5-P: Complement dependent cytotoxicity, flow cytometry and virtual cross-matches: Clinical relevance in renal transplantation

5-P: Complement dependent cytotoxicity, flow cytometry and virtual cross-matches: Clinical relevance in renal transplantation

Abstracts S11 5-P COMPLEMENT DEPENDENT CYTOTOXICITY, FLOW CYTOMETRY AND VIRTUAL CROSSMATCHES: CLINICAL RELEVANCE IN RENAL TRANSPLANTATION. Eric K. ...

41KB Sizes 0 Downloads 2 Views

Abstracts

S11

5-P

COMPLEMENT DEPENDENT CYTOTOXICITY, FLOW CYTOMETRY AND VIRTUAL CROSSMATCHES: CLINICAL RELEVANCE IN RENAL TRANSPLANTATION. Eric K. Ho,1 Elena R. Vasilescu,1 Adriana I. Colovai,1 Melissa Hallar,1 Glen S. Markowitz,1 Vivette D. D’Agati,1 David J. Cohen,2 Lloyd E. Ratner,3 Nicole Suciu-Foca.1 1Pathology, Columbia University, New York, NY, USA; 2Medicine - Nephrology, Columbia University, New York, NY, USA; 3Surgery, Columbia University, New York, NY, USA. Aim: Various assays are currently used to evaluate the immunologic risk in patients listed for deceased donor renal transplantation. The aim of our study was to assess the clinical significance of donor specific antibodies (DSA) detected by various cross-matching (XM) assays. Methods: Screening of anti-HLA class I and class II antibodies was performed by complement-dependent cytotoxicity (CDC) and solid phase assay (SPA) in 354 consecutive transplants. DSA were detected prospectively by CDC XM and retrospectively by flow cytometry (FC) and SPA (virtual crossmatch). Results: All transplanted patients had a negative CDC XM. DSA were identified by SPA and FC XM in 27 (8%) and 47 (13%) patients, respectively. Graft survival was ⬎90% at 1-year and ⬎80% at 3-years posttransplant, with no significant difference between primary and secondary kidney allografts. CDC, SPA and FC XM predicted graft loss at one year post-transplantation with a sensitivity of 5%, 15% and 17%, and specificity of 99%, 93% and 86%, respectively. At 3-yr post-transplant, the difference between graft survival in patients with and without DSA detected by SPA was significant (p⫽0.01). Positive FC XM was associated with an increased incidence of antibody-mediated rejection (AMR) in patients with a history of DSA (p⫽0.03). Conclusions: Screening and XM by CDC provide reliable results and optimize the patients’ chances to receive a transplant. SPA and FC XM are of great importance for early diagnosis and treatment of AMR in patients with a history of DSA.

6-P

FREQUENCY OF DP ANTIBODIES. Carly J. Callender, Kevin A. Chesterton, Inessa Kaplan, M. Sue Leffell, Andrea A. Zachary. Immunogenetics Laboratory, Johns Hopkins University, Baltimore, MD, USA. Aim: To determine the frequency of DP-specific antibodies. Methods: 287 sera from sensitized patients were tested with LABScreen® Single Antigen (SA) HLA Class II Antibody Detection Test (One Lambda, Canoga Park, CA) on the Luminex® 100™ IS Fluoroanalyzer. Results: 126 sera yielded positive results with DP beads, measured as MFI⬎500. The gender and race distribution among the patients with DP Ab⫹ sera was not different from the distribution among the entire group. DR1 and DR11 are known to share epitopes with certain DP antigens. 70/126 DP⫹ sera were also positive for DR1 and/or DR11. Properties associated with all DP-reactive sera and with those sera positive in the absence of reactivity to DR1 and/or 11 are shown in the table below. Conclusions: From these data, it appears that reactivity with DP is fairly common among sensitized patients. It is not possible to say if the sera reactive with DP and DR1 and/or 11 were stimulated by DR or DP. This is not relevant to reactivity with a graft but rather, to the immunogenicity of DP.

DP⫹ Sera All DR1-, 11-

No. 126 56

% ofTotal 43.9 19.5

PrevTx 56% 69%

Other Abs Present CI- CII-None 79%- 94%- 2% 89%-100%- 0%

500-1000 34% 26%

MFI 1000-5000 37% 39%

⬎5000 29% 35%