Comment on "The Pro-Factor D Cleaving Activity of MASP-1/-3 Is Not Required for Alternative Pathway Function".

A letter to the editor is presented in response to the article "Mannan-Binding Lectin-Associated Serine Protease (MASP)-1 Is Crucial for Lectin Pathway Activation in Human Serum, Whereas Neither MASP-1 nor MASP-3 Is Required for Alternative Pathway Function" by S. E. Degn and colleagues in a 2012 issue.