Cytokine Patterns in Severe Invasive Group A Streptococcal Infections

Abstract

Group A streptococcus (GAS), Streptococcus pyogenes, is an important human pathogen that can cause a variety of diseases, ranging from superficial infections of the skin and mucous membranes to severe invasive infections. During the last two decades, a marked increase in the frequency of highly aggressive invasive GAS infections associated with high morbidity and mortality rates, including streptococcal toxic shock syndrome and necrotizing fasciitis, was noted world-wide. This resurgence prompted intense research in the field of GAS pathogenesis and revealed a complex host—pathogen interplay involving several different virulence factors and host defense systems. In this chapter, we focus on the immunopathogenesis of severe invasive GAS infections, with particular emphasis on GAS virulence factors triggering cytokine responses, and we highlight the importance of specific cytokine patterns in determining the severity of invasive disease.