The complement system, a central part of the innate immunity that serves as a first line of defense against foreign and altered host cells, is an extremely effective cell-killing and inflammation-provoking pathway. However, complement activation is a double-edged sword because uncontrolled stimulation can be highly detrimental to host tissues. [1][2][3] In order to avoid self-damage, a plethora of inhibitory mechanisms are known to prevent overwhelming activation at all stages of the complement cascade. The alternative pathway (AP) of complement is particularly significant for survival against invading pathogens and can be triggered by several other conditions, such as trauma, surgery, or pregnancy. Inappropriate AP activation may be