Complement Abnormalities
The complement proteins are mediators of inflammation and they have several biologic activities including virus neutralization, opsonization, leukocyte attraction, and lysis of cells. Inherited deficiencies of all complement components have been reported and may be associated with sepsis and pyogenic infections (components 1 to 5), lupus erythematosis (components 1, 2, 4, 5, and 8), and recurrent gonococcal and/or meningococcal infections (components 5 to 8). Absent bacteriolysis may be the basis for the recurrent Neisseria infections in patients with components 5 to 8 abnormalities.
Comment: The method to measure complement activity in a patient with recurrent infections (especially those with meningococcus or gonococcus) is the assay for total hemolytic complement (CH5O) which is readily available.