In addition, in the HF subgroup analysis, we did not detect a significant difference in the proportions of B1 and Tr cells (2.25 ± 0.94% vs. 3.79 ± 2.32%, P = 0.18; 2.30 ± 1.75% vs. 3.88 ± 2.90%, P = 0.28) between β1-AR antibody-positive and β1-AR antibody-negative patients with HF (Additional file 1: Fig. S4 A, B). This evidence concerns the gene ADRB1 and hydrops fetalis.