Ureaplasma urealyticum respiratory tract colonization is associated with an increase in interleukin 1-beta and tumor necrosis factor alpha relative to interleukin 6 in tracheal aspirates of preterm infants - Patterson,A.M.; Taciak,V.; Lovchik,J.; Fox,R.E.; Campbell,A.B.; Viscardi,R.M. (Pediatr Infect Dis J, 1998)