Various cell surface markers, e.g., CD269 and CD138/Syndecan-1 on plasma cells, CD19, CD20, CD21, CD268, and CD79b on mature B cells, and CD27 on memory B cells are present or upregulated on B cell surface during disease progression and are useful targets for current B cell depletion therapies for MG (7). Here, SDC1 is linked to myasthenia gravis.