ISG15 and obesity due to melanocortin 4 receptor deficiency: When assessing the placental expression of factors related to viral recognition (TLR3, TLR7, and IRF3) and antiviral response (IFNs I and III, STING, RIG-I, MxA, and ISG15) from parturient with pregestational obesity (BMI ≥ 25), no changes were detected between the obese and non-obese samples.