Adoptive transfer of splenocytes enriched with NK cells that have undergone inhibitory killer-cell immunoglobulin-like receptor (iKIR) knockdown by small interfering RNAs (siRNAs) can reduce CCl4-induced liver fibrosis in BALB/c male SCID-Beige mice (lacking B/T/NK cells), evidenced by reduced expression of collagen and α-SMA. This evidence concerns the gene ACTA1 and Hepatic fibrosis.