The alterations of Breg cells unveiled upon unspecific stimulation in patients with some autoimmune diseases and cardiomyopathies (Bankó et al., 2017; Jiao et al., 2018) led us to examine the phenotypic distribution of B cells after stimulation with the oligonucleotide CpG plus recombinant CD40L (CpG + CD40L) in our cohort of CCD patients and NI donors (Supplementary Figures 2A, B, 3A–D). Here, CD40LG is linked to autoimmune disease.