2 Renal Unit, Belfast City Hospital, Belfast, BT9 7AB Correlation of Luminex –Single Antigen Bead Assay and Renal function for post-transplant monitoring Mahendra N Mishra 1, Tanya Shovlin 1, Ashley Meenagh 1, Aisling Courtney 2, Jeanie Martin 1 1 Northern Ireland Histocompatibility and Immunogenetics Lab, Blood Transfusion Service Building, Belfast City Hospital, BT9 7TS. 2 Renal Unit, Belfast City Hospital, Belfast, BT9 7AB Introduction BSHI / BTS guidelines recommend use of sensitive solid phase tests for detection characterization of both pre and post –transplant HLA Donor specific antibodies (DSA) Post-transplant single antigen bead (SAB) assay results relevance depends on risk stratification and is used to monitor immunosuppression Retrospective study: data of 25 non- consecutive renal allograft recipients analysed SAB assay at least twice on pre & post transplant samples HLA typing for recipient and donor by r-SSO /SSP Individual DSA > 1000 was taken as positive Temporal profile ,and MFI of DSA was correlated with creatinine levels Patients and Methods Aim and Objectives Evaluate SAB assay for post –transplant DSA monitoring & correlate with serum creatinine Study hierarchy of DSA leading to allograft dysfunction Locus Mismatched Recipients (antigens) DSA % showing DSA/ antigens A 22 32 11 34.4 B 20 28 10 35.7 C 16 5 22.7 DRB1 21 31 9 29 DRB345 17 26 34.6 DQB1 18 24 14 56 DPB1 4 15.3 Donor – recipient mismatches & DSA with MFI> 1000 Results Table 2: Parameter Value Recipient age Range 2 - 67 years, (Mean = 38) Female recipients 9 (36%) Deceased organ recipients 10 (40%) Retransplants HLA incompatible transplants 4 (16%) Demographic profile of 25 patients Results Table 1: Relationship of DSA with renal function HLA DSA in normal and compromised renal function Chart depicting peak DSA and mean creatinine for seven recipients with normal renal function SAB assay is used for post-transplant monitoring Anti–HLA DQB1 was most frequent and anti-DP least common with anti-HLA C intermediate value probably due to lower expression Recurrence of original disease seen in two cases with no DSA Reactivity against all 7 loci observed in patients with DSA, but normal renal function. Discussion Patients are non consecutive and all DSA is not de-novo Small sample size Post–Transplant DSA is done selectively, often for those with impending graft dysfunction Limitations Elevated DSA may not be concordant with rise in serum creatinine Existing methods were inadequate for discerning between pathogenic & innocuous antibodies Discussion HLA–DQB1 DSA were most common Both DSA levels and renal function have to be considered for treatment monitoring Clinical significance of individual & additive DSA values have to be correlated with allograft function Conclusions respect & dignity openness & trust leading edge learning & development accountability