Author: Gavin Giovannoni

What is happening to my cortex?

A very common analogy is the comparison of MS to an iceberg. Why?

Only one-eighth of an iceberg is visible above the water; to see what is below the water line requires specialised technology. The MS iceberg analogy refers to several observations:

1. For each clinical relapse, 10 or more MRI visible lesions are seen on MRI.
2. For each visible white matter lesions on MRI, there are at least an equivalent number or more grey matter lesions. In fact, it is now estimated that more than half the MS pathology is in the grey matter.
3. For every visible white matter lesion, either on MRI or with the naked eye, there are 20 or more microscopic lesions present in the white matter.
4. Despite only a relatively small amount of brain or spinal cord atrophy, there is almost three times as much neuronal loss underlying the atrophy.
5. Despite a relatively good recovery of function in a particular pathway, for example, after a relapse, there is a substantial loss of axons and hence reserve capacity in that pathway.
6. People with MS have many more hidden symptoms and disabilities than visible physical disabilities; early MS is often a hidden disease.

When you use newer technologies, for example, a 7 Tesla MRI to look at cortical or grey matter lesions in MS you begin to see how large the iceberg really is. Please remember the vast majority of cortical MS lesions (>90%) or not seen with conventional MRI. The bad news in the study below is that almost all the pwMS studied had cortical lesions and these, not surprisingly, correlated with disability and cognitive impairment. What is interesting is that the lesions on the surface of the brain (subpial), but not those on the grey-white matter interface (leukocortical), correlated better with cortical volume. However, the grey-white matter interface, or leukocortical, lesions correlated most strongly with cognitive impairment.  

What is becoming increasingly important is to try and target the grey matter pathology and prevent cognitive impairment in pwMS. The problem is we don’t routinely monitor brain and in particular grey matter atrophy in routine clinical practice; in fact it is largely ignored. If we did we would probably find many more pwMS opting for the higher efficacy treatments that have the greatest impact on brain atrophy (alemtuzumab and HSCT).

It is important for you to realise that you can be NEDA-3, i.e. no clinical attacks and MRI activity, and still have progressive grey matter atrophy. Why this is happening is debatable. Some evidence points to immunoglobulins and complement activation, rather than cytotoxic T-cells, being the major driver of cortical pathology. This why Barts-MS is exploring add-on drugs that will hopefully target the B-cell follicles and plasma cells within the central nervous system to try and slow down this process. We plan to start recruiting for our add-on study later this year.

I have little doubt that slowing down and preventing progressive brain and grey matter atrophy will become one of the treatment targets for the next generation of MSologists. To make this a reality we need to have tools to measure these processes reliably in clinical practice.

Harrison et al. Association of Cortical Lesion Burden on 7-T Magnetic Resonance Imaging With Cognition and Disability in Multiple Sclerosis. JAMA Neurol. 2015 Jul 20. doi: 10.1001/jamaneurol.2015.1241.

IMPORTANCE: Cortical lesions (CLs) contribute to physical and cognitive disability in multiple sclerosis (MS). Accurate methods for visualization of CLs are necessary for future clinical studies and therapeutic trials in MS.

OBJECTIVE: To evaluate the clinical relevance of measures of CL burden derived from high-field magnetic resonance imaging (MRI) in MS.

DESIGN, SETTING, AND PARTICIPANTS: An observational clinical imaging study was conducted at an academic MS center. Participants included 36 individuals with MS (30 relapsing-remitting, 6 secondary or primary progressive) and 15 healthy individuals serving as controls. The study was conducted from March 10, 2010, to November 23, 2012, and analysis was performed from June 1, 2011, to September 30, 2014. Seven-Tesla MRI of the brain was performed with 0.5-mm isotropic resolution magnetization-prepared rapid acquisition gradient echo (MPRAGE) and whole-brain, 3-dimensional, 1.0-mm isotropic resolution magnetization-prepared, fluid-attenuated inversion recovery (MPFLAIR). Cortical lesions, seen as hypointensities on MPRAGE, were manually segmented. Lesions were classified as leukocortical, intracortical, or subpial. Images were segmented using the Lesion-TOADS (Topology-Preserving Anatomical Segmentation) algorithm, and brain structure volumes and white matter (WM) lesion volume were reported. Volumes were normalized to intracranial volume.

MAIN OUTCOMES AND MEASURES: Physical disability was measured by the Expanded Disability Status Scale (EDSS). Cognitive disability was measured with the Minimal Assessment of Cognitive Function in MS battery.

RESULTS: Cortical lesions were noted in 35 of 36 participants (97%), with a median of 16 lesions per participant (range, 0-99). Leukocortical lesion volume correlated with WM lesion volume (ρ = 0.50; P = .003) but not with cortical volume; subpial lesion volume inversely correlated with cortical volume (ρ = -0.36; P = .04) but not with WM lesion volume. Total CL count and volume, measured as median (range), were significantly increased in participants with EDSS scores of 5.0 or more vs those with scores less than 5.0 (count: 29 [11-99] vs 13 [0-51]; volume: 2.81 × 10-4 [1.30 × 10-4 to 7.90 × 10-4] vs 1.50 × 10-4 [0 to 1.01 × 10-3]) and in cognitively impaired vs unimpaired individuals (count: 21 [0-99] vs 13 [1-54]; volume: 3.51 × 10-4 [0 to 1.01 × 10-4] vs 1.19 × 10-4 [0 to 7.17 × 10-4]). Cortical lesion volume correlated with EDSS scores more robustly than did WM lesion volume (ρ = 0.59 vs 0.36). Increasing log[CL volume] conferred a 3-fold increase in the odds of cognitive impairment (odds ratio [OR], 3.36; 95% CI, 1.07-10.59; P = .04) after adjustment for age and sex and a 14-fold increase in odds after adjustment for WM lesion volume and atrophy (OR, 14.26; 95% CI, 1.06-192.37; P = .045). Leukocortical lesions had the greatest effect on cognition (OR for log [leukocortical lesion volume], 9.65; 95% CI, 1.70-54.59, P = .01).

CONCLUSIONS AND RELEVANCE: This study provides in vivo evidence that CLs are associated with cognitive and physical disability in MS and that leukocortical and subpial lesion subtypes have differing clinical relevance. Quantitative assessments of CL burden on high-field MRI may further our understanding of the development of disability and progression in MS and lead to more effective treatments.

CoI: multiple

Barts-MS Hangout

The following are the results of our recent survey about doing a regular hangout for our readers. Based on these results the MouseDoctor and I will be doing a live hang-out together on Wednesday night, 23rd January 2019 from 17h30 to 18h00.

The live hangout will accessible via this link and will be recorded to YouTube so you can watch it later.

We are still mulling over the final topics that we will cover. See you on Wednesday and please don’t be shy to make additional suggestions.

To T or not to T (2)

Prof G what happens to MS disease activity if you stimulate T-cells?

About 2 years ago I attended a grand round during which a patient with a history of RRMS had had a catastrophic relapse after receiving ipilimumab for metastatic melanoma. The patient has a massive brain stem relapse and her MRI showed multiple Gd-enhancing lesions with several pseudotumoral lesions. She was in a bad way. Interestingly, this case was not unique as a very similar case had been published. In addition, there are series of other examples of ipilimumab and other immune checkpoint inhibitors exacerbating and/or triggering autoimmune diseases including an MS-like disease. I say MS-like because we don’t know for sure if these cases will turn out to have classic MS on biopsy, or at post-mortem, to prove they have definite MS according to a conventional definition of the disease.

Ipilimumab belongs to the class of drugs called ‘checkpoint inhibitors’ that are designed to remove one of the immunological brakes that control T-cell activation. Ipilimumab is one of many T-cell stimulants that have revolutionised the care of patients with various different cancers. Ipilimumab is a very smart drug it blocks CTLA-4, a cell surface molecule on T cells, which normally blocks or downregulates T cell activation when it binds to CD80 and CD86 on antigen-presenting cells. Ipilimumab enhances the anti-tumoral response while increasing the likelihood of autoimmunity.

So what has this really got to do with MS? Well, these cases are telling us in a not so subtle way that by stimulating T-cells we can exacerbate MS. In other words, T-cells are probably still active in established MS. What this experiment is not telling us is which population of T-cells is the culprit as CD4+, CD8+ and T-regulatory cells express CTLA-4 and are hence affected by Ipilimumab. Nor is it telling us about the APC side, which APC is stimulating the T-cells. Is it the B-cell, the macrophage/microglia or another APC?

The moral of this story is that it takes two to tango; the T-cell and its APC. The question is which APC is the preferred partner for the T-cell in MS. Based on the evidence the B-cell seems to be the dominant partner, but who knows in the presence of peripheral B-cell depletion other less dominant partners may take to the floor.

Gettings et al. Severe relapse in a multiple sclerosis patient associated with ipilimumab treatment of melanoma. Mult Scler. 2015 Apr;21(5):670.

56-year-old male, diagnosed in December 1997 with RRMS. Treated with glatiramer acetate in February 1998. Relatively good response to GA with only sensory relapses. In 2005 methotrexate was added. His MS stabilized and he was free of relapses from 2005 to 2013 with a slight increase in disability from an Expanded Disability Status Scale (EDSS) score of 1 to 1.5. In September 2009 diagnosed with melanoma. He had a recurrence in November 2012 with metastases to soft tissue and lymph nodes. He was started on ipilimumab. Methotrexate and glatiramer acetate were stopped prior to initiating ipilimumab. Within one month, he presented with subacute onset of left lower extremity hemiparesis, gait dysfunction and ataxia. An MRI revealed a new left centrum semiovale enhancing lesion consistent with active demyelination. His symptoms improved with high dose methylprednisolone. Ipilimumab was continued. In May 2013 he was readmitted for transient left-sided weakness and ataxia. MRI revealed an enhancing lesion in the right corona radiata. Follow-up imaging revealed a second enhancing lesion in the right frontal lobe and he was restarted on glatiramer acetate and steroids.

To T or not to T

I have always wondered why the genomic experts in the field of MS haven’t been able to sort out why specific human leukocyte antigen (HLA) subtypes increase your risk of getting MS and others don’t.



HLA or human leukocyte antigens are the so-called signposting proteins that antigen presenting cells (APCs) use to communicate with T-cells. The APCs continuously sample the environment and present small peptides in their HLA molecules to T-cells. The HLA molecules interact with the so-called T-cell receptor (TCR) and if the peptide (message) that has been loaded in the HLA groove (signpost) and TCR, which acts as a molecular reader, fit perfectly it tells the T-cell that it should go on the attack. In the context of MS, this attack is considered to autoimmune or dysfunctional and against a self-peptide. However, the attack could be entirely appropriate and targeted against a foreign protein or a self-protein that has been altered by a process called post-translational modification. Interestingly, smoking and solvents, exposure to which are both risk factors for developing MS, are two environmental exposures that are known to cause post-translational modifications of proteins.

The following YouTube animation shows you an example of how a TCR (reader) interacts with a specific HLA molecule (signpost) and the peptide (message) in the groove of a specific HLA molecule. By watching this video you may appreciate how specific this interaction really is.

The most important genetic risk factor for deevloping MS is the so-called HLA-DRB1*15:01 molecules. If you have one copy of this gene your risk of getting MS is ~3X greater than someone without this gene. If you have two copies your risk of getting MS is about ~6X greater. In other words from a genetic perspective, you don’t want to have the HLA-DRB1*15:01 signposts.

It turns out that there, not all HLA-DRB1*15:01 molecules are made equal and that if you have the African variety, compared to the European variety, your risk of getting MS is 3x lower. Interestingly, the African and European varieties of the HLA-DRB1*15:01 genes differ in their sequence in a way that would affect the so-called peptide binding groove of the HLA molecule. This would mean that they would bind peptides differently and hence affect the way that T-cells may or may not be activated. How interesting?

The African variety of HLA-DRB1*15:01 is presumably older and the genetic change in HLA-DRB1*15:01 that is now known as the European variant must have been selected for after man left Africa and migrated into Europe. The most likely evolutionary selection pressure for this selection was repeated exposure to an infection, which selected for this variant, with the later consequence of being an increased risk of getting MS.

What is the significance of these findings? It is telling us that MS risk is related to a very specific HLA-DRB1*15:01 variant and this variant, by definition, must be interacting with a specific family of peptides or possibly a single peptide in our environment or body. Wouldn’t it be great if we could find this peptide or family of peptides? It could potentially lead us to the cause of MS.

It is important to realise that the HLA-DRB1*15:01 association with MS, and these new findings in relation to the African and European variants, is telling us that the T-cell must be the central player, or conductor, in the pathogenesis of MS and must be upstream of the B-cell. I have mulled over this for many years and I can’t think of another way of interpreting these results. Do you agree?

Chic et al. Admixture mapping reveals evidence of differential multiple sclerosis risk by genetic ancestry. PLoS Genet. 2019 Jan 17;15(1):e1007808. doi: 10.1371/journal.pgen.1007808.

Multiple sclerosis (MS) is an autoimmune disease with high prevalence among populations of northern European ancestry. Past studies have shown that exposure to ultraviolet radiation could explain the difference in MS prevalence across the globe. In this study, we investigate whether the difference in MS prevalence could be explained by European genetic risk factors. We characterized the ancestry of MS-associated alleles using RFMix, a conditional random field parameterized by random forests, to estimate their local ancestry in the largest assembled admixed population to date, with 3,692 African Americans, 4,915 Asian Americans, and 3,777 Hispanics. The majority of MS-associated human leukocyte antigen (HLA) alleles, including the prominent HLA-DRB1*15:01 risk allele, exhibited cosmopolitan ancestry. Ancestry-specific MS-associated HLA alleles were also identified. Analysis of the HLA-DRB1*15:01 risk allele in African Americans revealed that alleles on the European haplotype conferred three times the disease risk compared to those on the African haplotype. Furthermore, we found evidence that the European and African HLA-DRB1*15:01 alleles exhibit single nucleotide polymorphism (SNP) differences in regions encoding the HLA-DRB1 antigen-binding heterodimer. Additional evidence for increased risk of MS conferred by the European haplotype were found for HLA-B*07:02 and HLA-A*03:01 in African Americans. Most of the 200 non-HLA MS SNPs previously established in European populations were not significantly associated with MS in admixed populations, nor were they ancestrally more European in cases compared to controls. Lastly, a genome-wide search of association between European ancestry and MS revealed a region of interest close to the ZNF596 gene on chromosome 8 in Hispanics; cases had a significantly higher proportion of European ancestry compared to controls. In conclusion, our study established that the genetic ancestry of MS-associated alleles is complex and implicated that difference in MS prevalence could be explained by the ancestry of MS-associated alleles.

To B or not to B

Is targeting the B-cell sufficient to get on top of MS or do we need something extra?

I spoke at the MS Nurses’ MS@TheLimits2019 meeting at the Royal College of Physicians yesterday. My brief was to cover the role of B-cells in the pathogenesis of MS and to review the converging evidence that supports B-cells being the central player in the pathogenesis of MS.

It is clear that depleting B-cell therapies are very effective in controlling relapses and MRI activity. With a very favourable safety profile and relatively low treatment and monitoring burden, B cell therapies are likely to become one of the most widely prescribed classes of DMT. However, B-cell therapies don’t match HSCT, alemtuzumab and natalizumab when it comes to downstream end-organ damage markers, in particular, brain volume loss. Why? I wish I knew. But if I knew the answer to this question I would have a pretty good idea about the cause of MS.

A clue may be in the ‘Field Hypothesis‘. It is clear to me that relapses and focal MRI activity are not the primary events in MS. Focal inflammation is not MS. Focal inflammation is in response to what is causing MS and the cause is likely to be something in the CNS. Focal changes occur in the white matter weeks to months before you get a Gd-enhancing lesion. When you stop natalizumab and allow re-trafficking of lymphocytes you get rebound disease activity way and above what one would expect from pre-treatment baseline levels of disease activity. What is happening in the brain, or field, of these patients to trigger such a vigorous inflammatory response? Could it be a virus? Importantly, B-cells appear to be needed for the rebound response. Rituximab, and I suspect ocrelizumab, are very effective in preventing rebound. However, as both these agents target a small subset of T-cells you can’t claim categorically that the rebound is only driven by B-cells.

The difference between HSCT, alemtuzumab and natalizumab and the anti-B cell therapies (rituximab, ocrelizumab and possibly cladribine) is the former take out or inhibit trafficking of both T & B cells. As HSCT and Alemtuzumab have the best data in relation to long-term remission, or potential cures, you have to conclude that you need to target both B cell and T cells (substantial peripheral depletion) if this is your treatment aim.

Please note that I classify cladribine as a B-cell depelter and not a dual B and T cell depelter. The level of T-cell depletion with cladribine is modest at the licensed dose (~50%) which is not sufficient to put it into the same class as alemtuzumab and HSCT. This is one of the reasons why I refer to cladribine as being a SIRT (selective immune reconstitution therapy) and the others as NIRTs (non-selective immune reconstitution therapies).

I have always made the point that to treat MS you need much more than an anti-inflammatory and that you also have to have neuroprotective therapies and potentially remyelinating agents on board as well. If you have disabilities we need to be thinking about neurorestorative therapies and finally you need to target lifestyle and wellness to tackle the issue of comorbidities and ageing.

So in short, targeting B-cells is important, but not sufficient to get on top of the shredder.

You will see that a large part of my talk was covering the link between EBV, B–cells and MS. The B-cell hypothesis at least strengthens the case for EBV being the cause of MS and the need for an EBV vaccine for MS prevention trials. Please don’t forget that EBV lives inside memory B cells and hijacks the B cell’s biology in many ways that have potential relevance to MS and other autoimmune diseases.

My talk will be available online in a few weeks to help you interpret my presentation. In the interim you can download my talk from my slide sharing site.

The next generation

Training the next generation of MSologists is one of my priorities.

I helped arrange and teach on the Pan-London Calman Specialist Registrar (SpR) teaching day yesterday. It was great to see so many young trainee neurologists attending; thank you. And to the speakers for giving up their time to teach and inspire the next generation of neurologists to become MSologists; thank you.

I hope you all enjoyed the day the following is the programme.

Neuro-Calman-MS-programme-16th-Jan-2019-gg3

I was impressed by the level of engagement of the audience. I was particularly happy with an insight from one of the trainees who suggested we should be managing MS they way rheumatologists manage RA; i.e. early and aggressively. This was music to my ears. I have been pushing the treat-2-target RA paradigm for MS for several years now. The only difference is that our treatment targets have gradually become more ambitious as we have moved from NEDA-1 (relapses) to NEDA-3 (MRI activity) to preventing end-organ damage as measured with MRI (normalising the rate of brain volume loss or NEDA-4) and normalising CSF and blood neurofilament levels (NEDA-5) and beyond. What I mean by beyond is that our ultimate aim is to cure people of having MS and to allow them to get to old age with as much brain as possible. Is this too ambitious?

The following is my presentation from yesterday that can be downloaded from my slideshare site.

At the end of my session, we got into a lively debate about whether or not everyone with MS needs to be treated. Obviously not, based on my presentation only people with active MS are eligible for treatment. Those who have inactive MS cannot be treated under current NHS England guidelines and if they remain inactive they will hopefully end-up having benign MS. Surely the aim of our treatments is to convert everyone with MS into having inactive MS that will hopefully turn out to be benign MS after 25-30 years of follow-up. What we did not cover in this mini-debate is what is active MS? Should it include smouldering MS?

If any of the trainees are reading this post can I please recommend that you read the following posts I have recently done and to bookmark my MS-Selfie site that is still under development.

Posts of potential interest:

  1. Why do MSers get worse despite being NEDA?
  2. Can we cure MS?
  3. Sequential therapies
  4. MS-relatedd fatigue
  5. Food Coma
  6. What the eye doesn’t see?
  7. MMR: to test or not to test?
  8. Radiologically isolated syndrome

Food coma: does it affect you?

This post explains why eating may exacerbate MS-related fatigue and what you can do to counteract it.

Do you suffer from food coma or excessive sleepiness and fatigue after eating a meal?

For ‘normal people’, we call this phenomenon postprandial somnolence or the siesta syndrome. Others refer to it as the ‘food coma’. It is my anecdotal experience that people with MS, in particular, people with more advanced MS, are particularly sensitive to postprandial sleepiness and fatigue. Why?

Postprandial somnolence (PPS) is a normal state of drowsiness or lassitude following a meal. PPS is a real phenomenon and has two components: (1) a state of perceived low energy related to activation of the parasympathetic nervous system in response to expansion of the stomach and duodenum from a meal. In general, the parasympathetic system slows everything down.  (2) A specific state of sleepiness, which is triggered by the hormone cholecystokinin (CCK) that is released in response to eating and changes in the firing and activation of specific brain regions. The reflexes responsible for PPS are referred to as neurohormonal modulation of sleep through the coupling of digestion and the brain. The signals from the gut to the brain travel via the vagus nerve.

My index patient is so affected by PPS that she now only eats one meal a day; her evening meal. She does this quite late so that she can crash and sleep about an hour after eating. She is a professional and needs to be functional during the day and finds if she eats anything substantial in the day she simply can’t work because of her overwhelming desire to sleep. We have tried caffeine, modafinil and amantadine to counteract PPS, but they only had a small effect in counteracting her PPS and allowing her to work productivel. Other patients reporting this have noticed some benefit from stimulants. Interestingly, my index patient, like a few others, finds carbohydrate-rich foods particularly potent at inducing ‘food coma’

Physiologists think that not all foodstuffs are made equal when it comes to causing PPS and it appears that glucose, or sugar, induced insulin is one of the drivers of this behavioural response. I suspect this why people who fast or eat very low carbohydrate or ketogenic diets describe heightened alertness and an ability to concentrate for much longer periods of time.

The reason for doing this post is to find out how common PPS is in the MS population and to give you some simple advice to counteract it. If you suffer from PPS can I suggest you review your diet and see if you identify ways to modify your eating habits and/or diets to coounteract PPS?

  1. You could adopt the above extreme solution and only eat one meal per day. Clearly, this not for everyone and is very difficult to implement. I say this, but many of my Muslim patients report feeling so much better during Ramadan when they essentially practice this type of eating pattern.
  2. You could reduce your meal size and cut out any carbohydrates from your daytime meals. You may find this difficult because it takes time for your metabolism to become optimised for ketosis. If any of you are interested in the science of ketosis I have written a Medium post on ketogenic and low-carbohydrate diets.
  3. Some of my patients find micro-meals helpful, i.e. instead of large meals you eat multiple small snacks during the day.
  4. The judicious use of stimulants. I tend to recommend caffeine, followed by modafinil and them amantadine. Please note you should probably not take stimulants later than about 3-4 pm as they have a long half-life and can cause insomnia.
  5. Some of my patients have also reported that exercise has helped them deal with PPS. I am not sure how exercise works except by possibly lowering glucose and insulin levels and improving insulin sensitivity. The latter will reduce hyperinsulinaemia that will not only cause PPS, but is an impotant driver and component of the metabolic syndrome.

Please note that PPS will be worse if you suffer from a sleep disorder and suffer from daytime sleepiness. Most pwMS have a sleep disorder so there is little point in focusing on PPS and ignoring the elephant in the room.

If you have a few minutes to spare can you please complete this survey and let us know if you come across any other effective treatments to manage your PPS.

Smouldering MS: does it exist?

… by taking an MRI-centric view of MS we may have lulled ourselves into a false sense of security. … an MRI worldview of MS has framed, and continues to frame, our perspective of MS and has created a cognitive bias.

I have recently posted on why you can have MS and have a normal MRI or a very low lesion load. I made the point that MS is a biological disease and not an MRIscopic disease, i.e. what you see on MRI is the tip of the tip of the iceberg and that most of MS pathology is hidden from view with conventional MRI. To capture this pathology we need to use unconventional imaging techniques or look at end-organ damage markers, i.e. whole brain, or preferably grey matter, volume loss or atrophy. Another option is serial CSF or possibly peripheral blood neurofilament levels. At least the end-organ damage markers will capture the end-result of MS pathology; the loss of neurones and axons.

In another recent blog post, I explained how someone with MS can still be deteriorating despite being NEDA (no evident disease activity). The NEDA here is referring to focal MS inflammatory activity, i.e. relapse(s) and new or enlarging lesions on MRI. The biology behind this worsening despite being NEDA could be driven by the delayed neuroaxonal loss from previous damage, ongoing diffuse inflammation which has become independent of focal lesions (innate activation), ageing mechanisms or focal inflammatory lesions that are too small to be detected with our monitoring tools. Of all the processes listed here, the last one is the only one that is modifiable by our current DMTs. Therefore I think we should reserve the term smouldering MS to this process, i.e. one that is modifiable by current DMTs.

The really important question this raises is when you treat someone a DMT and they become NEDA how do you know they don’t have smouldering MS and would benefit from being escalated to a more effective DMT? One commentator asked specifically about cladribine.

‘If a patient was treated with cladribine and was rendered relapse and MRI activity free how can we be sure that this patient did not have smouldering MS?’

This is why we need to start using end-organ damage markers and more sensitive inflammatory markers to look for and define smouldering MS. We may then be able to answer this question. However, this won’t necessarily tell us if escalating people with smouldering MS to more effective DMTs, for example, natalizumab, alemtuzumab or ocrelizumab will result in them doing better than them simply waiting for their smouldering MS to become overtly active MS before making a switch in their treatment.

A point has been made that primary progressive MS (PPMS) is simply smouldering RRMS and that all we are doing with our DMTs is converting people with RRMS to PPMS and delaying the inevitable progressive phase of the disease.  I don’t buy this because a proportion of pwMS who have been treated early on with an immune reconstitution therapy or IRT in particular with alemtuzumab or HSCT appear to be in very longterm remission and may even be cured of their MS (please read my previous post on this topic). Some would argue, I included, that this group of patients has not been followed up for long enough to be sure they have been cured. I agree with you and this is why I have proposed doing a deep phenotyping study to assess whether or not these patients have any evidence of ongoing MS disease activity. This study would help define smouldering MS, by looking for its absence.

What this post is telling me is that by taking an MRI-centric view of MS we may have lulled ourselves into a false sense of security. In other words, an MRI worldview of MS has framed, and continues to frame, our perspective of MS and has created a cognitive bias. Dare I call it an MRIscopic bias?