PLA2R1 and plasma cell myeloma: Since this ensures oriented binding of the IgG mAbs, similar to binding of anti-THSD7A IgG to coated THSD7A, we propose that this assay format provides more accurate results than using human IgG1-4 myeloma proteins directly absorbed onto plastic wells, an approach previously used to quantify anti-PLA2R IgG subclasses (35).