Immunosuppression in ME may underlie energy deficits that drive ME symptomology

Interview of Dr. Armin Alaedini by Bronc

In October of 2023 the UK the Department of Health and Social Care held a public consultation to improve the care/life outcomes for people with ME. It included an acknowledgement that there has been a lack of biomedical research into ME but failed to accept the very negative impact this has had on the lives of people living with the illness. It also failed to point the finger at those responsible for this which includes the National Institute of Clinical Excellence and the Medical Research Council amongst others.

Despite calling for more research into ME there is acknowledgement that this will need substantial sums of money for this to happen. The DHSC consultation also asked for views about its plans which included a section about disability benefits and how the Department of Work and Pensions wants to improve the service it provides to those people who claim disability benefits. This laughable comment ignores the war on people claiming disability benefits which has been waged by the DWP since 2010. To compound matters the British government recently announced that it wants to make it harder for people to claim disability benefits and snoop on their bank accounts.

The DWP has consistently failed to acknowledge the debilitating nature of ME and instead focuses on the fluctuating nature of the illness to deny many people with ME disability benefits such as ESA and PIP.

Thankfully, there is plenty of evidence revealing how people with ME suffer from a suppressed immune response which accounts for many of the debilitating symptoms of the illness.

I recently talked with Dr. Armin Alaedini about his recent research into this issue. Dr Alaedini is an assistant professor at Columbia University and principal investigator at the Alaedini Lab. Its research is aimed at identifying ‘novel biomarkers, understanding disease mechanism, and finding therapeutic targets in gastrointestinal and neuropsychiatric disease.’ He is chair of ME/CFS Biospecimen Resource Access Committee at the National Institute of Neurological Disorders and Stroke and a member of the Neurobiology of Pain Study Section at NIH.

Dr Alaedini took time out of his busy schedule to talk to me about his research into ME.

How did you get involved in the field of ME research?

I have always been interested in the study of complex medical conditions, especially those that are poorly understood and understudied. I became specifically involved in ME research because of my acquaintance with Dr. Suzanne Vernon, who at that time was the chief scientific officer at The Solve ME/CFS Initiative. I was fortunate to have her support for a NIH-funded project, which resulted in our recent publication that demonstrates how microbial translocation links gastrointestinal, immunologic, and metabolic defects in ME/CFS.

In the paper you co-authored, Suppressed immune and metabolic responses to intestinal damage-associated microbial translocation in myalgic encephalomyelitis/chronic fatigue syndrome, it notes that the relationship between immunologic, metabolic and gastrointestinal abnormalities remains unclear. In your study you examined two groups of people with ME: one at rest and one undergoing an exercise challenge. They were compared to a group of healthy people. Can you explain what differences you noted between the healthy control group and the people with ME and between the two groups of people with ME? What may have caused this elevated antibody response to microbial agents in people with ME?

I had been particularly intrigued by the fact that gastrointestinal complaints are common in ME/CFS. Data from the patients in our study clearly confirmed this, showing that gastrointestinal symptoms were indeed much more common and more severe in ME/CFS study participants than in the non-ME/CFS controls. Along with this, we found a specific marker of injury or damage to the intestinal lining, called FABP2, to be higher in the blood of ME/CFS participants than in controls, providing a potential biological link to least some of the associated gastrointestinal symptoms. Increased intestinal permeability due to damage can lead to greater translocation of dietary and microbial antigens, which are typically constrained within the gut lumen, across the intestinal barrier. This, in turn, may result in an immune response to those translocated dietary and microbial products to counter and remove the potentially inflammatory antigens from systemic circulation.

Indeed, our data pointed to a significant increase in antibody responses to microbial and dietary antigens in ME/CFS patients in comparison to controls. What especially surprised us, however, was the fact that we did not observe an expected rise in the more immediate, or what we call “acute-phase”, innate immune responses. Specifically, we found that despite the increased markers of intestinal damage and higher antibody responses, ME/CFS patients did not exhibit a significant acute-phase immune response to counter circulating microbial products. This was suggestive of a suppressed systemic immune response that could possibly explain some of the ME/CFS symptoms.

Your study also noted ‘Enhanced antibody response to dietary antigens in ME/CFS’. What might be causing this?

The antibody response to dietary antigens is likely part of the same process resulting from a dysfunctional intestinal barrier that results in an enhanced immune response to the contents of the gut lumen. These would include both microbial and dietary antigens that the immune system is generally tolerant to and does not mount a significant antibody response against under normal conditions.

People with ME suffer from post exertion malaise which means that exercise will exacerbate their symptoms. What differences did you note between the healthy participants and people with ME who took the exercise challenge? What might be causing the differences in their response to exercise?

Intense exercise is known to cause increased intestinal permeability. Therefore, a maximal exercise challenge can be a particularly useful tool to better understand the effect of gut barrier function on the dysfunctional immune responses we were seeing in the ME/CFS cohort. The data from the exercise challenge confirmed our earlier data, suggesting that ME/CFS patients have a dysfunctional immune response, characterized by a suppressed innate/acute-phase response that is ineffective at countering microbial translocation from the intestinal tract into systemic circulation.

At the same time, another part of the immune response, the adaptive immune system, tries to compensate for this dysfunction by producing antibodies against those microbial antigens. However, the antibody response appears to be inadequate, as the ME/CFS patients continued to have increased circulating microbial antigens. We hypothesize that these microbial antigens can trigger downstream inflammatory responses that impact the central nervous system and may contribute to some of the hallmark symptoms of ME/CFS, such as fatigue.

We also compared metabolic responses in response to exercise between ME/CFS and control study participants. Of particular significance, we found a suppression of glucose and citrate metabolic responses in ME/CFS that to some extent correlated with the suppressed innate immune responses in these patients. This dysfunctional metabolic response is not only conceivably capable of contributing to the observed immunosuppression in ME/CFS, but it may also further underlie energy deficits that drive ME/CFS symptomology.

In your study you observed an increase in antibody responses to both microbial and dietary antigens, reflecting greater epithelial cell damage, which point to enhanced translocation of gut luminal antigens across a compromised intestinal barrier in ME/CFS. Did your findings point to a possible treatment for this damage to the intestinal barrier?

Indeed, the data point to a number of potential targets to consider for therapy in the context of ME/CFS. These include reducing or repairing the intestinal damage in order to decrease the microbial translocation; blocking or sequestering the already translocated microbial antigens; reversing the identified defects in the acute-phase immune responses towards the microbial antigens, and targeting the suppressed metabolic pathways.

What further research is needed to address the issues highlighted in your study?

More research is needed to better understand the relevance and level of contribution of the identified defects in the intestinal barrier, immune response, and metabolic pathways to ME/CFS symptomology, as well as to further characterize the molecular pathways involved, in order to move this research closer to development of effective treatments for ME/CFS.

Post-exertional malaise in daily life and experimental exercise models in patients with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Post-exertional malaise (PEM) is commonly recognized as a hallmark of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and is often used as one of several criteria for diagnosing ME/CFS.

In this perspective paper we want to reflect on how PEM is understood, assessed, and evaluated in scientific literature, and to identify topics to be addressed in future research.

Studies show that patients use a wide variety of words and concepts to label their experience of PEM in everyday life, and they report physical or mental exertions as triggers of PEM. They also report that PEM may have an immediate or delayed onset and may last from a few days to several months.

When standardized exercise tests are used to trigger PEM experimentally, the exacerbation of symptoms has a more immediate onset but still shows a wide variability in duration.

There are indications of altered muscular metabolism and autonomic nervous responses if exercise is repeated on successive days in patients with ME/CFS. The decreased muscular capacity appears to be maintained over several days following such controlled exercise bouts. These responses may correspond to patients’ experiences of increased exertion.

Based on this background we argue that there is a need to look more closely into the processes occurring in the restitution period following exercise, as PEM reaches the peak in this phase.

Source: Nina K. Vøllestad, Anne Marit Mengshoel. Post-exertional malaise in daily life and experimental exercise models in patients with myalgic encephalomyelitis/chronic fatigue syndrome. Frontiers in Physiology, Volume 14- 2023. https://www.frontiersin.org/articles/10.3389/fphys.2023.1257557/abstract

Dry eye symptoms and signs in United States Gulf War era veterans with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Background: To examine ocular symptoms and signs of veterans with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) diagnosis, ME/CFS symptoms, and controls.

Methods: This was a prospective, cross-sectional study of 124 South Florida veterans in active duty during the Gulf War era. Participants were recruited at an ophthalmology clinic at the Miami Veterans Affairs Hospital and evaluated for a diagnosis of ME/CFS, or symptoms of ME/CFS (intermediate fatigue, IF) using the Canadian Consensus criteria. Ocular symptoms were assessed via standardised questionnaires and signs via comprehensive slit lamp examination. Inflammatory blood markers were analysed and compared across groups.

Results: Mean age was 55.1 ± 4.7 years, 88.7% identified as male, 58.1% as White, and 39.5% as Hispanic. Ocular symptoms were more severe in the ME/CFS (n = 32) and IF (n = 48) groups compared to controls (n = 44) across dry eye (DE; Ocular Surface Disease Index [OSDI]: 48.9 ± 22.3 vs. 38.8 ± 23.3 vs. 19.1 ± 17.8, p < 0.001; 5 item Dry Eye Questionnaire [DEQ-5]: 10.8 ± 3.9 vs. 10.0 ± 4.6 vs. 6.6 ± 4.2, p < 0.001) and pain-specific questionnaires (Numerical Rating Scale 1-10 [NRS] right now: 2.4 ± 2.8 vs. 2.4 ± 2.9 vs 0.9 ± 1.5; p = 0.007; Neuropathic Pain Symptom Inventory modified for the Eye [NPSI-E]: 23.0 ± 18.6 vs. 19.8 ± 19.1 vs. 6.5 ± 9.0, p < 0.001). Ocular surface parameters and blood markers of inflammation were generally similar across groups.

Conclusion: Individuals with ME/CFS report increased ocular pain but similar DE signs, suggesting that mechanisms beyond the ocular surface contribute to symptoms.

Source: Victor Sanchez BS, Colin K. Kim BS, Elyana V. T. Locatelli BS, Adam K. Cohen, Kimberly Cabrera MS, Kristina Aenlle PhD, Nancy G. Klimas MD, Robert O’Brien PhD, Anat Galor MD, MSPH. Dry eye symptoms and signs in United States Gulf War era veterans with myalgic encephalomyelitis/chronic fatigue syndrome. First published: 12 November 2023 https://doi.org/10.1111/ceo.14313 https://onlinelibrary.wiley.com/doi/10.1111/ceo.14313 (Full text)

Prevalence and Predictive Factors of Small Intestinal Bacterial Overgrowth in Patients With Chronic Fatigue Syndrome

Introduction: Chronic fatigue syndrome (CFS) is a poorly understood illness, characterized by fatigue and related symptoms including cognitive dysfunction, headaches, joint pains, and gastrointestinal distress. Irritable bowel syndrome (IBS) is common and present in approximately 60% patients with CFS while the prevalence of small intestinal bacterial overgrowth (SIBO) in IBS is approximately 40%. Our study aimed to 1) Determine the prevalence of SIBO in patients with CFS with and without IBS symptoms 2) Identify factors associated with increased risk of SIBO.

Methods: A retrospective chart review of 479 patients with CFS referred for hydrogen/methane breath testing. Clinical documentation was reviewed to identify positive breath test result diagnosing SIBO. Statistical analysis was conducted with 2-proportions z test and logistic regression analysis to identify predictive variables of SIBO diagnosis.

Results: 479 patients with CFS referred for glucose or lactulose breath testing were identified. Three hundred sixty-seven of those patients completed a breath test with available result: 152(41%) SIBO+ (mean age (SD) 50 (17)), 164(45%) SIBO- (mean age SD 46 (15)), and 78(21%) equivocal results. In CFS patients with conclusive breath test result, 48% tested positive for SIBO, and the diagnosis of IBS was present in 186/316 (59%). There was no difference in the prevalence of IBS between the SIBO+ vs SIBO-group [98/152 (64%) vs 88/164 (53%), P < 0.05]. Using multiple logistic regression analysis, age, unknown race, and IBS diagnosis all significantly predicted increased odds of having a positive breath test (Table 1). Conversely, PPI use was associated with decreased odds of a positive breath test. Due to the high prevalence of IBS in our cohort and the association between IBS and SIBO, an analysis was performed excluding patients with IBS diagnosis. When excluding patients with IBS, unknown race and TCA use were associated with increased odds of positive breath test, while diarrhea, hypothyroidism, PPI, and naltrexone use were associated with decreased odds (P< 0.05).

Conclusion: SIBO is highly prevalent in patients with CFS referred for breath testing. Older age and comorbid IBS diagnosis predict increased odds of positive breath test. Surprisingly, PPI use predicted decreased odds despite its prior implication as a possible risk factor for SIBO. Further studies are needed to explore the underlying mechanism causing the overlap between CFS, IBS and SIBO which may provide insights into potential therapies for CFS.

Source: Karhu, Elisa MD, MS; Neshatian, Leila MD, MS; Fass, Ofer MD; Sonu, Irene MD; Nguyen, Linda Anh MD. S1821 Prevalence and Predictive Factors of Small Intestinal Bacterial Overgrowth in Patients With Chronic Fatigue Syndrome. The American Journal of Gastroenterology 118(10S):p S1351-S1352, October 2023. | DOI: 10.14309/01.ajg.0000956924.26236.c4 https://journals.lww.com/ajg/fulltext/2023/10001/s1821_prevalence_and_predictive_factors_of_small.2162.aspx

An experimental study investigating the link between symptom reporting and heart rate variability in chronic fatigue syndrome patients

Abstract:

Our Master’s thesis falls within the research domain of Rehabilitation Sciences and Physiotherapy. In our study we investigated patients with chronic fatigue syndrome (CFS).

CFS is a complicated disorder of which the pathology is still poorly understood. Due to the significant prevalence, the socio-economic impact of the disorder is high. In addition to the physiological dysfunctions that are often reported in CFS literature, patients can also experience altered symptom perception. Patients for example show increased subjective responses to unpleasant somatic stimuli in comparison with healthy persons (Van den Houte et al., 2018). Therefore, this study project fits within the domain of pain, fatigue and somatically unexplained physical symptoms.

Despite a lot of articles reporting the role of altered symptom perception, they mainly focused on symptom perception in the lab. However, these laboratory measurements do not take day-to-day variability in symptoms into account.

We think that the lack of studies investigating the symptomatology in CFS patients via ecological momentary measurements is a gap in the literature. Therefore, in our study, we executed symptom assessments in the lab and in daily life.

In addition, we investigated the interactions between the reported symptoms and heart rate variability (HRV) in order to investigate, on a small scale, if psychological and physiological dysfunctions in patients do not work independently.

Extra information about the pathology of CFS is useful to all professionals in rehabilitation sciences and physical therapy who work with CFS patients. It will help professionals to understand the complex problem of CFS better and to tailor the care for these patients.

Our study is situated in a larger study project with the title “Identifying (psycho)physiology-based subgroups in chronic fatigue syndrome and their relevance for rehabilitation” and with study number S66452. The project is reimbursed by Fonds Wetenschappelijk Onderzoek. The project runs in collaboration with the Multidisciplinary Diagnostic Center of UZ Leuven, the Multidisciplinary Expertise Center Tumi Therapeutics, the Vlaams Instituut voor Biotechnologie KU Leuven Raes Lab and IMEC. All laboratory tasks were conducted in the University Hospital of Leuven.

The study is written in line with the central format. The study topics and research questions were determined in collaboration with Msc. Y. Dooms and Dr. Maaike Van Den Houte. Due to the fact that the study was a component of an ongoing research project, we were not involved in decisions about research design or methodology.

We carried out the academic writing procedure concerning this Master’s thesis. During the writing procedure, we received input from Msc. Y. Dooms. The thesis was written in close cooperation amongst both of us. We both independently contributed to the thesis, reviewed it, and wrote multiple sections together. The data-analysis was done in collaboration with Dr. Maaike Van Den Houte.

Source: Jentro Dest and Daan Grosemans.An experimental study investigating the link between symptom reporting and heart rate variability in chronic fatigue syndrome patients. Master Thesis [University of Hasselt] https://documentserver.uhasselt.be/bitstream/1942/41042/1/1b9fa48e-2513-4665-8ba1-a6b1eb7f2056.pdf (Full text)

The Potential Role of Ocular and Otolaryngological Mucus Proteins in Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating illness associated with a constellation of other symptoms. While the most common symptom is unrelenting fatigue, many individuals also report suffering from rhinitis, dry eyes and a sore throat.

Mucin proteins are responsible for contributing to the formation of mucosal membranes throughout the body. These mucosal pathways contribute to the body’s defense mechanisms involving pathogenic onset. When compromised by pathogens the epithelium releases numerous cytokines and enters a prolonged state of inflammation to eradicate any particular infection.

Based on genetic analysis, and computational theory and modeling we hypothesize that mucin protein dysfunction may contribute to ME/CFS symptoms due to the inability to form adequate mucosal layers throughout the body, especially in the ocular and otolaryngological pathways leading to low grade chronic inflammation and the exacerbation of symptoms.

Source: Kaylin Huitsing, Tara Tritsch, Francisco J. Carrera Arias et al. The Potential Role of Ocular and Otolaryngological Mucus Proteins in Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome, 24 July 2023, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-3171709/v1] https://www.researchsquare.com/article/rs-3171709/v1 (Full text)

 

Characterizing Sjögren-Associated Fatigue: A Distinct Phenotype from ME/CFS

Abstract:

Fatigue is the most commonly reported and debilitating extraglandular symptom of primary Sjögren′s syndrome (pSS). Fatigue and exertional intolerance are hallmark symptoms of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). We aimed to characterize fatigue and further symptoms among pSS patients and to determine whether there is a symptom overlap in pSS and ME/CFS.
In 19 patients with pSS, we assessed pSS symptom severity and disease activity via questionnaires as well as the Canadian Consensus Criteria (CCC) for ME/CFS. Hand grip strength (HGS) and levels of α1-, α2-, β1-, β2-, M3- and M4-receptor-autoantibodies were measured. A subgroup of pSS patients exhibited severe fatigue and had higher severity of pain (p = 0.045), depression (p = 0.021) and sleep disturbances (p = 0.020) compared to those with less fatigue.
Four of eighteen pSS patients fulfilled the CCC. HGS parameters strongly correlated with fatigue severity (p < 0.05), but strength fully recovered one hour after exertion in contrast to ME/CFS. Levels of β1-, β2- and M4-receptor-autoantibodies were elevated and correlated significantly with disease activity assessed by the ESSDAI (p < 0.05), but not fatigue severity.
Only a minor subgroup of pSS patients fulfills the CCC, and post exertional malaise (PEM) is atypical, as it is primarily triggered by mental/emotional but not physical exertion. HGS assessment is an objective measure to assess overall fatigue severity.
Source: Kim L, Kedor C, Buttgereit F, Heidecke H, Schaumburg D, Scheibenbogen C. Characterizing Sjögren-Associated Fatigue: A Distinct Phenotype from ME/CFS. Journal of Clinical Medicine. 2023; 12(15):4994. https://doi.org/10.3390/jcm12154994 https://www.mdpi.com/2077-0383/12/15/4994 (Full text)

Association analysis between symptomology and herpesvirus IgG antibody concentrations in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis (MS) are two complex and multifactorial diseases whose patients experience persistent fatigue, cognitive impairment, among other shared symptoms. The onset of these diseases has also been linked to acute herpesvirus infections or their reactivations.

In this work, we re-analyzed a previously-described dataset related to IgG antibody responses to 6 herpesviruses (CMV – cytomegalovirus; EBV – Epstein-Barr virus; HHV6 – human herpesvirus-6; HSV1 and HSV2 – herpes simplex virus-1 and -2; VZV – varicella-zoster virus) from the United Kingdom ME/CFS biobank. The primary goal was to report the underlying symptomology and its association with herpesvirus IgG antibodies using data from 4 disease-trigger-based subgroups of ME/CFS patients (n = 222) and patients with MS (n = 46). A secondary objective was to assess whether serological data could distinguish ME/CFS and its subgroup from MS using a SuperLearner (SL) algorithm.

There was evidence for a significant negative association between temporary eye insight disturbance and CMV antibody concentrations and for a significant positive association between bladder problems and EBV antibody concentrations in the MS group.

In the ME/CFS or its subgroups, the most significant antibody-symptom association was obtained for increasing HSV1 antibody concentration and brain fog, a finding in line with a negative impact of HSV1 exposure on cognitive outcomes in both healthy and disease conditions. There was also evidence for a higher number of significant antibody-symptom associations in the MS group than in the ME/CFS group.

When we combined all the serological data in an SL algorithm, we could distinguish three ME/CFS subgroups (unknown disease trigger, non-infection trigger, and an infection disease trigger confirmed in the lab at the time of the event) from the MS group. However, we could not find the same for the remaining ME/CFS group (related to an unconfirmed infection disease).

In conclusion, IgG antibody data explains more the symptomology of MS patients than the one of ME/CFS patients. Given the fluctuating nature of symptoms in ME/CFS patients, the clinical implication of these findings remains to be determined with a longitudinal study. This study is likely to ascertain the robustness of the associations during natural disease course.

Source: Tiago Dias Domingues, João Malato, Anna D. Grabowska, Ji-Sook Lee, Jose Ameijeiras-Alonso, Przemyslaw Biecek, Luís Graça, Helena Mouriño, Carmen Scheibenbogen, Francisco Westermeier, Luis Nacul, Jacqueline M. Cliff, Eliana Lacerda, Nuno Sepúlveda,
Association analysis between symptomology and herpesvirus IgG antibody concentrations in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis. Heliyon, https://doi.org/10.1016/j.heliyon.2023.e18250 https://www.sciencedirect.com/science/article/pii/S2405844023054580 (Full text)

Comparing Frequency and Severity Ratings for ME/CFS versus Controls

Abstract:

Most questionnaires for somatic symptoms focus on occurrence, frequency, or severity, and in doing so, they might not be able to comprehensively assess the burden that symptoms present to patients. For example, a symptom might occur at a high frequency but only a minimal severity, so that it is less likely to be a burden on a patient; whereas a symptom that has both a high frequency and severity is more likely to be negatively impacting a patient.
Study 1 examined frequency and severity scores for classic Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) symptoms among patients with ME/CFS versus a control group. Findings in Study 1 indicate there were more frequency/severity discrepancies for individuals with ME/CFS versus the control group. Study 1 concluded that collecting data on both measures of symptom burden provides unique indicators that can better assess the burden of the symptoms on patients.
In a separate data set, Study 2 reported reliability data on slight differences in the time period and the way the severity was assessed. Study 2 findings indicated high levels of reliability for these changes in the time period and the way questions were asked. These studies provide important psychometric properties that could lead to more reliable and valid assessments of patients with post-viral illnesses.
Source: Jason LA, Benner S, Hansel N. Comparing Frequency and Severity Ratings for ME/CFS versus Controls. Psych. 2023; 5(3):662-669. https://doi.org/10.3390/psych5030042 https://www.mdpi.com/2624-8611/5/3/42 (Full text)

Symptoms and signs of dry eye in US veterans with Myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Purpose: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is clinically defined as persistent and unexplainable post-exertional fatigue and can present with a wide range of cognitive, immunological, endocrinological, and autonomic symptoms. A notable feature of ME/CFS is its comorbidity with pain in multiple compartments. In this study, we examine ocular manifestations associated with ME/CFS, with a focus on ocular surface pain complaints.

Methods: We recruited 124 United States veterans and profiled them for symptoms and signs of dry eye (DE). Individuals were grouped by the presence (n=42) and absence (n=82) of ME/CFS.

Results: The mean age of the population was 55.49 ± 4.61 years, 88.7% of participants identified as male, 58.1% as White, and 39.5% as Hispanic. Demographics, medical comorbidities, and medication use were similar between groups except for depression (57.1% vs. 29.6%, p=0.003), and history of traumatic brain injury (9.5% vs. 1.2%, p=0.03) which were more prevalent in the ME/CFS group. Individuals with ME/CFS reported higher ocular surface pain complaints, both through DE specific questionnaires (Ocular Surface Disease Index, OSDI; 5-Item DE Questionnaire, DEQ-5) and pain specific questionnaires (Neuropathic Pain Symptom Inventory, modified for the Eye, NPSI-E; Numerical rating scale, NRS) (Table 1). Ocular surface parameters were similar between groups, except for persistent pain after topical anesthesia which was more frequent in the ME/CFS group (Table 2).

Conclusions: Individuals who met criteria for ME/CFS had more severe ocular surface pain, but similar signs of DE, compared to controls. This suggests that nerve, and not tear, abnormalities contribute to ocular surface pain in ME/CFS.

Source: Victor Sanchez; Colin Kim; Kimberly Cabrera; Elyana Vittoria Tessa Locatelli; Molly Johnson; Anat Galor. Symptoms and signs of dry eye in US veterans with Myalgic encephalomyelitis/chronic fatigue syndrome. Investigative Ophthalmology & Visual Science June 2023, Vol.64, 3978. https://iovs.arvojournals.org/article.aspx?articleid=2790532