Bortlik M, Copertino DC, Brailey PM, et al. - Since adaptive immunity takes time to mature and develop in infants, and maternal antibodies provide limited antiviral activity, innate and intrinsic immunity against HIV-1 in the young is of critical importance, researchers ascertained if restriction factor expression may be especially significant in children living with HIV-1 and correlate with progression of the disease. APOBEC3A, APOBEC3C, APOBEC3G, APOBEC3H, SAMHD1, ISG15, CDKN1A, MX2, TRIM5, and SLFN11 gene expression analysis was performed using qPCR in 121 CD4+ T cell samples from vertically infected children living with HIV-1. After adjusting for gender and age, BST-2/tetherin expression on CD4+ T cells demonstrated a significant positive association with viral load, CD4+ T-cell activation, CD8+ T-cell activation, and a negative CD4+ T-cell counts correlation. SAMHD1's expression correlated negatively with T-cell activation markers. Such findings indicate that certain restriction factors play an important role in the pathogenesis of HIV-1 in children.