Extended Data Fig. 2: Immunostaining of patient IgG binding to engineered cardiac tissues.

(a) Immunofluorescence images of engineered cardiac tissues treated with IgG isolated from each patient in the Myo- and Myo+ groups, followed by fixation and staining with anti-human IgG to visualize patient-specific IgG binding (yellow). Patient samples from the Myo+ group are subclassified as low MFI and high MFI based on quantification of human IgG staining in engineered cardiac tissues. (b) Immunofluorescence image of engineered cardiac tissues cultured with IgG isolated from an additional Myo+ SLE patient with elevated levels of myocardial inflammation (SUVmax = 12.4) and stained with secondary anti-human IgG.