CCL2 and congenital rubella syndrome: Recently, studies have shown that knocking out the GM-CSF gene in CAR T cells using transcription activator-like effector nucleases (TALEN) or CRISPR/Cas9 can significantly reduce the production and secretion of GM-CSF, which can consequently abrogate the macrophage-dependent secretion of CRS-associated biomarkers such as MCP-1, IL-6, and IL-8 (37, 40).