Deficient Fas expression by CD4+ CCR5+ T cells in multiple sclerosis

OBJECTIVE: To evaluate whether T cells expressing CCR5 and CXCR3 from multiple sclerosis (MS) patients are more resistant to apoptosis. METHODS: Expression of CD69, TNF-R1, Fas, FasL, bcl-2, and bax was investigated in 41 MS patients and 12 healthy controls by flow cytometry in CD4+ and CD8+ T cells expressing CCR5 and CXCR3. RESULTS: In MS patients, the percentage of CD69 was increased and Fas expression decreased in CD4+ CCR5+ T cells. INTERPRETATION: The lower Fas expression in activated CD4+ CCR5+ T cells might contribute to disease pathogenesis by prolonging cell survival and favoring their migration into the CNS.     

Preferential increase of IL-2R+ CD4+ T cells and CD45RB- CD4+ T cells in the central nervous system in experimental allergic encephalomyelitis.

We examined lymphocytes isolated from the spinal cord (SC), peripheral blood (PB) and lymph nodes (LN) draining the immunization site of Lewis rats with acute experimental allergic encephalomyelitis (EAE). Cells were analysed for T cell subset markers CD4 (mAb W3/25) and CD8 (mAb OX8), for IL-2R (mAb OX39), and for high molecular mass leukocyte common antigen (LCA, CD45RB) expression (mAb OX22). T cells expressing high (CD45RB+) or low (CD45RB-) molecular mass LCA are of different maturational stages and/or separate lineages. CD4+ T cells were more predominant in SC than in PB and LN; CD8+ T cells were scarce in SC but common in PB and LN. Activated CD4+ T cells (IL-2R+) were common in the SC and LN but infrequent in blood. CD4+ T cells that were CD45RB+ were scarce in the SC. In contrast, the majority of CD4+ T cells in the PB and LN were CD45RB+. The preferential accumulation of IL-2R+ CD4+ T cells and of CD45RB- CD4+ T cells in the central nervous system (CNS) indicates that a selective mechanism directs cell egress into CNS lesions in EAE.     

Direct demonstration of the infiltration of murine central nervous system by Pgp-1/CD44 CD45RB CD4 T cells that induce experimental allergic encephalomyelitis

In experimental allergic encephalomyelitis (EAE), autoimmune T cells infiltrate the central nervous system (CNS) and initiate demyelinating pathology. We have used flow cytometry to directly analyse the migration to the CNS of MBP-reactive CD4⁺ T cells labelled with a lipophilic fluorescent dye (PKH2), in SJL/J mice with passively transferred EAE. Labelled cells constituted about 45% of the CNS CD4⁺ population at the time of EAE onset. Almost all (>90%) of the PKH2-labelled CD4⁺ T cells from EAE CNS were blasts and were α/β T cell receptor (TCR)⁺, CD44(Pgp-1)^high, and the majority were CD45RB^low. By contrast, most PKH2-labelled CD4⁺ T cells in lymph nodes, although CD44^high, were CD45RB^high cells. The cells that were transferred to induce EAE were essentially similar to antigen-primed lymph node cell populations, containing less than 15% CD44^high cells, and most of them were CD45RB^high. The CD44^high CD45RB^low phenotype is characteristic of memory/effector T cells that have been activated by antigen recognition. The difference in CD45RB expression between CNS and LN could therefore reflect differential exposure and/or response to antigen. Consistent with this, PKH2-labelled CD4⁺ cells isolated from the CNS were responsive to MBP in vitro, whereas PKH2⁺ CD4⁺ cells from lymph nodes showed almost undetectable responses. In control experiments in which ovalbumin (OVA)-reactive T cells were transferred, a small number of fluorescent-labelled CD4⁺ T cells were also detected in CNS, but there were very few blasts, and these remained CD45RB^high. These results argue for induction of the memory/effector phenotype of CD4⁺ cells, their selective retention in the CNS, as a consequence of antigen recognition.     

Mannose receptor expression specifically reveals perivascular macrophages in normal, injured, and diseased mouse brain

Perivascular macrophages are believed to have a significant role in inflammation in the central nervous system (CNS). They express a number of different receptors that point toward functions in both innate immunity, through pathogen-associated molecular pattern recognition, phagocytosis, and cytokine responsiveness, and acquired immunity, through antigen presentation and co-stimulation. We are interested in the receptors that are differentially expressed by perivascular macrophages and microglia in both the normal CNS as well as in neuroinflammation and neurodegeneration. In this article we report the use of a well-characterized monoclonal antibody, 5D3, to localize the expression of the mannose receptor to perivascular macrophages in the normal CNS and in various models of brain pathology. Mannose receptor expression was limited to perivascular, meningeal, and choroid plexus macrophages in normal, inflamed, injured, and diseased CNS. In particular, activated microglia and invading hematogenous leukocytes were mannose receptor negative while expressing the F4/80 antigen, macrosialin (CD68), FcRII (CD32), scavenger receptor (CD204), and CR3 (CD11b/CD18). Since the perivascular macrophages expressing the mannose receptor are known to be the only constitutively phagocytic cells in the normal CNS, we injected clodronate-loaded liposomes intracerebroventricularly in control mice to deplete these cells. In these mice, there was no detectable mannose receptor expression in perivascular spaces after immunocytochemistry with the 5D3 monoclonal antibody. This finding underlines the value of the monoclonal antibody 5D3 as a tool to study murine perivascular macrophages selectively. Mannose receptor expression by macrophages located at blood-brain (perivascular), brain-cerebrospinal fluid (CSF) (meningeal), and CSF-blood (choroid plexus) interfaces supports a functional role of these cells in responding to external stimuli such as infection.     

CX3CR1 receptor is up-regulated in monocytes of coronary artery diseased patients: impact of pre-inflammatory stimuli and renin-angiotensin system modulators

Fractalkine/CX3CR1 pathway is considered a major modulator of atherosclerosis. In the present study, expression of CX3CR1 on PBMCs/monocytes of healthy individuals and coronary artery diseased patients was initially assessed by flow cytometry. Effects of pre-inflammatory cytokines interferon (INF)-gamma and tumor necrosis factor (TNF)-alpha on expression of CX3CR1 and a single representative of each major chemokine family (CCR5 and CXCR4) were further assessed in three cell models: THP-1 monocytes, Jurkat T lymphocytes and primary monocytes isolated from healthy donors. Finally, effects of angiotensin-converting enzyme (ACE) inhibitors captopril, lisinopril and angiotensin receptor blocker (ARB) losartan on chemokine receptor expression were evaluated in the same cell models either in a naive or stimulated state. INF-gamma significantly affected the chemokine receptor phenotype of THP-1 cells by increasing the rate of CX3CR1-positive cells. Pre-treatment with the ACE inhibitors, captopril and lisinopril, and the ARB, losartan, did not influence these effects. Captopril and lisinopril similarly had no effect on either stimulated or naive primary monocytes. Yet, a small but repeatable increase in CX3CR1 expression after treatment with losartan was noted. Nevertheless, the latter observation did not retain statistical significance after applying the Bonferroni correction. In conclusion, our data did not indicate any significant effect of the ACE inhibitors on the chemokine receptor phenotype of monocytes.     

Chemokine receptors on infiltrating leucocytes in inflammatory pathologies of the central nervous system (CNS)

Haematogenous leucocytes enter the central nervous system (CNS) during diverse disorders of varied aetiologies. Understanding the trafficking cues that mediate CNS leucocyte infiltration might promote the development of flexible and selective means to modulate inflammation to achieve clinical benefit. The trafficking machinery of leucocytes has been elucidated during the past decade and consists of cell-surface adhesion molecules, chemoattractant cytokines (chemokines) and their receptors. Recent work in our laboratory characterized chemokine receptors found on T lymphocytes and monocytes in brain sections from subjects with one pathological subtype of multiple sclerosis (MS), an immune-mediated inflammatory demyelinating disease. In these tissues, the types 1 and 5 CC chemokine receptors (CCR1 and CCR5) were detected on perivascular monocytic cells whereas only CCR5 was present on parenchymal macrophages. The type 3 CXC chemokine receptor (CXCR3) was present on virtually all CD3-positive T cells. In the current study, we evaluated the expression of these receptors on the infiltrating cells present in cases of other inflammatory CNS disorders including those of dysimmune, infectious, neoplastic, and vascular aetiology. Perivascular and parenchymal monocytic cells expressed CCR1 in all cases and CXCR3 was consistently present on a substantial proportion of CD3+ T cells. The occurrence of CCR5 on parenchymal macrophages was much less uniform across the varied disorders. These data implicate CCR1 in monocyte infiltration of the CNS and are consistent with reports of studies in CCR1-deficient mice. CXCR3 is also likely to play a role in accumulation of T cells in the inflamed CNS. By contrast, our findings suggest that regulation of CCR5 on phagocytic macrophages may be contingent on the lesion environment.     

Increased expression of CXCR3 and CCR5 on memory CD4+ T-cells migrating into the cerebrospinal fluid of patients with neuroborreliosis: the role of CXCL10 and CXCL11

The aim of this study was to evaluate the contribution of chemokine receptor CXCR3 and the corresponding ligands CXCL10 and CXCL11 to the recruitment of peripheral blood (PB) memory CD4+ T-cells into the cerebrospinal fluid (CSF) of patients with acute neuroborreliosis. Percentages of memory CD45RO+CD4+ T-cells expressing CXCR3 and CCR5 were significantly enriched in the CSF compared to the PB. Concentrations of CXCL10 and CXCL11 in the CSF of neuroborreliosis patients were significantly higher compared with the corresponding serum samples. Our results suggest that CXCL10 and CXCL11 create a chemokine gradient between the CSF and serum and recruite CXCR3-expressing memory CD4+ T-cells into the CSF of neuroborreliosis patients and that CCR5 also plays a role in this process.     

Loss rather than downregulation of CD4 T cells as a mechanism for remission from experimental allergic encephalomyelitis

SJL/J mice recover from clinical signs of experimental allergic encephalomyelitis (EAE) 2 to 3 days following the onset of the initial attack. The immunoregulatory events that induce clinical recovery are not well understood. In this paper we have compared the activation state of the T cells infiltrating the central nervous system (CNS) in symptomatic and remitted mice. We isolated mononuclear cells from the CNS at various time points during the course of EAE and used flow cytometry to describe the kinetics of CNS infiltration by CD45⁺, CD2⁺, CD3⁺, TCRαβ⁺, CD4⁺ cells. There was a 30-fold reduction in the number of CNS CD4⁺ T cells in remitted mice 10 days following the initial attack. More than 60% of CNS CD4⁺ cells were of a CD44^high, CD45RB^low memory/effector phenotype both in active EAE, peak EAE and in remission, contrast to lymph nodes where this phenotype never constituted more than 17%. The proportion of CD8⁺ T cells was not increased in remitted mice, and we detected no TCRγδ⁺ cells within the CNS. Our findings demonstrate an overt loss of CD4⁺ T cells from the CNS and the maintenance of an activated state by T cells within the CNS and during remission from EAE. This argues against downregulation of T cell function as a mechanism for remission.     

Acute aerobic exercise in humans increases cytokine expression in CD27− but not CD27+ CD8+ T-cells

Exercise alters the percentage of CD8⁺ T-cells in the bloodstream expressing type I and type II cytokines. It is unknown if this reflects a change in cytokine expression within individual cells, or whether these observations result from the exercise-induced shift in the proportions of early/intermediate (CD27⁺) and late (CD27⁻) differentiated cells, which have vastly different cytokine profiles. 16 males cycled for 60 min at 95% maximal steady state. Mononuclear cells isolated from blood collected before, immediately after, and 1 h after exercise were cultured overnight with and without phytohaemagglutinin stimulation. CD8⁺ T-cells were assessed for differentiation markers and intracellular cytokine expression by flow cytometry. The numbers and percentage of CD27⁻CD8⁺ T-cells increased immediately after exercise and fell below pre-exercise values 1 h later. At 1 h after exercise, an increased number and percentage of CD8⁺ T-cells expressing IL-2, IFN-γ, TNF-α, IL-6, IL-4, and IL-10 was observed in both stimulated and unstimulated cells. The cytokine response to exercise was confined to CD27⁻CD8⁺ T-cells, although cytokine expression among CD8⁺ T-cells was highest when the proportion of CD27⁻CD8⁺ T-cells was lowest. Moreover, the cytokine response to exercise could be predicted by the number of late cells in resting blood: cytokine expression was highest among those with low resting proportions of late cells. We conclude that exercise-induced changes in the percentage of CD8⁺ T-cells expressing cytokines are not due to proportional shifts in early/intermediate and late differentiated T-cells. Exercise may prime late-differentiated blood CD8⁺ T-cells to initiate effector functions in preparation for their extravasation into the tissues.     

Chemokine receptors and virus entry in the central nervous system

Several members of the chemokine receptor family are used as coreceptors together with CD4 for HIV and SIV entry in the central nervous system (CNS). CCR5 is the major coreceptor for HIV-1 infection of macrophages and microglia, the major target cells for HIV-1 infection in the CNS. CXCR4 and CCR3 are also expressed on microglia and can mediate infection by certain HIV-1 isolates but at lower efficiency than CCR5. Additional chemokine receptors that can function as HIV-1 and SIV coreceptors for a subset of viruses are expressed in the brain (i.e. Apj, CX3CR1, STRL33/BONZO, and gpr1), but their role in CNS infection has not been defined. The expression of CXCR4, and possibly other chemokine receptors, on subpopulations of neurons and glial cells may contribute to mechanisms of CNS injury that are independent of viral infection. Understanding the role of chemokine receptors and their chemokine ligands in HIV-1 and SIV infection of the CNS will elucidate mechanisms of viral tropism and pathogenesis and advance the development of new therapeutic strategies.     

Comparison of phenotypic and functional properties of immediately ex vivo and cultured human adult microglia

Microglial cells are resident cells of the CNS and are implicated as regulators and effectors of immune responses which occur within this compartment. The precise role of parenchymal microglia remains speculative because distinctions between these cells, perivascular “microglia,” and blood-derived monocytes/macrophages are not well defined. The current study describes the phenotype and function of microglia immediately upon isolation from the non-inflamed adult human CNS and the phenotypic changes which occur in these cells when maintained in tissue culture. We find that the characteristic phenotype of immediately ex vivo parenchymal microglia (CD11c^-/CD45^low/CD14^-) corresponds to that found in situ in the “normal” human brain. The phenotype differs from that of perivascular “microglia” in situ and PBDM (both CD45^hi/CD14⁺⁺). The immediately ex vivo microglia express B7-2 and HLA class II molecules and can support alloantigen-induced proliferation by CD4⁺ T cells freshly isolated from peripheral blood. Following in vitro culture, the cells are characterized by a bipolar morphology, continued lower levels of CD45 expression compared to PBDM, and slight upregulation of B7-1 and HLA-DR antigen expression. CD14 becomes expressed at high levels on the cells, suggesting that CD14 can serve as an apparent marker of microglia activation which is not based on changes in morphology or APC capacity. Further, treatment of the cells with IFN-γ and LPS causes further upregulation of HLA-DR and clear expression of B7-1 molecules on the surface. The capacity to characterize phenotypic and functional properties of microglia before and after activation provides an opportunity to determine means to manipulate the immune regulatory and effector properties of this cell type. © 1996 Wiley-Liss, Inc.     

Altered expression of Th1-type chemokine receptor CXCR3 on CD4+ T cells in myasthenia gravis patients

The expression of chemokine receptors on peripheral blood lymphocytes and thymocytes of myasthenia gravis (MG) patients was analyzed before and after therapy with special reference to the thymic histopathology. Before therapy, MG patients showed reduced frequency of CD4+ T cells expressing T-helper1 (Th1) type chemokine receptor CXCR3, with a significantly lower frequency in the thymoma group than in the thymic hyperplasia group, while the frequencies of CXCR3-positive CD8+ T cells remained normal irrespective of the thymic pathology. Both CD4+ cells and CD8+ cells of the hyperplasia group showed significantly increased expression of CCR1 on the cells followed by a reduction to the control level after therapy. No significant changes in the frequencies of CCR2, CCR3, CCR4, and CCR5 were observed in either MG group. There was a significant inverse correlation between the percentage of CXCR3-positive CD4+ T cells and the disease severity assessed with the MGFA scale (Fig. 1, r=-0.55, p=0.0047). The CXCR3 expression on CD4+ cells was increased toward the control level long after the initiation of therapy. The thymomas showed significantly higher percentages of CXCR3-positive CD4+CD8- single positive cells than the control thymuses and, though not significantly, the hyperplastic thymuses also showed higher percentages. These results indicated that Th1-type chemokine signalings were altered in the MG patients, particularly those with thymoma, and that the thymus and thymoma are important sites of Th1-type reactions. The slow clinical improvement of MG symptoms after treatment may be explained partly by the gradual normalization of CXCR3-mediated signaling.     

Direct demonstration of the infiltration of murine central nervous system by Pgp-1/CD44high CD45RB(low) CD4+ T cells that induce experimental allergic encephalomyelitis.

In experimental allergic encephalomyelitis (EAE), autoimmune T cells infiltrate the central nervous system (CNS) and initiate demyelinating pathology. We have used flow cytometry to directly analyse the migration to the CNS of MBP-reactive CD4+ T cells labelled with a lipophilic fluorescent dye (PKH2), in SJL/J mice with passively transferred EAE. Labelled cells constituted about 45% of the CNS CD4+ population at the time of EAE onset. Almost all (greater than 90%) of the PKH2-labelled CD4+ T cells from EAE CNS were blasts and were alpha/beta T cell receptor (TCR)+, CD44(Pgp-1)high, and the majority were CD45RB(low). By contrast, most PKH2-labelled CD4+ T cells in lymph nodes, although CD44high, were CD45RBhigh cells. The cells that were transferred to induce EAE were essentially similar to antigen-primed lymph node cell populations, containing less than 15% CD44high cells, and most of them were CD45RBhigh. The CD44high CD45RB(low) phenotype is characteristic of memory/effector T cells that have been activated by antigen recognition. The difference in CD45RB expression between CNS and LN could therefore reflect differential exposure and/or response to antigen. Consistent with this, PKH2-labelled CD4+ cells isolated from the CNS were responsive to MBP in vitro, whereas PKH2+ CD4+ cells from lymph nodes showed almost undetectable responses. In control experiments in which ovalbumin (OVA)-reactive T cells were transferred, a small number of fluorescent-labelled CD4+ T cells were also detected in CNS, but there were very few blasts, and these remained CD45RBhigh. These results argue for induction of the memory/effector phenotype of CD4+ T cells, and their selective retention in the CNS, as a consequence of antigen recognition.     

Expression of fractalkine (CX3CL1) and its receptor, CX3CR1, during acute and chronic inflammation in the rodent CNS

In this study, we investigate the expression of fractalkine (CX3CL1) and the fractalkine receptor (CX3CR1) in the naive rat and mouse central nervous system (CNS). We determine if the expression of this chemokine and its receptor are altered during chronic or acute inflammation in the CNS. In addition, we determine if CX3CL1, which has been reported to be chemoattractant to leukocytes in vitro, is capable of acting as a chemoattractant in the CNS in vivo. Immunohistochemistry was performed using primary antibodies recognizing soluble and membrane-bound CX3CL1 and the N-terminus of the CX3CR1. We found that neurons in the naive rodent brain are immunoreactive for CX3CL1 and CX3CR1, both showing a perinuclear staining pattern. Resident microglia associated with the parenchyma and macrophages in the meninges and choroid plexus constituitively express CX3CR1. In a prion model of chronic neurodegeneration and inflammation, CX3CL1 immunoreactivity is upregulated in astrocytes and CX3CR1 expression is elevated on microglia. In surviving neurons, expression of CX3CL1 appears unaltered relative to normal neurons. There is a decrease in neuronal CX3CR1 expression. Acute inflammatory responses in the CNS, induced by stereotaxic injections of lipopolysaccharide or kainic acid, results in activation of microglia and astrocytes but no detectable changes in the glial expression of CX3CL1 or CX3CR1. The expression of CX3CL1 and CX3CR1 by glial cells during inflammation in the CNS may be influenced by the surrounding cytokine milieu, which has been shown to differ in acute and chronic neuroinflammation.     

CNS-derived CCL21 is both sufficient to drive homeostatic CD4+ T cell proliferation and necessary for efficient CD4+ T cell migration into the CNS parenchyma following Toxoplasma gondii infection

Injury, infection and autoimmune triggers increase CNS expression of the chemokine CCL21. Outside the CNS, CCL21 contributes to chronic inflammatory disease and autoimmunity by three mechanisms: recruitment of lymphocytes into injured or infected tissues, organization of inflammatory infiltrates into lymphoid-like structures and promotion of homeostatic CD4+ T-cell proliferation. To test if CCL21 plays the same role in CNS inflammation, we generated transgenic mice with astrocyte-driven expression of CCL21 (GFAP-CCL21 mice). Astrocyte-produced CCL21 was bioavailable and sufficient to support homeostatic CD4+ T-cell proliferation in cervical lymph nodes even in the absence of endogenous CCL19/CCL21. However, lymphocytes and glial-activation were not detected in the brains of uninfected GFAP-CCL21 mice, although CCL21 levels in GFAP-CCL21 brains were higher than levels expressed in inflamed Toxoplasma-infected non-transgenic brains. Following Toxoplasma infection, T-cell extravasation into submeningeal, perivascular and ventricular sites of infected CNS was not CCL21-dependent, occurring even in CCL19/CCL21-deficient mice. However, migration of extravasated CD4+, but not CD8+ T cells from extra-parenchymal CNS sites into the CNS parenchyma was CCL21-dependent. CD4+ T cells preferentially accumulated at perivascular, submeningeal and ventricular spaces in infected CCL21/CCL19-deficient mice. By contrast, greater numbers of CD4+ T cells infiltrated the parenchyma of infected GFAP-CCL21 mice than in wild-type or CCL19/CCL21-deficient mice. Together these data indicate that CCL21 expression within the CNS has the potential to contribute to T cell-mediated CNS pathology via: (a) homeostatic priming of CD4+ T-lymphocytes outside the CNS and (b) by facilitating CD4+ T-cell migration into parenchymal sites following pathogenic insults to the CNS.     

Increased frequency of CD4+T cells expressing fractalkine receptor CX3CR1 in patients with HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), but its AIDS susceptible polymorphisms are not associated with the disease

To investigate whether fractalkine receptor CX3CR1 polymorphisms that have been associated with rapid progression to AIDS among HIV-1 positive individuals also affects the risk of human T cell lymphotropic virus type 1 (HTLV-1) associated myelopathy/tropical spastic paraparesis (HAM/TSP), we compared the allele frequencies of V249I and T280M between 233 HAM/TSP patients and 213 HTLV-1 seropositive asymptomatic carriers (HCs). Although the frequency and absolute number of peripheral blood CX3CR1+CD4+T cells were significantly increased in HAM/TSP patients compared to HCs and uninfected controls independent of HTLV-1 trans-activator protein Tax, we could not observe any association between the two polymorphisms and the risk of HAM/TSP in our cohort.     

Selective CC chemokine receptor expression by central nervous system-infiltrating encephalitogenic T cells during experimental autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is a CD4(+) T cell disease of the central nervous system (CNS) characterized by mononuclear cell infiltration, demyelination, and paralysis. Recent studies describing the relationship of chemokine expression with development of clinical disease have led to the hypothesis that distinct chemokine receptors corresponding to specific ligands are expressed by CNS-infiltrating antigen-specific encephalitogenic T cells as well as host-derived bystander T cells and monocytes. In an effort to study encephalitogenic T cell chemokine receptor expression, we examined CC chemokine receptor expression from resting, activated, and CNS-isolated CD4(+) T cells. CCR1, CCR2, CCR3, CCR5, CCR6, CCR7, and CCR8 mRNA is expressed by normal CD4(+) T cells. In vitro activated T cells expressed CCR1, CCR2, CCR3, CCR5, CCR6, CCR7, and CCR8 mRNA as well as CCR4. After EAE induction, CCR1 mRNA was expressed by donor-derived encephalitogenic and host-derived CD4(+) T cells isolated only from CNS and not from spleen. In vivo neutralization of the CCR1 ligand, macrophage inflammatory protein-1alpha (CCL3), resulted in less encephalitogenic CD4(+) T cell CNS infiltration. These results demonstrate the importance of CC chemokine receptor expression by CD4(+) encephalitogenic T cells for CNS infiltration and subsequent disease development.     

Characterization of natural killer cells in paired CSF and blood samples during neuroinflammation

Natural killer (NK) cells from paired CSF and blood samples of patients with multiple sclerosis (MS), other neuroinflammatory diseases (IND), and non-inflammatory neurological diseases (NIND) were characterized using flow cytometry. NK cell frequency in CSF was overall decreased compared to blood, particularly in MS patients. In contrast to blood NK cells, during neuroinflammation, CSF NK cells display an immature phenotype with bright expression of CD56 and CD27 and reduced CX3CR1 expression. Our findings suggest that, as for central memory T cells, CSF may represent an intermediary compartment for NK cell trafficking and differentiation before entering the CNS parenchyma.     

Elevated cerebrospinal fluid CD4/CD8 T cell ratio in myasthenia gravis

The proportions of CD2+, CD4+ and CD8+ lymphocytes were determined with the 3-layer indirect immunoperoxidase technique in the cerebrospinal fluid (CSF) of 31 patients with myasthenia gravis (MG) and 21 control subjects without autoimmune or central nervous system (CNS) diseases. None of the MG patients were using immunosuppressive drugs and all were thymectomized shortly after CSF sampling. Analysis of the reference population showed that the percentage of CD4+ lymphocytes and accordingly the CD4+/CD8+ T cell ratio is normally higher in CSF than in peripheral blood (PB). Compared to the controls, the mean percentage of CD4+ lymphocytes and the mean CD4+/CD8+ ratio in CSF were significantly higher in MG patients. In addition, the CD4+/CD8+ ratio was elevated in the CSF of 15 MG patients (48%) as a result of an elevation in the proportion of CD4+ and/or a decrease in CD8+ T cells. Among MG subjects the mean proportion of CD4+ lymphocytes was higher in the CSF of patients with also an elevated number of enlarged stimulated lymphoid cells in their CSF, which implies that these lymphocytes are often of the CD4+ phenotype. The percentage of CD4+ T cells in CSF was significantly higher in MG patients with a hyperplastic thymus or a thymoma than in those with an involuted thymus. Neither in MG patients nor in the reference population could an association be observed between CSF and PB lymphocyte subsets. In the controls this suggests that immunologic events of the CNS are normally not directly reflected in PB.(ABSTRACT TRUNCATED AT 250 WORDS)