T-cryptantigen (TCA) activation in surgical neonates: a hidden problem

The Thomsen-Friedenreich cryptantigen (TCA) is located on the surface of al l red cells, but is concealed by a layer of neuraminic acid. When bacteria that produce neuraminidase disrupt this coating, the TCA can be exposed and activated. If blood products containing antibody to the TCA are subsequent ly administered, haemolysis can result. While the relationship between TCA and necrotising enterocolitis (NEC) is well described, the incidence of TCA activation in other forms of sepsis in surgical neonates is not known. In a prospective study, 117 patients admitted to the Surgical Neonatal Nursery were examined for evidence of TCA activation. Of the 117 babies, 69 were c linically non-septic and only 1 had weak TCA activation (1.4%). Forty-eight were clinically or bacteriologically septic; 8 of these demonstrated TCA a ctivation (17%), 3;of whom died. Forty of the septic group showed no eviden ce of TCA activation although 27 grew organisms on culture; 17 in this grou p died. Two of the TCA-activated babies received unwashed red cells, and bo th haemolysed; 4 TCA-activated babies received washed red cells and none ha emolysed. although I of the well babies in this study demonstrated TCA acti vation, we would not recommend routine TCA testing on clinically well babie s. We would, however, recommend routine testing in all clinically septic in fants, as 17% showed signs of TCA activation in this study. We would also s uggest the adoption of a selective transfusion policy in TCA-activated pati ents to avoid the risk of haemolysis. This may help to reduce unnecessary m orbidity and mortality in a high-risk group of neonates.