CCL4 and polycystic ovary syndrome: Hierarchical clustering analysis of partial cytokine concentrations in the two groups showed that the normal-BMI PCOS group had significantly higher SDF-1α and MIP-1β levels in FF (mean: 1032.05 ± 61.69 vs. 878.57 ± 31.98 pg/ml; 51.78 ± 7.31 vs. 24.75 ± 4.78 pg/ml, respectively) (P < 0.05) (Fig. 3A and B).