Saturday, 21 January 2017

#ResearchSpeak: it's the B-cells again

How soon will it be before we can clear the MS brain of plasma cells? Not soon enough. #ResearchSpeak #MSBlog

The study below confirms what we already know that even early in the course of MS B-cells and plasma cells are up to no good. Gray matter, or cortical, atrophy correlates with an inflammatory chemokine (CXCL13) responsible for attracting B-cells into the CNS. 


Interestingly, the authors interpret the lower BAFF (a B-cell survival and growth factor) to indicate that it must be plasma cells that have entered the CNS from the periphery and not matured centrally. I don't agree with this interpretation, what is the evidence for this? If it was the case then peripheral clones would result in matched OCBs. In the MS the majority of OCBs are unmatched, in other words are due to local synthesis. Surely the low BAFF levels could be due to local consumption? 

Despite these subtleties in relation to the interpretation of the data this study suggest that intrathecal B-cell and their products are associated with gray matter atrophy; this is part of the brain that is responsible for cognition. If this is the case we will need to clear the CNS of pathogenic B-cells and plasma cells if we want to prevent long-term damage from occurring. This is why anti-CD20 therapies may not be good enough to prevent delayed worsening of MS. If you haven't read our previous posts on this you may find the most recent one on rituximab failing to prevent delayed worsening or in the old terminology non-relapsing SPMS.  

The intrathecal plasma cell; is this the new enemy from within?

Puthenparampil et al. BAFF Index and CXCL13 levels in the cerebrospinal fluid associate respectively with intrathecal IgG synthesis and cortical atrophy in multiple sclerosis at clinical onset. J Neuroinflammation. 2017 Jan 17;14(1):11. doi: 10.1186/s12974-016-0785-2.

BACKGROUND: B lymphocytes are thought to play a relevant role in multiple sclerosis (MS) pathology. The in vivo analysis of intrathecally produced B cell-related cytokines may help to clarify the mechanisms of B cell recruitment and immunoglobulin production within the central nervous system (CNS) in MS.


METHODS: Paired cerebrospinal fluid (CSF) and serum specimens from 40 clinically isolated syndrome suggestive of MS or early-onset relapsing-remitting MS patients (CIS/eRRMS) and 17 healthy controls (HC) were analyzed for the intrathecal synthesis of IgG (quantitative formulae and IgG oligoclonal bands, IgGOB), CXCL13, BAFF, and IL-21. 3D-FLAIR, 3D-DIR, and 3D-T1 MRI sequences were applied to evaluate white matter (WM) and gray matter (GM) lesions and global cortical thickness (gCTh).

RESULTS: Compared to HC, CIS/eRRMS having IgGOB (IgGOB+, 26 patients) had higher intrathecal IgG indexes (p < 0.01), lower values of BAFF Index (11.9 ± 6.1 vs 17.5 ± 5.2, p < 0.01), and higher CSF CXCL13 levels (27.7 ± 33.5 vs 0.9 ± 1.5, p < 0.005). In these patients, BAFF Index but not CSF CXCL13 levels inversely correlated with the intrathecal IgG synthesis (r > 0.5 and p < 0.05 for all correlations). CSF leukocyte counts were significantly higher in IgGOB+ compared to IgGOB- (p < 0.05) and HC (p < 0.01), and correlated to CSF CXCL13 concentrations (r 0.77, p < 0.001). The gCTh was significantly lower in patients with higher CSF CXCL13 levels (2.41 ± 0.1 vs 2.49 ± 0.1 mm, p < 0.05), while no difference in MRI parameters of WM and GM pathology was observed between IgGOB+ and IgGOB-.

CONCLUSIONS: The intrathecal IgG synthesis inversely correlated with BAFF Index and showed no correlation with CSF CXCL13. These findings seem to indicate that intrathecally synthesized IgG are produced by long-term PCs that have entered the CNS from the peripheral blood, rather than produced by PCs developed in the meningeal follicle-like structures (FLS). In this study, CXCL13 identifies a subgroup of MS patients characterized by higher leukocyte counts in the CSF and early evidence of cortical thinning, further suggesting a role for this chemokine as a possible marker of disease severity.

Fingolimod blocking Alemtuzumab action what does it tell us about MS?

Willis M, Pearson O, Illes Z, Sejbaek T, Nielsen C, Duddy M, Petheram K, van Munster C, Killestein J, Malmeström C, Tallantyre E, Robertson N. An observational study of alemtuzumab following fingolimod for multiple sclerosis. Neurol Neuroimmunol Neuroinflamm. 2017 Jan 10;4(2):e320.

OBJECTIVE:To describe a series of patients with relapsing multiple sclerosis (MS) who experienced significant and unexpected disease activity within the first 12 months after switching from fingolimod to alemtuzumab.
METHODS:Patients with relapsing MS treated sequentially with fingolimod then alemtuzumab who experienced significant subsequent disease activity were identified by personal communication with 6 different European neuroscience centers.
RESULTS:Nine patients were identified. Median disease duration to alemtuzumab treatment was 94 (39-215) months and follow-up from time of first alemtuzumab cycle 20 (14-21) months. Following first alemtuzumab infusion cycle, 8 patients were identified by at least 1 clinical relapse and radiologic disease activity and 1 by significant radiologic disease activity alone.
CONCLUSIONS:We acknowledge the potential for ascertainment bias; however, these cases may illustrate an important cause of reduced efficacy of alemtuzumab in a vulnerable group of patients with MS most in need of disease control. We suggest that significant and unexpected subsequent disease activity after alemtuzumab induction results from prolonged sequestration of autoreactive lymphocytes following fingolimod withdrawal, allowing these cells to be concealed from the usual biological effect of alemtuzumab. Subsequent lymphocyte egress then provokes disease reactivation. Further animal studies and clinical trials are required to confirm these phenomena and in the meantime careful consideration should be given to mode of action of individual therapies and sequential treatment effects in MS when designing personalized treatment regimens.

If the observation is correct and not a statistical artefact, it must be telling us something about MS.

We all know that alemtzumab is a pretty effective drug at blocking relapsing. Likewise fingolimod is pretty effective at blocking MS but when alemtuzmab was given following fingolimod, then it looks like alemtuzumab is not working.  Why?


Alemtuzumab was started before alemtuzumab was washed out and so the disease forming cells are trapped in the lymph gland and so can't be destroyed by alemtuzumab so once fingolimod wears off cells go bad in blood and off MS goes.

First what does fingolimod do?

We have been through this before 
http://multiple-sclerosis-research.blogspot.com/2012/02/education-how-does-fingolimod-work.html


Fingolimod is a sphingosine-1-phosphate one (S1P1) receptor modulator and when it binds to its target the receptor is down regulated. As S1P1 is involved in lymphocytes exiting the lymph glands require both S1P1 and a a chemokine receptor. It traps certain types of white blood cell in the lymph glands so they can't get into the blood and they can't get into the brain and so stop disease. 

Adaptive immunity depends on regular circulation of lymphocytes between blood and lymphoid tissue in the search for antigens. 


When an activating antigen is encountered in the lymph nodes, T cells are retained in the lymph node where naïve T cells become activated and central memory T cells (TCM) are reactivated. Following activation, these T cells return to the blood circulation, allowing them to reach sites of inflammation.

Fingolimod does not affect all cells but blocks exit of naive and central memory cells but not effector memory cells. The memory T cell pool functions as a dynamic repository of antigen-experienced T lymphocytes that accumulate over the lifetime of the individual. Recent studies indicate that memory T lymphocytes contain distinct populations of central memory (TCM) and effector memory (TEM) cells characterized by distinct homing capacity and effector function. This would imply that the disease causing cell is not in the TEM population as fingolimod does not block their movement of cells but blocks relapse. We all know that naive T cells would not be the cause of autoimmunity, as they havent been sensitized to a target yet, so that would leave the TCM (For all those old Tiswas fans its not The Condensed Milk)

The percentages of naïve T cells and TCM in peripheral blood were significantly reduced in patients treated with fingolimod compared with untreated patients, and consequently the percentages of TEM in peripheral blood increased significantly in fingolimod-treated patients compared with untreated patients. While fingolimod reduced the numbers of both CD4+ and CD8+ T cells, the effect was more pronounced for the CD4+ T-cell subset. 


Fingolimod also blocks B cells entering the blood.  These can come from lymph glands but also come from the spleen and fingolimod traps T and B cells in the bone marrow, where numbers go up.  

Maeda Y, Seki N, Sato N, Sugahara K, Chiba K. Sphingosine 1-phosphate receptor type 1 regulates egress of mature T cells from mouse bone marrow. Int Immunol. 2010; 22(6):515-25.

Although fingolimod is taken every it is eliminated from the system quite slowly, notably because it accumulates in the fat in the brain and elsewhere. Once you stop fingolimod , relapses can occur within 1-4 months so it may take a few weeks to a couple of months before cells exit the lymph glands. 

Alemtuzumab is a lymphocyte depleting antibody and destroys T and B cells. However you may not know is how it kills white blood cells. 
Antibodies can kill by complement fixation. This means that a cascade of small complement proteins are made and these serve to form a membrane attack complex that punches holes in cells. They cause the damaged cells to then liberate their contents and die.

Another way is antibody-dependent cellular cytoxicity. In this case the antibody binds to its target. The antibody is bound by a phagocytic cell by Fc receptors binding to the end of the antibody called the Fc region. The phagocytic cell then attacks and kills the target.

So if we look in a mouse with CD52 injected with alemtuzumab

Investigation of the mechanism of action of alemtuzumab in a human CD52 transgenic mouse model. Hu Y, Turner MJ, Shields J, Gale MS, Hutto E, Roberts BL, Siders WM, Kaplan JM. Immunology. 2009;128(2):260-70. 

If you remove complement (with cobra vnon toxin) it has no impact on killing of T (CD4 or CD8) or B cells (CD19) in the blood or the spleen. However if you deplete neutrophils (phagocytic white cell) or natural killer cells which are the ADCC  killing mechanism then you dont kill cells.

This is important because whilst you have loads of neutrophils and natural killer cells in the blood you have many fewer in the lmyphoid tissues such as lymph glands and bone marrow.

So whilst alemtuzumab may be good at depleting cells in the blood it will be less effective at killing cells in the lymph glands and bone marrow. Indeed this can be seen above. So whilst you can see that alemtuzumab kills about 90% of CD4 cells in the blood but only 75% in the spleen. 
          
If you look at the depletion in different tissues, it is not too bad in the lymph glands but less effective in the spleen and bone marrow
So whilst alemtuzumab can clear the blood it may be less good at clearing lymph glands and definately not too good at clearing the bone marrow. In humans, alemtuzumab is largely gone from circulation within about 2 weeks after infusion.

So if the disease causing cell is sequested in lymphoid tissue for more than this, then they won't get depleted and then once the fingolimod wears off they enter the circulation again. Whilst alot of emphasis is placed on fingolimod acting in lymph glands, alemtuzumab is not that bad at depleting T cells in lymph glands.

However in lymph glands, we and others have found that B cells are less sensitive to depletion than T cells.

There is relative saving of B cells in the lymph node cortex and follicles (B cell area black arrow) but the paracortex (T cell area blue arrow) is abit less dense (on right alemtuzumab treated) with low dose alemtuzumab in mice


                          Hu et al. 2009 

We showed that B cells are depleted even less than T cells notably in the lymphoid tissue compared to blood.

Depletion of CD52-positive cells inhibits the development of central nervous system autoimmune disease, but deletes an immune-tolerance promoting CD8 T-cell population. Implications for secondary autoimmunity of alemtuzumab in multiple sclerosis. von Kutzleben S, Pryce G, Giovannoni G, Baker D.
Immunology. 2016 Dec 7. doi: 10.1111/imm.12696. [Epub ahead of print]

This was shown by others too

Immune status following alemtuzumab treatment in human CD52 transgenic mice. Turner MJ, Lamorte MJ, Chretien N, Havari E, Roberts BL, Kaplan JM, Siders WM. J Neuroimmunol. 2013 Aug 15;261(1-2):29-36.
So B cells are depleted less than T cells and they recover faster probably because alemtuzumab does not deplete in the bone marrow or spleen.

Rituximab and oreliziumab depletes B cells so has this effect been seen after fingolimod treatment?

Ocrelizumab depletes via ADCC and so one wonders if it could be blocked by fingolimod similar to alemtuzumab. But as it is not approved there has not enough time to use it as a switching antibody. But an interesting experiment.

Rituximab depletes via completement and may be better at purging bone marrow cells. However  B cell depletion is maintained by 6 monthly dosing so if MS is B cell-mediated, disease won't return, if it is T cell-mediated is could...No reports of this yet.

So is this observation in MS telling us that MS is a T cell disease or is it all due to B cells?

What does MrT think?

If we did the experiment in the beasties it would be T cells but MS?

However, if you are taking fingolimod and need to switch, you need to talk this through before quickly switching to a depletion treatmenting antibody.

DrK will say even more reason to get a chemical depleter like cladribine back on the table as a small molecule is going to get into those Nocks and Crannies that antibodies like alemtuzumab won't...tick tock, tick, tock

Friday, 20 January 2017

#ClinicSpeak: turmeric usage in pwMS

Looks as if turmeric is not that effective in real-life #ClinicSpeak #MSBlog

My post on the Turmeric as a medicinal compound has received quite a lot of attention. The following are the headline results, which are self-explanatory. 


The tip of the iceberg?

It has been suggested that some people with Multiple Sclerosis have subtle evidence of disease activity long before they develop clinically-definite disease. The argument goes that if you performed detailed examinations and investigations, you would detect these subtle abnormalities in certain people before they meet diagnostic criteria for MS. In fact, according to one estimate, about 1/3 of people who have evidence of MS on neuroimaging go on to develop MS within 5 years.

We also now have good evidence that early, aggressive treatment improves long-term outcomes for people with Clinically Isolated Syndrome (‘pre-MS’). It is theoretically plausible that treating people even earlier – e.g. when they have abnormalities on brain imaging but no clinical signs or symptoms of MS – could reduce their risk of developing MS proper.

If preventing MS is going to be an achievable goal for the future, it is crucial that we are able to determine who is at risk of developing the disease so that we can target our therapy appropriately. The Genes and Environment in Multiple Sclerosis (GEMS) project has set out to do just this – it recruited 2632 1st degree relatives of people with MS to get a better understanding of how to predict the development and the progression of this protean disease. 

In a new paper, the GEMS investigators asked whether their MS risk score could predict who would have subtle clinical or radiological abnormalities suggestive of MS. To do this, they took a subset of 100 people from their study cohort, calculated each person’s risk using their previously published risk score, and then took the people in the top and bottom 10% of risk scores to investigate in more detail. They hypothesised that there would be a difference in clinical and radiological parameters relevant to MS between the ‘high’ and ‘low’ risk groups.

To avoid a gender bias, they focussed their analysis on women only. They compared 40 ‘high risk’ women to 25 ‘low risk’ women. Despite using a battery of clinical and imaging measures, they found no statistically significant differences between the groups in terms of age, height, cigarette smoking, vitamin D level, history of infectious mononucleosis, history of migraine, number of MRI lesions suggestive of MS, the prevalence of radiologically-isolated syndrome, EDSS, NHPT, or PASAT scores. There was, however, a significant difference in vibration sensitivity between the high and low risk groups, with the high risk group demonstrating a diminished sensitivity to vibration.

This study demonstrates nicely how difficult it is to detect subtle abnormalities in a small cohort. Even when comparing the highest and lowest risk groups as stratified by the GEMS risk score, only one parameter – vibration sensitivity – was significantly different between the groups. This is unsurprising. If early, ‘pre-MS’ is defined by subtle clinical or imaging abnormalities, then a big cohort is required to demonstrate this. When trying to study small effects, we need big numbers to reduce the chances of false negative results. The cohort of 60 or so people used in this study is simply not big enough to meaningfully prove or disprove the hypothesis at hand. I would take their lack of positive findings with a pinch of salt. 

The motivation behind the GEMS project is really laudable, and I imagine that lots of interesting data will come out as they follow their cohort over the next few years. Armed with a better understanding of who is at risk of MS, the paradigm may begin to shift from early treatment to prevention. Part of the problem is that it is notoriously difficult to demonstrate benefit in prevention trials as the number of people who will develop the disease without any treatment is small. Once we work out who is at high risk of developing MS we will be much better placed to design clinical trials that could show meaningful benefit for preventative therapies. 

***
The Paper

Abstract
Importance  Subclinical inflammatory demyelination and neurodegeneration often precede symptom onset in multiple sclerosis (MS).
Objective  To investigate the prevalence of brain magnetic resonance imaging (MRI) and subclinical abnormalities among asymptomatic individuals at risk for MS.
Design, Setting, and Participants  The Genes and Environment in Multiple Sclerosis (GEMS) project is a prospective cohort study of first-degree relatives of people with MS. Each participant’s risk for MS was assessed using a weighted score (Genetic and Environmental Risk Score for Multiple Sclerosis Susceptibility [GERSMS]) comprising an individual’s genetic burden and environmental exposures. The study dates were August 2012 to July 2015.
Main Outcomes and Measures  Participants in the top and bottom 10% of the risk distribution underwent standard and quantitative neurological examination, including disability status, visual, cognitive, motor, and sensory testing, as well as qualitative and quantitative neuroimaging with 3-T brain MRI and optical coherence tomography.
Results  This study included 100 participants at risk for MS, with 41 at higher risk (40 women [98%]) and 59 at lower risk (25 women [42%]), at a mean (SD) age of 35.1 (8.7) years. Given the unequal sex distribution between the 2 groups, the analyses were restricted to women (n = 65). When considering all measured outcomes, higher-risk women differed from lower-risk women (P = .01 by omnibus test). Detailed testing with a vibration sensitivity testing device in a subgroup of 47 women showed that higher-risk women exhibited significantly poorer vibration perception in the distal lower extremities (P = .008, adjusting for age, height, and testing date). Furthermore, 5 of 65 women (8%) (4 at higher risk and 1 at lower risk) met the primary neuroimaging outcome of having T2-weighted hyperintense brain lesions consistent with the 2010 McDonald MRI criteria for dissemination in space. A subset of participants harbor many different neuroimaging features associated with MS, including perivenous T2-weighted hyperintense lesions and focal leptomeningeal enhancement, consistent with the hypothesis that these individuals are at higher risk of developing clinical symptoms of MS than the general population.
Conclusions and Relevance  Higher-risk asymptomatic family members of patients with MS are more likely to have early subclinical manifestations of MS. These findings underscore the importance of early detection in high-risk individuals.
Trial Registration  clinicaltrials.gov Identifier: NCT01353547

#NeuroSpeak: MS Trust's Health Professionals Web Resources

Healthcare professionals working in MS may find the MS Trust's new web resource helpful #NeuroSpeak

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Health Professionals Web Resources
Here at the MS Trust we are always working to ensure that people with MS and the specialist health professionals who support them have access to up-to-date, relevant, accurate and useful information. Recently, we've been working with health professionals to look into the information resources currently used, and where there may be gaps. Many thanks to everyone who has been involved in this project and those who completed our survey.

A few topics emerged that professionals wanted more information on, so we decided to send a reminder about the resources we already provide in those areas. We believe the following resources will prove useful to MS health professionals, and support them in their professional development and in providing quality care to people with MS.
Writing an effective business case
We have recently updated a page on our website about capacity planning and writing a good business case, featuring highlights from our guide to writing an effective business case and our capacity planning tool, which are available in full on request.


Understanding commissioning and funding flows in MS services in England
This is a vastly complex subject, but can be hugely beneficial to understand when making a case for service improvement/development. We've created a straightforward, practical guide to funding flows in MS services in England.


Sharing examples of innovative practice
We have recently put together a resource for health professionals highlighting opportunities to implement change in MS services. Featured on this webpage are a number of examples of innovative practice from MS teams across the UK (and the opportunity to add to this list yourself) and suggestions for small steps you can implement to help take forward the action statements from MS Forward View.


Developing an effective, responsive and efficient relapse service
In the summer of 2016, we sent every MS nurse a copy of our guide Eight steps to improving your relapse service: a guide to best practice for MS specialist nurses, which explained relapses, discussed the clinical management of relapses, and set out our 'eight steps' needed to deliver an effective relapse service. We also hoped that this resource may be useful for other MS health professionals and GPs.
Auditing your service with a user survey
The MS Trust offers all UK MS nurse and therapist teams the chance to use this survey through a free service whereby we take away most of the work involved.  By taking part, you will receive a valuable presentation giving evidence of the benefits of your service to patients along with service users' experiences and suggestions for improvement.


Improving the efficiency of disease modifying drug provision
As part of MS Forward View, we looked at the DMD pathway in MS and investigated how capacity may be created in this area of MS care. This report provides a detailed explanation of the current workload associated with DMDs and how this impacts MS teams, models how this workload may develop in future and where capacity may be freed up in this pathway. 
Improving services for people with advanced MS
Another area of MS services we looked at as part of MS Forward View was care for people with advanced MS. Recently, concerns have arisen that this was an aspect of care that was often difficult for teams to fully implement as demands on MS services in general continue to rise. This report outlines the findings of our work on this area, and our recommendations for how services can better meet the needs of people with advanced MS.  


Other resources you may find useful
We hope you find these resources useful, let us know if you have feedback on any of them – we're keen to hear what you think.   
All the best, 
Health Professionals Programme Team  
Multiple Sclerosis Trust
Spirella Building, Bridge Road, Letchworth Garden City, Hertfordshire, SG6 4ET
Phone: 01462 476700  |  Email: info@mstrust.org.uk