Anti-CD40 antibodies being a main pathogenic factor in FSGS are in contrast to previous studies, which suggested a smaller protein fraction (30–50 kDa) to contain the pathogenic plasma intrinsic factor, as immunoglobulins have a size of 150 kDa (Sharma et al. 1999; Vidarsson et al. 2014). Here, CD40 is linked to focal segmental glomerulosclerosis.