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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.

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

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.

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, 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.

There are wider implications of the treatments described by Sharma et al.1 Bortezomib works by promoting apoptosis in long-lived and short-lived plasma cells responsible for long-lived immunity. These cells produce background levels of vaccine-induced protective antibodies. Therefore, there may be reduced titers of immunoglobulins against measles, mumps, and tetanus after bortezomib treatment of systemic lupus erythematosus.2 Bortezomib is now also considered treatment in many antibody-mediated chronic autoimmune diseases. It may provide a rapid reduction in antibody titers in treatment-refractory neurologic antibody–mediated diseases, such as NMDAR encephalitis, if standard immunotherapies are ineffective.3 Standard immunotherapies, such as methylprednisolone, rituximab, and cyclophosphamide, do not target these long-lived and short-lived plasma cells4; however, as some patients do not respond when these antibody-secreting cells are targeted, there is clearly more complexity to the immunopathogenesis than is currently understood.5 Neurologists should be aware of the potential pan-immunodeficient risks, particularly when it comes to vaccination-induced immunity, and also the potential therapeutic options in antibody-mediated neurologic conditions.