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

The Thomsen-Friedenreich cryptantigen (TCA) is located on the surface of all 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 subsequently 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 clinically non-septic and only 1 had weak TCA activation (1.4%). Forty-eight were clinically or bacteriologically septic; 8 of these demonstrated TCA activation (17%), 3 of whom died. Forty of the septic group showed no evidence of TCA activation although 27 grew organisms on culture; 17 in this group died. Two of the TCA-activated babies received unwashed red cells, and both haemolysed; 4 TCA-activated babies received washed red cells and none haemolysed. Although 1 of the well babies in this study demonstrated TCA activation, we would not recommend routine TCA testing on clinically well babies. We would, however, recommend routine testing in all clinically septic infants, as 17% showed signs of TCA activation in this study. We would also suggest the adoption of a selective transfusion policy in TCA-activated patients to avoid the risk of haemolysis. This may help to reduce unnecessary morbidity and mortality in a high-risk group of neonates.