Frequency and severity of autonomic dysfunction assessed by objective hemodynamic responses and patient-reported symptoms in individuals with myasthenia gravis.

Introduction: Myasthenia gravis (MG), a rare autoimmune disorder, poses diagnostic and management challenges, with increasing incidence in Europe and significant impact on patient quality of life. Despite prevalent autonomic symptoms, comprehensive assessments integrating subjective and objective measures are lacking. We aimed to investigate the prevalence and severity of autonomic dysfunction in patients with MG and healthy controls (HCs). Materials and methods: We used beat-to-beat hemodynamic responses during standardized autonomic function tests (AFTs) and the Composite Autonomic Symptom Score 31 (COMPASS-31) questionnaire. Study participants including, 53 patients with MG and 30 age- and sex matched HCs underwent standardized cardiovascular AFTs and completed the COMPASS-31 questionnaire. Patients were categorized into Non-CAN and CAN groups based on their Cardiovascular Autonomic Neuropathy (CAN) status, as evaluated using the Composite Autonomic Scoring Scale (CASS). During the AFTs, cardiovascular parameters including heart rate, systolic blood pressure (BP), diastolic BP, mean BP, stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were measured. Results: Twenty patients with MG (38%) exhibited mild CAN (CASS ≥2) with a median total CASS score of 1.00 and CASS 0.00 in HCs. Adrenergic impairment was observed in 27 patients (52%), with 13 patients (24.5%) exhibiting longer pressure recovery time after Valsalva maneuver (VM). Cardiovagal impairment was evident in 71% of patients, with abnormal results observed in 39.6% for the deep breathing test and 56.6% for the VM. CAN MG showed worse scores than HCs for the total COMPASS-31 (p < 0.001), orthostatic (OI) (p < 0.001), secretomotor (p = 0.004), and pupillomotor domains (p = 0.004). Total COMPASS-31 and OI scores were correlated with worse disease outcomes (disease duration, severity), hemodynamic parameter changes (SV, CO, TPR) during phase II late of VM, and with changes (Δtilt-supine) in Δsystolic BP, Δdiastolic BP, Δmean BP, ΔTPR during head-up-tilt test, but not with CASS score. Conclusion: Our findings demonstrate mild cardiovascular autonomic impairment in adrenergic and cardiovagal domains in patients with MG. Additionally, patient-reported autonomic symptoms correlated with hemodynamic changes during AFTs and worse disease outcomes and not with the grade of autonomic abnormalities. Incorporating beat-to-beat hemodynamics during AFTs may offer further insights for characterizing orthostatic intolerance symptoms in MG group.

Diurnal cognitive functioning in patients with myasthenia gravis with the role of chronotype and depression: a pilot study.

Purpose: Myasthenia gravis (MG) is an autoimmune disease manifested by fatigue and weakness of the skeletal muscles. Recent research has indicated that MG patients perform significantly worse than healthy controls in cognitive domains such as attention, verbal fluency, visual learning, and memory. This study aimed to investigate the diurnal fluctuations in cognitive performance in patients with myasthenia gravis in relation to selected clinical and socioeconomic parameters of the disease course, along with the role of chronotype and depression. Methods: The participants were recruited from a neurology outpatient clinic. Patients' cognitive functions were assessed twice: in the morning and the evening of the same day. Neuropsychological diagnosis included attention, memory, executive, verbal, and visuospatial abilities. Mood was measured with the Beck Depression Inventory-II and Positive and Negative Affect Schedule. The Morningness-Eveningness Questionnaire was used to examine chronotype. Results: The analyses performed showed no significant differences between subjects and within subjects, apart from semantic fluency. Patients receiving antidepressant treatment obtained better results on attention and working memory tasks. Conclusions: The data obtained show that diurnal neuropsychological performance in MG patients is associated with depression. Routine assessment and treatment of mood disorders could significantly improve cognitive functioning in myasthenia gravis patients.

Comparative Analysis of Serum Amino Acid Profiles in Patients with Myasthenia Gravis and Multiple Sclerosis.

Background: Multiple sclerosis (MS) and myasthenia gravis (MG) are autoimmune diseases that attack the central nervous system (CNS) and the neuromuscular junction, respectively. As the common pathogenesis of both diseases is associated with an autoimmune background and the involvement of T and B lymphocytes, the overlapping of selected clinical symptoms may cause difficulties in the differential diagnosis of both diseases. Methods: The aim of the study was to use Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (LC-ESI-MS/MS) in conjunction with multivariate statistical analyses to examine the changes in amino acid metabolic profiles between patients with MG, MS, and a control group. Results: Comparative analysis of amino acids (AA) between patients with MG, MS, and within the control group allowed for the identification of statistically significant differences in the amino acid profile. Comparing the patients (patients with MS and MG) with the control group, and after taking the results of multiple tests into account, it was observed that amino acids such as ARG, PRO, TRP, CIT were significantly different between the groups. When considering the comparison between the AA concentrations in MS and MG patients, we found three AAs that were significantly different in the MS and MG groups, after correcting for multiple testing (CIT, GABA, and AAA). Higher concentrations of amino acids that showed significant differences were observed in patients with myasthenia gravis. Conclusions: Our results have indicated AAs that may prove valuable for improving the diagnostics of MS and MG patients. To better assess the potential utility of these markers, their performance requires further validation in a larger study group and limitation of possible confounding factors, e.g., medications and diet.

Correlation between Cardiovascular Autonomic and Pulmonary Ventilation Functions in Myasthenia Gravis Patients.

This study aimed to investigate the relationship between pulmonary function and cardiac autonomic function parameters in clinically stable myasthenia gravis (MG) patients. A total of 22 MG patients and 22 healthy controls (HCs) were evaluated. Pulmonary function test parameters, heart rate variability (HRV), baroreflex sensitivity (BRS), and cardiovascular autonomic function test parameters (the Valsalva ratio, expiration/inspiration (E/I) ratio) were assessed. Compared with the HCs, the patients demonstrated a similar diffusion capacity for carbon monoxide (DLCO); a lower forced vital capacity (FVC%pred); a lower forced expiratory volume in 1 s (FEV1%pred); lower BRS and HRV, including high-frequency and total power spectral density; and a higher percentage of abnormal cardiovagal function test results (p < 0.05). A lower BRS in the patient group was associated with worse clinical disease outcomes and reduced pulmonary function (DLCO%pred, R = 0.59; TLC%pred, R = 0.48). Age, forced vital capacity, and total lung capacity predicted the E/I ratio (R2 values ranging from 0.48 to 0.49). Our study demonstrated a significant relationship between a reduced pulmonary ventilation function and respiratory mechanics with cardiovascular autonomic parameters, including the E/I ratio, BRS, and HRV measures at rest, as shown in the MG group. Future studies should focus on the interplay between respiratory and autonomic function testing, as well as pulmonary rehabilitation, to mitigate cardiovascular risk in these patients.

Association between Daytime Sleepiness, Fatigue and Autonomic Responses during Head-Up Tilt Test in Multiple Sclerosis Patients.

We aimed to assess dynamic changes in hemodynamic and autonomic function in response to the head-up tilt test (HUTT) in patients with multiple sclerosis (MS) compared to healthy controls (HCs) and evaluate its relationship with the patients' reported daytime sleepiness and fatigue symptoms. A total of 58 MS patients and 30 HCs were included in the analysis. Fatigue and sleepiness were evaluated using the Chalder Fatigue Scale (CFQ) and the Epworth Sleepiness Scale (ESS), respectively. Hemodynamic response, baroreflex sensitivity, heart rate variability, and systolic and diastolic blood pressure (BP) variability (SBPV, DBPV) parameters were calculated at rest, and in response to the HUTT. The MS patients displayed attenuated BP responses coupled with a more pronounced decrease in cardiac index as well as a reduced increase in the low frequency (LFnu) of DBPV (p = 0.021) and the sympathovagal ratio (p = 0.031) in the latter-phase orthostatic challenge compared to HCs. In MS patients, the ESS score showed no correlation with CFQ or clinical disease outcomes, but exhibited a moderate correlation with LFnu of BPVrest. Fatigue and disease variants predicted blood pressure response to HUTT. These findings underscore the importance of subjective daytime sleepiness and fatigue symptoms and their role in blood pressure regulation in MS patients.

Altered Cardiac Autonomic Regulation in Individuals with Myasthenia Gravis-A Systematic Review and Meta-Analysis.

The aim of this systematic review with meta-analysis was to determine differences in cardiovascular autonomic parameters between patients with myasthenia gravis (MG) and healthy controls (HCs). Two reviewers searched four electronic databases, namely PubMed, Web of Science, EMBASE, and SCOPUS, from database inception to 7 July 2023 for studies investigating cardiovascular autonomic parameters in MG vs. HCs. A random-effects meta-analysis was performed to compute Hedges' g ± 95% confidence intervals (CI). Out of a total of 2200 records, 8 observational studies with a sample size of 301 patients with MG and 454 HCs were included in the systematic review. Meta-analysis revealed lower values of expiration/inspiration ratio (g = -0.45, I2 = 74.7), baroreflex sensitivity (g = -0.56, 95%CI -0.80, -0.33; I2 = 0.3), percentage of adjacent NN intervals differing by more than 50 ms (g = -1.2, I2 = 82.8), square root of the mean of squared differences between successive beat intervals (g = -1.94, I2 = 95.1), mean of the standard deviations of all NN intervals (g = -0.83, 95%CI -1.37, -0.28; I2 = 55.5), and high frequency of HRV during tilt (g = -0.75, 95%CI -0.11, -0.39; I2 = 0). MG patients vs. HCs had higher systolic blood pressure (g = 0.39; I2 = 56.1), sympathovagal balance at rest/during tilt (LF/HF-RRIsupine, g = 0.44; I2 = 0; LF/HF-RRItilt, g = 0.86; I2 = 0; LF/HFtilt, g = 0.40; I2 = 0). As a group, MG patients have altered cardiac autonomic function, including decreased parasympathetic function, lower baroreflex sensitivity, and higher sympathovagal balance at rest and during orthostatic challenges.

Serum amino acid profiling in differentiating clinical outcomes of multiple sclerosis.

AIM OF THE STUDY: Amino acid metabolism is crucial for regulating immune responses and can be monitored in blood serum samples. This study aimed to analyse serum amino acid profiles in people with multiple sclerosis (pwMS), taking into account differences depending on the disease outcomes. CLINICAL RATIONALE FOR THE STUDY: Serum amino acid profiling is a promising, reproducible and minimally invasive technology, available at different stages of the disease, enabling the search for a specific biomarker to differentiate MS clinical outcomes. MATERIAL AND METHODS: The serum concentrations of 29 amino acids were determined using high-performance liquid chromatography mass spectrometry. RESULTS: A total of 121 pwMS (41 relapsing-remitting MS-RRMS; 55 secondary progressive MS - SPMS; and 25 primary progressive MS-RRMS) with a median Expanded Disability Status Scale (EDSS) score of 6 and 53 healthy controls (HCs) were included. We found significantly higher serum total amino acids concentrations in pwMS compared to HCs. Serum concentrations of arginine, 1-methyl-L-histidine and proline were higher in pwMS, while circulating citrulline, α-aminobutyric acid and tryptophan were lower in pwMS. We observed significant differences in serum total amino acids concentrations depending on MS type, with the highest level in the PPMS group and the lowest in the RRMS group. We found significantly higher serum levels of beta-aminoisobutyric acid in PPMS patients compared to those with RRMS and SPMS, and significantly higher serum levels of aspartic acid in PPMS patients compared to RRMS patients. From visual inspection, no trend was observed in total amino acids concentration with respect to the EDSS score. When analysing serum total amino acids concentration in pwMS with EDSS ≤ 5 compared to those with EDSS > 5, no significant differences were found. CONCLUSIONS AND CLINICAL IMPLICATIONS: Amino acid metabolism is altered in pwMS and depends on the clinical type of the disease. Further studies are needed to determine whether serum metabolomic profiling of amino acids may have an application in the search for clinical phenotype-specific MS biomarkers.

Serum amino acid profiles in patients with myasthenia gravis.

Myasthenia gravis (MG) is an autoimmune disease characterized by weakness and rapid fatigue. Diagnostic methods used for myasthenia gravis are not conclusive and satisfactory, therefore it is necessary to develop reliable tools to help diagnose myasthenia gravis as early as possible. The aim of the study was to use HPLC-MS in conjunction with multivariate statistical analyses to investigate changes in the amino acid metabolic profiles between myasthenia gravis patients compared and controls. In addition, the effect of treatment regimens and myasthenia gravis type, on the observed changes in amino acid metabolic profiles were assessed. Serum levels of 29 amino acids were determined in 2 groups of individuals-28 patients with myasthenia gravis and 53 control subjects (CS). The results of our study indicate that serum levels of several amino acids in patients with myasthenia gravis changed significantly compared to the control group. Statistical analysis revealed differences between amino acids concentration in patients with different therapeutic scheme. In conclusion, amino acids may be involved in mechanisms underlying myasthenia gravis pathogenesis as well as may be potential biomarkers in MG patients diagnosis. However, considering the multifactorial, heterogenous and complex nature of this disease, validation on a larger study sample in further research is required before application into diagnostic practice.

Alterations in short-term blood pressure variability related to disease severity and autonomic symptoms in myasthenia gravis patients.

OBJECTIVES: We aimed to evaluate beat-to-beat blood pressure variability (BPV) during head-up tilt test (HUTT) in patients with mild and moderate myasthenia gravis (MG) compared to healthy controls (HCs), and its association with the severity of autonomic symptoms. METHODS: A total of 50 MG patients and 30 HCs were evaluated. Patients were stratified into 2 groups regarding Myasthenia Gravis Foundation of America (MGFA) classification: mild (I,II MGFA), moderate form (III MGFA). Autonomic symptoms were assessed by COMPASS-31 questionnaire. Cardiovascular parameters, indices of very short-term systolic (SBPV), and diastolic blood pressure (BP) variability (DBPV) were assessed at rest, and during HUTT. RESULTS: Moderate MG patients were characterized by an overall shift of sympathovagal balance toward sympathetic predominance, either at rest and during HUTT, as well as lower values of high frequency (HFnu) of DBPV during HUTT, compared to HCs and mild MG. Similarly, moderate MG showed higher resting low frequency (LFnu) of DBPV (p=0.035), higher COMPASS-31 score (p=0.031), and orthostatic intolerance sub-score (p=0.019) than mild MG patients. Compared to HCs, mild MG patients showed lower Δmean BP (p=0.029), Δdiastolic BP (p=0.016). Autonomic symptoms were associated with lower BP values, at rest and during HUTT, and lower LF BPV parameters during HUTT. CONCLUSION: MG patients present significant alterations in BPV, both at rest and in response to orthostatic stress, which are related to autonomic symptoms and disease severity. This study confirms the importance of monitoring BPV when evaluating cardiovascular autonomic function and its evolution over the course of MG disease.

Swept-Source Optical Coherence Tomography Thresholds in Differentiating Clinical Outcomes in a Real-World Cohort of Treatment-Naïve Multiple Sclerosis Patients.

This study aimed to determine whether peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness thresholds for single-time-point swept-source optical coherence tomography (SS-OCT) measures can differentiate the clinical outcomes of treatment-naïve people with multiple sclerosis (pwMS). A total of 275 patients with the clinically isolated syndrome (n = 23), benign MS (n = 8), relapsing-remitting MS (n = 185), secondary progressive MS (n = 28), primary progressive MS (n = 31), and with no history of optic neuritis were included. The mean Expanded Disability Status Scale (EDSS) score was 3.0 ± 1.6. The cut-off values of pRNFL (87 µm and 88 µm) and GCIPL (70 µm) thicknesses have been adopted from previous studies using spectral-domain OCT. PwMS with pRNFL ≤87 µm and ≤88 µm had a longer disease duration, more advanced disability, and more frequently progressive MS variants compared to those with greater pRNFL thicknesses. In distinguishing pwMS with disability greater than or equal to the mean EDSS score (EDSS ≥ 3) from those with less severe disability, GCIPL thickness <70 µm had the highest sensitivity, while pRNFL thickness ≤87 µm had the greatest specificity. The optimal cut-off values differentiating patients with EDSS ≥ 3 from those with less severe disability was 63 µm for GCIPL thickness and 93.5 µm for pRNFL thickness. In conclusion, pRNFL and GCIPL thickness thresholds for single-time-point SS-OCT measurements may be helpful in differentiating the disability status of treatment-naïve pwMS.

Autonomic nervous system involvement in chronic inflammatory demyelinating polyradiculoneuropathy: a literature review.

BACKGROUND AND AIMS: Although dysautonomia is a well-recognized complication of acute demyelinating polyradiculoneuropathy, it is rarely reported and evaluated in chronic demyelinating neuropathies. The purpose of this review is to search and synthesize the current literature on the prevalence and type of autonomic dysfunction (AD) in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). METHODS: PubMed and Web of Science were searched for studies reporting AD in CIDP. RESULTS: Twelve studies, including 346 patients with CIDP, were found eligible for the review. Seven studies used autonomic tests only as an additional component of the comprehensive clinical evaluation, and found that dysautonomia in CIDP may indicate the presence of a comorbid disease (e.g., diabetes) and facilitate the differentiation of CIDP from other neuropathies (e.g., amyloid neuropathy). Five studies performed quantitative assessment of autonomic function in CIDP as a primary goal. Two studies have used the Composite Autonomic Severity Score (CASS) to assess severity and distribution of dysautonomia. The reported prevalence of dysautonomia in CIDP during quantitative assessment of autonomic function ranged from 25 to 89%, depending on the battery of tests used, with CASS not exceeding 4 points. The abnormalities in autonomic tests indicated both sympathetic and parasympathetic dysfunction and did not correlate with the duration, severity and variant of CIDP. CONCLUSIONS: Clinical or subclinical involvement of the ANS has been shown to be common and relatively mild in CIDP. The impact of autonomic impairment on disability and of its possible response to therapy in CIDP needs to be further investigated.

Cognitive Function and Postural Control Strategies in Relation to Disease Progression in Patients with Parkinson's Disease.

AIM: This study assessed the influence of performing an additional cognitive task on center of pressure (COP) displacement in the early and advanced stages of patients with Parkinson's disease (PD) compared to age-matched healthy controls (HCs). METHODS: The study included 40 HCs and 62 patients with PD: early PD (n = 38) and advanced PD (n = 24). COP parameters were determined by static posturography during quiet standing with open eyes (ST, single task) and simultaneous performance of a cognitive task (DT, dual task). Cognitive functioning was examined with a Mini Mental State Examination, number-counting-backward test, and number of enunciated words during DT. RESULTS: In the advanced-PD group, DT significantly reduced the sway radius (p = 0.009), area of stabilogram (p = 0.034), medio-lateral length (p = 0.027), and velocity (p = 0.033) compared to ST. In HCs, DT showed a significant increase in the sway radius (p = 0.006), total length (p = 0.039), sway velocity (p = 0.037), anterior-posterior length, and sway velocity. Both PD groups showed worse cognitive performance compared to HCs. CONCLUSIONS: Both early and advanced patients with PD showed significant delay in cognitive performance associated with executive function compared to the HCs. During additional cognitive tasks, patients with advanced stages of PD may reduce stabilographic parameters in medio-lateral direction, and this is probably an adaptive strategy to restore balance.

Amino Acid Levels as Potential Biomarkers of Multiple Sclerosis in Elderly Patients: Preliminary Report.

BACKGROUND AND PURPOSE: Aging in multiple sclerosis is associated with both disease- and age-dependent neurodegeneration. Serum metabolomic profiling of amino acids seems to be a promising method for searching for biomarkers of neurodegenerative disorders. The aim of this study was to determine the profile of nonessential amino acids in the serum of elderly patients with secondary progressive multiple sclerosis (SPMS). METHODS: We used high-performance liquid chromatography to evaluate the serum concentrations of nonessential amino acids in subjects aged >65 years: six patients with SPMS and 20 control subjects (CS). RESULTS: The serine and alanine levels were significantly higher in SPMS patients than in CS, whereas the concentrations of aspartic acid, arginine, and cysteine were significantly lower in SPMS patients. These observations indicate that amino acids may be involved in SPMS neurodegeneration mechanisms. There were no significant differences in the serum concentrations of the other four amino acids investigated (glutamic acid, glycine, proline, and tyrosine) between patients with SPMS and CS. CONCLUSIONS: The preliminary results obtained in the study suggest that the metabolism of some amino acids is altered in patient with SPMS. We also conclude that amino acid profiling might be helpful in searching for putative biomarkers of central nervous system diseases. However, considering the multifactorial, heterogeneous, and complex nature of SPMS, further validation research involving larger study samples is required before applying these biomarkers in diagnostic practice.

Association of Cardiac Autonomic Responses with Clinical Outcomes of Myasthenia Gravis: Short-Term Analysis of the Heart-Rate and Blood Pressure Variability.

Introduction: The aim of the study was to assess cardiac and autonomic function in patients with myasthenia gravis (MG) and to explore its relationship with disease outcomes. Methods: Thirty-eight patients with an MG were enrolled (median age 40.5 years; median disease duration 5.5 years). Cardiovascular parameters, baroreflex sensitivity (BRS), spectral indices of short-term heart rate (HRV), and systolic blood pressure variability (SBPV) were compared with age- and gender-matched controls (n = 30). Cardiac autonomic function was assessed during the response to standing (tilt) and deep breathing tests (expiration/inspiration ratio-E/I). Results: HR and BP responses to the tilt test were similar in both groups. MG patients, as compared to controls, were characterized by altered SBPV at rest, significantly reduced HR response to the deep breathing test (p < 0.001), increased sympathovagal balance after tilt (delta LF/HF-RRI, p = 0.037), and lower values of BRS (p = 0.007) and hemodynamic parameters, i.e., cardiac index, index contractility, left ventricular work index, at rest and during tilt. There was no association between disease duration and autonomic parameters. Disease severity, as determined by MGFA (Myasthenia Gravis Foundation of America) corrected for age and sex, was an independent predictor of diminished vagal tone (E/I ratio) and increased sympathetic response to tilt (delta LF/HF-RRI) as measured with HRV. Lower BRS was associated with greater disease severity and older age. Hemodynamic parameters were predominantly predicted by age and sex. Conclusion: Our results confirm cardiac autonomic dysfunction among MG patients with predominant parasympathetic impairment. Clinicians should consider evaluation of autonomic balance in MG patients with, or at risk for, cardiovascular disease.

Cardiovascular autonomic dysfunction in multiple sclerosis-findings and relationships with clinical outcomes and fatigue severity.

OBJECTIVES: This study evaluates cardiovascular autonomic dysfunction (CAD) in multiple sclerosis (MS) and explores if CAD is related to clinical outcomes and fatigue severity. METHODS: A total of 53 MS patients (30 relapsing-remitting, RRMS; 23 progressive, PMS) and 30 healthy controls were evaluated. TaskForce® Monitor was used to assess impedance cardiography parameters, heart rate (HRV), and blood pressure (BPV) variability during head-up tilt test (HUTT). Expiration/inspiration (E/I) ratio was assessed in response to a deep breathing test. Fatigue severity was evaluated using Chalder Fatigue Scale (CFQ). RESULTS: Compared to controls, PMS patients were characterized by increased sympathetic-parasympathetic ratio at rest (p < 0.01), decreased resting values of parasympathetic parameters (high-frequency HRV, p < 0.05; E/I ratio, p < 0.001), and index of contractility (p < 0.05), whereas RRMS patients showed reduced E/I ratio (p < 0.01). Compared to RRMS group, PMS patients had higher sympathovagal ratio and lower cardiac inotropy parameters (p < 0.05). No intergroup differences were observed for cardiovascular and autonomic function test parameters after HUTT. PMS and low CFQ physical score were identified as independent predictors of sympathetic hyper-reactivity as measured with HRV. Greater disability and male sex were predictors of diastolic BP increase and reduced cardiac inotropy parameters, and older age was predictor of decreased vagal tone (E/I ratio, high-frequency HRV). CONCLUSION: Cardiovascular autonomic modulation is altered in MS and highly dependent on disease variant, disability level, fatigue severity, and patients' demographics.

Amino acids levels as a potential biomarker in myasthenia gravis.

The search for new diagnostic and therapeutic approaches for myasthenia gravis (MG) is highly desirable. Therefore, the aim of the present study is to assess the profile of non-essential amino acids in the serum of MG patients. We evaluated the serum levels of non-essential amino acids in MG patients (n = 10) and control subjects (CS, n = 10) using high-performance liquid chromatography (HPLC) method and assuming a two-fold concentration difference between the groups as significant. Serum levels of aspartic acid and glutamic acid in MG patients were significantly higher than in CS. There were no significant differences in mean serum levels of glycine, proline, alanine, serine, cysteine, arginine and tyrosine between MG patients and CS. The results indicate the need for further research to assess the role of non-essential amino acids in MG. Moreover, our preliminary results suggest that the metabolism of some amino acids seems to be changed in patients with MG. Therefore, we conclude that amino acids profiling might be helpful in searching for putative biomarkers of the central nervous system diseases such as myasthenia gravis.

COVID-19 pandemic year in a sample of Polish myasthenia gravis patients: an observational study.

AIM OF THE STUDY: Coronavirus disease 2019 (COVID-19) incidence, mortality, recovery and hospitalisation rates vary in different countries. This study aimed to present the clinical characteristics of a sample of unvaccinated Polish myasthenia gravis (MG) patients during the first year of the COVID-19 pandemic, taking into account the number of MG exacerbations, a detailed description of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection course, and the need to modify immunosuppressive therapies. Clinical rationale for the study: To assess the impact of the first COVID-19 pandemic year on MG course in a sample of unvaccinated patients. MATERIALS AND METHODS: A retrospective observational study involving 30 unvaccinated Polish MG patients consulted in a neurological outpatient clinic on 11-31 March, 2020 (baseline) and 11-31 March, 2021 (endpoint). RESULTS: During the period of evaluation, exacerbation of MG requiring hospitalisation was reported in 11 patients. Among them, four were treated with intravenous immunoglobulin and another six required plasma exchange. In the study group, COVID-19 was identified in 10 patients. Of them, seven experienced a mild course of SARSCoV-2 infection with spontaneous recovery. In the remaining three patients, both MG exacerbation and SARS-CoV-2 infection were reported. These patients experienced MG exacerbation in the preceding month or concurrently with COVID-19 and were aged over 50 years. Due to the SARS-CoV-2 infection, they required antibiotic and oxygen therapy, and hospitalisation was necessary in the case of two obese patients. None of the patients died due to COVID-19, and nor did any require discontinuation of immunosuppressive therapies during the study period. In total, 12 patients in the study group experienced neither MG exacerbation nor SARS-CoV-2 infection. CONCLUSIONS: In the presented sample of Polish MG patients, favourable outcomes of COVID-19 were observed. Further studies are needed to evaluate the reliable course of COVID-19 taking into account international differences, the types of treatment applied, and the ratio of vaccinated to unvaccinated MG patients.