DE NOVO ANTI-HLA ANTIBODIES HAVE THE HIGHEST INCIDENCE IN THE FIRST YEAR AFTER TRANSPLANTATION.

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DE NOVO ANTI-HLA ANTIBODIES HAVE THE HIGHEST INCIDENCE IN THE FIRST YEAR AFTER TRANSPLANTATION.
Alin Girnita MD , Rene Duquesnoy PhD , Anthony Demetris MD , Carol Bentlejewski BS , David Guaspari BS , Kenneth McCurry MD , Steven Webber MD , Ron Shapiro MD , John Fung MD and Adriana Zeevi PhD . Pittsburgh PA, University of Pittsburgh, 15261, Pathology ; Surgery and Cardiology .

Anti-HLA antibodies (HLAab) are associated with worse outcomes in solid organ transplantation (Tx). While a laborious screening has reduced the incidence of pre-Tx humoral sensitization, post-Tx development of de novo HLAab is a noteworthy event. The aim of this prospective study was to describe the level and dynamics of de novo and donor-specific HLAab developed post-Tx, and their clinical significance.
Methods. 1440 serum samples from 322 patients were screened for HLAab, by ELISA and CDC-AHG. The cohort consisted of 75 lung, 51 heart, 79 kidney, 74 liver, 33 pancreas, and 20 intestine transplanted patients. The mean follow-up was 2.3 years, range 9 months – 6 years.
Results. De novo sensitization at 1 year was 14% in lung, 15% in heart, 14% in kidney, 17% in liver, 18% in pancreas, 20% in intestine transplanted patients, and half of de novo HLAab appeared in the first 3 months. After 1 year, de novo sensitization increased with 5% per year. De novo Class I HLAab had a higher incidence in the first 3 months, while Class II HLAab after 9 months (p<0.0001). HLAab were positively correlated with the prevalence of high-grade acute rejection in lung and kidney groups.
Conclusions. The level and dynamics of de novo HLAab showed a similar pattern in all transplants. In the first year post-Tx, 15% of patients developed de novo HLAab, while a steady increase of 5% de novo producers per year was noted thereafter. Anti Class I de novo HLAab were more frequent in the first 3 months, and de novo Class II after 9 months. A combination of a sensitive screening method with a good sampling frequency allowed the detection of clinically relevant de novo and donor-specific HLAab.