from nu/nu previously injected with CD filtrates.     

Seroreactivity of patients with Crohn's disease with lymph nodes of primed nude mice is independent of the tissue used for priming

Athymic nude mice, injected with a cell-free filtrate of intestinal tissue from patients with Crohn's disease, have been shown to express antigens in their lymph nodes to which sera from patients with Crohn's disease contain antibodies. In the present study, immune reactivity was assessed with a histochemical indirect immunoperoxidase assay on paraplast-embedded tissue sections. The reactive lymph node cells were identified as sinus macrophages. We confirmed earlier findings of immunofluorescence studies that the reaction showed some antibody specificity, the proportion of patients with Crohn's disease who were positive (84%) being higher than of patients with ulcerative colitis (29%). However, reactivity of Crohn's disease sera was found to be antigen nonspecific, as it was equally observed with lymph nodes of mice primed with saline or with homogenates from patients with ulcerative colitis, diverticulitis, or volvulus. Hence, this nude mouse model does not seem appropriate to identify a transmissible etiology of Crohn's disease.     

Crohn disease lymph node homogenates produce murine lymphoma in athymic mice.

To study the putative agent(s) related to Crohn disease, we intraperitoneally in injected mesenteric lymph node homogenates from four patients with active Crohn disease into 10-week-old athymic (nu/nu) mice. Control mice (nu/nu) were injected with homogenates of mesenteric lymph nodes from two patients with ulcerative colitis and four patients undergoing elective cholecystectomy, and with a homogenate of a cervical lymph node containing sarcoid granuloma. Thirty-four mice received filtered or unfiltered homogenates from Crohn disease lymph nodes. Thirty-two mice received homogenates or filtrates from lymph nodes of control patients. Four mice from the group injected with Crohn disease homogenates from four different patients developed generalized lymphadenopathy due to lymphoma 10-28 weeks after th injection. Two additional mice developed lymphadenopathy due to plasma cell hyperplasia. None of the control mice developed lymphomas or lymphadenopathy. Two lymphomas were homogenized, filtered, and injected intraperitoneally into a second group of nu/nu mice, which also developed lymphoma within 8 weeks of injection. Two lymphomas were cultured in vitro and B cell sur?ACE MARKERS WERE IDENTIFIED. Indirect immunofluorescence studies in two lymphomas showed cytoplasmic staining of lymphoma cells with sera from 10 patients with active Crohn disease but not with sera from 13 control subjects, including 6 with ulcerative colitis and 7 with other gastrointestinal disorders. These results suggest that a transmissible factor present in Crohn disease lymph nodes produces lymphoma in nu/nu mice. Furthermore, sera of Crohn disease patients contain an antibody that recognizes an "antigen(s)" in the murine lymphoma.     

Specificity of antibodies secreted by hybridomas generated from activated B cells in the mesenteric lymph nodes of patients with inflammatory bowel disease.

Hybridomas have been prepared from active B cells in lymphoid tissue draining lesions of Crohn's disease (CD) and ulcerative colitis (UC), by fusion of fresh mesenteric lymph node suspensions with the murine JK myeloma. Two hundred and fifty nine immunoglobulin secreting hybridomas have been obtained from nine patients. The antibodies have been screened for binding to food antigens, sections of human gut, and bacteria including two unidentified acid fast isolates from CD lymph nodes. Autoantibodies, and antibodies to food antigens implicated by others in the aetiology of CD were rare, comprising 1.2%, and 2.5% respectively. Most donors yielded none of these. Thus neither food antigens nor autoantigens are major antigenic stimuli in nodes draining inflammatory bowel disease. On the other hand between 19% and 83% of supernatants from different donors bound to one or more bacterial genus. The mycobacteria and the CD isolates were amongst the genera to which most antibodies bound, though binding to E coli was more frequent. Significantly more CD than UC derived supernatants bound to BCG. As mycobacteria are not though to be part of the normal bowel flora, the high percentage of hybridomas secreting antibodies which bind to this genus is surprising.     

Lymph node activating factor from mixed cultures of allogeneic lymphoid cells: effect on the lymph nodes of euthymic and athymic mice.

The action of "lymph node activating factor" (present in supernatants from 4hr cultures of allogeneic lymphocytes) on the lymph nodes of athymic nu/nu mice, nu/+ hybrids and euthymic BALB/c mice was studied. An increase in lymph node weight, cellularity and changes in lymph node morphology, i.e. an increase of the dense lymphatic tissue of the cortex and paracortex and appearance of follicles with light centers, were found in all mice. Lymphocyte activation evaluated by the presence of lymphocytes with RNA synthesizing nucleoli occurred only in nu/nu mice and nu/+ hybrids. Marked changes in lymph node morphology found in nu/nu homozygotes suggest relation of the lymph node activating factor to mediators acting directly on B cells.     

Induction of granulomas in mice by Crohn's disease tissue

Normal and immunodeficient CBA and A2G strain mice were inoculated with crude (100 to 20 to 30 micrometer), cell-free (0.2 micrometer) filtrates of Crohn's or noninflammatory bowel disease tissue homogenates, which were either fresh or frozen to -70 degree C. Mice of each strain developed epithelioid and giant cell granulomas both locally at the site of injection and systemically in response to crude and cell-free filtrates of Crohn's tissues. Control mice did not develop such changes. The granulomas evolved slowly, predominantly between 9 and 27 months. The granuloma-inciting agent has been shown to be present in ileum, colon, and mesenteric lymph nodes of patients with Crohn's disease and it withstands freezing to -70 degree C. The use of Crohn's tissues common to this study and one in rabbits previously reported, suggests that the induction of granulomas by this agent is not strain- or species-specific, and is independent of the immune status of CBA mice.     

Cell wall-defective variants of pseudomonas-like (group Va) bacteria in Crohn's disease

Several animal transmission studies have indicated that Crohn's disease may be caused by a filterable agent. Filtrates of homogenized tissues were prepared from 8 patients with Crohn's disease, 9 patients with chronic ulcerative colitis, and 20 control patients without inflammatory bowel disease. Conventional bacteriological cultures and hypertonic cultures for cell wall-defective bacterial variants were performed on the filtrates. Bacterial revertants (parent forms) of cell wall-defective variants were obtained from filtrates of various tissues including mesenteric lymph nodes of all patients with Crohn's disease. In no instance were revertants cultured from tissue filtrates of the other patients. The 11 revertants isolated from the 8 patients were identified as Pseudomonas-like bacteria, most closely identifiable with group Va.     

Evidence for the isolation of a new virus from ulcerative colitis patients

To assess the possible role of viral infection in the development of ulcerative colitis (UC) and of Crohn's disease (CD), electron-microscopic, physical, and chemical studies were performed on viral agents cultivated in tissue culture following inoculation with surgical specimens obtained from patients with CD, UC, and from control patients with other gastrointestinal diseases. Viral isolates obtained from CD patients were compared with those from UC patients. Each of the agents produced cytopathic change (CPE) in the tissue culture systems used, rabbit ileum (RI), Peking duck, and Riff free chick embryo, and had similar physical and chemical properties including ether resistance, temperature stability, and lack of inhibition by methotrexate. The three tissue culture systems supported viral growth and produced virus-like particles from CD filtrates with similar morphologic appearance, including a central core and an outer coat. Electron-microscopic studies revealed that the particle from CD has a diameter of 60 nm (range 42–71 nm). The agent isolated from UC patients also has a mean particle diameter of 60 nm (range 45–75 nm). The CD and UC agents produced different CPE in RI tissue culture. Agents different from CD-and UC-derived viruses were isolated from one patient with necrotizing enterocolitis and from three patients with carcinoma of the colon. Ileal homogenates of other control patients failed to reveal evidence of viral contaminants and evaluation of the tissue culture systems revealed no adventitious agents. Virus was found in diseased as well as in adjacent histologically normal CD tissue. Guinea pig antibody prepared against CD-derived agents inhibited the growth of each of the CD agents but not of the agents from UC, necrotizing enterocolitis, or colon carcinoma. Antibody directed against the agents from UC failed to inhibit growth of the agents from CD, necrotizing enterocolitis, or colon carcinoma. The current studies therefore suggest that a virus has now been cultivated from UC patients which produced CPE different from the viruses previously cultivated from CD patients and which lacks cross-reactivity with the CD derived virus. Since each filtrate produced viruses in the three different tissue culture systems, these viruses are not tissue culture contaminants but are derived from the human filtrates. These studies also suggest an association between viruses and inflammatory bowel disease but do not establish an etiologic relationship.Supported by a grant from the National Foundation for Ileitis and Colitis.     

Newly-formed lymph nodes in the submucosa in chronic inflammatory bowel disease

BACKGROUND AND AIMS: Routine diagnostic work revealed cell aggregates reminiscent of lymph nodes in the bowel submucosa in occasional cases of chronic inflammatory bowel disease. We therefore investigated whether they fulfill criteria for classification as lymph nodes. METHODS: Colon with terminal ileum from a patient with florid Crohn's disease and a colectomy specimen from a patient with ulcerative colitis were investigated. Sections were immunostained with antibodies that recognize endothelial and sinus-lining cells, immune-accessory cells, and lymphoid cells. RESULTS: Circumscribed collections of cells that fulfill all the major criteria for classification as lymph nodes were found in the large and small bowel. They had marginal and intermediate sinuses (positive for BMA 120, CD34, CD31, X-11, and von Willebrand's factor), afferent lymph vessels, T- and B-regions, and a capsule. Small collections composed predominantly of B cells that had only a marginal sinus were also occasionally observed. CONCLUSION: Secondary mucosa-associated lymphoid tissue, typically seen as follicular lymphoid hyperplasia, also appears to occur as secondary submucosal lymph nodes. This phenomenon seems inconsistent with the notion that lymph nodes do not develop after birth. We have also noted secondary development of lymph nodes in lymphangioma and lymphangioleiomyomatosis. It is possible that local lymph vessel proliferation, possibly with chronic lymphedema of the tissue involved, is an important prerequisite for lymph node neogenesis.     

IgG antibodies against common gut bacteria are more diagnostic for Crohn's disease than IgG against mannan or flagellin

INTRODUCTION: Antibodies to baker's yeast (mannan) have been widely used to aid in diagnosis of Crohn's disease. Recently, there has been interest in antibodies against a flagellin from Clostridium coccoides subphylum. We hypothesized that reactivity with these antigens is a surrogate marker for a generalized increased IgG response against intestinal microbiota in Crohn's disease. METHODS: We compared the diagnostic utility of IgG antibodies against flagellin and mannan with two complex surface antigen preparations, one derived from B. vulgatus (Bv), the other from over 20 common mucosa-associated microbiota, a multibacterial membrane preparation (MBP). IgG antibodies were measured in sera from two age- and sex-matched populations: 120 Crohn's patients (CD) and 160 gastroenterology controls (CON) comprising 40 ulcerative colitis (UC) and 120 non-IBD patients. RESULTS: IgG was elevated against all antigen preparations in Crohn's but statistical analysis of receiver operator characteristic (ROC) plots showed that IgG against the complex antigen preparations MBP and Bv had better diagnostic accuracy to distinguish the two populations (CD and CON) than IgG against mannan (P < or = 0.01) or flagellin (P < or = 0.04). Concentrations of antibody reactive with distinct individual antigens correlated weakly. DISCUSSION: The findings support our hypothesis that measurement of IgG reactivity against individual antigens gives an indication of a generalized increased IgG response against individual intestinal microbiota in Crohn's, rather than measuring specific immune responses important for pathogenesis. The data are consistent with either a mucosal defect that facilitates increased exposure to microbial antigens or an altered immune response, both of which could occur due to known genetic and molecular defects in Crohn's disease.     

In vivo tissue distribution of CD4 lymphocytes in mice determined by radioimmunoscintigraphy with an 111In-labeled anti-CD4 monoclonal antibody.

The tissue distribution of CD4 lymphocytes in normal C57/BL mice and CD4 knockout mice was determined by biodistribution measurements and gamma camera imaging with an 111In-labeled rat IgG2b monoclonal antibody directed against the murine CD-4 antigen. In normal mice high concentrations of antibody accumulated in the spleen and lymph nodes. At 45 hr after injection, the concentration of radiolabel in the spleen and lymph nodes of normal mice were 10- to 20-fold greater than in the corresponding tissue of the CD4 knockout mice and nonlymphoid tissues of both types of mice. At 24 and 45 hr, gamma camera images showed high concentrations of radiolabeled antibody in lymph node and spleen of normal but not knockout mice. These results indicate that radioimmunoscintigraphy with 111In-anti-CD4 is an excellent method for studying tissue distribution of CD lymphocytes in mice. Using an equivalent anti-human CD antibody, this method might be useful for studying the pathophysiology of conditions in which these cells play a critical role and for monitoring therapies for these disorders.     

Immunity to cytopathic agents associated with Crohn's disease: a negative study.

Serum and peripheral blood lymphocytes from 10 patients with Crohn's disease and 10 healthy subjects were examined for immunological reactivity against chick embryo cell cultures displaying cytopathic effects after inoculation with 0.2 micro filtrates prepared from Crohn's disease intestinal tissues. Although the assay systems (indirect immunofluorescence, lymphocyte transformation, and cytotoxicity) yielded positive results using well-characterized cytopathic viruses (mumps, measles), neither Crohn's disease nor healthy subjects showed immune reactivity to the chick embryo cell cultures inoculated with Crohn's disease intestinal tissues in any of the assay systems. These experiments provide evidence against the hypothesis that the in vitro cytopathic effect on chick embryo cell cultures produced by Crohn's disease intestinal filtrates are caused by a replicating virus or viruses.     

Effect of the immune modulating agents cyclophosphamide, methotrexate, hydrocortisone, and cyclosporin A on an animal model of granulomatous bowel disease.

This study was undertaken to determine the effect of cyclophosphamide, methotrexate, hydrocortisone, and cyclosporin A on a model of granulomatous infiltration in the terminal ileum and draining lymph nodes of the guinea pig. Treatment groups of six animals were used and compared to untreated groups of 12. Epithelioid cell granulomas and primary macrophage granulomas were induced by the inoculation of BCG (Pasteur) and irradiated Mycobacterium leprae respectively into the terminal ileum of the guinea pig. The response to purified protein derivative of tuberculin was reduced in both groups of animals receiving any of these agents. Cyclophosphamide and methotrexate treated animals inoculated with BCG or M leprae showed a significant reduction of granulomatous infiltration at the inoculation site (p less than 0.05 and p less than 0.001 respectively). BCG inoculated animals treated with either hydrocortisone or cyclosporin A showed no reduction in granulomatous infiltration at either the inoculation site or the draining lymph nodes. By contrast M leprae inoculated animals receiving either of these agents showed a significant reduction of granulomatous infiltration at both the inoculation site (p less than 0.001) and in the primary draining lymph node (p less than 0.001). Ziehl Neelsen staining showed an increased proportion of animals with detectable acid fast bacilli (AFB) at the inoculation site in the groups receiving hydrocortisone (50%) and methotrexate (67%) compared to untreated controls (8%). No AFB were observed in any of the animals inoculated with M leprae. In conclusion, this model may be helpful in elucidating the mechanism of T lymphocyte response in Crohn's disease and the variable clinical response seen with the use of immunosuppressive agents in this condition.     

EB virus: malignant lymphoma in cottontop marmosets following inoculation and recovery of the virus from cells of an experimental tumor maintained in organ culture.

The oncogenic potential of Epstein-Barr virus (EBV) was investigated in cottontop marmosets. Neoplasia resembling human malignant lymphomas, reticulum cell sarcoma type, occurred following inoculation of materials containing EBV. One of 4 monkeys that received autologous cells transformed in vitro by EBV developed lymphoma in mesenteric lymph nodes seven and one-half months after inoculation. Three of 4 marmosets inoculated with cell-free EBV developed lymphoma. The latent period for given with EBV accelerated the course of disease. Nevertheless malignant lymphoma occurred in an animal given only cell-free virus. Six of 8 marmosets inoculated with EBV demonstrated antibodies to the virus. Four marmosets not exposed to the virus, of which 2 received immunosuppressive drugs, have not developed tumors, nor EBV antibodies. EBV antigen detectable by immunofluorescences has been found in 2% of cells shed from one tumor maintained in organ culture. These results imply that EBV is capable of inducing malignant lymphoma in at least one primate species. Additional experimental evidence is required, however, before its oncogenic capacity in this host can be accepted without reservation.     

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。     

The sentinel node technique is useful for studies of intestinal immunology in inflammatory bowel disease patients

OBJECTIVE: Mesenteric lymph nodes may play a crucial role in the pathogenesis of human inflammatory bowel disease. We have used the sentinel node technique to analyze mesenteric lymph nodes draining inflammatory lesions sentinel nodes and corresponding site of inflamed bowel in patients with ulcerative colitis or Crohn's disease. METHODS: Thirty-two patients undergoing surgical treatment of inflammatory bowel disease were included. Sentinel nodes were identified intraoperatively. The T cells were harvested from the mesenteric lymph nodes and characterized by flow cytometry. RESULTS: The distribution of CD4CD62L (homing-marked) and CD4CD69 (activated) T cells was studied in mesenteric lymph nodes draining inflammation, nodes draining normal intestine, blood, and mucosa. The turnover of T cells was markedly increased in the lymph nodes connected to inflammatory segments. The immunologic activity of the sentinel lymph nodes correlated with the degree of intestinal inflammation. CONCLUSION: Mesenteric sentinel nodes provide important information about locoregional immunology and pathogenesis in inflammatory bowel disease.