Clinical and immune-related factors associated with exacerbation in adults with well-controlled generalized myasthenia gravis

Predictive Factors for Poor Outcomes Associated with COVID-19 in a Retrospective Cohort of Myasthenia Gravis Patients

Purpose

To investigate the predictors for poor outcomes (including disease exacerbation, hospitalization and myasthenic crisis) in patients with pre-existing myasthenia gravis (MG) following Coronavirus disease 2019 (COVID-19), and to explore the potential effects of COVID-19 on inflammatory and immune responses in MG patients.

Patients and Methods

This retrospective cohort study analyzed medical records of 845 MG patients who were diagnosed with COVID-19 between January 2020 to March 2023 at a single medical center.

Results

Generalized MG at onset and comorbidities (chronic kidney disease and malignancy) were independent risk factors of poor outcomes. Patients achieving minimal manifestation or better status before COVID-19 had a significantly reduced risk for poor outcomes. Furthermore, patients with older onset age or anti-acetylcholine receptor antibody had a higher risk of exacerbation and hospitalization than those without. Prednisone or immunosuppressant treatment had the potential to reduce the occurrence of poor outcomes, while the duration of prednisone or immunosuppressant usage was associated with a higher risk of poor outcomes. Of the 376 MG patients with blood results available, patients with COVID-19 tended to have higher levels of leukocyte counts, neutrophil-lymphocyte-ratio, hypersensitive C-reactive protein, and Interleukin-6, as well as lower percentages of lymphocytes and regulatory T cells compared to patients without COVID-19.

Conclusion

Disease severity at onset, comorbidities, and unsatisfactory control of myasthenic symptoms predicted the occurrence of poor outcomes in MG patients following COVID-19. The risk of poor outcomes was reduced in patients controlled by short-term immunosuppressive therapy. Novel coronavirus might affect inflammatory and immune responses in MG patients, particularly in altering interleukin-6 and regulatory T cell levels.

Identification of disease phenotypes in acetylcholine receptor-antibody myasthenia gravis using proteomics-based consensus clustering

BACKGROUND

The clinical heterogeneity of myasthenia gravis (MG), an autoimmune disease defined by antibodies (Ab) directed against the postsynaptic membrane, constitutes a challenge for patient stratification and treatment decision making. Novel strategies are needed to classify patients based on their biological phenotypes aiming to improve patient selection and treatment outcomes.

METHODS

For this purpose, we assessed the serum proteome of a cohort of 140 patients with anti-acetylcholine receptor-Ab-positive MG and utilised consensus clustering as an unsupervised tool to assign patients to biological profiles. For in-depth analysis, we used immunogenomic sequencing to study the B cell repertoire of a subgroup of patients and an in vitro assay using primary human muscle cells to interrogate serum-induced complement formation.

FINDINGS

This strategy identified four distinct patient phenotypes based on their proteomic patterns in their serum. Notably, one patient phenotype, here named PS3, was characterised by high disease severity and complement activation as defining features. Assessing a subgroup of patients, hyperexpanded antibody clones were present in the B cell repertoire of the PS3 group and effectively activated complement as compared to other patients. In line with their disease phenotype, PS3 patients were more likely to benefit from complement-inhibiting therapies. These findings were validated in a prospective cohort of 18 patients using a cell-based assay.

INTERPRETATION

Collectively, this study suggests proteomics-based clustering as a gateway to assign patients to a biological signature likely to benefit from complement inhibition and provides a stratification strategy for clinical practice.

FUNDING

CN and CBS were supported by the Forschungskommission of the Medical Faculty of the Heinrich Heine University Düsseldorf. CN was supported by the Else Kröner-Fresenius-Stiftung (EKEA.38). CBS was supported by the Deutsche Forschungsgemeinschaft (DFG-German Research Foundation) with a Walter Benjamin fellowship (project 539363086). The project was supported by the Ministry of Culture and Science of North Rhine-Westphalia (MODS, "Profilbildung 2020" [grant no. PROFILNRW-2020-107-A]).

Therapeutic effect of ofatumumab in patients with myasthenia gravis: immunoregulation of follicular T helper cells and T helper type 17 cells

Introduction

This study aimed to study the therapeutic effects of ofatumumab in patients with myasthenia gravis (MG) in addition to the immunomodulatory effects on peripheral follicular T helper (Tfh) cells and T helper type 17 (Th17) cells.

Methods

Thirty-one patients with anti-acetylcholine receptor (AChR) antibody-positive MG were included in this study. At weeks 0, 1, 2, and 4, an initial dose of 20 mg of ofatumumab was injected subcutaneously, with a 2-month follow-up after completing this first cycle. At baseline, 1 month, and 3 months, we assessed the Quantitative MG (QMG), 15-item MG-Quality of Life (MG-QOL15), and MG-Activities of Daily Living (MG-ADL) scales and measured the frequencies of Tfh, Th17, and B cells and the levels of anti-AChR antibody, IL-6, IL-21, and IL-17 in the peripheral blood.

Results

At 1 month and 3 months, the QMG, MG-QOL15, and MG-ADL scores were all significantly reduced. At 3 months, doses of prednisone were reduced by an average of 37%. Decreased frequencies of Tfh and Th17 cells, depletion of B cells, and reduced levels of IL-6, IL-21, and IL-17 were all observed at 1 month or 3 months.

Discussion

Therefore, the therapeutic effect of ofatumumab could be detected after one cycle of treatment, which was maintained for 2 months. The immunomodulatory effect of ofatumumab during the observation period may involve depletion of B cells, reduction of Tfh and Th17 cells frequencies, and reduced levels of IL-6, IL-21, and IL-17. The findings provide novel data for the potential application of ofatumumab in MG.