Growing evidence shows that late-onset myasthenia gravis (MG) has a different biological basis than early-onset disease, a discovery that may eventually guide more precise treatment strategies, according to a study published recently in the Annals of Neurology.
Scientists found that patients who developed the autoimmune condition after age 50 (called late-onset MG, or LOMG) had higher levels of certain inflammatory proteins that were not as pronounced in younger patients.
This new analysis drew on blood samples from the BeatMG study, which included 21 patients with early-onset MG (average age 38.3 years, 76% women) and 28 patients with LOMG (average age 67.3 years, 25% women). Researchers measured 768 proteins linked to inflammation. They found 73 that differed between the two groups, with 57 elevated in late-onset disease. Pathways tied to white blood cell development, immune regulation and migration were especially active in the older group.
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To confirm these signals, the team turned to the UK Biobank, a large population resource, and then to a separate validation study with 39 patients with MG and 41 healthy volunteers. Three proteins (IL18R1, CXCL17 and CCL11) stood out as being specifically associated with LOMG. These markers did not appear to be affected by thymectomy, disease duration or use of steroid-sparing medications, reinforcing their potential as true indicators of disease type.
“Further confirmatory studies are needed in a large cohort of treatment-naive patients with MG to better understand the implications of these proteins, confirm their role as biomarkers rather than age-associated proteomics changes, and potentially identify new therapeutic targets for LOMG,” explained the authors of this study.
These results help explain why younger patients are more likely to undergo thymectomy, a surgery that removes the thymus gland and can improve symptoms, while older patients generally do not. More than half of early-onset patients in the study had the operation, compared with none of the late-onset group. Despite these differences in treatment history, the distinct protein patterns in LOMG remained.
For patients, this research may open the door to new tools for earlier recognition of late-onset MG and eventually to therapies more tailored to the underlying immune activity. While more studies are needed, identifying proteins that track specifically with LOMG brings the field closer to targeted care that could improve daily function and long-term outcomes.
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