ABSTRACT
The effects of pregnancy on the immune system are intriguing and clinically recognizable. A viral pharyngitis in pregnancy may persist for weeks on end while fulminate vulvar condyloma may suddenly regress in the postpartum period. The immune system is an exceptionally complex and elegant network of cells, cytokines, chemokines, antibodies, and regulatory proteins. The innate arm of the immune system is the first line of defense and includes (i) epithelial cells, (ii) macrophages, (iii) neutrophils, (iv) natural killer (NK) cells, and (v) complement. The epithelial barrier to the environment provides the first line of defense against the intrusion of pathogens. Complement is a collection of serum proteins that bind pathogens, leading to immediate destruction, opsonization, or chemotaxis. Maternal complement levels in pregnancy are similar or greater than those of nonpregnant controls. Macrophages are innate sentinel cells that function as effector cells against certain pathogens.
