T and Tk antigen activation in necrotising enterocolitis: manifestations, severity of illness, and effectiveness of testing

Aims-To determine if T or Tk antigen activation is associated with different and more severe manifestations of illness in infants with necrotising enterocolitis (NEC); and if a policy of testing infants with suspected sepsis or NEC for T and Tk antigen activation is effective. Methods-A case-control study of infants with confirmed NEC, born after the introduction of screening, was undertaken:17 activated infants were compared with 28 non-activated controls, matched for gestation and weight. A historical control study compared the outcome of infants before and after the introduction of testing. Results-Of 201 infants with confirmed NEC, 27 were T or Tk antigen activated-10 (9%) before and 17 (19%) after the introduction of testing. T or Tk antigen activated infants had a significantly higher mortality (35% vs 7%); more frequent (71% vs 21%) and severe haemolysis, hyperkalaemia, renal impairment, acidosis; and they received more colloid for resuscitation. While only known activated infants in both time periods were managed with the use of low titre T antibody blood products, there was a significant increase in mortality (odds ratios 2.6; 95% CI 1.2, 5.6) and incidence of surgery (OR 2.7; 1.5, 4.9) after the introduction of testing. The increased mortality (OR 2.6; 0.8, 5.2) and incidence of surgery (OR 1.8; 0.9, 3.7) were no longer significant after adjustment for several perinatal risk factors. Conclusions-In a retrospective case-control study, routine testing of at risk infants increased the detection rate of T and Tk antigen activation. The use of low titre T plasma products in these patients did not reduce mortality compared with historical controls. A randomised controlled trial of testing in at risk infants, or of the use of low titre T plasma products in babies with NEC and T activation, is warranted.