+C4a is a potent peptide, a fragment released during activation of the [Complement System](/wiki/Complement_System). As a mild [Anaphylatoxin](/wiki/Anaphylatoxin), it signals the [Immune System](/wiki/Immune_System), gently stirring inflammation and directing immune cells.
+## See also
+- [C3a](/wiki/C3a)
+- [Complement](/wiki/Complement)
+- [Inflammation](/wiki/Inflammation)
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