Sex Differences in Immunity and Inflammation: Implications for Brain and Behavior

The immune system is the body's defense against disease; however, inherent differences in how the male and female immune systems detect and respond to immune threats dictate susceptibility to illness and immune-related diseases. Sex differences in the immune system begin during development and continue throughout life, with males and females showing different periods of immune susceptibility and resilience. Given that these differences likely stem from sex-dependent requirements for species survival, this chapter discusses how this evolutionary "need" for sex differences in immune function carries with it far reaching effects on both the periphery and the brain. This chapter highlights basic immune-related differences between men and women, describes how these differences translate into sex-dependent risk for immune-related diseases, discusses the implications for brain function, and outlines potential mechanisms to explain these differences. Finally, we conclude by discussing sex-dependent immune effects on behavior and how differential immune function drives the manifestation of comorbid disease states.