IL6 and hydrops fetalis: In a recent study of Kop and colleagues (2010) who recruited 908 patients, free of CAD, for a median follow-up period of 13.3 years, it was demonstrated that among depressed participants, HF power of HRV was negatively correlated with CRP (r = −0.205), IL-6 (r = −0.233) and WBC (r = −0.292).