Patient tissue slices were allowed to come to room temperature and immunostained with primary and secondary antibodies for 1 hr each at room temperature with triple PBS+ washes between antibody incubations. HKs in Figure 1 were fixed in methanol and processed for immunofluorescence. Primary antibodies described above and patient IgG present in tissues was detected with Alexa Fluor-conjugated secondary antibodies. Widefield fluorescence microscopy was performed as previously described (Stahley et al., 2014 (link)). Super-resolution structured illumination microscopy (SIM) was performed using the N-SIM system equipped with a 100x/1.49 NA oil immersion objective and 488- and 561-nm solid-state lasers. 3D SIM images were captured with an EM charge-coupled device camera (DU-897, Andor Technology, UK) and reconstructed using NIS-Elements software with the N-SIM module (version 3.22, Nikon, Melville, NY). Colocalization analysis via Mander's coefficient was performed using ImageJ Fiji and plugin JACoP (Bolte and Cordelieres, 2006 (link)).