Post liver transplant class II donor specific HLA antibodies of the DQ subtype with MFI >5000 are predictive of allograft dysfunction

BACKGROUND AND AIMS Liver allograft fibrosis is often seen on protocol liver biopsies and class II donor specific HLA antibodies have been implicated. Evidence lacks to determine appropriate MFI cut off values or on relative importance of subtypes. METHODS Cross-sectional study including stable LT recipient children having undergone protocol biopsy between 2012-2015. Biopsies were assessed for fibrosis and inflammation, HLA antibody detection using Luminex platform wad done pre-LT and simultaneous to protocol biopsy. Date evaluation and statistics: Impact of HLA antibodies and other variables was analyzed using cumulative logistic regression. Then Polyserial correlation coefficients were computed for MFI of antibody subclasses and histological characteristics and Receiver Operating Characteristic curve used to determine MFI threshold. RESULTS 102 children were included, allograft fibrosis and portal fibrosis correlated to presence of post-LT class II DSA (OR=6.13, p=0.01 and OR=5.18, p=0.02 respectively). Allograft inflammation significantly correlated to presence of post-LT class II DSA in the portal area (OR=8.02,p<0.01). Higher polyserial correlation coefficients with portal inflammation and fibrosis were found for DQ (PCC=0.77 and 0.50) than for DP or DR antibody subclasses. The DQ subclass enabled 5000 MFI enabled a sensitivity (83.3% for inflammation and 75.0% for fibrosis) and specificity (71.4% for inflammation and 57.1% for fibrosis). CONCLUSIONS Among the post-LT class II DSa, DQ subclass with MFI>5000 is associated with allograft inflammation and fibrosis in the portal area.