Neurological Deficit and Structural Changes in Lymphoid Structures of the Tracheal Wall in the Immediate Stage of Experimental Hemorrhagic Stroke in Rats with Different Behavioral Activity.

Specific features of neurological deficit and changes in the cellular composition of tracheal lymphoid structures during the immediate stage (day 1) of hemorrhagic stroke were studied in rats with various behavioral parameters. Modeling of hemorrhage in the left caudate nucleus of the brain was followed by the development of motor disturbances in the forelimb use asymmetry test and corner rotation paradigm. These animals preferred to use the left forelimb (ipsilateral to the side of hemorrhage) to lean on the cylinder wall. The frequency of using the right forelimb or both forelimbs was reduced under these conditions. The number of left-sided rotations increased, while the percentage of right-sided rotations decreased. The observed changes were accompanied by immune dysfunction. It was manifested in the depletion of lymphoid aggregates of the tracheal wall in lymphocytes and plasma cells. The severity of abnormal neurological symptoms and disturbances in immune homeostasis during the immediate stage of hemorrhagic stroke was greater in behaviorally passive rats than in active specimens.

Atrophy of primary lymphoid organs induced by Marek's disease virus during early infection is associated with increased apoptosis, inhibition of cell proliferation and a severe B-lymphopenia.

Marek's disease is a multi-faceted highly contagious disease affecting chickens caused by the Marek's disease alphaherpesvirus (MDV). MDV early infection induces a transient immunosuppression, which is associated with thymus and bursa of Fabricius atrophy. Little is known about the cellular processes involved in primary lymphoid organ atrophy. Here, by in situ TUNEL assay, we demonstrate that MDV infection results in a high level of apoptosis in the thymus and bursa of Fabricius, which is concomitant to the MDV lytic cycle. Interestingly, we observed that in the thymus most of the MDV infected cells at 6 days post-infection (dpi) were apoptotic, whereas in the bursa of Fabricius most of the apoptotic cells were uninfected suggesting that MDV triggers apoptosis by two different modes in these two primary lymphoid organs. In addition, a high decrease of cell proliferation was observed from 6 to 14 dpi in the bursa of Fabricius follicles, and not in the thymus. Finally, with an adapted absolute blood lymphocyte count, we demonstrate a major B-lymphopenia during the two 1st weeks of infection, and propose this method as a potent non-invasive tool to diagnose MDV bursa of Fabricius infection and atrophy. Our results demonstrate that the thymus and bursa of Fabricius atrophies are related to different cell mechanisms, with different temporalities, that affect infected and uninfected cells.

Oral inoculation of neonatal Suffolk sheep with the agent of classical scrapie results in PrP(Sc) accumulation in sheep with the PRNP ARQ/ARQ but not the ARQ/ARR genotype.

Scrapie is a transmissible spongiform encephalopathy that can be transmitted amongst susceptible sheep. The prion protein gene (PRNP) profoundly influences the susceptibility of sheep to the scrapie agent. This study reports the failure to detect PrP(Sc) in nervous or lymphoid tissues of Suffolk sheep of the PRNP ARQ/ARR genotype after oral inoculation with a U.S. scrapie isolate. Lambs were inoculated within the first 24 h of birth with 1 ml of a 10% (wt./vol.) brain homogenate derived from a clinically affected ARQ/ARQ sheep. The inoculated sheep were observed daily throughout the experiment for clinical signs suggestive of scrapie until they were necropsied at 86 months post inoculation. Tissues were collected for examination by immunohistochemistry and enzyme immunoassay, but all failed to demonstrate evidence of scrapie infection. Neonatal sheep of the ARQ/ARQ genotype receiving the same inoculum developed scrapie within 24 months. Lambs of the ARQ/ARR genotype that received the same inoculum by intracranial inoculation develop scrapie with a prolonged incubation period and with abnormal prion present within the central nervous system, but not peripheral lymphoid tissues. Results of this study suggest that ARQ/ARR sheep are resistant to oral infection with the scrapie isolate used even during the neonatal period.

[The age changes of lymphoid organs structure: review of literature].

Numerous and often contradictory research results specify that the mechanism of increased susceptibility to diseases in old age has no satisfactory explanation so far. Together with it in literature almost completely there are no comparative data on features of surgery and injury influence on a structure and functions of lymphoid organs at patients of different age groups. However, lymph nodes are a marker of activity of inflammatory process in the region, on their changes it is possible to estimate precisely productivity of different medical actions, to predict development of many complications, and, thus, successfully to take actions for their prophylaxis. All this is especially important and actual because of constant increase in average age, in life expectancy of human population and strengthening of surgical activity at patients of advanced and old age.

A study of lymphoid organs and serum proinflammatory cytokines in pigs infected with African swine fever virus genotype II.

African swine fever virus (ASFV), the causative agent of one of the most important viral diseases of domestic pigs for which no vaccine is available, causes immune system disorders in infected animals. In this study, the serum levels of proinflammatory cytokines, as well as the histological and cellular constitution of lymphoid organs of pigs infected with ASFV genotype II were investigated. The results showed a high degree of lymphocyte depletion in the lymphoid organs, particularly in the spleen and lymph nodes, where ASFV infection led to a twofold decrease in the number of lymphocytes on the final day of infection. Additionally, ASFV-infected pigs had atypical forms of lymphocytes found in all lymphoid organs. In contrast to lymphocytes, the number of immature immune cells, particularly myelocytes, increased dramatically and reached a maximum on day 7 postinfection. The serum levels of TNF-α, IL-1ß, IL-6, and IL-8 were evaluated. Proinflammatory cytokines showed increased levels after ASFV infection, with peak values at 7 days postinfection, and this highlights their role in the pathogenesis of ASFV. In conclusion, this study showed that ASFV genotype II, like other highly virulent strains, causes severe pathological changes in the immune system of pigs.

Expression of toll-like receptors and co-stimulatory molecules in lymphoid tissue during experimental infection of beef calves with bovine viral diarrhea virus of low and high virulence.

The objective of this study was to compare the mRNA expression of Toll-like receptors (TLR3 and TLR7), and costimulatory molecules involved in activation of lymphocytes and antigen presenting cells (CD80, CD86, CD28, and CD40L) after experimental infection of beef calves with low or high virulence noncytopathic (ncp) bovine viral diarrhea virus (BVDV) strains. Thirty BVDV-naïve, beef calves were intranasally inoculated with low (LV; n=10, SD-1) or high (HV; n=10, 1373) virulence ncp BVDV or with BVDV-free cell culture medium (Control, n=10). Calves were euthanized on day 5 post-inoculation and tracheo-bronchial lymph node (TBLN) and spleen samples were collected for mRNA expression through quantitative-RT-PCR. Levels of mRNA for TLR3 and TLR7 were increased in spleen of HV group (P<0.05), but not in LV group, compared to the control group. Expression of CD86 mRNA was up-regulated in TBLN of both LV and HV groups (P<0.05). A significant up-regulation of CD80 mRNA was observed in TBLN for LV calves (P<0.05), but not for HV calves. In conclusion, experimental inoculation with high virulence BVDV-2 1373 stimulated the expression of TLR3, TLR7 and CD86 in spleen and TBLN on day 5 post infection. In contrast, experimental challenge with the low virulence BVDV-1 SD-1 uniquely resulted in up-regulation of both CD80 and CD86 in TBLN samples on day 5 post infection. The observed differential expression during acute infection with high or low virulence BVDV might reflect differences in immune activation by these strains, which could be associated with differences in genotype and/or virulence.

Artery tertiary lymphoid organs contribute to innate and adaptive immune responses in advanced mouse atherosclerosis.

Tertiary lymphoid organs emerge in tissues in response to nonresolving inflammation. Recent research characterized artery tertiary lymphoid organs in the aorta adventitia of aged apolipoprotein E-deficient mice. The atherosclerosis-associated lymphocyte aggregates are organized into distinct compartments, including separate T-cell areas harboring conventional, monocyte-derived, lymphoid, and plasmacytoid dendritic cells, as well as activated T-cell effectors and memory cells; B-cell follicles containing follicular dendritic cells in activated germinal centers; and peripheral niches of plasma cells. Artery tertiary lymphoid organs show marked neoangiogenesis, aberrant lymphangiogenesis, and extensive induction of high endothelial venules. Moreover, newly formed lymph node-like conduits connect the external lamina with high endothelial venules in T-cell areas and also extend into germinal centers. Mouse artery tertiary lymphoid organs recruit large numbers of naïve T cells and harbor lymphocyte subsets with opposing activities, including CD4(+) and CD8(+) effector and memory T cells, natural and induced CD4(+) regulatory T cells, and memory B cells at different stages of differentiation. These data suggest that artery tertiary lymphoid organs participate in primary immune responses and organize T- and B-cell autoimmune responses in advanced atherosclerosis. In this review, we discuss the novel concept that pro- and antiatherogenic immune responses toward unknown arterial wall-derived autoantigens may be organized by artery tertiary lymphoid organs and that disruption of the balance between pro- and antiatherogenic immune cell subsets may trigger clinically overt atherosclerosis.

Neuroendocrine stimulation of mucosal immune cells in inflammatory bowel disease.

Crohn's disease and ulcerative colitis are the major inflammatory bowel diseases (IBD) in humans. With the incidence of increasing world-wide, it currently affects 4 million people in Europe and in the USA. It is an idiopathic, chronic relapsing intestinal disorder of complex pathogenesis. The etiology of both diseases remains unknown, but recent data suggest that they appear in genetically predisposed individuals, because of an exaggerated mucosal immune response to commensal microbiota present in the gut. There is increasing evidence for an alteration of the immune regulation mechanisms in patients, with mucosal T lymphocytes playing a crucial role in the pathogenic events leading to tissue damage. It is clear that the disease is the result of environmental factors acting on genetically predisposed individuals. In humans, psychological trauma, stress or depression, have been involved as precipitating or relapsing factors of the disease, although this link remains elusive. However, several published works using colitis animal models subjected to stress conditions, have given consistent proof as to the molecular link between emotional stress, increase in epithelial permeability, alteration of the gut microflora composition and activation of pre-sensitized T lymphocytes. Gaining knowledge of the cross talk between components of the brain - gut - immune system axis may be fruitful in the design of future therapeutic approaches, such as the use of vasointestinal peptide (VIP) in this pathology.

IL-6 regulates adipose deposition and homeostasis in lymphedema.

Lymphedema (LE) is a morbid disease characterized by chronic limb swelling and adipose deposition. Although it is clear that lymphatic injury is necessary for this pathology, the mechanisms that underlie lymphedema remain unknown. IL-6 is a known regulator of adipose homeostasis in obesity and has been shown to be increased in primary and secondary models of lymphedema. Therefore, the purpose of this study was to determine the role of IL-6 in adipose deposition in lymphedema. The expression of IL-6 was analyzed in clinical tissue specimens and serum from patients with or without LE, as well as in two mouse models of lymphatic injury. In addition, we analyzed IL-6 expression/adipose deposition in mice deficient in CD4(+) cells (CD4KO) or IL-6 expression (IL-6KO) or mice treated with a small molecule inhibitor of IL-6 or CD4 depleting antibodies to determine how IL-6 expression is regulated and the effect of changes in IL-6 expression on adipose deposition after lymphatic injury. Patients with LE and mice treated with lymphatic excision of the tail had significantly elevated tissue and serum expression of IL-6 and its downstream mediator. The expression of IL-6 was associated with adipose deposition and CD4(+) inflammation and was markedly decreased in CD4KO mice. Loss of IL-6 function resulted in significantly increased adipose deposition after tail lymphatic injury. Our findings suggest that IL-6 is increased as a result of adipose deposition and CD4(+) cell inflammation in lymphedema. In addition, our study suggests that IL-6 expression in lymphedema acts to limit adipose accumulation.

Atypical molluscum contagiosum accompanied by CD30-positive lymphoid infiltrates.

Atypical presentations of molluscum contagiosum require histophathologic examination and may show pleomorphic lymphocytic infiltrates of a reactive nature, mimicking cutaneous lymphoproliferative diseases. Serial sections of specimens or polymerase chain reactions to show T-cell receptor clonality may be helpful for differential diagnosis. We report a case of atypical molluscum contagiosum accompanied by atypical lymphocytic infiltration showing CD30 positivity.

Experimental evidence of cell dissemination playing a role in pathogenesis of IgA nephropathy in multiple lymphoid organs.

BACKGROUND: Since the pathogenesis of immunoglobulin A (IgA) nephropathy (IgAN) remains unclear, the rationale for current IgAN therapies is still obscure. Recent studies have shown that galactose-deficient IgA1 (GdIgA1) plays a critical role in the pathogenesis of IgAN and can be a non-invasive IgAN biomarker, although the origin of the pathogenic cells producing GdIgA1 is unknown. We examined the cell types and localization of pathogenic cells in IgAN-prone mice. METHODS: We transplanted bone marrow (BM) or spleen cells with or without specific cell types from IgAN-prone mice, which have many features similar to human IgAN, to identify cell types responsible for the IgAN phenotype and to determine their localization. RESULTS: BM transplantation and whole spleen cell transfer from IgAN-prone mice reconstituted IgAN in normal and severe combined immunodeficiency mice. Depletion of CD90(+) spleen cells had no affect on reconstitution, whereas CD19(+) B cells from the spleen were sufficient to reconstitute IgAN in both recipients. CONCLUSIONS: These results indicate that CD19(+) B cells, which can regulate nephritogenic IgA production in a T-cell-independent manner, are responsible for the disease and are disseminated in peripheral lymphoid organs.

[Update on special surgical approaches in the therapy for lymphedemas]. / Die Vielfalt in der chirurgischen Therapie beim Lymphödem - was ist aktuell?

Despite recent medical progress primary and secondary lymphedemas still represent a therapeutic challenge and they often lead to a significant reduction in quality of life. Lymphedemas usually develop in the extremities, the male external genitals as well as the female breast as a consequence to the axial alignment of the lymphatic collectors. Early stages are characterized by an excess of lymph fluid increasing the volume of the affected part of the body whereas later stages represent an increasing amount of solid tissue. Thus therapeutic efforts can focus on the reduction of the surplus of liquid and/or solid components. Generally there are conservative and operative strategies. Conservative measures mainly focus on the improvement of fluid mobilization and drainage and comprise compression garments, manual lymphatic drainage, and apparative intermittent compression. Operative approaches comprise procedures for surgical tissue reduction (symptomatic/ablative approaches) and/or procedures with the intention of enhancing lymphatic transport (causal approaches). Surgical tissue reduction can be performed by open resection and/or liposuction. Traditional surgical causal techniques such as transposition of local flaps aim at leading lymph away from the congested region of the body. Modern microsurgical causal approaches contain methods of reconstruction of interrupted lymphatic pathways as well as techniques for the conduction of lymph into local veins. In this review we depict and discuss the features of the multiform spectrum of the surgical therapy of lymphedemas on the basis of literature as well as our own clinical and experimental experience.

Inducible tertiary lymphoid structures, autoimmunity, and exocrine dysfunction in a novel model of salivary gland inflammation in C57BL/6 mice.

Salivary glands in patients with Sjögren's syndrome (SS) develop ectopic lymphoid structures (ELS) characterized by B/T cell compartmentalization, the formation of high endothelial venules, follicular dendritic cell networks, functional B cell activation with expression of activation-induced cytidine deaminase, as well as local differentiation of autoreactive plasma cells. The mechanisms that trigger ELS formation, autoimmunity, and exocrine dysfunction in SS are largely unknown. In this article, we present a novel model of inducible ectopic lymphoid tissue formation, breach of humoral self-tolerance, and salivary hypofunction after delivery of a replication-deficient adenovirus-5 in submandibular glands of C57BL/6 mice through retrograde excretory duct cannulation. In this model, inflammation rapidly and consistently evolves from diffuse infiltration toward the development of SS-like periductal lymphoid aggregates within 2 wk from AdV delivery. These infiltrates progressively acquire ELS features and support functional GL7(+)/activation-induced cytidine deaminase(+) germinal centers. Formation of ELS is preceded by ectopic expression of lymphoid chemokines CXCL13, CCL19, and lymphotoxin-ß, and is associated with development of anti-nuclear Abs in up to 75% of mice. Finally, reduction in salivary flow was observed over 3 wk post-AdV infection, consistent with exocrine gland dysfunction as a consequence of the inflammatory response. This novel model has the potential to unravel the cellular and molecular mechanisms that regulate ELS formation and their role in exocrine dysfunction and autoimmunity in SS.

The pathophysiology of lymphedema - 2012.

Lymphedema of the limbs has become a frequent pathological condition after soft tissue inflammation, trauma, removal of lymph nodes in cancer and long-lasting ulcerations. Lymphatics draining the diseased tissues become occluded. Microsurgery helps in the formation of anastomoses and collaterals bypassing the obstruction site. Surgeons operating on the lymphatics should be aware of the tissue fluid/lymph formation mechanism, hydraulics of tissue fluid/lymph, tissue metabolism and waste material utilization, immune function in terms of elimination of microbial and tumor antigens and raising tolerance to own tissue antigens of injured tissues necessary for wound healing as well as classification of diseases of lymphatics. In this review we present the actual definition of the lymphatic system, how it is changed in lymphedema, and, in particular, tissue fluid/lymph biochemistry, pressure and flow, histopathology and tissue fluid location, and finally how to manage the most common complication dermato-lymphangioadenitis. Detailed knowledge of the anatomy of upper limb limphaties should prevent their damage and loss of function.

Pathophysiologic significance of B-cell clusters in chronically rejected grafts.

The role of antibodies in the pathogenesis of chronic rejection is increasingly acknowledged. In contrast, whether B-cell clusters, which have been recently identified in chronically rejected allografts, actively participate in the process or are only an epiphenomenon remain a matter of debate. Integrating recently published data, we put forward explanations that reconcile the conflicting conclusions of experimental and biopsy-based studies. Finally, we propose a unified model in which B-cell clusters as part of intragraft tertiary lymphoid tissue can play deleterious or regulatory roles and therefore actively modulate the kinetics of chronic rejection.

Gut-associated lymphoid tissue, T cell trafficking, and chronic intestinal inflammation.

The etiologies of the inflammatory bowel diseases (IBD; Crohn's disease, ulcerative colitis) have not been fully elucidated. However, there is very good evidence implicating T cell and T cell trafficking to the gut and its associated lymphoid tissue as important components in disease pathogenesis. The objective of this review is to provide an overview of the mechanisms involved in naive and effector T cell trafficking to the gut-associated lymphoid tissue (GALT; Peyer's patches, isolated lymphoid follicles), mesenteric lymph nodes and intestine in response to commensal enteric antigens under physiological conditions as well as during the induction of chronic gut inflammation. In addition, recent data suggests that the GALT may not be required for enteric antigen-driven intestinal inflammation in certain mouse models of IBD. These new data suggest a possible paradigm shift in our understanding of how and where naive T cells become activated to yield disease-producing effector cells.

[Lymphoid neogenesis and lymphangiogenesis: two newcomers in the pathophysiology of chronic rejection]. / Néogenèse lymphoïde et lymphangiogenèse: deux nouveaux mécanismes impliqués dans la physiopathologie du rejet chronique.

Chronic rejection is one of the main causes of late allograft failure and no therapy is currently available to prevent efficiently its development. Improving the comprehension of the mechanisms involved in the pathophysiology of chronic rejection is a mandatory step to propose innovative therapies that would prolong grafts' survival. Using the rat aortic interposition model of chronic vascular rejection, we have demonstrated that the intragraft inflammatory infiltrate progressively organized itself into a functional ectopic lymphoid tissue (tertiary lymphoid organ) supporting the local synthesis of alloantibody. Thus, during chronic rejection the graft is at the same time the target and the site of elaboration of the humoral allo-immune response. This hypothesis has been confirmed in the clinical setting by the analysis of human grafts (kidneys, hearts and lungs) removed for terminal failure due to chronic rejection. This lymphoid neogenesis process, previously identified in other chronic inflammatory diseases, occurs with a strikingly high frequency in chronically rejected grafts, suggesting that an additional mechanism synergizes to initiate the development of tertiary lymphoid organs during chronic rejection. We propose that the defective lymphatic drainage of chronically rejected organs triggers lymphoid neogenesis and we discuss the complex crosstalk between lymphoid neogenesis and lymphangiogenesis that takes place during chronic rejection.

Distribution of Foxp3(+) T-regulatory cells in experimental autoimmune neuritis rats.

T-regulatory cells expressing the forkhead box transcription factor 3 (Foxp3) play essential roles in immune homeostasis. Experimental autoimmune neuritis (EAN) is an autoantigen-specific T-cell-mediated disease model for human demyelinating inflammatory disease of the peripheral nervous system. We investigated the distribution of Foxp3(+) cells in sciatic nerves, spleen and lymph nodes of EAN rats, and the influence of FTY720 on the localization of Foxp3(+) cells in EAN rats. In sciatic nerves of EAN rats, accumulation of Foxp3(+) cells was not seen during the pre-symptomatic phase (until Day 9) or during early or peak disease activity. In contrast, Foxp3(+) cell accumulation was regularly seen in the recovery from neurologic disease, suggesting a contribution of Foxp3(+) cells to the resolution of EAN. FTY720 was given at onset of EAN (Day 10) until Day 18. Following FTY720 administration, percentages of Foxp3(+) cells in EAN rats were increased in circulating blood, but reduced in lymph nodes compared to the PBS control. FTY720 treatment suppressed total numbers but increased percentages of Foxp3(+) cells in sciatic nerves of EAN rats. These data not only suggests a protective role of Foxp3(+) cells in EAN but also provides a potential way to alter localization of Foxp3(+) cells in vivo.