Main findings
In this analysis of complement proteins and activation products in young women, we find evidence of complement dysregulation in patients with PCOS. Activation of the complement cascade was evident in the fasting state as well as postprandially, and involved both the activation (C3, C3(adesArg), factor H) and terminal pathways (C5a(desArg), TCC). Furthermore, complement dysregulation was most pronounced in metabolically unhealthy subjects, and correlated with both obesity and insulin sensitivity.