Elevated plasma concentrations of such biomarkers as TNF-alpha, interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-8 (IL-8), galectin-3 or growth differentiation factor 15 (GDF15) are widely believed to be typical in HF [85, 101–103]. Here, IL6 is linked to hydrops fetalis.