Donor-specific anti-HLA antibody production following pediatric ABO-incompatible heart transplantation.

ABO-i heart transplantation can be performed in infants with end-stage heart failure to increase organ availability. The development of newly detected DSAs is associated with decreased cardiac graft survival, and the effect of ABO-i transplantation on DSA production is unknown. We examined DSA production and rejection frequency in infant recipients of ABO-i and ABO-c heart transplants via a retrospective cohort study of infant heart transplant recipients transplanted at a single pediatric center between January 2004 and November 2014. Patients were included if they were less than 1 year of age at transplant and had a minimum of 6 months follow-up. DSA positivity was examined under two categories, either the lowest level detectable (MFI > 500) or a level presumed to have clinical relevance in our immunogenetics laboratory (MFI > 5000). Of 52 patients, 36 received ABO-c transplants and 16 received ABO-i transplants. Compared to ABO-c recipients, the ABO-i group showed a consistent but statistically non-significant finding of less frequent ndDSA positivity (69.4% ABO-c vs 43.8% ABO-i with MFI >500, P = 0.122; 41.7% ABO-c vs 25% ABO-i with MFI >5000, P = 0.353). Additionally, ABO-i patients were less likely to have any form of rejection (12.5% vs 47.2%, P = 0.027) or acute cellular rejection (6.3% vs 38.9%, P = 0.021). Our data suggest that infants receiving ABO-i heart transplants may be less likely to develop ndDSAs or have rejection compared to same age ABO-c recipients. Larger multicenter studies are needed to confirm results from this single center study.