In atherosclerosis, complement receptors (CR1, CR2, CR3, gC1q‐R as well as C3aR and C5aR) were identified to be expressed in plaques, and the mRNA levels of C1r, C1s, C4, C7 or C8 were found to be upregulated, whereas local productions of regulators including CD46, C1–INH, C4BP, DAF and CD59 were also detected. This evidence concerns the gene C4A and atherosclerosis.