A mild neutrophilic infiltrate involves part of the wall of the umbilical vessel. The inflammatory cells are of fetal origin.
Funisitis (cord inflammation) is the result of activated neutrophils migrating out of the fetal circulation toward the infected amnionic fluid. Since only mature neutrophils can respond to chemokines, funisitis is usually seen after 20 weeks gestation, when the fetal immune system has developed. Microscopically, one sees inflammatory infiltrate in the umbilical vessels and Wharton's jelly.
Acute funisitis is associated with preterm premature rupture of the membrane (PPROM), preterm deliveries, and perinatal death.
Acute funisitis is the fetal response to intrauterine infection.
Kim CJ, Yoon BH, Park SS, Kim MH, Chi JG. Acute funisitis of preterm but not term placentas is associated with severe fetal inflammatory response. Hum Pathol. 2001 Jun;32(6):623-9.