Immunological clues to sex differences in parasitic diseases.

The effect of sex on the prevalence and severity of parasitic diseases is an emerging area of research. Several factors underlie sex-based differences, including sociocultural influences that affect exposure to parasites, and physiological disparities linked to biological sex. Hence, human studies must be interpreted cautiously; however, studies conducted under controlled laboratory conditions are important to validate findings in humans. Such research can more effectively elucidate the role of sex-determining physiological factors (particularly their impact on immune responses), as well as the role of sex-specific differences in resistance to, or severity of, parasitic diseases. This review focuses on the overarching impact of biological sex variables on immunity. Both human and rodent experimental data are discussed, with a focus on selected protozoan and helminth infections.