Choroidal extranodal marginal zone lymphoma diagnosed by full-thickness retinochoroidal biopsy: case report and review of the literature

The case of an 89-year-old man who was referred for a painless decrease of vision in his right eye (RE) is reported. Fundus examination of the RE showed an elevated amelanotic lesion located in the posterior pole with an adjacent focal round pigmented lesion. There was also a more peripheral amelanotic lesion extending from 6 to 9 o’clock clockwise inferotemporally. Uveitis workup and imaging studies of brain and orbits were normal. A retinochoroidal biopsy was done and showed the presence of choroidal extranodal marginal zone lymphoma. The patient was treated with external beam radiotherapy. This report presents a review of the literature of all reported cases of choroidal extranodal marginal zone lymphoma.

Pars plana vitrectomy through the Boston Keratoprosthesis type 1

PURPOSE

To ascertain the feasibility of pars plana vitrectomy (PPV) through a permanent Boston Keratoprosthesis type 1 (KPro) without the use of a temporary KPro.

METHODS

A retrospective interventional case series. Eyes implanted with Boston KPro type 1 between 2008 and 2011 requiring PPV for vitreoretinal complications were included. Feasibility of PPV through the KPro, its anatomical and functional success were studied.

RESULTS

Five out of 70 patients required PPV for vitreoretinal complications post-KPro surgery resulting in an incidence of 7%. PPV was feasible through the Boston KPro with no deleterious effects on the corneal carrier or the KPro itself. Repeat PPV was necessary in some cases. Although anatomical repair of the vitreoretinal complications was achieved in most cases, post PPV visual acuity remained poor in the majority.

CONCLUSION

Our study suggests that although PPV through the Boston KPro is a viable approach for vitreoretinal disease repair, visual rehabilitation remains poor.

Death receptor expression and function at the human blood brain barrier

The blood brain barrier (BBB) is composed of specialized endothelial cells tightly anastomosed to one another and surrounded by a thick extracellular matrix, the basement membrane. Together these components restrict the diffusion of cells and molecules from the periphery into the central nervous system (CNS), providing immune privilege and homeostasis. Dysregulation of the BBB and trans-endothelial migration of immune cells are amongst the earliest CNS changes partaking in lesion formation in multiple sclerosis (MS). Death receptors are members of the tumor necrosis factor receptor (TNFR) super-family. They are expressed on a variety of tissues including endothelium, but the consequence of their triggering appears to be cell type specific. In this study, we describe the expression of death receptors TNFR1, Fas and DR5 on primary cultures of human BBB-derived endothelial cells (ECs), as well as the effects of receptor activation on human brain endothelial cell (HBEC) function. We show that HBECs are resistant to cell death mediated via TNFalpha, FasL and TRAIL and that neither receptor ligation induces cellular proliferation of HBECs. TNFR1 ligation induces NFkappaB activation and the upregulation of chemokines MCP-1 and IL-8, as well as adhesion molecules ICAM-1 and VCAM-1, while Fas and DR5 triggering activate the extracellular signal regulated kinases-1 and -2 (Erk 1/2, p42/44 MAPK) inducing the release of matrix metalloproteinase 9 (MMP9) by BBB-derived ECs.

Th1 and Th2 lymphocyte migration across the human BBB is specifically regulated by interferon beta and copolymer-1

Lymphocyte migration into the central nervous system is a central event in lesion formation in MS. Both interferon beta (IFNbeta) and copolymer-1 (Cop-1) reduce the overall lymphocyte entry into the brain through the blood-brain barrier (BBB) as judged by MRI based studies. In this study, we used a modified Boyden chamber assay in which human brain microvascular endothelial cell (HBEC) monolayers are grown on a fibronectin coated transwell membrane to evaluate in vitro migration of allo-antigen Th1 and Th2 lymphocytes across brain endothelium. We confirmed previous observations showing that migration rates of Th2 lymphocytes across HBECs were higher than migration rates of Th1 cells. When HBECs were pre-treated with IFNbeta (100 U/ml) 30 min prior to migration, the migration rate of Th1 was significantly decreased (45% reduction) while the migration of Th2 remained unchanged. Addition of Cop-1 (30 microg/ml) to HBEC monolayers 30 min prior to migration significantly increased the migration rate of Th2 cells and did not affect the migration of Th1 cells. We did not observe any changes in (1) the expression of adhesion molecules on the surface of HBECs and (2) the pattern of chemokine production by HBECs after IFNbeta or Cop-1 treatment. The changes in cellular migration rates were not paralleled with changes in diffusion of large molecular weight tracers across brain ECs. Our data support the notion that immuno-modulators used for the treatment of MS selectively and differentially regulate the migration of T helper lymphocyte subsets and that Cop-1 promotes trans-endothelial migration of Th2 cells across the BBB.

Interferon beta promotes nerve growth factor secretion early in the course of multiple sclerosis

BACKGROUND

Interferon beta therapy has been shown to reduce the rate of clinical relapse and the frequency of magnetic resonance imaging-defined T2- weighted lesions in patients with multiple sclerosis (MS). When given early, interferon beta also reduces the rate of development of brain atrophy and improves axonal integrity. Nerve growth factor (NGF) can retard the severity and course of experimental allergic encephalomyelitis.

OBJECTIVE

To determine whether interferon beta effects on patients with MS could be related to modulation of neurotrophin production within the central nervous system.

DESIGN

We studied neurotrophin production by human glial and brain endothelial cells in response to coculture with MS patient-derived lymphocytes, and correlated levels of NGF secretion with clinical and magnetic resonance imaging-defined markers of disease.

RESULTS

We demonstrate that production of NGF by human brain microvascular endothelial cells is triggered by interaction with T lymphocytes derived from MS patients. No such response was observed using human adult microglia or human fetal astrocytes. Nerve growth factor production by endothelial cells was potentiated by pretreating lymphocytes with interferon beta in vitro, and by using lymphocytes derived from MS patients treated with interferon beta in vivo. By using this assay, we show that levels of NGF induced by lymphocytes from MS patients inversely correlate with magnetic resonance imaging measures of brain atrophy and axonal injury.

CONCLUSION

These findings suggest that interferon beta-mediated production of NGF at the level of the blood-brain barrier, whether acting as an immunomodulator or directly on neural cells, is another potential mechanism contributing to the magnetic resonance imaging-defined effect of interferon beta on brain atrophy when given early in the course of MS.

Kinin B1 Receptor Expression on Multiple Sclerosis Mononuclear Cells

BACKGROUND

We have previously shown that the inducible kinin B(1) receptor is expressed on T lymphocytes during relapses and progression in multiple sclerosis.

OBJECTIVE

To evaluate the correlation between the expression of B1 receptor on peripheral blood mononuclear cells derived from patients who have multiple sclerosis with serial, clinical magnetic resonance imaging and immunological study-derived measures.

DESIGN

Using frozen samples obtained from a high-frequency magnetic resonance imaging-immunological study, we analyzed B1 receptor messenger RNA (mRNA) expression in peripheral blood-derived mononuclear cells serially collected from 6 patients with multiple sclerosis and 8 healthy control subjects by semiquantitative radioactive duplex reverse transcriptase-polymerase chain reaction amplification. Time-course kinin B1-actin mRNA ratios were subsequently compared with corresponding clinical magnetic resonance imaging and immune parameters.

RESULTS

The time-course kinin B1-actin mRNA ratio correlated positively with the Expanded Disability Status Scale index (P<.001), occurrence of clinical relapse (P = .02), volume of lesion on T2-weighted images (P<.003) and interleukin 2 receptor and major histocompatibility complex class II expression on CD4+ lymphocytes, but not with gadolinium-enhancing lesions. The time-course kinin B1-actin mRNA ratios were 5 to 25 times lower in samples derived from healthy controls.

CONCLUSION

The correlation of kinin B1 receptor mRNA levels with dynamic clinical and magnetic resonance imaging measures suggests that expression of this receptor can serve as an index of disease activity in multiple sclerosis.

Regulation of cellular and molecular trafficking across human brain endothelial cells by Th1- and Th2-polarized lymphocytes

We used adult human brain-derived endothelial cells (HBECs) to model migration of peripheral blood lymphocytes across the blood brain barrier (BBB) as occurs in MS. We demonstrate that enhanced expression of adhesion molecule ICAM-1 and production of chemokines CXCL10/IP-10, CCL2/MCP-1, and CXCL8/IL-8 by HBECs induced by supernatants derived from allogeneic or myelin basic protein-reactive Th1 cells is only partially reversed with anti-IFNgamma antibody. This effect is not reproduced with IFNgamma or TNFalpha alone, implicating the interaction of multiple factors in the overall functional response. Supernatants from Th2 cells neither suppressed nor amplified Th1-induced effects. Although both Th1 and Th2 supernatants modulated the expression and localization of tight junction molecules zonula occludens (ZO)-1 and ZO-2, neither supernatant altered the permeability of HBEC monolayers to albumin or increased subsequent T cell migration rates. Prior migration of Th1 or Th2 cells across HBECs did enhance subsequent passage of cells and soluble molecules. Our results suggest that initial infiltration of either Th1 or Th2 polarized lymphocytes across the BBB contributes to the continuation of an inflammatory response in the central nervous system.

Inflammatory potential and migratory capacities across human brain endothelial cells of distinct glatiramer acetate-reactive T cells generated in treated multiple sclerosis patients

We asked whether GA-reactive T cells with distinct cytokine profiles (Th2 versus Th1/Th0), induced during GA therapy of multiple sclerosis (MS) patients, have different migratory capacities across human brain endothelial cells (HBECs), and distinct effects on inflammatory responses at the level of the blood-brain barrier (BBB). We confirmed that GA therapy induces a range of GA-reactive T cells defined by distinct profiles of cytokine expression. Supernatants from Th0/Th1 GA-reactive cells significantly upregulated pro-inflammatory chemokine and adhesion molecule expression in HBECs. Post-treatment Th2-polarized GA-reactive cells were significantly less pro-inflammatory but did not suppress the effects induced by Th1 cells. All lines migrated across a HBEC/fibronectin-based model of the BBB with similar efficiencies. We conclude that the spectrum of GA-reactive T cells induced in treated MS patients may differentially impact inflammatory responses at the BBB level. Future studies will determine whether this could contribute to variable clinical response to GA therapy.

Determinants of human B cell migration across brain endothelial cells

Circulating B cells enter the CNS as part of normal immune surveillance and in pathologic states, including the common and disabling illness multiple sclerosis. However, little is known about the molecular mechanisms that mediate human B cell interaction with the specialized brain endothelial cells comprising the blood-brain barrier (BBB). We studied the molecular mechanisms that regulate the migration of normal human B cells purified ex vivo, across human adult brain-derived endothelial cells (HBECs). We found that B cells migrated across HBECs more efficiently than T cells from the same individuals. B cell migration was significantly inhibited by blocking Abs to the adhesion molecules ICAM-1 and VLA-4, but not VCAM-1, similar to the results previously reported for T cells. Blockade of the chemokines monocyte chemoattractant protein-1 and IL-8, but not RANTES or IFN-gamma-inducible protein-10, significantly inhibited B cell migration, and these results were correlated with the chemokine receptor expression of B cells measured by flow cytometry and by RNase protection assay. Tissue inhibitor of metalloproteinase-1, a natural inhibitor of matrix metalloproteinases, significantly decreased B cell migration across the HBECs. A comprehensive RT-PCR comparative analysis of all known matrix metalloproteinases and tissue inhibitors of metalloproteinases in human B and T cells revealed distinct profiles of expression of these molecules in the different cell subsets. Our results provide insights into the molecular mechanisms that underlie human B cell migration across the BBB. Furthermore, they identify potential common, and unique, therapeutic targets for limiting CNS B cell infiltration and predict how therapies currently developed to target T cell migration, such as anti-VLA-4 Abs, may impact on B cell trafficking.

Regulation and functional effects of monocyte migration across human brain-derived endothelial cells

We have used human brain-derived endothelial cells (HBECs) maintained under basal culture conditions in a Boyden chamber assay system as an in vitro model of migration of cells of systemic immune origin across the blood brain barrier (BBB) during the initiation of a CNS-directed inflammatory response. In this study we evaluated the molecular mechanisms that regulate passage of ex vivo peripheral blood-derived monocytes across this barrier and the effects of such migration on the properties of both the HBECs and the monocytes. Our results indicate that monocytes can migrate across HBECs in the absence of inflammatory conditions, at rates exceeding those of lymphocytes. Monocyte migration could be significantly inhibited by the addition of blocking antibodies to intercellular adhesion molecule (ICAM)-1, very late antigen (VLA)-4 integrin, and monocyte chemoattractant protein (CCL-2/MCP-1), or treatment with tissue inhibitor of metalloproteinase (TIMP-1). Following monocyte migration there was a significant increase in permeability of soluble molecules and an enhanced rate of T cell migration across HBECs. The enhanced permeability could be partially prevented with anti-TNF-alpha antibody. The migration process did not induce the upregulation of either co-stimulatory molecules or chemokine receptors on the monocytes. These studies emphasize the functional role of monocyte-endothelial interactions in permitting target access of a CNS-directed cell-mediated immune response.

Differential effects of Th1 and Th2 lymphocyte supernatants on human microglia

We assessed the effects of soluble molecules (supernatants) produced by pro- (Th1) and anti- (Th2) inflammatory T-cell lines on the capacity of adult human CNS-derived microglia to express or produce selected cell surface and soluble molecules that regulate immune reactivity or impact on tissue protection/repair within the CNS. Treatment of microglia with supernatants from allo-antigen and myelin basic protein-specific Th1 cell lines augmented expression of cell surface molecules MHC class II, CD80, CD86, CD40, and CD54, enhanced the functional antigen-presenting cell capacity of microglia in a mixed lymphocyte reaction, and increased cytokine/chemokine secretion (TNFalpha, IL-6, and CXCL10/IP-10). These Th1-induced effects were not reproduced by interferon-gamma (IFNgamma) alone and were only incompletely blocked by anti-IFNgamma antibody. Th2 cell supernatant treatments did not alter costimulatory/adhesion molecule expression or induce cytokine/chemokine production by microglia. Th2 treatment, furthermore, failed to reduce the induction observed in response to Th1 supernatants. Neither Th1 nor Th2 supernatants induced production of the neurotrophin molecules, nerve growth factor, or brain-derived neurotrophic factor. Our results suggest that soluble molecules released by Th1 and not Th2 cells that infiltrate the CNS can stimulate resident microglia to acquire enhanced effector and accessory cell functions; the Th1-induced effects were not downregulated by Th2 supernatant-mediated bystander suppression.

Human brain endothelial cells supply support for monocyte immunoregulatory functions

Blood-derived monocytic cells comprise a significant component of most inflammatory responses that occur in the CNS. We utilized human brain-derived endothelial cells (HBECs) coated membranes in Boyden chambers to assess immune function related properties of human blood-derived monocytes following interaction with HBECs. Monocytes in contact with HBECs maintained functional antigen-presenting capacity and chemokine/cytokine production in contrast to monocytes that migrated through the HBEC barrier. These results indicate that HBECs, although themselves incapable of serving as competent antigen-presenting cells during the course of inflammatory CNS disorders, supply support needed for infiltrating perivascular monocytes to maintain their functions. Monocyte migration across HBECs was inhibited by interferon-beta.

Migration of multiple sclerosis lymphocytes through brain endothelium

CONTEXT

T-lymphocyte migration through the blood-brain barrier is a central event in the process of lesion formation in multiple sclerosis (MS).

OBJECTIVES

To assess the ability of lymphocytes derived from the peripheral blood of patients with clinically active and inactive MS to migrate across an artificial model of the blood-brain barrier and to elucidate the molecular mechanisms involved in such a process.

DESIGN

We developed an in vitro model of lymphocyte migration using a Boyden chamber coated with a monolayer of human brain microvascular endothelial cells.

RESULTS

The rates of migration of lymphocytes obtained from patients with acutely relapsing and active secondary progressive MS was significantly increased compared with those obtained from healthy controls and patients with inactive secondary progressive disease. Ribonuclease protection assays and enzyme-linked immunosorbent assays indicated that monocyte chemoattractant protein 1 and interleukin 8 were the major chemokines produced by brain endothelial cells grown under the culture conditions used for the migration assays. The rate of migration of the MS lymphocytes could be inhibited by 60% with an antimonocyte chemoattractant protein 1 monoclonal antibody, indicating a functional role for this chemokine in the migration process. In agreement with previous reports, we found that the tissue inhibitor of metalloproteinase 1, a matrix metalloproteinase inhibitor, also reduced migration of MS lymphocytes by 50%.

CONCLUSIONS

The results demonstrate an increased migration rate of MS T lymphocytes across the brain endothelium barrier and that such migration is dependent on chemokine monocyte chemoattractant protein 1 and on matrix metalloproteinases.

Regulation of Th1 and Th2 lymphocyte migration by human adult brain endothelial cells

Endothelial cells of the blood-brain barrier (BBB) have the ability to regulate and restrict the passage of cells and molecules from the periphery to the CNS. We have used an in vitro assay of lymphocyte migration across monolayers of human adult brain endothelial cells (HBEC) as a model of lymphocyte migration across the BBB. We found that human allogeneic or MBP-reactive Th2-polarized lymphocytes migrate more avidly than Th1-polarized lymphocytes. Migration of Th2 but not Th1 cells across brain endothelium was inhibited by antibodies directed at MCP-1, a chemokine produced by HBECs. We could detect CCR2, a chemokine receptor that recognizes MCP-1 on Th2 but not Th1 lymphocytes. ICAM-1 and VCAM-1 molecules were expressed on the surface of HBECs under basal conditions and were upregulated by Th1 but not Th2 cell-derived supernatants. Migration of both lymphocyte subsets was dependent on LFA-1/ICAM-1 interactions. Blocking VLA-4/VCAM-1 binding did not influence actual trans-endothelial migration. These results suggest that HBECs composing the BBB favor the migration of Th2 cells. We postulate that this selectivity may help prevent activated Th1 lymphocytes, the putative CNS autoimmune disease initiating cells, from reaching the CNS parenchyma and favor entry of Th2 cells, a putative means to induce bystander suppression in the CNS.

Glial cell influence on the human blood-brain barrier

The blood-brain barrier (BBB) is a specialized structure of the central nervous system (CNS) that restricts immune cell migration and soluble molecule diffusion from the systemic compartment into the CNS. Astrocytes and microglia are resident cells of the CNS that contribute to the formation of the BBB. In this article, we consider the influence of these glial cells on the immune regulatory functions of the microvascular endothelium, with special emphasis on the human BBB. A series of in vitro studies demonstrate that soluble factors produced by glial cells, under basal culture conditions, help restrict development of inflammation within the CNS. These soluble factor effects include upregulating expression of molecules including HT7, UEA-1 lectin-binding sites, and angiotensin receptors that help define the phenotype of endothelial cells. These factors also induce tight junction formation between brain endothelial cells, contributing to the restricted permeability of the BBB. In contrast, these factors have little effect on expression of molecules by ECs that either promote lymphocyte migration, such as chemokines and adhesion molecules or molecules that are required for competent antigen presentation, such as MHC and co-stimulatory molecules. Glial cells that become activated in response to signals derived from the immune system or generated within the CNS, produce an array of inflammatory molecules that increase permeability and promote lymphocyte trafficking and persistence. These observations emphasize the bidirectional nature of neural-immune interactions; this dynamic system should be amenable to therapeutic interventions.

T lymphocytes conditioned with Interferon beta induce membrane and soluble VCAM on human brain endothelial cells

Vascular cell adhesion molecule (VCAM)-1 plays a critical role in mediating inflammatory cell adhesion and migration. Factors regulating the expression of membrane (m)VCAM and its cleaved counterpart soluble (s)VCAM are poorly understood. We previously demonstrated that serum sVCAM levels are increased in multiple sclerosis (MS) patients treated with interferon beta 1b (IFNbeta1b), which correlated with a reduction in gadolinium enhancing lesions on magnetic resonance imaging. However, subsequent studies have shown that IFNbeta does not directly induce VCAM expression on endothelial cells. We demonstrate here that co-culture with IFNbeta-conditioned T cells induces mVCAM on human brain endothelial cells (HBEC). Further, rapid shedding of sVCAM occurs, which mirrors the response after in vivo IFNbeta treatment. The VCAM induction is mediated partially through tumor necrosis factor (TNF)alpha and can be abrogated by sTNF receptor. VCAM could also be induced on astroglioma lines using IFNbeta-conditioned T cells, which suggests the effect is not specific for HBEC. Kinetic studies demonstrated an increase in the sVCAM to mVCAM ratio over time, which may contribute to the ultimate therapeutic effect of IFNbeta in patients. These data have important implications for understanding the events occurring at the blood brain barrier in vivo, and for determining the mechanism of action of IFNbeta in MS.

Kinin B1 receptor expression and function on human brain endothelial cells

The kinin B1 receptor is an inducible receptor expressed in response to inflammatory mediators. We sought to determine whether kinin B1 receptor can be expressed on human brain endothelial cells (HBECs) in vitro and whether signaling via this receptor can regulate permeability and chemokine production properties of these cells. Multiplex RT-PCR amplification and western blot techniques were used to evaluate B1 receptor expression by HBECs. Although B1 receptor mRNA and protein could not be detected on resting HBECs, interferon-gamma induced a dose- and time-dependent up-regulation of B1 receptor mRNA and protein on HBECs. Stimulation of interferon-gamma-treated HBECs with the selective B1 agonist R-838 (Sar [D-Phe8] des Arg9-BK) induced a dose- and time-dependent increase in the production of inositol 3,4,5 tri-phosphate and nitric oxide. Permeability of the HBECs monolayer, as measured by BSA diffusion, was significantly increased by application of the B1 agonist. This biological effect of R-838 could be prevented by R-715, a B1 receptor antagonist and by L-NAME, a nitric oxide synthase blocker. R-838 also inhibited interleukin-8 release from HBECs. We demonstrate that B1 receptors can be up regulated on the surface of HBECs by molecules released during inflammatory response and that signaling via this receptor can regulate BBB permeability and chemokine production in vitro.

B7 expression and antigen presentation by human brain endothelial cells: requirement for proinflammatory cytokines

Interaction between systemic immune cells with cells of the blood-brain barrier is a central step in development of CNS-directed immune responses. Endothelial cells are the first cells of the blood-brain barrier encountered by migrating lymphocytes. To investigate the antigen-presenting capacity of human adult brain endothelial cells (HBECs), we used HBECs derived from surgically resected temporal lobe tissue, cocultured with allogeneic peripheral blood derived CD4+ T lymphocytes. HBECs in response to IFN-gamma, but not under basal culture conditions, expressed HLA-DR, B7.1 and B7.2 antigens. Despite such up-regulation, these IFN-gamma-treated HBECs, in contrast to human microglia and PB monocytes, did not sustain allogeneic CD4+ cell proliferation, supported only low levels of IL-2 and IFN-gamma production, and did not stimulate IL-2 receptor expression. CD4+ T cell proliferation and increased IL-2 receptor expression could be obtained by addition of IL-2. Our data suggests that, although HBECs cannot alone support T cell proliferation and cytokine production, HBECs acting in concert with cytokines derived from a proinflammatory environment could support such a response.