CCL4 and spontaneous abortion: In the dM1, transcripts CCL2, CCL3, and CCL4, which are macrophage-inflammatory proteins, were present in group D only, whereas CCL20 was in the three groups of EPL but not in group D. CXCL2 was present in groups A, C, and D but not in B. These cytokine-chemokine molecules, along with superoxide dismutase 2 (SOD2), which was found in the dM1 clusters of groups B and C, supported our recently reported finding that cytokine-cytokine receptor interaction was the common pathway in spontaneous miscarriage [51].