ABSTRACT
This chapter reviews some human complement deficiencies, with special emphasis on infectious complications. In general, patients with deficiencies of complement components have responded appropriately to antimicrobial agents. More specific treatment would hopefully be aimed at correction of the deficiency, in a manner analogous to correction of coagulation component deficiencies. Complement deficiencies acquired in the course of complement activation may indeed predispose patients to subsequent infection. Investigators have spoken of "consumptive opsinopathies" as a syndrome in which intense complement consumption impairs host defenses. Sickle cell anemia, an inherited hemoglobinopathy, is associated with a predisposition to serious systemic infection, especially with encapsulated bacteria such as Streptococcus pneumoniae and H. influenzae. Protein-calorie malnutrition, a major problem of underdeveloped countries, is associated with an array of serious infections, prominently Gram-negative bacteremia and disseminated herpes simplex virus infection. Patients may demonstrate anergy and diminished febrile responses during infections.
