HLA-DR expression in neonates after cardiac surgery under cardiopulmonary bypass: a pilot study

Monocyte HLA-DR expression has been reported as a marker of immunosuppression and a predictor of sepsis development. However, to date, there is no report on monocyte HLA-DR monitoring exclusively in neonates (< 28 days of life) who underwent cardiac surgery under cardiopulmonary bypass (CPB), which have a high risk of nosocomial infection. In this pilot study, we studied nine neonates with a diagnosis of congenital heart disease requiring surgery under CPB. There was a significant reduction in monocyte HLA-DR expression for the first two postoperative days, as compared to preoperatively (p = 0.004). Moreover, neonates who displayed an episode of NI had a dramatically lower HLA-DR expression at day 4, as compared to neonates without NI (4257 AB/c [2220-5895] vs 14,947 AB/c [9858-16,960]; p = 0.04). Our preliminary results could indicate that HLA-DR expression may be a useful biomarker of immunosuppression-induced secondary infection after CPB in neonates.