Considering the connection between the classical complement activation pathway and the risk of autoimmunity, it is interesting that we found a correlation between on the one hand C4d/C4 ratio, which reflects the degree of complement consumption, and on the other hand the proportion of Th2 cells among effector memory Th cells, as Th2 cells are known to play important roles both in type 2 inflammatory conditions and in autoimmune pathogenesis. Here, C4A is linked to Autoimmunity.