TLR4 and TNF receptor 1-associated periodic fever syndrome: Healthy human DF regulate inflammatory responses by expressing various cell surface receptors, including TLR4 (25); therefore, to determine if TRAPS DF also continue to express TLR4 in vitro, and successfully respond to LPS stimulation, we studied the expression of TLR4 on the cell surface in primary DF, from HC (n = 3) and also from TRAPS patients, respectively, bearing T50M, C88R, and c.472 + 1 slice site TNFRSF1A mutation.