A Prospective Study of the Incidence of Myasthenia Gravis in the East Midlands of England.

OBJECTIVES: A number of worldwide studies have highlighted a rising incidence of myasthenia gravis (MG) over the past few decades. This is largely due to an increase in numbers in older patients. To establish whether this was a consistent finding in the United Kingdom, we conducted a large, 4-year prospective cohort study of all known patients with new-onset MG in the East Midlands of the United Kingdom. METHODS: Between 2014 and 2018, all 120 patients with a new diagnosis of MG who were residing in the East Midlands were enrolled. RESULTS: Median age at disease onset was 63 years (78% aged over 50 years) and most patients (57%) were male. The average annual incidence rate (IR) was 17.6/1,000,000 (95% CI 10.7-28.6). IRs remained stable between 2014 and 2018 except for rising IRs in patients over 65 years of age (p value for trend, <0.001). CONCLUSIONS: Twenty years after the last comprehensive prospective incidence survey of MG in the east of England, we have demonstrated a rising incidence. The greatest increases seen were in patients over 65 years. Given the rigorous study methods employed, future replicate prospective studies from the same region will establish whether these rising figures are due to biological factors, independent of improved case ascertainment.

Ocular presentation of myasthenia gravis: A natural history cohort.

INTRODUCTION: There are limited data on the natural history of untreated myasthenia gravis (MG) with ocular presentation. METHODS: We analyzed 93 patients from symptom onset who presented to the Birmingham Midlands Eye Centre (BMEC) between January 2004 and July 2015. We used multiple stepwise logistic regression to identify predictive factors of generalization and Kaplan-Meier analysis on time to generalization. RESULTS: Forty-six percent of patients developed generalized symptoms during the study period. Median time to generalization was 7 months. Time to generalization was earlier in patients seropositive for acetylcholine receptor (AChR) antibody (median 5 months vs. 21 months, P < 0.0001) and bilateral ptosis at onset (P = 0.015). Multivariate analysis identified AChR seropositivity [hazard ratio (HR) 5.03; 95% confidence interval (CI) 1.48-17.14; P = 0.001] and disease onset < 50 years (HR 3.58; 95% CI 1.18-10.90; P = 0.035) as risk factors for generalization. DISCUSSION: As patients were steroid-naive before generalization, our cohort approximated the natural history of the condition. Muscle Nerve 57: 622-627, 2018.

Quantitative Assessment of Response to Long-Term Treatment with Intravenous Immunoglobulin in Patients with Stiff Person Syndrome.

BACKGROUND: Stiff person syndrome (SPS) is an autoimmune condition involving antibodies against several components of the inhibitory synapse in the spinal cord, with glutamic acid decarboxylase antibodies being the predominant immune marker. SPS affects approximately 1 patient per million population per year. The effect of intravenous immunoglobulin (IVIG) has been established, but studies on the long-term efficacy of regular IVIG are limited. OBJECTIVES: To review clinical details and long-term treatment response using a patient-reported questionnaire in SPS and related syndromes. METHODS: Patients were identified from a tertiary neuroimmunology clinic based on classical clinical symptoms, autoimmune profiles, and neurophysiological changes (Dalakas criteria). They were followed up after treatment to assess the response to IVIG. RESULTS: A total of 23 patients fulfilled the selection criteria. Patients' demographic profiles and clinical presentations were akin to that reported in literature. There was significant improvement in the functional ability (assessed by the modified Rankin scale [mRS]) and quality of life (QoL) following treatment with IVIG within 4 to 10 weeks (pre-mRS vs. post-mRS, P < 0.0001; pre-QoL vs. post-QoL, P = 0.0003) and sustained after 5 years of treatment (pre-mRS vs. present mRS, P = 0.0003; pre-QoL vs. present QoL, P = 0.0002). CONCLUSIONS: This article describes one of the largest single-center experiences of 23 patients with SPS and related syndromes and is the first to establish the long-term efficacy of regular IVIG using a patient-reported scoring system (Birmingham Response to Immunomodulatory Therapy [BRIT]). Consistent improvement in QoL and functional scores were seen over nearly 5 years after regular use of IVIG. It is recommended to use BRIT scores to assess the initial response as well as to monitor continued improvement to immunomodulation in SPS.

Lung cancer prediction in Lambert-Eaton myasthenic syndrome in a prospective cohort.

To evaluate the Dutch-English Lambert-Eaton Myasthenic Syndrome (LEMS) Tumour Association Prediction (DELTA-P) score in a prospective cohort of patients with newly diagnosed LEMS to assess the clinical validity of this tool in a real-world setting. Clinical features from 87 patients with LEMS, occurring within three months from disease onset, were collated to produce a DELTA-P score for each patient. Lung cancer was detected in 44/87 (51%) LEMS patients. Weight loss ≥ 5%, tobacco use at LEMS onset and age at onset ≥ 50 years were independent predictors for the development of small-cell lung cancer (SCLC) in LEMS patients in multivariable analysis. Median DELTA-P scores were significantly higher in SCLC-LEMS patients (3.5, 95% CI 3 to 4) compared to non-tumour-LEMS (2, 95% CI 1 to 2) (P < 0.0001). Higher DELTA-P scores increased the risk of SCLC stepwise (score 0 = 0%, 1 = 18.8%, 2 = 45%, 3 = 55.5%, 4 = 85.7%, 5 = 87.5%, 6 = 100%). The area under the curve of the receiver operating curve was 82.5% (95% CI 73.9% to 91%). The DELTA-P cancer prediction score, calculated at the time of LEMS diagnosis, is an effective tool for cancer screening in an independent, prospective study setting.

Neuronal antibody detection and improved lung cancer prediction in Lambert-Eaton myasthenic syndrome.

Since approximately 50% of patients with Lambert-Eaton myasthenic syndrome (LEMS) subsequently develop small-cell lung cancer (SCLC), it is important to be able to predict cancer occurrence in these patients at neurological presentation. We aimed to determine whether circulating biomarkers were effective and objective predictors of cancer development in LEMS. We found that the presence of either SOX2, N-type voltage gated calcium channel or GABAb antibodies at LEMS diagnosis was highly sensitive (84%) and specific (87%) for the detection of SCLC. Screening for SOX2 and neuronal antibodies is a useful adjunct to clinical predictive scoring tools in predicting SCLC in LEMS.

False-positive acetylcholine receptor antibody results in patients without myasthenia gravis.

Acetylcholine receptor antibodies are very specific for myasthenia. During a large prospective cohort study of myasthenia, we encountered five patients, positive for acetylcholine receptor (AChR) antibodies by radioimmunoprecipitation assay (RIA), whose clinical course revealed diagnoses other than myasthenia. Two patients had transiently raised AChR antibodies associated with Guillain-Barré syndrome. Antibodies to clustered AChRs, in a live cell-based assay, were negative in all five patients, suggesting that results from the RIAs were false-positives. It is possible that the AChR antibodies detected by RIA in these cases were non-pathogenic, and directed to intracellular epitopes of the AChR.

miR-30e-5p as predictor of generalization in ocular myasthenia gravis.

Objective: To determine a predictive factor for the risk of conversion from ocular myasthenia gravis (OMG) to generalized MG (GMG) in a prospective study. Methods: RNA was isolated from serum samples and detection of microRNA (miRNA) expression analyzed with qPCR. In the discovery set, 179 human miRNAs were assayed for profiling of five OMG patients and four age- and gender-matched healthy controls. Based on the specific accumulation pattern of 19 miRNAs from the discovery set, in addition to miRNAs previously found elevated in generalized MG (GMG; miR-150-5p and miR-30e-5p), 21 miRNAs were subsequently analyzed in a validation cohort of 83 OMG patients (82 immunosuppression treatment naive; 49 male) within 3 months of diagnosis and at a follow-up visit (median duration 28 months from first visit). Results: Thirteen patients generalized 14.8 ± 12.0 months after the diagnosis and the majority (85%) belonged to the late onset MG group. Two miRNAs were significantly higher in secondary GMG (SGMG) patients compared to OMG patients with late onset MG: miR-30e-5p (9.1 ± 0.5 vs. 6.3 ± 0.9; P < 0.0001) and miR-150-5p (7.4 ± 1.1 vs. 6.4 ± 1.1; P = 0.01). The sensitivity for miR-30e-5p in differentiating OMG and SGMG was 96% in all OMG patients and 100% in late onset OMG patients. Interpretation: This is the first study to describe a potential predictive factor associated with the risk of generalization for patients with OMG. Raised levels (>8) of miR-30e-5p at initial presentation in patients with ocular MG symptoms, give a predictive cut-off for subsequent generalization of 96-100%.

Circulating microRNA miR-21-5p, miR-150-5p and miR-30e-5p correlate with clinical status in late onset myasthenia gravis.

There are no biomarkers for late onset myasthenia gravis (LOMG; onset >50 years). We evaluated circulating microRNA in a discovery cohort of 4 LOMG patients and 4 healthy controls and in a prospective diagnostic validation cohort of 73 LOMG patients (48 male) with longitudinal follow-up samples. In immunosuppression naïve patients, levels of miRNAs miR-150-5p, miR-21-5p and miR-30e-5p decreased in parallel with clinical improvement after initiation of immunosuppression and their levels positively correlated with the clinical MG composite score. Levels of miR-150-5p and miR-21-5p were lower in patients with ocular compared to generalized LOMG. Circulating miR-150-5p, miR-21-5p and miR-30e-5p correlate with the clinical course in LOMG.