Cytokines in the placenta of Pakistani newborns with and without intrauterine growth retardation.

Although intrauterine growth retardation (IUGR) is a major risk factor for increased neonatal mortality and morbidity, the mechanisms behind it are not clear. We analyzed cytokine gene expression and gene polymorphisms in infants with and without IUGR in Pakistan, where IUGR is very common. 45 IUGR and 55 control mother/infant pairs were studied. mRNA for IL-10, IL-8, TNF-alpha, TGF-beta, IL-6, IL-4, IL-1beta, IL-12, IFN-gamma and GAPDH was quantified with RT-PCR from placenta. Cytokine and cytokine receptor gene polymorphisms for -1087IL10, -308TNFA, -174IL6, +915TGFB1, intron 2 IL1RN, +36TNFR1, 150V IL4RA and -159CD14 were determined from genomic DNA. The serum levels of IL-1beta, IL-6, IL-8, IL-10, IL-12, TNF-alpha and TGF-beta were measured. There was a significant decrease of IL-10 and IL-12, but increase of TGF-beta in the decidua and similarly decrease of IL-10, but increase of TGF-beta in the trophoblasts of the IUGR placentas compared with the non-IUGR placentas. We found significantly lower levels of IL-1beta in serum from the mothers of the IUGR infants and of TGF-beta in serum of the infants with IUGR compared with the non-IUGR infants. We note that the IL-10 mRNA expression in the decidua was down-regulated, but the TGF-beta mRNA up-regulated in IUGR placentas of mothers from a population with multiple risk factors for IUGR. We propose that the low IL-10 in the placenta may be involved in the pathogenesis of IUGR and might possibly be treatable.